I found Todd/AWE's postings on the "variation" of dyno's data extremely interesting.

http://forums.rennlist.com/rennforum...7-turbo-3.html

Any load type dyno, whether Mustang, Maha, Dyno-Dynamics, or Dynapak, can be calibrated to show whatever you want them to show. The shape of the curve is linked to the load which is adjustable on all these dynos. The scale is linked to the software correction factors, which is adjustable on almost all these dynos. Therefore, there is not one "right" dyno as they are all at the mercy of their software parameter set-up.

HOWEVER, as long as the software parameters that are used for the baseline are ALSO used for the modification test, the results are valid, REGARDLESS OF SHAPE OR SCALE. Sorry for shouting, but this is an essential concept to understand. The "delta" or difference between the curves is all that matters as long as the load being supplied to the car is not unrealistic.

For example, we could have loaded up the 997 GT2 lower in the curve to produce more boost in that area which in turn would make the low end look more powerful. HOWEVER, such a load caused clutch slippage, which immediately told us we were loading the vehicle in an unrealistic manner. On an engine dyno, there is no clutch to worry about. But there is a clutch to worry about on the street and track, which is where the power is being used in the real world. Thus, clutch spec is an important factor to consider when looking at chassis dyno results.

The only major dyno that does not have variable load control is the Dynojet. Instead, they rely on a rather unconventional mathematical calculation of power as a function of how fast their known roller mass can be accelerated to a given speed. Without a variable load control, realistic adjustment to the vehicle is not possible, resulting in rather "isolated from reality" results, in my opinion and others.

 

I never get what EVO claimed in my local mustang dyno..
When I have exhaust/header/IPD/filter I get 433awhp. this is 93 octane (their baseline car got this much awhp on their dyno)
When I get the 620kit with ECU and intercooler I get 489awhp. with 103 octane.(their 620 car got 525awhp)
When I get the evt700 and cat removal with their newest software I just dynoed last week,565awhp with 103 octane. (their 700 car got 607awhp)...


I understand I can not compare the dyno result between different dynos so I forget about it.The car is good and I am very happy then thats it..

 

I think your example above shows one weakness of comparing dyno data. Different conditions, different fuels, different setups...comparison to cars run on different dynos, etc.

You hit the nail right on the head...You are happy with it. And that is all that matters

 

I feel that dyno testing is a controlled laboratory environment . It's actually a common discussion about the X51 (997S) where when Porsche releases a power upgrade it is tested in all climates and conditions. Porsche does not offer power pack upgrades so a person who wants more out of his car will turn to the aftermarket .

If one wishes to view sales data as absolute then I think he's overlooking that one snapshot in a laboratory is simply a glimpse of that moment .

The key is to go out and drive the car .

When I say that my car "pulls harder" and accelerates more linear" than stock it's not just as a result of a software flash but the combination of parts of a kit mated with the software . The modified Turbos took time and careful construction to make and the result is phenominal .

I am sure that there are other great cars but I am happy with mine . If one is out to set 997tt records then I guess he can split hairs over which dyno or tuner clamied X , y or Z or he can lok at who tends to cross the finish line consistently with good numbers and how content are others with those cars .

I can only speak for the car I have . I am keeping it and cant say enough praise for the workmanship that went into it .