Post
by Dippy » Tue Mar 22, 2005 2:54 pm
I can give you 'armchair' advice as follows:
The torque graphs shown on the AmD website are rather useful, although it is a shame they don't have a stock graph as well.
For your £1K the stage 1 remap will not be a 'step-change' in performance. You should be able to feel the extra mid-range torque and top end power, and the engine ought to feel smoother, but you are not going to be stunned.
I would still say the same for the £1500 stage 2 tune, and indeed the difference between stage 1 and 2 for £500 is relatively negligible.
The stage 3 tune however is a step-change in performance. If you go from stock to stage 3 then you will notice the difference. You will feel the car pulling harder throughout the rev range, and indeed it should be smoother. I also expect it to be quite louder too. Of course this does cost £3200!
Now regarding the RS4, I'm not sure what Audi have done to the engine. The quoted peaks of 430 Nm at 5500 and 420 PS at 7800 are obviously higher than your S4's 410 Nm at 3500 and 344 PS at 7000. But most significant is that on the RS4 at least 90% of peak torque is produced between 2250 and 7600 rpm. This means that whereas your car is producing around 350Nm at 7000, and an AmD stage 3 will be about 390Nm (and both falling rapidly), the RS4 will have at least 387Nm and falling slowly because it has 387Nm at 7600, about 380Nm at 7800 and probably still around 330-350Nm at the 8250 redline.
What this means is that undoubtedly Audi have done serious tuning to the S4 V8 for the RS4. What I expect is that the engine performs similarly to an AmD stage 1 up to about 6500 rpm, but then as the S4 torque tails off, the RS4 will be pulling very strong to the redline.
Coupled with the weight reduction and transmission changes (I understand that the RS4 will have a rear bias), this will make the RS4 one hell of a racing car.
I guess the AmD stage 3 S4 will still produce more mid-range torque than the RS4, but the weight difference will cancel that out on the road. Then of course there will still be 'some' tuning potential on the RS4 because I have no doubt that the OEM ECU map will still be conservative and the somewhat exhaust restrictive. Exactly how much more can be got out of it remains to be seen.
So in conclusion you need to decide what you want out of a car, and I suggest you examing how you drive. I believe that for general fast road driving (i.e. mid range accelaration and not much redlining), a stage 3 S4 will be comparable to an RS4. However on full sprints and on the track, the RS4 will show clear superiority.
This is the basis on which I decided not to get a B5 RS4 or a B6 S4. I do not track my car, I do not do many road sprints, and don't go to the redline much. On this basis my 560 Nm peak is quite satisfying in comparison to what the new S4 and RS4 can offer.
(Plus I am in no position to buy an new car anyway!)
2001 Silver S4 Avant
AmD remap, APR R1 DVs, APR bipipe, Full Miltek exhaust
H&R coilovers, AWE DTS, Porsche front brakes, Short-shifter, 18" RS4 replicas
Defi-HUD boost gauge / turbo-timer (with afterrun pump modification), Phatbox
)