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Intro: Focus RS vs Golf R vs WRX STI vs Evo X




You read that right. We're going to put these cars to the test, including the highly anticipated 350 hp Focus RS, not just on the street, but also on our very own excellent local track - Atlantic Motorsport Park. We will hit the track first in September to learn two of the cars and then back in October to learn the other two cars and set lap times in all four. We will also take them on the street to see which one is more comfortable  (although we won't care as much about that portion because, well, we don't). But first, let's introduce the cars.

The WRX STI and Evo X are very well established. They're to AWD turbo compacts what Mustangs and Camaros are to muscle cars. They have huge followings and very loyal fans and, regardless of which is on top, they both are very capable and are the result of years of experience and continuous improvement. The Golf R isn't exactly new, now in its second generation, and it has been with us in one form or another for over a couple of decades, succeeding the R32, which was also an AWD Golf that slotted above the GTI. However, the Mk6 Golf R was a bit lackluster in performance and so was the R32, when compared to the class stalwarts. The Mk7 Golf R wants to be taken more seriously. The RS is the new kid on the block as an AWD turbocharged compact. On paper, it sounds like it means business. Whether you like the looks or not, it sure doesn't look like your ordinary Focus and Ford wants to make sure you don't mistake it for one. Despite that, it's got the most to prove. The RS is the first AWD hot Focus. Luckily, Ford didn't mess around and didn't care about Mustang hierarchy - this Focus has a starting price above that of a Mustang GT. So what does it bring to the table?




The RS makes the most power of this group, putting out 350 hp and 350 lb-ft torque. I've seen several dyno results for this car, one as low as 250 hp, but COBB Tuning claims that the low number are due to an error in how others dyno this car. That's because it's typically dyno'ed as an AWD dyno but it should be dyno'ed in FWD mode. The reason being is that the AWD system is designed to spin the rear wheels faster than the front to help with rotation which means that if you spin all wheels at the same speed, what an AWD dyno would do, the computer thinks the front wheels are spinning and cuts power. When dyno'ed in FWD mode, on 93 octane, COBB got 304 hp (Read more here: COBB Tuning Focus RS Power Gains and Development). That would put drivetrain losses at approximately 13% to have 350 hp at the crank, which seems very reasonable (remember, they disabled AWD and dyno'ed only at the front wheels, so 13% isn't unrealistic)

The real party piece to the RS, though, is its trick AWD system. Built by GKN, the Focus AWD system does away with traditional centre and rear differentials and brings a clutch pack to proportion power to the rear axle and two clutch packs on the rear axle, one for each half axle, to proportion power side to side. Tyrone Johnson - Ford Performance Vehicle Engineering Manager - said they've seen over 90% of the engine's power being sent to the rear axle at peak, but it sends 70% on average. The rear axle can then send all of that (100%) to one wheel or another. Although the front axle makes do with only brake based limited slip action, it can get as little as 10% of power at peak, and only 30% on average, making the handicap far less of a problem compared to a FWD car. In Canada, the RS comes standard with the winter package of wheels and tires. Because, it's Canada. This allows Ford to sell the car, standard, with Michelin Pilot Sport Cup 2 tires on the 19" wheels. Did I mention that the RS means business?




The Evo X is the dark horse in this test. It is has been discontinued by Mitsubishi but, worse yet, it is based on a car that is one generation behind all the competitors here. Despite that, Car and Driver put down the same lap time at VIR (in *ahem* 2011) as the current WRX STI did. In 2015. Sure, it had dual auto and it was an SE so those would have been worth some time, but the point is that it is competitive.

The Evo X also has a trick AWD system, but it doesn't make too much noise about it because it's always had a good AWD system. It can send more power to the rear axle to help the car rotate, not just improve traction, and then split that power side-to-side. Better yet, it has a helical gear limited slip front differential, bettering both the Golf R and the Focus RS - which rely only on brake based limited slip action on the front axle. In the centre, the Evo uses a traditional differential with a clutch pack that can progressively lock in case of slip to send power to one axle or another. The rear axle uses a torque vectoring differential that can send power to either wheel to help the car rotate, like the RS. It isn't behind in a straight line either, putting down similar numbers to the RS and STI and bettering the R. So don't dismiss it just because it's old.




