Quote:
Originally Posted by pbonsalb
Uncorrected is important for tuning since it is the power you are actually making under the actual weather conditions. But people want comparable results that are standardized to certain conditions and SAE does that. If one guy is making 375 rwhp at the North Pole and another guy is making 325 rwhp at the Equator, it does not mean much to me if I am in neither of those two place. I want to see standardized results. This is why car makers report their engine horsepower and torque in a standardized format (SAE for the USA where I live).
While I like standardized results for comparison purposes, I agree they do not tell everything. If a car is knocking and retarding timing or breathing poorly due to extreme heat or bad gas or has old spark plugs or a clogged air filter or clogged cats or there is no dyno fan, the reasons for the poor performance won't be reflected in any standardized dyno format. I think this is why there is a significant variation among even SAE Dynojets of the same make and model car.
|
Well said from a theoretical point of view.
You already know what SAE is used for so I won't bore you with that info.
The problem which we have seen as tuners on our own dyno, Supersprint's dyno and dyno's we regularly use all over the world is that SAE correction is flawed within a range of temperature and atmospheric pressure.
We noticed this long ago when we were tuning the same exact cars over again after dealer updates.
I have the graphs and weather conditions to show this.
All of the testing we have ever done has data logged vanos, ignition and many other variables.
So we know the DME is not suddenly deciding to play a role.
In all cases the engines would produce the EXACT power curve, just higher or lower on the scale.
What we found was the SAE correction was over an under correcting for small changes in barometric pressure and these particular engines just don't react like that.
After speaking to dyno manufacturers they also confirmed this as many of them produce engine dyno's which are operated in weather controlled test rooms. They tuners alter pressure, humidity and temperature and high efficiency engines just do not respond in the way SAE suggests.
I do not want to fill this thread with this information but if anyone is genuinely interested in seeing the results we have carried out over the years, please contact us or we can create a separate thread on the subject.