New bone stock dyno #'s on my '09 CTS-V: - Motorgen - Automotive Events, Meets, Cruises and Forums

Gary Wells · 10-12-2010, 03:48 AM

OK, I had a bone stock re-dyno done yesterday for a new baseline at Church Automotive Testing in Wilmington, CA. They did 4 pulls, the 1st one being the best, (before any heat soak set in), 521.6 RAHP, 536.2 RATQ, 8.50 PSI boost, AFR about 14.6 at 2400 RPM, began dropping down at about 2800 RPM to about 11.7 or so and then dropping down to about 11.3? Next pull definitely pulled out timing and dropped to about 502 or so RAHP and corresponding RATQ, and then 2 more pulls of about 510 & 512 RAHP both giving me an overall average of about 510 RAHP and about 531.2 RATQ. Shawn advised that the increase on RAHP & RATQ was probably due to motor breaking in. I am at about 2300 miles on it now. Dyno was a Dynopack. This was on crappy Kali 91 octane UL. Going in the tank soon is 100 octane UL and then a re-dyno after about a month of running 100 octane UL. I will report my results. My last dyno at Church on 10-16-2009 at about 1000 miles was 498.1 RAHP & 514.9 RATQ.

94cobra69ss396 · 10-12-2010, 07:16 AM

Now just make sure that this is the only dyno you use for testing. All dynos will read different so you want to test at the same one to judge your increases when you make changes.

Gary Wells · 10-12-2010, 10:52 AM

Quote:

Originally Posted by 94cobra69ss396

Now just make sure that this is the only dyno you use for testing. All dynos will read different so you want to test at the same one to judge your increases when you make changes.

You're kidding me, right?

http://www.motorgen.com/forum/showthread.php?t=21321

94cobra69ss396 · 10-12-2010, 11:24 AM

I tried to explain to you in the other post how those numbers could be different but you guys didn't seem to want to listen so I thought I'd help. I've dyno'd my Cobra on three different Dynojet dynos that all used the same correction factor. One was at Powertrain Dynamic's in Huntington Beach, the second was at GTR High Performance in Rancho Cucamonga and the third was at K&N Engineering in Riverside. The temp and humity varied every time and all numbers were within a few horsepower. So why would you think I'm kidding?

Gary Wells · 10-12-2010, 12:50 PM

Quote:

Originally Posted by 94cobra69ss396

I tried to explain to you in the other post how those numbers could be different but you guys didn't seem to want to listen so I thought I'd help. I've dyno'd my Cobra on three different Dynojet dynos that all used the same correction factor. One was at Powertrain Dynamic's in Huntington Beach, the second was at GTR High Performance in Rancho Cucamonga and the third was at K&N Engineering in Riverside. The temp and humity varied every time and all numbers were within a few horsepower. So why would you think I'm kidding?

I do not understand what you are trying to say, and do you have a hot-link to the other post?

94cobra69ss396 · 10-12-2010, 01:08 PM

In the Dynojet to Dynomite Dyno Comparison of a 2011 CTS-V Coupe: thread you questioned why one dyno would read different than another. I told you why it was possible. You guys were then talking about how much was gained by different upgrades and so on. Then you opened another thread about all the different numbers from different dynos. Then you opened up this one. I was simply telling you that you need to keep to one dyno so you know how much it improved over the previous run.

If the dyno shop is not using a correction factor and just straight numbers then you would have to run your car when the temp, humidity and pressure are exactly the same as they were from the previous time. Like I said in the other thread the SAE J1349 correction factor is Air temp 77 deg F (25 deg C), 29.235 Inches- Hg (990 mb) altitude-corrected barometric pressure, 0 ft ( 0 m) altitude, 0% relative humidity. So if it is 45 degrees outside with 30.000 Inches -Hg and your testing at sea level your numbers are going to be higher if they are straight numbers than if you use the SAE J1349 correction factor.

Gary Wells · 10-12-2010, 01:26 PM

Quote:

Originally Posted by 94cobra69ss396

In the Dynojet to Dynomite Dyno Comparison of a 2011 CTS-V Coupe: thread you questioned why one dyno would read different than another. I told you why it was possible. You guys were then talking about how much was gained by different upgrades and so on. Then you opened another thread about all the different numbers from different dynos. Then you opened up this one. I was simply telling you that you need to keep to one dyno so you know how much it improved over the previous run.

If the dyno shop is not using a correction factor and just straight numbers then you would have to run your car when the temp, humidity and pressure are exactly the same as they were from the previous time. Like I said in the other thread the SAE J1349 correction factor is Air temp 77 deg F (25 deg C), 29.235 Inches- Hg (990 mb) altitude-corrected barometric pressure, 0 ft ( 0 m) altitude, 0% relative humidity. So if it is 45 degrees outside with 30.000 Inches -Hg and your testing at sea level your numbers are going to be higher if they are straight numbers than if you use the SAE J1349 correction factor.

In the Dynajet to Dynomite comparison thread the #'s vary because a Dynomite dyno reads considerably higher than any other dyno. I think that most of the variation is due to inaccuracy of the Dynomite dyno more so than the correction factor dynamics. I myself don't remember questioning why they read different, but I think that some people did. And I think that their query was tongue in cheek anyway. I think that most know also.
I open up the other thread with different #'s from different dynoes because I want other people to realize the amount of variation that can be involved and that some of that has to be from inaccuracies.
And I opened up this one for the reasons stated in the opening post. Those #'s are from the same dyno and I believe that they vary because the motor is at least partially broken in. And that was what I was told by the dyno shop
I post what I post intentionally, not by accident, and not by happenstance.

94cobra69ss396 · 10-12-2010, 01:32 PM

Got it. For now on I won't try to help in your threads as I'll know you already know the answer.

Gary Wells · 10-12-2010, 01:49 PM

Quote:

Originally Posted by 94cobra69ss396

Got it. For now on I won't try to help in your threads as I'll know you already know the answer.

I don't believe that the response that you supplied addresses the major reason for the variation, but I am sure that it addresses a portion of it. I believe that the majority of the variation is due to the inaccuracy of the different dynoes involved, and that is why I posted the data from all of the different dynoes on the same chart.
And if you want to respond, that's fine. And if you don't want to respond, that's fine also. And I am the 1st one to cop to the fact that threads are open territory, and I respond to a lot of threads, and I am sure that some of my responses are appreciated, and I am sure that some are not appreciated.

jedhead · 10-12-2010, 01:55 PM

Quote:

Originally Posted by 94cobra69ss396

Now just make sure that this is the only dyno you use for testing. All dynos will read different so you want to test at the same one to judge your increases when you make changes.

I agree with you. Whenever Spectre Performance installs the production intake on my car I plan to test the intake on the dynos that I have baseline readings to I can see what gains I have from the intake.

Bob