One other point that people don't seem to comprehend is the fact that dynos employ a correction factor to take into account weather and altitude. Therefore it is meaningless to say "it was really hot that day" or whatever. Whether it is 40 degrees or 104 degrees the corrected horsepower is the same. The ACTUAL power is obviously not. As an example, when I ran my car on the Mustang dyno it was 98 degrees outside. The car actually was only putting down 396. This was multiplied by a CF of about 1.03 to indicate what the true power would have been under standardized conditions. I saw a post where I guy had his car dynoed in Denver after installing a blower. The result was like 550, so he said, "Imagine what it would have been at sea level!" Well, the sad truth is that 550 IS what it would be at sea level. What he was ACTUALLY producing at 5000 ft. was more like 375.

 

i would have thought a good tune would net more than 8whp

 

Frankly I, too,was expecting more. I'm sure he could have eeked out a few more horses with higher octane, but 91 is what we have. He worked on it literally all afternoon and I am confident he extracted everything it had (up to 8000 RPM, no less). His tuning skill is top tier. I was happy to see a substantial increase with the CAI, despite what the naysayers claim. Taking all factors into consideration, of the three tunes I've had, including AED and Steeda, TracKey is the most enjoyable. For lack of a better term, it is the "raciest."

 

I thought about trackey but I wanted aftermarket for mod friendliness.

Plus I enjoy revving to 7800.

 

people need to remember that tunes are not simply about max hp and tq numbers. The tune is also about how and when it makes that power.

 

I actually was going to mention this since I "went first" with my dyno comparison. I chose not to because I did not remember what went into the correction factor.

However, I do believe that the correction factor only addresses certain variables and not others, so it's not really 100% standardized. For certain the dyno make is significant, . And my dyno guy told me the most significant variable is air quality. We ran my car twice, and the second time the results were slightly higher, which he felt was due to a cooldown period. None of these factors was present in the correction factor.

It should be mentioned that the dyno operator has the choice of modifying the correction factor, so when you get dynoed it's probably a good idea to ask for the correction factor and whether it was calculated automatically. If it was manually determined it might be a good idea to ask how it was determined. I suspect that entering a manual correction factor would make the results a little hard to trust.

 

This is a great point. The reason I initially went aftermarket is because early reports on the TracKey reported little to no peak horsepower gains on the dyno. I then contacted Shaun and he told me his tune would "blow away the TracKey." The biggest improvement with the AED tune was a somewhat stronger midrange and a smoothing out of some of the cam timing transitions. Had I gone on to mods that required further tuning I would have stuck with AED but since I had essentially ruined most of my previous cars by overmodding (cough, Griggs, cough) that was not in the cards for my Boss. For me the TracKey improves the overall driving experience more than the other two tunes I had and it isn't necessarily something that shows up on a dyno.

 

Very true. The farther away the prevailing conditions are from standard the larger the correction factor and the greater the chance for error. Change from baseline during the same dyno session and the trend should be fairly representative of what is happening, though. I'm not sure exactly what your guy meant by "air quality." The only thing that really matters is density and the only variable that will affect density during an individual session is IAT. During both my sessions the different dynos had their own weather stations and calculated the CF automatically. In the case of AED he started at about 1 PM and ended around 5 PM and I did notice that the CF changed slightly as the day wore on. Shaun's dyno fan also uses cooled air which probably keeps results a bit more consistent. I also asked Shaun if he uses SAE or STD. He said, "STD because people like to hear bigger numbers." How true.

 

I think he was talking about smog, dust, pollen levels, etc., i.e., foreign particulates in the air. I can see how these would affect oxygen density. I can't remember the exact number but he said "if we were doing the test at 4:00 am it would easily add x". So probably he was talking specifically about smog due to vehicle activity. My test was like at 11:00 am.

 

I sort of had that feeling and think that is, to put it kindly, rather dubious. Unless you live in China and have to wear a mask I can't imagine any region in the US where the air is so polluted it would affect horsepower. And certainly pollen and other particulates would be stopped by your air filter. The only significant difference between 4 AM and 11 AM, powerwise, is temperature. Where I am it was 48 degrees at 4:00 and is 63 now, so it is absolutely true that the actual power would have been higher seven hours ago. The correction factor would also have been different so the final reading would be the same.

 

Well I certainly won't argue with him or you, but I do have to say he seems very knowledgeable, is well regarded and is also one of two dynos in my city. Your points are taken as well. Anything I have to say is guesswork but when I think about oxygen densities in gas mixture flow rates through a particulate filter I am hesitant to dismiss the notion out of hand. For example, "smog" molecules... they still burn right? Do they release the same energy as pure oxygen?

 

Airaid PJ CAI - FRPP 84.5 TB - Borla ATAKs

 

Those are nice numbers. Now get rid of the cats with a tune your at 425 or more.

 

Wanna keep TracKey. At least for now. I'm pretty happy with how the car moves on and off the track. But Kook headers, side pipes and catted H pipes are on my wish list.

 

Nice numbers, seems with intake and tb would net me around 15whp. Ouch, for the price I will just go with a MRT quad h pipe and cat deletes and get almost double that.

 

Since the temperature during your runs was within a few degrees of STD, I assume you are at some godawful elevation to have a correction factor of 24%.

 

I just now noticed your town. Higher than a mile. That explains it. It also explains the modest results from your mods. There just isn't that much extra O2 waiting to be sucked into the intake.

 

So your actual rwhp was around 338.

 

Nice