The Ram's Eye - A Driver's Blog: November 2012



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Tuesday, 20 November 2012

The 2013 Audi S8 - A Closer Look

A few days ago, I made a post about about Motor Trend's test of the Audi S8. It does a 0-60 mph sprint in 3.5 seconds and goes through the 1/4 mile in 11.8 @ 118.3 mph.. very impressive numbers. Even more so when you look at a couple other cars:

2012 Porsche Panamera Turbo S
0-60 mph: 3.5 s
1/4 mile: 11.8 s @ 118.0 mph
Power: 550 hp
Torque: 553 lb-ft
Weight: 4,388 lb

2012 Audi R8 GT
0-60 mph: 3.5 s
1/4 mile: 11.5 s @ 125.1 mph
Power: 560 hp
Torque: 398 lb-ft
Weight: 3,484 lb

Now let's compare those to the Audi S8
0-60 mph: 3.5 s
1/4 mile: 11.8 @ 118.3 mph
Power 520 hp
Torque: 481 lb-ft
Weight: 4,619 lb

The Panamera and R8 have weight to power ratios of 7.98 lb/hp and 6.22 lb/hp. The S8? Well, that one has a weight to power ratio of 8.88 lb/hp... The identical 0-60 time of the R8 GT and S8 can somewhat be explained by their engines' way of induction. Since the R8 is NA, the torque curve probably isn't as meaty so even though it weighs a lot less and has a higher weight to torque ratio, the torque curve is probably more peaky and the Audi S8 has a lot more torque off the line. The 1/4 mile reflects the additional power and superior weight to power ratio compared to the S8

But what about the Porsche? It has more power, a lot more torque, it has the same method of induction and it is significantly lighter (231 lbs). How could the Audi match its numbers? I immediately thought of 3 possibilities: someone spent a lot of time on gearing to get the numbers that low for bragging rights, the car is hugely underrated (again, for bragging rights) or a combination of both. A few days ago, I was hoping someone would dyno the S8 which could tell part of the story.

Luckily, Motor Trend did just that. In fact, they dyno'ed two cars on the same day which is even better for comparison. I know dynos are mainly tuning tools and not measuring tools because there are so many parameters that could change - both external and inherent to the dyno - that could alter the results. It can provide some insight though in this case, especially when you have two different cars dyno'ed back to back.

The two cars are the car in the question - the 2013 Audi S8 - and a 2013 BMW Alpina B7.
The BMW is rated at:
540 hp and 538 lb-ft of torque
and put down:
414 hp and 437 lb-ft of torque

The Audi is rated at:
520 hp and 481 lb-ft of torque
and put down:
479 hp and 422 lb-ft of torque

The Audi started out with a 20 hp disadvantage and yet it came out with a 65 hp advantage, before drivetrain losses.. Using 15% drivetrain losses (MT used 20% but I think that's too high for a modern car), The Audi should be making about 564 hp at the crank and the BMW 487 hp - a 77 hp advantage for the Audi which, on paper, was the "underdog" of the comparison.. and that's only half the story.

BMW is known for underrating their engines. A lot of factors could have caused a low reading on that day and at that time. If that is true, the BMW should be making a lot more than 487 hp.. which would mean that the Audi is also making a lot more than 564 hp. I wouldn't be surprised if the Audi is making as much as 600 hp under ideal conditions - much more than the rating of 520 hp. Next time you look at a test of an Audi and the acceleration numbers look too good for the specs on paper, remember that they probably are because it seems like Audi is joining the "doing more with less" club.

Friday, 16 November 2012

Faster than A Corvette Z06? - A Closer Look

"its test-track acceleration numbers would match the Porsche Panamera Turbo and embarrass a Chevrolet Corvette Z06 owner." That's what Motor Trend had to say about the 2013 Audi S8 after a test. Let's get the facts out of the way first: the Audi S8 is fast.. very fast, especially for a 4,600+ lb sedan.

According to their test, it gets from 0 to 60 mph in 3.5 seconds and finishes a 1/4 mile in a mere 11.8 seconds @ 118.3 mph. That's impressive. Apparently, though, it's not impressive enough to attract readers so something extra had to be said. Track test acceleration numbers would embarrass a Chevrolet Z06 owner? How? I looked up Z06 acceleration numbers.. from Motor Trend tests. I found 5 different tests and all of them pull a 0-60 mph in a consistent 3.8 seconds, except for the Z06 with the Z07 package which does it in 3.7 seconds. 1/4 mile? 2 tests are at 11.6 seconds, 1 test is at 11.7, 1 is at 11.8 and another at 11.9. So out of 5 tests, the Corvette was quicker in 3 tests, tied the Audi in 1 test and was slower by only 1 tenth in one of the tests.

Needless to say, the Corvette has a trap speed that's far higher, anywhere between ~ 122.5 - 126.6 mph.. at 1/4 mile, the Corvette would be flying past the Audi. The one (and only) metric where the Audi clearly excels at is the 0-60 time and by only 3 tenths. I'm not going to get into handling because it was not brought up and only a fool would compare the handling of an Audi S8 to a Corvette Z06. When evaluating a car's straight line performance, whether you're road racing or drag racing, 0-60 times tell you very little. 1/4 mile acceleration metrics give a much better picture.

