Dyno test on 996 (2003)

5 of us in NC went to a shop and had a Dyno test today. All 911's (2003, 1988, 1973, 1971, 1970). We had alot of fun and it was interesting also. The other cars were doing some tuning on their cars, I basically went to get a baseline on mine. We all did the same test: wide open throttle (WOT), we were in 4th gear at 45 mph and went full throttle in 4th gear to 110 mph. The other cars had to drop it down to 105 mph. My max HP (at the rear wheel) was 232.7 @ 108 mph. The shop had a Mustang Dyno and the technian divided our numbers by 0.75 (or about 310 hp for my car). Factory advertising states a max of 320 HP for my car, this is close. My car has 3,500 miles on it with no mods (yet), this is why I wanted to get a baseline. Anyway, just wanted to share a fun day with fellow P-car owners.

25% loss at the wheel seems like a pretty high number even for an automatic. Not that I know what the exact loss is but from all the times i've read about it-it's always been under 20%?

Porsche uses 13% loss at the rear wheels (on a 6speed). Not sure what it is for a tip, but its deff. not 25%. Even at 20% your only at 280BHP. Somthing doesn't sound right...

Mine is a 6 speed. We questioned that 25% as well, he stated that is what his Dyno (Mustang) is set up as????? We are researching a bit more as well. Thanks!!!

Ok... I Dyno can be a very innacurate tool.. Some general stuff I know... 1. Temprature and humidity mess with the performance (accuracy)of the dyno... that is why most of them ask for a "wet bulb" or some other adjustment to help accomodate for the weather in the reading... 2. No one seems to really tune them, or take care of them... 3. Different days..different cars... WAY Different readings... 4. Operator error ? Innacurate driveline adjustments and corrections .. Man.. might as well use a g-tech pro (hehe) I will say this.. You were absolutely on the right track when you said "baseline" The best thing I have been able to determine from a dyno is changes in a cars performance. I try to make adjustments to other cars I have (racers etc. not the 996) before and as soon after as possible to determine the difference between the baseline and the moded run. Then no matter how goofed the actual estimate was... if the dyno is not broken at least you will have a reasonable idea (which in Texas can be hard because the weather changes A LOT .. IE 3 inches of snow in Dallas,Tx two days ago and 45 and sunny today heading to 50 and 60 by Wednesday) So you have weather effecting you cars performance, the dyno's performance, driveline corrections, out of "tune" adjustments, then start mentioning fuel quality, etc etc etc .. OH and also a clean ground for the dyno to read off... well let's put it this way... If each of only the main things that could (and most likely are) wrong are off 2% each (let's fac it that is kind) then you are talking about 2% on about 5 things... 10% ... or on your car if the factory estimate is 320 crank HP .. well there ya go... 32 HP alone in MINOR corrections... not to mention that some can correct one way or the other to mix the results. I guess what I am saying, though not to quickly, is that dynos are fun and if you are doing same day tuning and changes it sia nice to to get a relative "gain or loss" change in what you have done... other than that... it is a $5 to $15k to IMHO. FWIW...

$5k to $15k toy that is... man I type bad.... hope you got he point anyway..

I've done a lot of dyno testing. The best dyno, most knowledgeable operation combo I have used is Dennis Wells, of Wells Racing Engines [phone removed]. No affiliation, etc.