C&D comparison: S6 vs M5 vs AMG E63

[sakimano]

Because believe it or not they don't always know that their cars are bring used in a comparison test.

quote="P_G"]Like said believe it or not. You chose not, that's fine with me.[/quote]

it defies logic and sound business practice
but doesn't matter either way

C&D - Hi...Audi? This is Car and Driver. Can we borrow an S6 for 3 days?

(Audi covering the phone, talking amongst themselves) - guys...it's Car and Driver and they want an S6...anyone know why? Hmm...I guess they are probably going to test it and maybe do a comparison. Of course maybe they just need some transportation while they're over here on holiday? Ask them. Actually no, scratch that...just give them one. Let's roll the dice!

Audi - Hi C&D. Sure. Just come and pick it up and we won't ask what you need it for, or what you are using it for. Make sure you don't tell us either. We want to go in blind and be surprised.

[ArthurPE]

Because believe it or not they don't always know that their cars are bring used in a comparison test.

Like said believe it or not. You chose not, that's fine with me.

it defies logic and sound business practice
but doesn't matter either way

C&D - Hi...Audi? This is Car and Driver. Can we borrow an S6 for 3 days?

(Audi covering the phone, talking amongst themselves) - guys...it's Car and Driver and they want an S6...anyone know why? Hmm...I guess they are probably going to test it and maybe do a comparison. Of course maybe they just need some transportation while they're over here on holiday? Ask them. Actually no, scratch that...just give them one. Let's roll the dice!

Audi - Hi C&D. Sure. Just come and pick it up and we won't ask what you need it for, or what you are using it for. Make sure you don't tell us either. We want to go in blind and be surprised.

maybe when I go to Germany I'll call up Porsche and ask for a Turbo

Me (in fake voice): hey, I'm from C&D can I have a Turbo for a week?
Porsche: sure, just pick it up
Me: how about just mailing me the keys and leaving it in a car park?
Porsche: sure, just mail them back
Me: suuuuuure I will

[adsgreen]

perfect example of HP vs Torque
HP is simialr, yet the heavier car is much faster
HP +10%
torque +35%
wt, the S6 is about 10% heavier, negating any power/wt advantage
but yet the S6 is much faster...torque

Considering the quarter mile for the S6:

1st gear = launch control at 5000+ rpms, grabbing around 4000+ rpms, then run out to to 6500 rpms and shift
2nd gear = 3700-6500 rpm then shift to 3rd
3rd gear = 4200-6500 rpm then shift to 4th
4th gear = 4700-6200 rpm (end 1/4 mile, trapping at 115 mph)

You're using plenty of that powerband where the car acts/behaves like a 500hp car. No wonder it kicked so much ass.

Lets look at 2nd gear alone for fun on the S6 at the start of its engagement in the quarter mile, to half way through the gear, to redline. Assume the Audi supplied dyno curve is accurate, and that on good gas the car is 6% under-rated from the factory numbers (as they've done on the other recently released forced induction cars).

Audi S6 (C7)
At 3700 rpm when second is engaged, the car is making around 430tq/300 horsepower.
At 5000 rpm, about half way through 2nd gear's service in the 1/4 mile, it is making about 430 tq/410 hp
At 6500 rpm it is making about 365tq/450 hp

Now lets look at another '420 hp' car in 2nd in the quarter mile:

Audi RS4 (B7)
At 4500 rpm when second is engaged, the car is making around tq/300 horsepower.
At 6250 rpm, about half way through 2nd gear's service in the 1/4 mile,it is making about 380 hp
At 6500 rpm it is making about 400 hp (peak 420 is made around 500 rpm earlier)

Add to this the fact many think the RS4 is if anything slightly OVER-rated...not underrated...and you can see the gap could be even bigger. This is 2nd gear...where the cars both hit 60 mph...so weight is not much of a factor here on in. The difference is about 300lbs for interests sake.

Considering the RS4 is launching with around 300 tq and the S6 is launching with 430 tq with launch control...and DSG to make shifts INSTANT vs. a 2 to 4 tenths of a second stretch where the RS4 is shifting/not accelerating...then add in the power gap at the various points and the superior curve/work the S6 exhibits, and you have your 6-7 mph difference in trap speed and 6-7 tenths ET difference.

But you're not counting 7 speeds v's 6 launch control and near zero shift time which over 1/4 mile do make a differnce.
I can't recall exactly but with the RS4 10% of the time it's changing gear so not under any power.
That could easily account for the 3-4 mph difference and then result in identical times... which isn't a surprise given identical power.

And the fact that the torwue curves look very different.

I would have expected the arguement that peak torque is everything to show that +35% (!) more would make a huge difference.


At least compare like with like

[adsgreen]

Saks - where do you get the figures from?
When I shift from 1st to 2nd in the rs4 I don't drop anywhere near 4.5k... that'd be like shifting about 7k rpm by my calc?
I reckon it'd be about 5k?

