disasterman

I race NASA GTS 2 (HP to weight ratio class) and was DQ'd on Sunday and sent to the back after qualifying. They sent me to the Dyno and they gave me some absurd numbers.

Does anyone here have information regarding dyno measurements for a stock 951 on either a dyno jet or a mustang dyno? Can someone explain the necessary SAE equations for assessing a turbo vs. naturally aspirated car.


I have a stock 1988 951 with 89k miles on it. I have removed my AC but retained the original DME. I had the car dyno'd on a Mustang Wednesday and produced 195 horsepower with 205 ft lb of torque. I was dyno'd at the track and the Dyno Jet had me producing 205 horsepower and 224 ft lb of torque. I know that is not possible. I need some help here.

brrgrr

Those numbers don't look out of line for a dynojet - they tend to read ~10% higher than the mustang. Do you have any mods ? - Exhaust, boost enhancer, etc - that would easily explain why you are making ~240 hp.

Van

You drive too fast?

Ski

+1 on the numbers sounding good. When we've had club dyno days, stock ones would come in 180 to 195 on the mustang. We changed a FP regulator on the 180 car, took some FP away(he was smoking black) and he went to 192.

File a grievance, have some of your competitors dyno'd but more than likely, you're beating a guy who IS cheating because he drives like $hit. good luck

gt37vgt

changing the FQR may get you legal .
I guess the other option is ask about the calibration of both dynos

Lemming

The GTS rules are screwy with respect to dynos. You can use any dyno for your classification sheet, but if you are protested, then only a dynojet can be used. Dynojets read higher then mustang dynos, it is a well known fact. I would suggest only using a dynojet for your classification sheet in the future.

Just for comparison, my car pushes 210 rwhp on a mustang and 227 on a dynojet.

docwyte

What he said. NASA only uses dynojets, so that's what you ought to use to figure out your power level. Mustang dyno's will always read lower than a dynojet, so your results aren't surprising.

disasterman

I want to learn more about Dynojet and I am going to a certified NASA shop to confirm my numbers before the next race. It seems that this dyno is biased against turbo cars. I had similar numbers when the SAE correction factor was not used on the Mustang Dyno.

Although I'm starting to calm down, I was totally pissed off and to make matters worse, I got a nice love tap (with damage) in the cluster*** of fighting my way up from the back with an extra 150 pounds.

docwyte

Every dyno (even from dynojet to dynojet) will read a little differently. A dyno works be measuring how quickly known mass (the roller) is accelerated and uses the rpm signal (usually a spark plug wire signal) to know the engine rpm. It uses several barometric sensors to then know what temperature, humidity and elevation it's at to make the SAE correction factor.

However, there's no way for a dyno to be "biased" against turbo cars. They read what they read, they don't know if the car is turbo, supercharged, naturally aspirated, etc.

disasterman

I am ready to say screw it and go to GTS 3. Take out a little more weight and add some more horsepower.

Skip Wolfe

How much do you weigh? My $0.02 is to go to GTS3 with a lighter car. A buddy of mine detuned and added weight to a Boxster to run in GTS2 and he said he had a tough time being competitive to the lighter lower hp cars, went through tires and pads like mad and just didn't have as much fun driving a heavier car.

docwyte

Yep, I run time trials with NASA and instead of adding weight I'll most likely just run less boost to stay in the class I want...

disasterman

I like the idea of light too. When are going to run Skp? Amos was racing with us in GTS, a bunch of PCA'ers were there.

mudbuddha

I know it's slightly off topic but how about a superflow compares to dyno jet, mustang etc. Let's say I am making 300 rwhp on a dynojet and all other parameters being equal.

Sorry, back to topic...

ritzblitz

Next time, let some air out of the back tires and say you changed your tune quick haha.