The Ram's Eye - A Driver's Blog


Saturday, 24 June 2017

2014 BMW 335i xDrive M Sport Review

Post-refresh 2015 F30 3-series pictured. 

Which is better, an F30 3-series or an E46? The F30 has certainly taken its fair share of heat. But if you thought I was going to say the E46, you'd be dead wrong. The F30 3-series is better. Far better. It is quicker, faster, safer, more practical, more efficient, more refined, quieter.. the list goes on. A lot of reviews and people I talk to consider the F30 to be an abomination. Frankly, I don't see it. You'd have to be mad to think the E46 is better. Completely out to lunch. I don't know who in their right mind would prefer the E46..  Trouble is, since when were people buying sports cars in their right minds? Here, lies the real problem.

"Raw rather than refined in its noises, pounding ride, heavy clutch, 50 grand and cloth seats?"
".. and not at all shy about its performance compromises. It always acts like the automotive jock it is, every mile of every day."
"Raw and quite loud.. And sometimes rude."
"Cramped back seat, fussy climate controls, perennial overdog.

Do you know what car the above comments are in reference too? The E46 3-series. The comments are from a couple of Car and Driver reviews (an M3 and a 330i). They paint a pretty ugly picture on their own. Despite that, the 3-series was the benchmark of the segment. It was hailed by reviewers. I, personally, love it. It is easily my favourite generation and the E46 M3 is probably my favourite M3 (it would easily be the favourite, if not for my inflicted love for all things V8 powered like the E9X M3)

The E46 3-series, in its day, sold nearly twice as many cars as the C-class and nearly three times as many as the A4. Others tried to duplicate its formula. It was a huge success. But while everyone was trying to figure out that formula, the folks at BMW (since, you know, they already knew the formula) were busy figuring out how to sell even more of them. And they did. The market wants luxury, practicality, but no sacrifice in performance. The results? The E9X 3-series being larger and slightly softer than the E46, yet more capable. The F30 became larger still and even more luxurious. That came at a price, though; more and more isolation from driving to maintain performance without taking a hit in comfort or luxury.

Take this 335i xDrive I drove, for instance, with M Sport package no less. Power is plentiful. It doesn't even sound half bad despite being turbo. I actually like it better than the M3/M4 noise. There's slightly more straight six signature in it than the M cars based on it. Power is not only plentiful, it's plentiful everywhere. Coupled with the ZF 8-speed auto, this drivetrain makes you wonder why every automaker doesn't just go to BMW and ask to license it for every RWD car needing an automatic, six cylinder drivetrain with roughly 300 hp. The AWD gives you more traction than you can safely exploit in everyday driving on dry roads. It's pretty good in the snow too, although power transfer to the front front a stop isn't as seamless as it could be. But it's a blast (pun intended) to put your foot down and pull away every chance you get. Do you see an on or off ramp? Chug the car in there and power out. I doubt you'll be able to upset it.

It will understeer at the limit, but it's an AWD all-weather car so hardly a surprise. And it isn't a pig, this is a 3-series after all. Turn-in is sharp and front grip is plentiful, even on the all-season tires. You won't find understeer unless you are pushing. I would be surprised if you found understeer frustrating on a nice back country road, unless you are trying to impress a stopwatch (don't). Body and wheel motions are very well controlled. Despite that, the ride is not punishing, especially when you consider you are driving a 3-series with an M package. And we still haven't got to the best part yet; the seats. My gosh, those front seats are good. I was stuck in them for about four hours and I have no complaints, which is rare as you'll find the more cars I review. Yet, they have great support, which is a tough balance to hit. Did I mention I love those seats?

It all adds up to a very good car. An excellent one, in fact. But is it a good 3-series? That's where the narrative starts falling apart. This takes us back to that pesky E46. There is just something missing that you used to get from an old 3-series. An E46 3-series feels alive. Maybe it's the relative lack of NVH and improvement isolation. Maybe it's the softer suspension. It just doesn't feel as exciting. Digging into some specs, you find some numbers to support the symptom.

The wheelbase goes up by more than 3 inches. That's less than the difference in wheelbase between this 335i and a current Mercedes E-class. It's only 1 inch away from being a 5-series of the same vintage - the E39. Front and rear tracks are both widened relative to the E46, but they are less square. The E46 had 57.9 and 58.4 inches front and rear tracks - nearly square. In the F30, they go up to 60.5 and 62.1. The change in wheelbase and relative front/rear tracks contribute to a more stable, more refined car, but one that isn't as agile. And it weighs over 200 lb. more, with slightly more front weight bias (the E46 330i had a very slight rear weight bias in C&D testing, with "only" 49.2% of weight over the front axle vs 50.6% in the F30). The result is a lazier chassis, which is motivated by a turbo engine that, while being an absolute gem, isn't quite as excited to be wrung out as the old N/A 3.0 litre. Then you take it all and wrap it with more insulation and the car as a whole just feels entirely different. And you haven't even got to the steering yet..

Yes, I'm sorry, you're going to have to hear about another guy complain about BMW steering feel. It really is that bad. I think my old '08 Ford Escape had more steering feel than this 335i. Forget hot hatches like Golf GTIs and Focus ST's. My Boss 302 would probably be insulted if I compared it to this 335i, and that statement should be an insult to any 3-series. The steering is very direct and very accurate, don't get me wrong. It's very easy to place the car exactly where you want it once you get familiar with its response. But it just tells you nothing about what's happening. The sharp handling and response is actually very disconcerting, because I'm used with this kind of muted, isolated steering in a 10 year old Chevy Impala and you can imagine how that handles. This combination of excellent steering performance but abysmal steering feel really threw me off. And that's on the street. Taking it to a back road or, even worse, a track where you could take the car to the limit would be an exercise in telepathy between you and the tires. You'll have to learn to look for other clues about how close you are to overwhelming the front tires. Tire noise, steering response, or something.

It's a very conflicted personality for a sports car, in my opinion. You see, a well-behaved car such as the 335i would be a great car to learn high performance driving in (sans AWD and automatic transmission if you're a little bit of a purist like me). You never have to worry about it biting you or doing something unpredictable. It's stable, but not in an understeer-till-you-sap-all-the-fun kind of way. But you have no idea what the front wheels are doing. And I would be surprised if the rear tires started yapping at the limit either.

I read, on C&D I believe, that when someone at BMW was asked about the feel and feedback, he said that their customers said they didn't want it. A lot of people say BMW can't do steering anymore, but I don't believe that for a second. I think BMW is just listening to their customers. But you know what? Mercedes can do that JUST as good. And so can Audi, Cadillac, Jaguar, etc. Everyone can listen to their customers. What makes a car special is what the brand ends up delivering and BMW used to deliver the best in small, luxury sport sedans and defining what that should look like. Not anymore. This reminds me of Jeremy Clarkson's review of E60 M5 (between 2004 and 2010). He complained about having so much adjustability (gearbox settings, suspension, etc.) and how BMW people are the experts. They're the ones who should set up the car properly instead of giving the choice. This couldn't be more true here, except BMW took the choice away all together, set the car up wrong for the wrong people, and then put it on sale.

