Help with dyno numbers

[seddon]

I pretty sure this should be posted somewhere else but I don't know where the stickied thread is for L99's. But here goes I dynoed my car along with my 2 friends yesterday a E90 M3 and a C6 Z06 I have a 2SS LS3. All cars are stock and was one on a Mustang Dyno it was a fourth gear power pull. The M3 went first and dynoed as expected 335 rwhp average which is about right since he has 414 to the crank. I went next and the first pull 414 rwhp then the tech was like its suppose to be 426 to the crank right I said yes so he pulled it again. The second pull was 428 and the third was 429 rwhp weird. The tech said "you have a very strong motor and I need a tune AFR is off". The Z06 went next and he dynoed an average 495 rwhp again weird because he has 505hp to the crank. We then put the M3 back on and he dynoed 335 rwhp. Here is the the 2 print out the tech gave me. What do you guys think

[SGOS252382]

Find a different dyno.

[seddon]

I have always used a dyno just as a base for my mods but I know these numbers are crazy. We are planning another dyno with the same cars again. Its just weird how the M3 was right and the 2 anerican cars were basically putting out the crank power. I wonder if anyone else has experience this?

[Bear]

The Mustang Dynos usually show a lower number compared to the Dynojets. This is really weird.

[BLACK10]

either the dyno was wrong or your camaro is a freak that came with a 500+ hp motor from the factory.

[Roger Ramjet]

Looks to me like these are uncorrected values (not corrected to SAE standard day weather conditions). If you have the temp, humidity, and baro press for the pulls I will correct the numbers to see if it is more believable.

[Roger Ramjet]

Using recorded weather information on your Zip code, the temp was 44 F, 47% RH, and 29.85 in hg baro press. Those numbers calc a SAE HP correction factor of 0.9447.
0.9447 x 414 = 391 SAE Corrected HP

[mike@newera]

Mustang dynos can be calibrated to read higher or lower dyno numbers. Don't worry about the dyno number, it is better used as a tuning tool. Just note that if you put an intake and headers on your car, you might want to go back to the same dyno to get dyno'd again or you might be disappointed in your "dyno numbers" somewhere else.

[Slowhawk]

I have the same dyno and would say they either don't have a built in weather station or they screwed with the settings too much.A stock Z06 is ussually 440-460rwhp,so I'm going by that.Also there are settings that have to go in to load the car.If they are wrong the #'s are off.

Also,they need to print the graphs better.There is no need to have the A/F bouncing all over the graph when in truth it is only 11.6-1 A/F jumping to 12-1 A/F. Makes it look alot worse than it actually is.

[seddon]

Originally Posted by Roger Ramjet

Using recorded weather information on your Zip code, the temp was 44 F, 47% RH, and 29.85 in hg baro press. Those numbers calc a SAE HP correction factor of 0.9447.
0.9447 x 414 = 391 SAE Corrected HP

Thanks for the SAE HP correction. You are right they never factored the weather in because the dyno is in some type of a vacuum camber we wanted them to leave the door open so I can hear the car wide open but the tech said no he is gonna loose vacuum.

[seddon]

Originally Posted by mike@newera

Mustang dynos can be calibrated to read higher or lower dyno numbers. Don't worry about the dyno number, it is better used as a tuning tool. Just note that if you put an intake and headers on your car, you might want to go back to the same dyno to get dyno'd again or you might be disappointed in your "dyno numbers" somewhere else.

I usually use a dyno just for a baseline for my mods but I wanted a real baseline to start with I knew 429 was way off. It just weird that the M3 was right on 330rwhp, maybe they calibrated the machine different for the SS and the vette.

[axis]

Originally Posted by seddon

Thanks for the SAE HP correction. You are right they never factored the weather in because the dyno is in some type of a vacuum camber we wanted them to leave the door open so I can hear the car wide open but the tech said no he is gonna loose vacuum.

I'm interested in hearing about this "vacuum chamber".

[THE EVIL TW1N]

Mustang Dyno's are definately better for tuning, but they have too many variables that have to be set in order for them to read correctly. DynoJets are usually what you'll see posted online and are more comparable to one another.