Vijay

So I was checking out APR's ECU options for the S6. By their testing, the S6's 4.0TT produces 480hp and 464lb-ft of torque. Is the engine that underrated from the factory? It could certainly explain a 3.7 second 0-60. I know the S8 engine is definitely underrated and has been calculated to be putting out almost 580hp by dyno testing.

DeerHunter

Most of the AWD dyno tests put the S6/7 at or just under 400 awhp. There's no way that drivetrain losses are only 20-30 hp, so if you take the rule-of-thumb drivetrain loss for AWD cars of 15-20%, then the APR number looks reasonable. Also, quarter mile trap speeds are a pretty good indicator of power-to-weight ratio. If you use an on-line calculator, estimated flywheel horsepower is around 480 or so.

cagambler

check out this thread from this summer when I had a dyno done on my S6:

https://www.audiworld.com/forums/sho....php?t=2848321

Deer Hunter's comments at the time:
Nice numbers. 12% drivetrain loss is very good, for any vehicle but especially for one with AWD. Perhaps the Generation VI Quattro (with the Crown gear center differential) is more efficient than previous versions.

My original post:


MCE Racing at Thunderhill, the SCCA-owned track in Northern California, has the only DynoJet Linx-424 All-Wheel-Drive dyno in Northern California. Kevin seems to know what he's doing and has interesting stories. He says Google rents the track once a month for any of its employees to come play on. Recently bled the brakes properly for a Google employee that bought a $1.3 million McClaren and tried to bleed the brakes himself and brought it to the track three days after he bought it. He did the dyno on it as we'll.

I've been reading that AWD has drivetrain losses of 20%. He measured (not estimated) the drivetrain losses at only 12%.

Oh, you want to know the numbers? Brake horsepower of 397.43 with losses of 53.31HP for crank HP of 451.
On crummy 91 octane California gas (although the track sells both 100 and 110 octane Sunoco) and test conditions of 98 degrees F. Torque of 402. Says the car is set really lean (California EPA again?) until 3500 rpm, making the value of launch control (which he didn't use) even more apparent.

NeddyPlast

I must be the only person who still thinks the factory rating is about right, maybe 10-20hp under.

I do not think that the engine makes more than 450. Forget calculations from dynos and 0-60 times. Taking into account 1/4 trap speeds and factor in the DSG and you're looking at 450.

Notice just about every car people think is overrated has twin turbo's with DSG. The increased midrange torque and keeping the engine under boost during shifts nullifies any type of calculation anyone is doing.

Even with my APR tune, at the pocono roll event from 60-130 the M5 walked me a good 3 car lengths all 3 times we raced. And of course everyone will chime in and say the M5 is also underrated.

It's not. But thats no big deal. It's just numbers. Who cares if you make 350 or 850hp. Its the end result, the 1/4 mile time or the 60-130 time that matters.

HyperS4

Actually, I have no problem saying the M5 is "overrated" (in general, not power).

We just took a brand new one in on trade. 9k miles on it, owner took a 20k hit. Its a gorgeous looking car(outside) but inside it feels very cramped and cold. Not a very intuitive interior like on our cars.

arjanh

I Have seen 4 of them on the dyno, they all are doing between 480 and 490 hp. On 98 octane.
The are rolled exactly the same as rs4's c6 rs6's, r8's, ttrs's etc....

I have never seen ABT and MTM tuned cars doing the hp and torque they say they do, don't know about APR.....but...

DeerHunter

S6s or M5s?

AndreyATC

M5 walking you is somewhat expected, since this thing traps @ 120mph stock
M5 is also RWD, which i think is better for top end
It has higher redline of 7200rpm and the max power is held all the way to it without taper
And whether S6 and M5 are both underrated or spot on, it's still 140HP difference
M5's gearing is probably utilizing higher revs better

All that a side, my 2008 335i MT car was possibly underrated
Dynos for most N54 engines were 280 WHP with close to 300 WTQ
This is on 300hp/300tq factory rated spec

Of course we can argue different dyno and how sometimes they read higher than they should
Just a thought however

AndreyATC

I think he meant M5s
They dyno just at or below 500
And based on his location (Holland) 98 oct in EU is 93 in US
All seems logical

NeddyPlast

My S6 is tuned, so claimed 560hp. Thats my point. its no match for the M5's stock 560. If we race from a roll, i beat it down the 1/4 mile depending on how good they get off the line.

What i'm saying is that its irrelevant what the actual HP figure is. What matters is the actual timing and the race event being measured. I can sit there and say my car has 560hp per APR's numbers, but when an M5 walks me on a roll it does no good.

Dont get me wrong, I love it, it has ample power with the tune. But everyone seems so focused on it being underrated.