My RS4 dyno numbers...

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Originally Posted by silverRS4

Of course inlet mass density is the primary issue. Do temps that are 40 degrees cooler explain a 60+ hp difference? If so, that all it is. If not, then the decreased ignition correction seen numerous times at cooler temps is also playing a part.

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along with a temp drop of 40F the humidity will drop and the atm P increase...for typical conditons that will account for 10% or so...40HP
I don't buy the 60HP delta, and I don't consider the vagcom torque accurate...it is map based on rpm/temp/throttle/fuel/etc., NOT measured, ie, mean eff cylinder pressure...
of course it will match the factory rating curve...
also the timing differences are not an 'issue' but a normal operating parameter, it's adjusted to optimize combustion, so if it's warmer/less dense/etc., it will have a different set-point...and limit...

the question is: is 109 at 72F 420 HP or is 113 at 40F 420 HP
imo, the 109 at 72F for a ~4150 lb car (3980 + driver) with high awd losses is the 420 (rated)

Seems like the stock timing map is too agressive. When the ECU senses knock and starts to pull significant timing, it will pull more than the ideal amount, ie. a milder map with less aggressive base settings might yield more power. A dyno pull on race fuel would be interesting.
Have anyone done a Pbox power pull (there are programs out there that generate whp graphs from Pbox data) or a correctly performed G-Tech power pull (ie flat road and correct weight). That would exclude potential dyno problems. That said, on a Mustang Dyno, the rollers are connected, so there should not be issues with different roller speeds, as can be the case with DD, Rototest, Dynapack, etc dynos.

I use an accelerometer based device, developed by the folks that make the Mustang Dyno , it generates numbers that are spot on with a pull on a correctly calibrated Mustang dyno. The great thing is that it measures the performance on the road, so when bogus stuff like cone filters show a massive power loss, the usual excuses like lack of airflow on the dyno does not apply. I have tested plenty of cars, but no B7 Rs4s so far, as they are extremely rare over here (used ones are still well over $200,000)

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Originally Posted by S4_Artillery

Are you really giving BP a hard time for destroying the environment when we all drive 4000 lb, 400 HP cars? Really??? Think about it for a minute.

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id say BP is doing the environment a little dirtier than us...