The car is very capable, there is no doubt about that. The speeds you can carry because of the grip and the rate of acceleration made possible by the power and traction also guarantee you'll enjoy driving the car. It's certainly fun to drive. But is it a sports car? Well, it depends on how you define one. I don't think it's a car meant to do double duty as a track car and daily driver. It's meant to allow someone looking for a sporty luxury car to take it to as many High Performance Driving Schools (HPDS's) as he or she can dream of doing. It's a small, very sporty grand tourer; a quieter, more comfortable, more practical, and more luxurious car than an E46. It's a much better car, but it's a worse 3-series for it. And that.. that is a darn shame.

Monday, 22 May 2017

Rocket Racing's 97 BMW M3 GT3 - The Prologue

If you've followed this blog, you'd know I started racing last year. I was fortunate enough to be involved with one of the best race team in the region - Vantage Motorsports (link: The Ram's Eye Goes Racing!). This year, my good friend John Drysdale, also fulfilled his dream of wheel to wheel to racing. That said, his start was much more dramatic than mine in the (excellent) IT-B '95 GTI race car. In his words:

"How does one become a race car driver? Maybe more importantly, what makes someone a good race car driver? Maybe I have the odds stacked against me in this game called racing. I started on track with true tarmac and rubber when I was 32.

To my benefit, I was imprinted, like a duckling, with cars from a very young age. My dads stacks of Road and Track, and Car and Driver, made an early impression. When I was seven years old I was drawing air cooled Porsche 911's (and in 2014, I got one). In the early 90's I was playing "Need for Speed" in a Dodge Viper. I didn't really start driving to any degree until I graduated University in 2003. And I was pretty bad at it. My girlfriend (now wife) at the time was terrified (of note, I still terrify her now, but for different reasons). I grew up in the country and did not know what to do at an intersection in the big city. The lights were green but I would always slow as I was quite sure someone would come out in-front of me.

In 2006 or so, my wife made the mistake of getting a Play Station 2 to play "Rock band." The next thing she knew I picked up a copy of Gran Turismo 3, and a logitech wheel with two pedals and force feedback. Between the PS2, Xbox 360, PS3, and later PC, I logged on countless hours and laps on tracks all over the world. I quickly upgraded my rig to a respectable one with three pedals and a six speed shifter. I always drove with all assists off.

In August of 2012 I went to my first high performance driving school (HPDS) with the BMW Club Atlantic Canada. I had a new to me 2009 BMW 328xi (AWD). After the initial fear and shock, I was the fastest in my beginner class. Real life driving was much different, but in many ways easier as you had more feedback. The digital lessons I leaned about smoothness and the cornering line carried over into real life. In that first school, only a black Ferrari 430 spyder did not wave me by... and I was catching him steadily before he pulled into the pits. I was hooked.

After that first school I became a member of just about every local car club that ran schools at our local track, Atlantic Motorsport Park (AMP). I was keen to learn, and did every school I could. Over the next four years, I brought out my restored 1973 BMW 2002Tii, a used 2010 Mazda Speed 3 that I bought from a buddy, a 1984 911 3.2 Carrera, My dads 2006 BMW Z4 M coupe, and finally a 2016 Ford Focus RS. Lap times went from 1:31 in the 2002Tii, to 1:27 in the 911, to 1:25 in the M coupe, to 1:24 in the speed3 (with sport cup tires). The 911 then came back hotrodded and did a 1:21. Finally, in it's maiden voyage to the track ,the Focus RS did a rather effortless 1:20 (in comparison to my assist free, snarling air cooled 911).

In the Spring of 2016 I did my first and second away visits to other tracks. In visiting family in England I opted to rent a lightweight, guttless 2002 Peugeot 106 GTI race car, and a Caterham Academy race car, for use at Brands Hatch and Donnington Park GP Circuit respectively.

To me racing was not a matter of if, but rather when. I had planned to start in 2018. I was going to buy something fun, but sensible like a Spec Miata, or Spec e30. All plans went south when "the Rocket" came on the market.

The Rocket is a bit of a dream build in these parts. It was a lowly, but rust free, 1997 BMW M3 coupe that had seen plenty of HPDE track time locally. It had bad engine knock. Steve Phillips of ISI Automotive, with a partner, purchased this car, and Steve began to turn it into a full out race car. No corners were cut: Top to bottom this was a professional build. S54 engine swap, MCS suspension, full fire suppression and roll cage, full telemetry. In our neck of the woods it was considered to be quite the "Hollywood" build. And it was Quick!

In it's maiden year of local competition, it dominated it's class and won the class championship. On Hoosiers it did under a 1:11.6 lap, which was the fourth fastest lap AMP had ever seen in a GT car. In 2016 it ran 2-3 races only. In the winter of 2016, with only 20 hours on the car, it was put up for sale. It was a chance of a lifetime, and I bought it.

All I can say is that the winter of 2016/17 was one of the longest ever. I was quite excited, but starting out in a race car with this kind of prowess seemed like a bad idea waiting to happen, even in my books..."

Make sure to head over to Rocket Racing Motorsport to read Part 2: Four Seconds and find out how he did for lap times his first time out!

Sunday, 5 February 2017

2018 Ford Mustang Upgrades!

Ever since I bought my Mustang, I have been gradually growing loyal to the brand. I’m not sure why. I like a lot of different cars and never felt like picking a camp, but I guess when you buy a car, you start to have to defend its honour (and your decision) whenever someone takes a stab at it. For someone who is so into cars, I think only one of two things can happen: you are either convinced of what “foes” claim and start to regret your decision, or you find more conviction as you defend your decision and love the car even more. Count me among the latter and, needless to say, I was properly excited when I found out about the updates Ford is bringing to the 2018 Mustang.

For starters, the Mustang finally (probably.. hopefully) will get its horsepower mojo back. When Ford unleashed its 5.0 litre Coyotes to prey on the competition circa 2010, it was basically undisputed. The Camaro SS was usually slower in tests. You couldn’t say Challenger R/T in the same breath; you had to go up to the mighty SRT8 to compete, and even that couldn’t stand its ground until Mopar minions bestowed the 392 (6.4 litre) V8 upon the Challenger that it was really competitive and it wasn’t until you got into serious lose-your-license speeds that the Challenger hp advantage started to show. Otherwise, its weight disadvantage let it down. GT500 vs ZL1? Well, we all know how that went.. Chevy debuted the 570 hp Camaro ZL1, but before it had any chance to be proud, Ford unleaded the 663 hp GT500. But all that changed with the new S550 Mustang..

The GT500 went the way of its S197 platform.. The 5.0 litre V8 made a little more hp but not enough to make up for the weight gain, making the new one a little slower than the old S197. To make matter worse, the new Camaro came out with more hp AND less weight. The GT wasn't the only issue. Ford neutered its V6, which used to be easily quicker than the Camaro and Challenger V6’s. The EcoBoost barely kept up with a last generation S197 V6. If hp and speed were the reason you wanted a new pony car but you weren’t loyal to a brand and you didn’t care too much for modifying, the Camaro was calling your number (assuming you could put up with the sight lines, which aren't as bad as people make them out to be, but still seriously compromised). You can read my comparison of a 2016 Camaro SS vs 2016 Mustang GT here. Of course, there's a lot more to buying a car than horsepower and acceleration numbers, but they are very important to a lot of buyers.

