nyet

<img src="http://nyet.org/fats/uploads/b7rs4-stock-3rdgearLOG-01-003-xxx-xxx.png">

<img src="http://nyet.org/fats/uploads/b7rs4-stock-4thgearLOG-01-003-xxx-xxx.png">

THANKS to RI RS4 for the valuable data and helping to improve nyetfats

RI A6

You've been incredibly helpful.

These runs were done on my RS4 with &gt; 10,000 miles on the odometer. They were taken using VAG-COM and dumping the group 3 RPM data. Vag gives us time stamps and rpm readouts, that can then be converted to speed in MPH. To calibrate the rpm/mph conversion, I turned on the cruise control, and dumped the rpm readings from VAG-COM and calibrated it against a Garmin GPS.

With my car and tires, Pilot Sport A/S, the conversions are:

2st gear = 118.6 rpm/mph
3rd gear = 81.01 rpm/mph
4th gear = 60.036 rpm/mph
5th gear = 49.19 rpm/mph
6th gear = 41.95 rpm/mph

YMMV

This gives the FATS software enough data to computer acceleration over time. Also, an env file is input that I've included at the end.

The vehicle weight was calculated, not measured. So it is only approximate and based on the published RS4 weight, plus the additional driver load (which is huge), his dog, his computer, a couple of quarts of oil, and minus the 6 gallons of fuel down from full.

With all this data, Nye's software computes an acceleration curve, and then computes the power delivered due to kinetic energy and aerodynamic drag, to determine peak whp. From this, he uses the 0.28 drivetrain loss constant to compute bhp.

What is quite amazing is the consistency between the two runs. These were done within 1/2 hours of each other, but on two different roads and in two different gears. One was in 3rd gear and the other in 4th. Also the numbers for whp are darn close to what Der Kimbo measured on a dyno a few months back.

In our case, the difference between the two runs was 1% (412 vs 416) and we're right in the correct engine HP range, which is 420 HP(din) 414 HP(SAE), assuming the 0.28 driveline loss factor is correct. Wheel HP was calculated at 297 and 299 HP across the two runs.

So much for the theory that stock RS4s being down on power.


______________________________________________

temp=40F # this is a comment
alt=100ft
#barometric pressure 30.29
hum=60 # DO NOT PUT % sign after


mass=4180lbs # car + driver + dog + stuff - 6 gal down from full fuel load
driveline_loss=.28 # who knows? 19" rims with 9" wide tires==more loss???
Cd=0.31 # coefficient of drag
FA=2.17 # frontal area in sq meters from RS4 spec sheet
#rpm_per_mph=81.01# 3rd gear yo! calibrated with Garmin GPS and VAG-COM rpm reading
rpm_per_mph=60.036# 4th gear

rpm_start=5500
rpm_end=7800
redline=8250

cleanthrottle=1 # set to zero if you think you have throttle cut

hp_div=5 # vertical scaling: set to a bigger number if your hp is lower, lower if your hp is higher
vagcom=-1 # set to 1 for vagcom, 0 for ecux, -1 for autodetect

vag_fit_order=4 # dont mess with this
ecux_fit_order=6 # dont mess with this
dev=png # dont mess with this

octane=93
mods='stock'
comment='b7 rs4'

jwolf::ASP S3

Looks like it would be on par with OTS AWE stg3, no?

RI A6

Treat him nicely!

nyet

*better* than awe OTS stg3 hp wise on 91 imo

nyet

i can be bad too

bhvrdr

mustang, dynojet or dynapac and that 300whp (assuming those very from about 22% to 26% drivetrain loss for quattro) on only a very very underrerporting dyno dynamics (seen as bad as 32 to 36% loss on those). I routinely see over 310whp on an S4 with full exhaust on a mustang and there is no way I am making close to 420chp. Stock they routinely see 265 to 280whp. My guess is the calculations are underreporting likely what you would see on an average dyno.

Godfather | Jay

Also, am I reading this right that the 3rd gear pull is about 67.9 to 96.3 MPH?

Very interesting! Good work guys.

daveak05

how are you compensating for drivetrain losses in all this? The only true measure is bench(bhp) SAE net. Dyno's vary, that's the flaw in trying to truly measure HP on Dynos. And you can't accurately build HP back in, no matter the formula you use.

wagongotya

you hit peak torque around 5500rpms