I don't think comparing 2nd gear engagement rpm is that useful without showing the roadspeed and gear ratios.
If we assume (which isn't true) that 2nd gear engagement is at the same road speed for both cars then the torque of the s6 is completely killed by it needing a much longer gear than the RS4.
Its engine is only spinning at 3700rpm where as the rs4 is much higher. Higher rpm vs road speed means shorter gear.

If as I believe 2nd engagement on the rs4 is higher than 4.5k (just checked my car simulator and it shows 1st is good for 41mph so it would be about 5k into 2nd) then assuming same roadspeed the S6 would need a 2nd gear 1.35 times the length of the RS4. You could imagine this by having a rs4 gearbox with a longer final drive ratio. 430tq / 1.35 = 318tq when normalised through the gearbox differences.

edit: - Oi! cheat! youv'e got the s6 making 450 bhp!

[adsgreen]

Thats odd...
how does it go 0-60 in 3.7 and 5-60 in 4.9??
I know audi may underrate their turbo cars but 1.1 seconds from the published 0-60?
Given the car has launch control and DCT gearbox the 0-60 should be repeatible everytime.

Heh - wonder if they got the RS6 mule by mistake

[sakimano]

I can believe the trap speed - it's the same power as the RS4 with <beep> load torque and near zero shift times plus launch control and only slightly heavier (IIRC).

check this out...here's a reasonably well driven B7 RS4 with manual transmission. Not flatfoot (no lift) shifting by any means....but a good driver shifting briskly. I've seen some videos of this guy driving and he's solid. About 0.3 seconds per shift. Maybe 0.4. That's decent.




Now here's a DSG B8 S4 driven by an 18 year old kid. Find me the shifts lol. It's amazing. Still...it's boring unfortunately...but very effective.

[sakimano]

Thats odd...
how does it go 0-60 in 3.7 and 5-60 in 4.9??
I know audi may underrate their turbo cars but 1.1 seconds from the published 0-60?
Given the car has launch control and DCT gearbox the 0-60 should be repeatible everytime.

Heh - wonder if they got the RS6 mule by mistake

launches at 5000 rpm well into boost and peak torque

from a 5mph roll (that's how they do it...they don't just measure your 0-60 and trim out the 0-5 mph time...they actually have you roll at 5mph then punch it till you hit 60), the car is at 950 RPM so it has to wait for boost to hit before it pulls hard.

The other two cars are even worse at this test due to RWD slowing them down a little as well as being out of boost.

[HYFR]

are you sure it launches at 5k?

the TTRS launches at 3.5k

[sakimano]

But you're not counting 7 speeds v's 6 launch control and near zero shift time which over 1/4 mile do make a differnce.
I can't recall exactly but with the RS4 10% of the time it's changing gear so not under any power.
That could easily account for the 3-4 mph difference and then result in identical times... which isn't a surprise given identical power.

And the fact that the torwue curves look very different.

I would have expected the arguement that peak torque is everything to show that +35% (!) more would make a huge difference.


At least compare like with like

Are you talking to me? Or Arthur?

I was using these examples to show someone that the S6 is sneaky fast because those who focus on the peak 420 hp number are forgetting

1. it's a sandbagged number
2. the torque curve is insane
3. the DSG shifts like greased lightning
4. the DSG launches like greased lightning.

You're agreeing with me.

When you look at the time the RS4 is shifting while coasting (it doesn't cost time in a 1:1 basis...it just means you're not accelerating) and if you look up at the graph I showed, a decent driver is shifting in 0.3-0.4 seconds per shift. On 3 shifts that's about 0.9-1.2 seconds when you're not accelerating.

On a good driver it's more like 0.2-0.3 seconds per shift...or about 0.6-0.9 seconds when you're not accelerating. On the DSG its about 0.1 seconds per shift. That's about 0.3 seconds. So the S6 DSG is accelerating for an extra 0.6 to 0.9 seconds. Certainly important, but not going to create a 7-8 mph trap speed divide on a car that is 250 lbs heavier than the RS4. Nor is more effective launch control (my RS4 cut low 1.8 second 60 foot times...and I bet a Coke the S6 is only around 1.75 thus not more than a tenth in it there, and the 1.75 vs. 1.85 difference isn't going to effect trap speed much).

[sakimano]

are you sure it launches at 5k?

the TTRS launches at 3.5k

yes

the B8 S4 launches at 3.5 k.

the RS5 launches at 5.5 k.

the RS4 launches at 5.5 k.

[JCviggen]

the C6 RS6 trapped 119-120mph routinely.

Mapped ones, sure. Bone stock? Maybe a freak, I've looked around and 115-116 is a lot more common than going on 120. Even came across a slip from an APR mapped one that says 118.
Remapped 120-121 is about what they do, with close to 700bhp that is...