You might say: BUT you are forgetting the Shelby GT350, you idiot! Why aren’t you talking about that?? Sure, it’s a fantastic thing. I love the GT350. There is a local dealer that has a few (yes, a few) new ones and every time we drive by, I just want to drive in and stare at them. Trouble is: it’s quite a few grand more than a Camaro SS, and A LOT more if you factor in Camaro discounts and GT350 markups. The gap is even bigger compared to a Mustang GT because that is cheaper than a Camaro SS to start with, which is much cheaper than a GT350. So if you were Mustang loyal, you had a very sizeable gap between the Mustang GT and the Shelby GT350. You could tap into the Ford Performance parts catalogue, but those reduce powertrain warranty from 5 years to 3 years, and make the car basically as expensive as a Camaro SS, which handles better and has a better warranty. It wasn’t the best solution, but it may have been the only one. However, it looks like Ford is looking to light some fire under the class again..

Fire, let’s take a moment to mourn the death of the 3.7 litre V6.. Ok, moment is over. Don’t get me wrong, I was a big fan of it and I always thought it punched above its weight but it was long overdue for an update. An update that Ford didn’t want to provide because of its EcoBoost-infested vision of the future. Might as well let it die in peace. Speaking of the EcoBoost, it's getting more torque with an overboost function, although Ford isn't saying how much. People have been tuning them with great results so we all know it has more potential. It'll be interesting to see how much difference it makes, but Ford says it was substantial enough to warrant a transmission upgrade. Sound good? You bet! Hopefully, it's not just marketing talk.

But the real treat is the V8, which will finally get direct injection but will retain port injection, overcoming fueling issues at high rpm and valve fouling associated with direct injection-only engines. Direct  Injection allows for better atomization resulting in better combustion, and better power as a result. Moreover, that results in a cooling effect which, when combined with better control on fuel delivery, allows for higher compression ratio, again resulting in more power. The end result? Ford won’t say yet, but I think it will come real close to the Camaro’s hp (at least). I’m hoping for 470 hp, but that may be too optimistic. And better yet, Ford didn’t just focus on power.

The handling is addressed too, with a retuned suspension and stiffened chassis, plus the option of magnetic shocks across the board, including the EcoBoost! Ford says the base suspension now is as good as the Performance Pack. But the highlight of all is, IMO, is the tires. The Michelin Pilot Sport 4 tires are the successor to the excellent Pilot Super Sport. One of the best street/track tires available in the last few years IMO. There were plenty of tires that were much stickier, better in the wet, longer lasting, or forgiving but none could match the balance the PSS provided between of all these criteria and more. The new one can only be better. This is the area I care about the most, as I pointed out in the review I posted above, the Mustang became more grown up than the last generation while the Camaro became more playful. As a car guy inflicted with the track bug, I couldn't be happier that Ford is improving the handling and overall capability.

And if you thought that was all, you’re wrong! Things just keep getting better. It may be trivial, but I wasn’t a fan of the front end at all since it debuted. It wasn’t ugly by any means, but it was too much corporate Ford and not nearly enough Mustang. The headlights were the worst offenders and I’m VERY happy to see them GONE. The new headlights are more of an evolution of the S197 headlights that are made “squintier” and pulled into the fender. They are still not as good as the S197 IMO, but they look much more modern and sinister, yet far more muscular the very-nearly-identical Fusion headlights that are available now. Better still, the upgrades to the front fascia make the car more aerodynamic, reducing drag and lift at higher speeds. Hard to complain. Out back, the GT switches to quad exhausts and Ford will offer electronically controlled exhaust valves to vary tone, something I liked a lot about the Camaro SS in my comparison posted above.

The end result is a Mustang that looks better, handles better, goes faster, and still packs a V8. What is there to complain about? If I had to complain about something, it would be that Ford made the new Mustang so much better that I really want one now..

Wednesday, 25 January 2017

AMG GT R First Drive - A Closer Look

Motor Trend basically started the first drive review (2nd paragraph) by saying that the folks at AMG have a sense of humour for naming this car "the Beast from the Green Hell." Maybe I don't get German sense of humour, but the joke is completely lost on me. Of course, that's assuming there is a joke there to begin with.. You see, I highly doubt the response AMG hoped for is a chuckle. And if I'm right, I think they can rest easy, because beasts aren't funny, and those that come from hell are probably less so, whatever colour that hell may be. Now, fierce, brutal, menacing, loud.. those are the things you might expect a beast to be. And if that name alone doesn't conjure any of those beastly characteristics, play the video below and skip to 0:28.

What a NOISE! This will be one of those cars that, should it roll up next to you at a traffic light, you quiet everyone down and roll down the windows to hear it pull away. If you're tired of hearing about how AMG knows how to make a V8 sound great, I don't blame you, but the only reason why everyone sings poetic about it is that they ARE very good at it. And remember, this isn't a deep breathing big V8 like what you used to find in all V8-powered AMG's. It's a relatively small 4.0 litre that was designed to be able to rev to 7,900 rpm (source: C&D Deep Dive). It's even got a pair of noise-muffling turbos strapped to it. The end result has no business sounding this good. Yet, it does. So it has the noise to match the name, an angry face, and a gaping maw that even looks like it has fangs. The big question then is this: does it drive like a beast?

At first glance, I'm afraid not. For one, compared to the sort-of predecessor - the SLS - this always sounds like a much more manageable car in reviews. Beasts aren't manageable. Then you have rear wheel steering helping you keep the back end more obedient and cooperative. And, reading the review, you find that AMG put Bernd Schneider, a five-time DTM champion, at the wheel to give Car and Driver a ride along. Instead of demonstrating the car's traction and tactility at the limit by switching all assists off, he pinned the throttle to the floor in corner exits and relied on traction control to sort it out, with "no subtlety." It has a stability control system that can't be completely turned off and allows you to pay no mind to "separating braking and steering inputs. Rather, this is a full-commitment reliance on technology." It all sounds very wrong. But there's more to it than the above would suggest.

For starters, the upgraded coil-over suspension is adjustable. The front track has been widened by almost one inch. On each side! The rear track has been widened by MORE than an inch on each side. And despite all the suspension upgrades, the downforce, the big sticky tires, and the rear weight bias, it still effortlessly turns the rear tires into smoke if you aren't careful, a sign of a true AMG. But above all, the one thing that really made me think the car is serious is chassis tuning. In Motor Trend's words, "The GT R’s chassis, like nature, abhors a vacuum: If you’re not on the brakes, it wants you to be on the throttle—even lightly—to feel absolutely balanced." This is a car that doesn't like coasting; a sign of a proper thoroughbred. You know what other type of car doesn't like coasting and asks you to always push? Race cars.

And this is where I was stuck with this car. I didn't know what to make of it. Is it a triumph of technology or a proper driver's car? Then I figured it out. You know what AMG has done? It has in, fact, built a beast. But most of us aren't The Stig so, while a few people can perfectly handle a beast, the rest can't. Instead of taming said beastie, AMG decided to saddle it, so that you can more easily ride it. Make no mistake, a bucking bronco is a bucking bronco, saddled or not. Saddling it just makes it easier for you to get a handle on things, but doesn't change the nature of the beast itself. What AMG has done is use all the electronic aids to build a really good saddle for a very capable beast. That makes it a very cool car IMO, but there are a couple of issues with it, although they have more to do with other cars than the AMG GT R itself.