The STI, on the other hand, is the default challenger in this test - since it is the only well established name that is still in production. It gives you three diffs like the Evo but only one of them is electronically controlled - the centre one. You can manually adjust the centre diff's power distribution to adjust the car's attitude or leave it in auto. Like the Evo, it uses a helical limited slip differential on the front axle, bettering the RS and the R, but it loses to both the RS and the Evo in rear axle control.

It uses a mechanical Torsen limited slip differential on the rear axle, which is an excellent differential in my experience, but cannot be manipulated to change the car's attitude. That should make it feel more natural than the Evo and RS, something I'm a big fan of. However, that does mean it will be ultimately limited at the rear axle since a Torsen diff can only send to the outside wheel as much torque as what the inside wheel (unloaded and traction limited) can handle, times a multiple - typically in the 2 to 4 torque bias ratio (TBR) range, depending on design. In other words, if the inside wheel can only handle 10 lb-ft of torque, for example, due to being unloaded and TBR is 3, the diff can only send 30 lb-ft of torque to the outside wheel, whereas an electronically controlled clutch pack can lock and send as much as 100% of torque to that wheel, or as much as it can handle, whichever is higher. In the STI, it is slightly better because it can also use brake based limited slip action on the rear axle like the RS does on the front, to create artificial drag on the inside wheel and send more power to the outside, but it's not quite as effective. Still, having a Torsen diff means you need to apply a fraction of the drag (1/TBR) to the inside wheel that you would need to get the same effect in an open diff, and in a recent Car and Driver comparison, it had the best launch compared to a Focus RS and Mk7 Golf R, so it certainly can put power down. Saying the STI is handicapped is foolish.




The R is a bit of an underdog on paper. It has the least power and the least sophisticated AWD system, a Haldex type that you'd see on a nice SUV or crossover. It normally operates in FWD mode and only sends power to the back in case of slip. It's the only car that will not send power to the rear just to help the car rotate, based on literature I found, and only do so in response to slip. It's stable and secure but may not be the fastest way. Moreover, it can only proportion power side to side using the brakes, putting it at a double disadvantage to the other 3 when it comes to putting power down. With that said, it is the lightest car here, by a significant 260 lbs (approximately) than the heaviest car - the Evo X - and a still substantial 160 lbs (approximately) than the other cars. Our track is a short and technical track and it loves light cars. 3,292 (C&D tested) isn't exactly lightweight, but it's easily lighter than the other three. Plus, although it "only" has 292 hp where all the others make 300+ hp, let's not forget that those are German horses. The kind that always likes to be modest and forget about a few extra horses in the barn. In other words, don't count this one out just yet.

To recap, on paper, the Evo has the most capable AWD system but it is the oldest with the worst power to weight ratio. The RS and STI are closely matched, with the RS having slightly better rear axle control (more beneficial) while the STI has better front axle control. The RS has the best power-to-weight ratio in the group but the STI seems to have the best launch in historical tests. The Golf R ties the STI for power-to-weight ratio, but betters the entire group in weight anf by a good margin compared to the Evo.

Can't wait for the results? Neither can we! Stay tuned for preliminary results the first week of September and final results the first week of October - including lap times, hot lap videos, telemetry, and more! Make sure to like the blog page on Facebook (to the right of the page or click here!) or follow on Google+ and Blogger!


Comments

  1. Great post Mike, can't wait for the results!

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  2. Nice write-up (golf R owner)... The Golf is winner based on untapped potential it has with Stage 1 tune which every serious driver that owes one is silly for not getting... Bringing the car up to 370 bhp for about $700. It's a completely different car and one to experience but I get that it's impossible to compare "tuned" cars but I think even for owners of the other cars which are also high modded.... The golf wins.

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    Replies
    1. Thanks!

      We are trying to keep them as close to stock as possible for this comparison, so that we know what they're capable of off the showroom floor and also have a baseline. We actually will try to retest after with some common modifications to see how they fare, if owners are still interested.

      With that said, we couldn't even find them 100% stock and will make a post about the few modification(s) each car will have. Stay tuned!

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    2. Yes, would be entirely interested in re-test after some common mods.

      I'm looking forward to the results.

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