I decided to look for cars that use lightning quick dual-clutch transmissions.
Let's take an M3 DKG. 420bhp NA 7-speed close gearing. 60-130mph is close about identical to the S6 actually. It loses a second or so to 60 (RWD) but that doesn't really influence trap speed negatively. How much do standard DKG M3's trap at? 111mph on average.
111 to 115 is a big difference, as you rightly pointed out at that level it takes a lot of power to increase trap speeds. That power should be visible in the 60-130 times but it is not.
12.5 seconds 60-130 does not match the 115mph trap speed.

[ArthurPE]

+1 gear compensates for shorter power band (RS4 90% torque band 2500 to >7500 over 5000 rpm, S6 1200 to 5800 ~ 4600, 10% less so 1 more gear)
launch is an advantage, but an RS4 with awd negates a good bit of the lc advantage, and both have awd
no way that accounts for 3-4 mph, now maybe a few tenths of a sec...maybe, RS4 hase 2 changes, S6 has 3, so some DCT advantage is given back

torque curves are similar, flat and wide with the S6 shifted down 1500 rpm but it's power peak is much lower
but that is moot, each cars gears are optimized/matched to the engine
+10% more wt
+10% more HP
1 more gear but shorter power band
+35% torque
7-8 tenths faster, 7-8 mph trap speed
same HP, higher wt, power/wt is the same
the only obvious difference is torque quantiy

perfect example of HP vs Torque
HP is similar, yet the heavier car is much faster
HP +10%
torque +35%
wt, the S6 is about 10% heavier, negating any power/wt advantage
but yet the S6 is much faster...torque

But you're not counting 7 speeds v's 6 launch control and near zero shift time which over 1/4 mile do make a differnce.
I can't recall exactly but with the RS4 10% of the time it's changing gear so not under any power.
That could easily account for the 3-4 mph difference and then result in identical times... which isn't a surprise given identical power.

And the fact that the torwue curves look very different.

I would have expected the arguement that peak torque is everything to show that +35% (!) more would make a huge difference.

At least compare like with like

[HYFR]

are you sure it launches at 5k?

the TTRS launches at 3.5k

yes

the B8 S4 launches at 3.5 k.

the RS5 launches at 5.5 k.

the RS4 launches at 5.5 k.

yes but the RS 4 and RS 5 are NA and the S4 and TTRS are FI

[ArthurPE]

RS4 has 2 shifts per 1/4 mile
2-3 and 3-4, you launch in 1st so 0.4 to 0.6 under no power, but still moving!, probably cost a fraction of that in ET, a few tenths at most

the S6 has 3 changes, or 0.3 sec of dead time, or 0.15 less than the avg RS4, and only a fraction of that will show up in the ET

I saw a RS5 time, same engine as the RS4 (more power, same torque), 7 speed DCT and same weight, C&D(?) got 12.5 http://media.caranddriver.com/files/201 ... ts-v-2.pdf
RS4's have pulled 12.8's, so 3 tenths not counting the wider torque band

Motor Trend
We developed a work-around and measured a 0-60 time of 4.3 seconds and a quarter-mile run at 12.8 sec at 108.2 mph.
Read more: http://www.motortrend.com/roadtests/sed ... z1wNw93lYA
so the DCT did not give it much of an advantage

avg of 12.65 vs 12.8 and it had a better wt dist, launch control, wider power band, better diff system, and 20 mm wider tires
the DCT can't have much advantage at the strip now on a road course, different story, being able to keep your hands on the wheel and the cumultive advantage of 100's of shifts

[sakimano]

the C6 RS6 trapped 119-120mph routinely.

Mapped ones, sure. Bone stock? Maybe a freak, I've looked around and 115-116 is a lot more common than going on 120. Even came across a slip from an APR mapped one that says 118.
Remapped 120-121 is about what they do, with close to 700bhp that is...

I decided to look for cars that use lightning quick dual-clutch transmissions.
Let's take an M3 DKG. 420bhp NA 7-speed close gearing. 60-130mph is close about identical to the S6 actually. It loses a second or so to 60 (RWD) but that doesn't really influence trap speed negatively. How much do standard DKG M3's trap at? 111mph on average.
111 to 115 is a big difference, as you rightly pointed out at that level it takes a lot of power to increase trap speeds. That power should be visible in the 60-130 times but it is not.
12.5 seconds 60-130 does not match the 115mph trap speed.

my bad if I'm wrong, but I was sure they trapped higher than that (C6 RS6). Maybe it's overrated at 580hp/4500 lbs

As for the M3, Car and Driver did this review. Have a gander at the M3's trap speed last year...

12.4 @ 114

http://media.caranddriver.com/files/201 ... ts-v-2.pdf