The first is its sort-of predecessor; the SLS AMG. This car can't quite match its elegance or charisma. And it looks a lot more "corporate Mercedes" as opposed to a one-of. Don't get me wrong, the AMG GT R is better in every way, as a car. But the SLS had something the AMG GT doesn’t – some flair, perhaps, and stunning looks. And while this AMG GT sounds glorious, it can't quite match the snarl of the naturally aspirated M159 6.2 litre V8. On the other hand, you have the 911 (991) GT3 RS. Yes, I know, it's technically out of production, but if the AMG GT was meant to compete with the 911, what is this GT R version meant to compete with? It may be out of production but the target market and performance is the GT3 RS and here, again, the GT R falls a little short. It's a lot more of a brute and a bruiser. It isn't quite as pure a driver's car as far as I can tell and I can't imagine it being as rewarding to toss around and push at 10/10th.

That's where I am at with this car. It's not quite as mad as traditional AMG's, yet it can't match the excellence of the GT3 RS. For some people, I'm sure it strikes an absolutely perfect balance between the two ends of the spectrum but, for me, it just comes off as being less special than either. For a car that basically costs $200,000, it needs to feel a lot more special than that. I may never have that problem, but if I had that kind of money and I was looking at a German track car, it would have to be the 911 GT3 RS, even if it meant getting a slightly used one. The only thing I would be missing is that AMG V8 noise..

Wednesday, 4 January 2017

2017 Ford GT - A Closer Look

"The new GT is so purposeful, so exactingly and innovatively designed, that it reaches beyond the genre of European two-seat screamers built for maximum envy induction at felony speed. Ford hasn't built a supercar. It's created a weapon." How could you not desperately want to drive this car? Of course, what we already know about it from Ford, the way it looks, and the name should be more than enough reasons to start dreaming. But if they aren't to you, the above - what Road & Track had to say about the new Ford GT in the first ride review - should easily push you in the right direction. For me, though, I've wanted to drive it since I first saw it after its debut at the 2015 North American International Auto Show. This car is very, very special.

The story of the original GT, the GT40, is all too familiar. Ford wanted to buy Ferrari but Ferrari backed out. Ford wanted to show Ferrari who is boss so it built the GT40 and took it to Le Mans. After fiddling with it for a couple of years, the GT40 won for four consecutive years; from 1966 to 1969. Very impressive, but more importantly, it established the name GT40 and demonstrated that Ford is capable of building a car that not only can go head to head with the best in the world, but beat them at their own game. Now, the second generation, which came out in 2004 - the first Ford GT, sans 40 - was not a true successor to the GT40 in my opinion. Don't get me wrong - it was a fantastic thing. It is on my must-drive bucket list of cars and think it should be on everyone's list. But it was a tribute. It was an excellent tribute, but a tribute nonetheless. It couldn't trace its own roots in racing. It didn't come out with the purpose and focus of the original; track dominance. This new one, though, has all the right ingredients.

Back in the day, it was much more common for production cars to be homologated cars to allow competition in racing. Such was the case for the original BMW M3, for example. The original Mustang Boss 302 and Camaro Z/28, original (C2) Corvette Grand Sport, a myriad of Porsches, etc. That isn't the case anymore, though, as you can see by the rarity of modern homologation cars (as of 2010) listed on FIA's website (link: FIA - List of Previously Homologated Cars). Porsche, for example, has 59 cars listed and non of them (that's zero) are from the year 2000 or newer and only 4 are 90's cars. That could be for one of two reasons, I suspect. First is that even base versions of production cars now are very good and can serve as great starting points for race cars (mechanically, not electrically) as opposed to back then, where base engines, suspension, and chassis would have required many more modifications so you had to create a special edition that's a road-legal version of the race car. The second is race cars now being more heavily modified and further removed from the production cars they're based on. Either way, the result is the same. Cars on the road are more loosely tied to their distant racing prepped cousins. The GT, though, is a breath of fresh air of true racing-based development.

I don't know if the guys at Ford first decided they want to race a factory mid engine car or they first wanted to produce another Ford GT and wanted it to be a thoroughbred. But that matters little at this point, because this one has already had one season of racing under its belt, even before Ford rolled a single road going version off the line. Oh, and it already has secured a Le Mans (class) win. How can you argue with that? This car has heritage and pedigree in spades. To an average car guy or gal who likes it, the GT is just a cool mid-engine car that may be special because it pays homage to the original GT40. For a motorsport-stricken, slightly crazed car guy, this is very special. The kind of car that you get all giddy just reading about. Count me with the latter. Of course, if you count yourself with us in the latter group, you may have some explaining to do every time you hear something along the lines of, say.. I don't know.. IT'S GOT A V6!

In an era of downsizing and turbocharging, you may have a leg to stand on. But, this isn't actually the era of downsizing and turbocharging.. you're led to believe it is, but it isn't, not yet anyway. Not unless you look at mainstream cars. The Mustang GT350 has a 5.2 litre V8, for example, to replace the 5.0 litre that was in the car it replaced, the Boss 302. The Corvette lives on with a 6.2 litre V8 that can be naturally aspirated or supercharged. Dodge is stuffing a 700+ hp supercharged 6.4 litre V8 in anything it can get its hands on. Lamborghini will only sell you two cars, one that can only be had with a V10 and the other a V12. Aside from one generation of M3 and M5 preceding the current iterations, the current ones maintain cylinder counts - straight six and V8 - as the previous couple of generations and actually beat the originals. They may have lost a little displacement, but they gained a couple of turbos, each. The 991 GT3 RS has the largest displacement yet, tied with he last gen; a 4.0 litre flat 6. Sure, a few joined the downsizing trend like Porsche with the rest of the lineup but it's hardly the age yet. So what is Ford doing sticking a V6 in the GT?

As far as car news, learning that the GT won't have another supercharged V8 or the 5.2 V8 in the GT350 was very sad. Learning it won't even have the 5.0 litre V8 from the Mustang GT was devastating. But then, I am almost ashamed to admit, I started to warm up to the idea.. For starters, it has been racing in a Daytona Prototype with Michael Shank Racing since the 2014 season. That gives it pedigree. If that's not enough, it has set the fastest lap (ever) on the Daytona oval of 40.364 seconds. And it set a new record top speed of 222.971 mph, blowing the previous record of 210.364 mph out of the water. And it set a new record for the first 10 kms and the first 10 miles from standing starts. If the only problem you have with the engine is the smaller number of cylinders vs a competitor with eight or more cylinders, then fight fire with fire. The numbers above should not only make up for the smaller cylinder count, but provide enough ammunition to defend the engine till we're blue in the face. But for me, and many car guys, numbers aren't the only thing that matters. And here, too, the little 3.5 V6 makes a very strong case for itself.

For starters, it has the same soul and good, humble nature that the previous engine had. It's based on a truck engine, just like the 5.4 supercharged V8 in the last GT was. It's a working class hero, as Jeremy Clarkson put it multiple times. Then you get to packaging, where the smaller engine means a smaller engine bay that allows for the stunning teardrop shape with the flying buttresses where air-to-air intercoolers live. That, in turn, also allows for excellent aerodynamics. The only thing that could hurt it is lag, tactility, and linearity of throttle response but, assuming (reasonably) that they'll all be excellent, the only problem, really, is noise. But the first drive indicates that Ford got that covered too.

