Quote:
Originally Posted by esquire
The graphs are temperature and humidity corrected. If you've read my posts throughout, I don't argue that temperature and humidity could not have played a role here, in fact I admit they can. My point is that after STD/SAE correction, what little hasn't been corrected for, cannot explain the size of the gains.
One thing you don't distinguish above is whether the 20-30 whp differences you say on bubu's car were while viewing uncorrected or corrected graphs. I personally have never seen 20-30 whp differentials on a corrected graph, if you're talking about the exact same car, same mods, same fuel, etc. I can certainly see those kinds of differentials happening on an uncorrected graph.
Another important factor here is that the weather conditions tugged in opposite directions. On day 1 (dynoing the Akra Midpipe), the temperature was hotter, but the Humidity was very low. On day 2, (dyoing the MRF midpipe) the temperature was cooler, but the humidity was considerably higher.
I will definitely try to get another dyno day going soon, and try to do back to back runs of the Akra and MRF (and maybe even OEM midpipes). Might be some time away though  Thanks for the feedback. |
Well posted.
However, there are variables that the dyno is not aware of which is the DME itself which will fluctuate the ignition timing and AFR depending on environment and adaption values.
Ignition timing can make a huge difference on it's own as many have seen.
Without logging ignition timing really the results are somewhat crude for comparisons sake.
What is also not often logged is the actual inlet temperature. Again, this directly effects AFR and ignition angle.
For a true test, these variables must be logged and shown.
Let me give you an independent example from Italy, Supersprint.
Stock E92 M3 vs Supersprint X Pipe (High Flow CATs) and Rear Exhaust
A massive +36rwhp
However, is it a completely fair test?
Well... yes and no. They are using SAE correction factors here however SAE just could not compensate enough. It corrected for the delta of 6 degC in both ambient and inlet temperature BUT could not take into account the difference in ignition timing.
Let us look a little further at the ignition timing:
Baseline run:
You can see the ignition timing (Zundung) runs at around 33deg midrange and around 28deg high rpm.
Supersprint full system Run:
Igniting timing at the higher rpm is 2 degrees higher and around the same in the midrange. After 5000rpm it is always higher than the base line run.
The temperatures were higher with the stock run and this was out of Supersprints' control. The DME decided to run slightly lower timing.
So, this amazingly higher gain in power is not just down to the exhaust system itself but the difference in temperature and eventually the amount of ignition timing. So the results even in this tightly controlled test are still slightly skewed.
Now, consider this. If the tests were done with the conditions reversed the gains would be less than they should be. I do have an example of this if anyone would like to see it.
Notice that on both tests the barometric pressure and humidity are almost equal. SAE is doing it's best but cannot compensate for what the DME is doing.
We all know that a stock car can run at least 30deg timing and even sometimes 32 if the conditions are right.
Hope this adds a new dimension to dyno testing for you guys.