That's besides the point, though, because Motor Trend editors know that. They know the complete picture and I'm sure (at least I hope) they remember that the Corvette only loses from 0-60 because of the AWD launch advantage but it's a different story at the 1/4 mile. What they're probably trying to do is write stuff that gets people arguing, commenting and coming back to the site. This does bother me a little but it doesn't really get on my nerves. What does get on my nerves is what ends up happening: creating tools.

One of the comments was by a guy saying that (and I'm paraphrasing) his grandma could drive this car with grandchildren in the back and a trunk full of groceries and beat the Corvette Z06 at a traffic light. No.. I don't encourage street racing but a Corvette Z06 would most likely live it in the dust. You see, in order to get that perfect 0-60 time, you have to rev the engine up to the optimum rpm, hold the revs up high (making yourself look like a fool if you're at a traffic light) and lift off the brakes right away. This guy took "embarrass a Chevrolet Corvette Z06 owner" to mean that an Audi S8 is a lot faster, period, regardless of:
1- having an extra couple hundred pounds worth of groceries and kids in the back
2- a street start that gives up most of the AWD launch advantage
3- the possibility that you don't know the best launch rpm because most people don't time and practise their 0-60 launches
4- whether or not the race continues after 60 mph

I usually just laugh when I look back at running into tools like that and arguing with them but while I'm arguing, it's VERY annoying and stuff like that make running into those people a much more frequent occurrence. This is why pulling stuff like that off in car reviews gets on my nerves; it plays a huge rule in increasing the number of tools.. the same way The Fast and The Furious caused a large boost in the number of tools and ricers on the road, except this huge exaggeration is even worse in a way.. it is coming from a much more legit source/influence: an instrumental car test and review.

Monday, 12 November 2012

An unfortunate first post.. or is it?

Well, I took my car in for service today because my passenger side rear tire was losing pressure. The car had been parked during the last week of October because of the bad weather. When I took the car out last week, a low tire pressure warning came on and I thought it was just because the car was parked for a week in cold weather so I simply filled up the tires and drove away. While I was filling the tires, I heard a slight "hissing" noise but I didn't think much of it and thought it was just the air compressor.

The next day, the low tire pressure warning was back and I figured the hissing noise must have been coming from one of the tires. I checked tire pressure all around and one of them was down to 15 psi. Now I know I definitely have a problem. I filled it up because I had to go run some errands and drove away. I get in the car the next morning and, yes, the warning was back. I scheduled an appointment to get the tire checked because I couldn't see any damage.

I knew the tires were expensive because I have wide low profile tires (stock) but I didn't check how expensive before I went. When I got back in the car today to take in for service, there was no warning light, even though the car has been parked all of yesterday. I was starting to get a little hopeful but when I went in and had it looked at, I was in for a shock.. the tire had a nail in the sidewall (no idea how it got there) so it was not repairable. I always like to replace damaged tires instead of repairing them because I believe the integrity of the tire just won't be the same but I still would have liked to have the option.. but no, at least one tire has to be replaced.

Now I already have a few concerns; the rear tires are going to have unequal treads, I don't want to replace two rear tires because I have a perfectly fine tire, and they will be very expensive to replace.. how expensive, exactly? $617.99 + taxes (15% where I live) + $30 for installation and balancing.. PER tire. Almost anything auto related is more expensive in Canada and tires are no exception.

The tire is a lot cheaper in the US but, unfortunately, ordering it online doesn't save that much because by the time duties and shipping charges are added, they cost nearly the same. Still, some savings are better than nothing. However, I have wanted to downsize wheels for a while. My car comes stock with 19" wheels and I have been interested in lightweight 18" wheels so this might be the time to replace!

I started to try to convince myself to shell out the money.. cheaper 18" replacement tires compared to the stock 19" replacement tires, slightly better gas mileage because of the reduced unsprung and overall weight, and better track performance. Am I convinced? I think so! I have until the spring because I also have a truck that I will be driving through the winter so I'm going to wait until the spring or a good sale to buy new wheels. At this point, where most married men would have to try and convince their wives, I've been fortunate enough to have a wife that leaves all car related decisions up to me so.. it's time to go wheel shopping!

Well, I finally put it into gear!

Hi everyone, my name is Mike. I am very passionate about cars and I enjoy driving to the fullest. I enjoy long stretches of highways and twisty backroads.. a late night drive and a rush hour commute.. I'm almost always up for a drive, regardless of time, place and purpose, but there are a couple of things that could ruin a drive for me; bad road manners and poor road conditions, namely broken up roads. As a result, I almost always have something to say about what happens on the road, car news and car reviews so I figured I would start blogging.

I decided to start a driving blog a while back but I haven't got to it yet. I have finally put it into gear, though, so here's what to expect: I will share anything from everyday driving experiences to track driving and possibly car reviews. I will be filming while driving - using a car camera mount, not while holding the camera - and will include relevant clips along with some posts. I think this concludes my introduction so drive safe and I hope you enjoy the content!