To quote Road & Track again, they said: "Fear not: The street-legal GT sounds excellent. Turbo whoosh is subtle, an undertone of boost beneath the engine note. The sound is somewhere between a silken straight-six and an exotic small-bore V8, a subdued but purposeful growl. Imagine a McLaren 570S with a higher redline and a little less rasp, and you'll be on the right track. It's worlds away from the woeful moan of the Le Mans racer." Nice. I'm genuinely looking forward to hearing it now, and that's far more than I can say for any downsized engine that replaces a previously bigger, naturally aspirated engine with a higher cylinder count. And better still, all of the above, when combined, draws a much better overall picture. Don't get me wrong, I still would have preferred to see a V8 in there, but I cannot reasonably defend the preference in any way. I can only say I just prefer a V8 and leave it at that.

So what do you have? A stunning mid engine supercar with legendary heritage, forged in the fire of motorsport, powered by a record-breaking engine, that goes, drives, and sounds like nothing else. I truly can't fault the car for anything. But I could fault Ford for one thing.. the price. I can't get over the price - estimated to be north of $400k. I can kind of understand the selection process, if Ford really is picking people so that it can make sure that whoever buys it will use it and showcase Ford's efforts instead of locking them up in a pristine garage. But with production numbers being so low and price so high, it really isn't a working class hero. Not even close. It's as blue blooded as the most exotic Euro supercars and it doesn't even come with an exotic brand name. It's a more rare and expensive car than most Ferraris, and you can actually buy a Ferrari if you can afford one, but not this. If this car walked into a big Cars & Coffee, it would stick its nose up at Lamborghinis and McLarens. But here, once again, I can kind of reason myself out of it..

It may be confirmation bias, but that kind of requires that I already believe something, not be against it and then change my mind. I hated the price of this car when I found out and the selection process. But when you think about cost a little, it seems more reasonable. Alright, maybe reasonable isn't the right word for a car that costs more than a nice house. Let's say it's somewhat justified.

The first car that comes to mind when you start thinking about the price is the C7 Corvette Z06 with the Z07 package - the best bang for the buck track performance you can get. It starts at just under $100k. If you want to go another step up, you can't do better than the Viper ACR, unless you wait for the Corvette that's been spotted testing with a big wing - presumably the ZR1. The Viper ACR is basically $140k and I suspect that upcoming Vette won't be a whole lot different. No one confuses the Viper or the Z06 with fancy cars - they're expensive because they have expensive hardware. Now, factor in added costs for a more expensive chassis layout, more exotic materials, more complicated transmission, active aero, etc. and it seems very reasonable to go much higher from $140k.

At that point, it really doesn't matter a whole lot if it's $200k or $400k, for the purpose of being a humble car. The price isn't humble either way. The car will have to be far out of reach for most. But think of it this way: it's the big brother that stands up for you against bullies. Sure, you can't actually buy this car and stand up for yourself against the likes of Ferrari and Lamborghini, but you can call on your big brother, who is still part of the humble family, to go give them a bloody nose. Ferrari would never sell a $20k car. Neither would Lamborghini or McLaren, or Aston Martin. That would tarnish the image and dilute the brand. The GT, though, has no problem sharing the family name with its little sisters. That is why it is still the people's supercar, even if it can't be bought by "the people."

I doubt there is a lucky owner in our region so I have no idea when I could be seeing and hearing one in person, but I sure hope it'll be soon. Finding out how it performs and just how capable the production version is? That can't come soon enough!

Thursday, 22 December 2016

Chevrolet 1LE & Grand Sport - How do they do it? Part 3

In Parts 1 and 2 (Links: +Chevrolet 1LE & Grand Sport - How do they do it? Part 1 & Part 2), I concluded that grip is where Chevys excel and decided to try and figure out how they do that by looking at test data from Car and Driver's Lightning Lap features. The first thing that stood out to me when the 5th generation Camaro 1LE came out was the wider tires compared to the Mustang Track Pack of the time and even the Boss 302. The tires on the ZL1 and Z/28 stood out as much.. only on those, they stood out compared to just about anything that isn't a supercar. So I decided to start looking there; tire sizes.

To evaluate tire sizes, I calculated a weight-to-tire-section ratio for each car. Similar to the idea of power to weight ratio, where the number tells you how much weight each hp is burdened with, this tells you how much weight each mm of tire section is burdened with, so to speak. For example, a BMW M235i weighs 3,490 lb, as tested during the LL feature. It has 225/40/18 front tires and 245/35/18 rear tires. The total available tire width footprint, pressure, tread, and tire deformation notwithstanding, is 940 mm (225 x 2 + 245 x 2), which gives it a weight-to-tire ratio of 3.71 lb/mm. Here is where the trust in measured data that I hopefully established in Part 2 comes into play. Without a monumental amount of work going into looking up tire pressure specs, tire wall and tread stiffness spec (IF manufacturers share in the first place), and calculating actual contact patch areas for each car, we can look at measured data (i.e. lap times) and see if we find a correlation strictly between tire size and lap times. Here's a plot of that weight to tire section ratio for each car vs that car's lap time.

You may have read or heard about how wider tires don't increase contact patch size and are only useful for managing thermal stresses and changing the shape of the contact patch. Whether it's due to the contact patch size increasing, better thermal management and patch shape, neither, or both is irrelevant here so I won't get into the theory. What's relevant is the real world result: cars tend to go faster on wider tires. It's unarguable that quicker cars have more tire width for every pound of weight. I couldn't find an advantage in specs in terms of power, weight, downforce, etc. but could tire size be a factor? Below is a table listing different weight to tire width ratios for Camaros and Vettes and a few other cars. If you arrange cars tested over the last three Lightning Lap features in terms of weight/tire mm, the Corvette GS is 4th best, Z06 is 8th best, and 5th gen Z/28 and 6th gen SS 1LE are 14th and 15th, and that's out of 50 cars (excluding special features like race and police cars).

Car lb/mm
Viper ACR 2.62
SRT Viper TA 2.64
911 GT3 RS 2.67
Corvette GS 2.78
Alfa Romeo 4C 2.81
Cayman GT4 2.83
Corvette Z06 2.86
Shelby GT350R 3.00
911 GT3 3.02
Ferrari 488GTB 3.12
McLaren 570S 3.13
Audi TTS 3.16
(5th gen) Camaro Z/28 3.17
Camaro SS 1LE 3.17

Clearly, Chevys measure up really well here. This is something you might have noticed in the past by looking at specs, and Chevy even bragged when it released the Z/28 and said it had the widest front tires (305) fit to a production car. You might have also found a lot of angry anti-Camaro comments on reviews that go along the lines of this: "throw wider tires on [insert car] to match the Camaro and see how it stacks up!" There is reason to the madness. Now, slapping a set of huge tires on a car not set up to handle the grip won't win races without a proper setup and supporting hardware, but the point is that you do need big tires. Chevy's clearly got that base covered. So, is that all, you just need wider tires?

Although they do have good tire-to-weight ratios, you can see from the table above and the one posted in Part 2 that they beat cars (in lateral g forces) with better numbers and, as mentioned in Part 2, they rank above nearly 200 cars in lateral g forces measured in the first corner of the track, which is especially impressive for the current Camaro SS 1LE, since it doesn't use the same type of aggressive tires like the Z/28 and top dog Vettes. If it's just down to this ratio, that shouldn't be the case, so it's likely not the only factor/advantage. What else could it be? Bear with me on this one.. I think it's wheel size. Now, everyone avoids big wheels like the plague. But what if the bigger wheels actually help? Let's first look at why big wheels are bad.

First is weight. Weight is the enemy of speed. Bigger wheels tend to be heavier, so that's more weight you have to accelerate, brake, and turn. Weight is also critical because wheels and tires are unsprung – meaning the car’s springs and entire suspension is downstream of it (relative to the road) and can’t directly respond to forces generated by the road on the wheels. Wheels actually have a suspension system, but it consists of just the tires and air filling them, and those components form the spring and damping properties. Since they aren't nearly as effective as a car's suspension system, especially on low profile tires, they transmit a lot of those forces from the road to the car instead of absorbing and dissipating the energy, and the heavier the wheels, the bigger those forces are. The suspension’s job of keeping tires in contact with the road, then, becomes harder with heavier wheels, resulting in relatively compromised grip and ride, all else being equal.

Then there's moment of inertia and rotational energy. I can't adequately cover these properties here but, putting it simply, moment of inertia is comparable to mass but for rotational motion as opposed to linear. Just as it gets harder to move something the heavier it is, it gets harder to rotate something the heavier it is, but also how far it is from the axis around which you are trying to rotate. If all else is equal, a bigger, heavier wheel results in a higher moment of inertia, making it harder to change its state/speed (i.e. accelerate and brake it). But worse yet, a wider diameter wheel pushes the weight of the wheel's rim/barrel and the tires further out, making that moment of inertia even higher. Moment of inertia, typically referred to as I, is defined as:

I = mass * r²,

where r is the "effective" radius - A distance from the axis of rotation that the entire mass can theoretically be concentrated at with the same result, similar to the idea of a centre of gravity. The heavier something is or the further it is from the axis, the higher the moment of inertia - I - and harder it is to turn. Then there is rotational (kinetic) energy, defined as:

E = 0.5 * I * ω²,

where ω is the rotational speed. That means that the higher the moment of inertia, rotational speed, or both, the more energy there is that you have to deal with. Pretty straight forward.

But what if you could minimize those disadvantages? Chevy has been using forged wheels on their high performance models for a while now. I can't find specs on the 6th gen SS 1LE wheels yet, which may be even lighter, but their 20" x 11" wheel on the 5th gen weighs approximately 28 lb. That's definitely not light, but if you do some research, you'll find that most good aftermarket cast aluminum 18" x 10" wheels weigh low-to-mid 20's lb, unless you get into the more expensive sub 20 lb options. And a cast aluminum would probably have a thicker rim/barrel since it's weaker than forged, so more of the weight is put further out away from the centre, which is worse than just adding weight. In fact, that 20" x 11" wheel is lighter than the 19 x 10" wheel Ford used on the back of the 2012-2013 Boss 302 Laguna Seca, which weighs approx 33 lb, although these were cast. 991 GT3 20" centre-lock wheels weigh 24 lb and 27 lb front and rear (source: Rennlist Forums: 991 GT3 Stock 20 Wheel Weights) and they have to deal with a good 300-400 lb lower curb weight. So, while no featherweight, the weight of those 20 inchers aren't nearly as bad as off-the-shelf 20" wheels that people upsize to for looks and are clearly well designed. 

Rotational energy is a double edged sword. On one hand, a bigger wheel, generally being heavier, negatively affects the weight element of the moment of inertia, making it more resistant to accelerating and braking (i.e. needing more power to do either). On the other hand, a wider diameter wheel and tire package has a longer circumference/perimeter, so one revolution covers a longer distance, which means it can spin slower than a smaller wheel and tire package while the car's speed is unchanged and, therefore, the speed element of the rotational energy goes down. To illustrate, if you compare the BMW M4, which has 255/35/19 front tires, and the M235i, which has 225/40/18 front tires, to the Camaro, you'll find that, because the Camaro's wheels and tires are bigger with a longer circumference, they spin less for the same speed. The Camaro's front tires have a circ. of 7.00 ft, the M4's are 6.81 ft, and the M235i's are 6.57 ft. That means that the M4's tires need to spin 2.79% faster and the M235i's 6.5% faster than the Camaro's to match its speed. And because rotational energy is a function of the square of the rotational speed, the M4 front wheels and tires would have 5.7% more rotational energy than the Camaro's and the M235i's would have 13.4% more energy while all three cars are going at the same speed, if moment of inertia (I) is the same in the E equation above for all three cars.

In other words, more braking power and acceleration (engine) power are needed to brake and accelerate the smaller M4 19" and M235i 18" wheels and tires, compared to the 20" Camaro wheels, assuming an equal moment of inertia (I). I expect the Camaro's wheels to have a higher (worse) moment of inertia, but it has to be at least that much worse for the Camaro's wheels and tires, in comparison, to need the same amount of rotational energy to accelerate and decelerate, let alone more energy. A similar story is true for the rear tires. The overall net affect is impossible to calculate without knowing the wheel's effective radius around its centre, but the point is that, once again, it isn't as bad as people think for well designed and constructed wheels.

So let's say you use light weight and well designed wheels to overcome most of the downside, what's up the side, just looks? I don't think so. Looking back to the data for answers, here are lap times vs (rear) wheel diameter.

Could it be? Do quicker cars tend to have bigger wheels? Only one car with a lap time under three minutes (3:00) uses 18" wheels - the Cadillac ATS-V - but everything else is 19" or larger. Ironically, the ATS-V rides on the same chassis that gave birth to the current Camaro.. and it has very slightly more power along with a fast shifting 8-speed auto vs the manual in the Camaro. Yet, it is noticeably slower, to the tune of a very significant five seconds (for the ATS-V sedan, the coupe is "only" 4.4 seconds slower than the SS 1LE). And, aside from the Viper, every car with a lap time under two-minute-fifty (2:50) uses 20" or larger rear wheels. Quicker cars tend to be expensive, special performance models, exotic, or any combination. You could argue that this makes them more likely to have larger wheels just for looks to match the "status". But there are two problems with that thinking. One is called the 991 GT3 RS and the other is called the Viper ACR.

These two cars are two of the most, if not THE most, hardcore production cars that are dedicated to the noble cause of speed and track performance. The 991 GT3 RS uses not 19" or even 20", but 21" rear wheels. What does that tell you? Keep in mind, that's the same car that, in pursuit of saving weight, does away with door handles and gives you something that James May described as "little bits of rag," in his review of the last generation Boxster Spyder on Top Gear. Do you think they would do that just for looks? The list of weight saving efforts on the 991 GT3 RS includes stuff like carbon-fiber panels for the engine cover, the front trunk, and fenders, a magnesium roof, lightweight lithium ion battery, removal of air conditioning, removal of audio system, centre locking wheels, and lightweight suspension components. It is hugely unreasonable to expect them to go through all of that and simply through big wheels on for looks. The GT3 (non RS) uses 20" wheels, not 21", by the way. The 911 R, the less hardcore, less capable, manual-transmission option that is not obsessed with lap times also uses 20" wheels. The story is similar for the Viper, where the less hardcore TA model uses 19" rear and 18" front wheels. The ACR uses 19" wheels front and back. You can draw your own conclusions.

Do you need more proof? Well, in a Car and Driver test of upsized wheels and tires (link: Effects of Upsized Wheels and Tires Tested), they found that 235/35/19 wheels generated 0.01 lat-g's less than the smaller 225/40/18 (0.88 g vs 0.89 g). Test tires were Goodyear Eagle GT so C&D asked Goodyear for their explanation and "they postulated that the added [tire] width may have given the outside tire more grip, which would increase body roll and could therefore decrease the load on the inside tire enough to lose 0.01 g on the skidpad." No mention of bigger wheels, more weight, etc. or even the suspension not being able to handle the added weight, despite the test car being a 2010 VW Golf with stock 15" wheels that, combined with 15" tires in stock size, weigh 14 lb LESS than the 19" ones.. EACH, meaning the suspension is guaranteed to not be designed to handle the added weight. The trouble was too much weight transfer. A little off topic, but the reason for that is the non linearity between the ability of a tire to generate grip and weight. In other words, two tires with 800 lb on them, each, will generate more grip overall than one tire with 1,200 lb and another with 400 lb, because the increase in friction forces at the loaded tire due to an additional 400 lb of vertical load is less than the drop at the unloaded tire due to losing 400 lb of vertical load.

Back to topic, if you dig a little deeper, the theoretical reason why bigger wheels help is their effect on tires. Bigger wheels better control tire flex under load. Limiting tire flex results in a stiffer tire. You'll hear people refer to sticky tires as "soft compound" sometimes, but there's a difference. You want a soft surface to conform to the road texture and shape but you want a stiff tire structure. Limiting tire flex effectively increases stiffness. And tire grip is directly proportional to its cornering stiffness. Increasing tire stiffness is why high performance cars have low profile tires. The stiffer tires also provide a lot of benefits like better response, less deformation and heat buildup, better stability at high lat-g loads, etc.

Chevy doesn't use the biggest wheels. That would be the rear wheels on the GT3 RS (21") and the front and rear wheels on the Audi RS7 (21"). But aside from those, it uses either the biggest in its class or tied for the biggest. The Camaro uses 20" front and rear wheels on both 1LE models, the V6 and the SS. The Corvette Grand Sport and Z06 use 19" front and 20" rear wheels. I suspect the reason why the Corvette doesn't use front 20" wheels is that it doesn't need to, because its front end isn't nearly as loaded as the Camaro, with a better rear weight bias combined with a more rearward engine placement. As a result, the tires have to deal with less load and can be downsized from the Camaro's. What Chevy is doing is more effectively using wheels and tires to maximize available grip that can be extracted from the tires. This thinking of maximizing available grip extends beyond wheels and tires. Going back to the weight transfer issue from one paragraph up, all manufacturers try to minimize weight transfer for better handling but Chevy goes a step further.

Since weight transfer minimizes available grip, you could throw the best wheels and tires available but if you transfer too much weight, you can't use them to their capacity. Plus, a lot of weight transfer means delayed responses, less stability and confidence, etc. An easy solution is to just increase roll stiffness through springs and dampers, but that also increase vertical stiffness and you may not want to do that. Roll bars are better in that regard, but you increasingly couple left and ride sides if you rely on them too much. The best solution is widening track - the distance between the centre lines of the two wheels and tires on one axle. Performance cars use a combination of all the above, but here's how Chevy's push one step further.

If you exclude light cars like the Fiesta ST and Miata, and exclude very front-end-light cars like mid-engine and rear-engine cars (including front-mid engine like the Corvette, Viper, and AMG GT), the Camaro 1LE has the widest front track for its weight of all cars tested over the last three years, with the exception of the spiritual successor to the BMW 2002 - the M2. Meanwhile, the 5th gen Z/28 had the widest track, period, of any car ever tested by C&D for Lightning Lap features over the same period, tying the Ferrari 488GTB for the honour. Does that matter? Once again, if you look at the data and plot front track widths, you'll find a very clear correlation between quicker lap times and wider tracks. The same is true for rear track.

So far, everything is done to maximize overall grip. The final piece of the puzzle is focusing on longitudinal grip and putting power down - the differential. Namely, the electronic limited slip differential. A differential that can make better use of available traction makes a massive difference in a car's ability to put power down and bringing down lap times. And, to quote Sir Jackie Stewart: "The exit of the corner is far more important than the entry of the corner, with regards to smoothness." You obviously have get the entire corner right to get the most out of a car, but corner exit is more important than corner entry as far as lap times. That's especially true for non-momentum cars like these. I have experienced first hand the improvement different types of limited slip diffs can make but, going by the numbers, a good comparison to demonstrate the difference was done by Car and Driver in 2015 (link: What's the Diff?), putting a Lexus RC-F to the test with the standard limited slip diff and the optional Torque Vectoring diff. The difference was 0.03 lat-g around a 300 ft skidpad (0.94 vs 0.91 g) and nearly half a second (0.4 s) on a minute-nineteen-second (1:19.1) course. That's on an otherwise identical car.

Now, Chevy doesn't use a torque vectoring differential, but a good, electronically controlled, variable locking limited slip differential should be able to provide the same traction benefits of a torque vectoring differential, just not the yaw control due to the steering effect from torque vectoring. The V6 1LE does away with an electronically controlled diff all together, like the one the V8 Camaros and Corvette use, but I suspect that there isn't much to be gained beyond a good mechanical LSD, considering the much lower power output of the V6, combined with the much, much lower low end torque compared to the V8's.

After I concluded that the above seem like the advantages, I started testing my conclusions by comparing those components in Chevys vs cars they beat to see if the advantages do hold up. And they seemed to. For the most part.. there two cars stood out; the 991 GT3 RS and the Cayman GT4. The above components or a combination of them (big wheels and tires, wide tracks, and good LSD's) point to a Chevy advantage for the vast majority of cars but not the Porsches. They do beat their closest Chevy competitors (if classed by specs) - namely the Corvette Grand Sport and the Camaro SS 1LE. But Just.

The GT3 RS is darn near 300 lb lighter than the Vette. It has 40 hp more and far better power to weight ratio (6.3 lb/hp vs 7.5 lb/ hp for the Vette). It has rear wheel steering. It has more downforce. It also uses a variable electronic locking differential, big, wide, lightweight centre locking wheels, and even has a slightly better lb/tire section ratio (2.7 vs 2.8 for the Vette) and upsized wheels (20" and 21" front and rear vs 19" and 20" for the Vette). How is it that all of this nets no more than one tenth - that's 0.1 sec - advantage, despite having Porsche's excellent PDK, which should alone save a multiple of 0.1 sec in total shift times compared to the Grand Sport's 7 speed manual? A similar story is true for the SS 1LE vs the Cayman GT4, although with a bigger time gap (0.8 sec), no auto transmission, but much better tire to weight ratio (2.82 lb/mm vs 3.17 lb/mm for the Camaro). Both Porsches should have a big traction advantage because of engine location. It seemed like it should be a bigger gap for both cars, especially the GT3 RS. That kept hanging over what I concluded, convincing me I must be wrong. But after going through the numbers (a few times), I finally found a consistent advantage - gross tire footprint.

The GT3 RS has a slightly better tire to weight ratio than the Vette as mentioned, but, if you sum up its total tire footprint at all four corners, it comes up 60 mm short of the Vette's - nearly one fifth of a foot narrower. The Cayman has an even bigger discrepancy, with a total tire foot print that's 100 mm narrower than the Camaros, darn near four inches or a whopping one third of a foot narrower. Does it matter that much? Going back to that table of lb/tire section ratio, showing cars that have better lb/tire ratio but don't beat the Camaro in lat-g forces measured in the first corner, you'll probably conclude a resounding yes. Every single car that has a better tire to weight ratio but lower grip (judged by lat-g) has less overall tire footprint, with the exception of the GT350R. But, assuming my earlier conclusions are true, that can be explained with the other factors since it doesn't use an electronic LSD like the Camaro SS 1LE and it has smaller wheels.

Obviously, suspension design and tuning is critical. If not done properly, everything falls apart. And it's critical to ensure the car is fun to drive, stable, predictable, etc. The C&D test I mentioned earlier of upsized wheels and tires is critical in remembering that you have to think of the complete package and the entire car. Putting my conclusions together, assuming they are true in the first place, and making modifications to a car on that basis without proper development, testing, and supporting upgrades is like pitting a Mustang GT and a GT500 against each other in a drag race and, when the GT500 wins, you make the conclusion that you need a supercharger, so you go out, buy one, and slap it on top of the engine in the GT and call it a day. Without supporting modifications and tuning.

The point here is that, assuming proper development from all manufacturers, that seems to be how Chevy carves an edge; wide tires, big but light and well designed wheels, wide suspension track, and good differentials. It seems that, when those are combined with a great chassis and a genuine focus on performance and handling, the results on track or a good back road are very impressive.

Wednesday, 21 December 2016

Chevrolet 1LE & Grand Sport - How do they do it? Part 3

GM, in general, is starting to build a very strong reputation for chassis engineering but Chevrolets, in particular, have very strong performance on track these days, not just good handling feel and fun to drive attitude. In Part 1 (link: Chevrolet 1LE & Grand Sport - How do they do it? Part 1), I looked at different aspects and concluded that Chevys appear to have the advantage in grip. If you are still unsure that grip is where those cars excel, perhaps this number will change your mind: 1.11. That's how much lateral forces, measured in g, the 2017 Camaro SS 1LE generated in Turn 1 of Virginia International Raceway (VIR) during Car and Driver's Lightening Lap 2016 feature. 1.11 g also happens to tie the 2014 Viper TA, the 2014 Ferrari F12 Berlinetta, and even the 2016 Ferrari 488GTB. It gets more interesting too..

Car Max Lat-g
2015 Chevy Corvette Z06 1.20
2017 Chevy Corvette Grand Sport 1.19
2009 Mosler MT900S 1.16
2015 Chevy Camaro Z/28 1.16
2015 Porsche 918 1.16
2015 Nissan GT-R NISMO 1.15
2016 Dodge Viper ACR 1.15
2016 Porsche 911 GT3 RS 1.14
2015 Lambo Huracán LP610-4 1.13
2014 Ferrari F12 1.11
2014 SRT Viper TA 1.11
2017 Chevy Camaro SS 1LE 1.11
2016 Ferrari 488GTB 1.11

If you pay attention to the order, you'll notice that the list isn't arranged in order of age or model year - i.e. starting with the Camaro, being 2017, then the 488GTB, being a 2016, then the Viper and F12, both 2014 cars - or vice versa. Despite all being listed at 1.11 g, the order goes F12, Viper, Camaro, and 488GTB; two 2014's, a 2017, and a 2016. Unless you want to believe it was random, that must mean that if you look at more decimal places, the Camaro beat the 488GTB and was beat by the F12 and Viper. That's a humble pony car beating a purpose built, mid-engine (new) Ferrari in grip.

It also places 12th out of every car ever tested in Lightning Lap features. The tally adds up to 201 cars and this Camaro beats 189 of them, including cars like the 458 Italia, 911 Turbos (pick a generation, it beat them all), 991 GT3 (non RS). Cars that beat the 2017 SS 1LE include stuff like the GT-R Nismo, Viper ACR, 911 GT3 RS, Porsche 918, you get the picture. Going further up the hall of fame, you find that three of the top 5 cars are Chevys, taking 1st (Z06), 2nd (Grand Sport), and 4th (fifth gen Camaro Z/28). The Mosler MT900S managed to just barely beat the Camaro (both are listed at 1.16 g, meaning they must be separated by a few 1/1000th's), but everything else is beat by the top dog Corvettes. I think I rest my case that Chevy knows grip. And it's easy to see why Chevy focused on grip.

If you can't grip the road properly, you can't put down power, you can't brake as aggressively, you can't carry speed through turns, etc. That's why everyone who's been around a track a few times will tell you that tires are one of, if not the most, crucial piece of the going-fast puzzle. If you have good tires, generally resulting in better grip, any individual under-performing aspect of a car doesn't necessarily have the same effect on others. For example, a low-powered car doesn't necessarily mean it's slow - it could have great brakes, great handling, great downforce, or any combination. Not having much power hurts acceleration, but the brakes can still do their job slowing the car down, suspension can do its job keeping tires in contact with the road, aero components can still generate downforce to increase grip at high speed, etc.

Even within one aspect such as handling, for example, you could have a car that understeers on entry - a bad handling characteristic - but it could very well be good at putting power down. You could still be quick if you slow it down, turn it, nail the apex, and hammer the throttle. Tires, on the other hand, can single handedly ruin all aspects of a car setup and prevent ALL of them, simultaneously, from performing properly if not chosen well and grip is compromised. Conversely, they can improve every single aspect of the car, if maximized. The question then becomes this: how do they generate more grip? It isn't compound because, while they do use good tires, they don't use anything more aggressive than what other manufacturers use (aside from manufacturer specific tuning).

To try and figure out where Chevy's stand out in any one area, or if they do at all, I looked at Lightning Lap numbers in more detail. I collected data from the last three Car and Driver's Lightning Lap features about each car, including lap time, front and rear wheel and tire sizes, front and rear track widths, power, torque, and weights. Then, I trended a bunch of different parameters about the cars vs lap times to see if I find any correlations pointing to a Chevy advantage. First, look at this graph of lap times at VIR during C&D Lightning Lap features vs power to weight ratios (expressed here in the inverse, lb/hp ratio) for the cars.

This isn't relevant to figuring out how those Chevys go quicker, but I just want to establish trust between you and data, if you're someone who isn't used to looking at empirical data, and making observations and conclusions, without knowing all factors. Generally speaking, cars with better weight to power ratios are faster. You probably already know that. But if you didn’t and you had no idea how power and weight affect a car, you’d look at that graph and say that as this weight-to-power ratio number goes down, lap times go down. Here's another graph.

This one is of lap times vs weight distribution over the front wheels wheels (i.e. the lower the number, the less weight there is on the front axle and tires as a fraction of curb weight; more rear weight bias). You could also look at the lap times vs weight distributions and say that front end heavy cars tend to be slower and as you move weight to the rear wheels, cars tend to be quicker. You could make this correlation, and the above between power-to-weight ratio and lap times, while all other factors are unknown - some of which are actually crucial to the going fast puzzle - just by looking at the test data. And you'd be right. With that in mind, can we use the data for more? Even without a deep dive into suspension geometry and roll centres, torsional stiffness, spring and damping rates, etc., can data point to a Chevy advantage, in the suspension or otherwise? Stay tuned for the conclusion tomorrow in Part 3 Chevrolet 1LE & Grand Sport - How do they do it? Part 3!