The graphs I am about to show compare two stock baseline runs that showed a difference of power vs. two similar fully modded (literally port to tailpipe w/ two high flow catalytic converters and full midpipe) runs.
Here's the full compiled graph of the two modded runs vs. two baseline runs.
Note that at the top end we made 29hp. Granted, that the lowest modded power run vs. the lowest baseline, but the higher baseline wasn't recorded up that high and it certainly appeared to be going the same direction. :-(
I want everyone to get as much information as possible, and the reality is, our modded runs are extremely consistent while the factory baselines do show some variance from one pull to the next. The reality is those variations are going to exist in the real world and I want to show all of the data I have. On the main graph with everything shown, I have all four runs so that you can see there is very little variance between the modded runs (half the time one is higher, half the time the other is higher on both torque and hp). I took the run with the higher peak hp (by .6hp)/lower peak torque (by .25 ft lb) as the modified pull and compared it directly to the two baseline pulls and have generated the following graphs:
Horsepower:
Torque:
Here is some futher data on the gains at these points:
Monday we will be returning to the dyno to test Tainen's car as it sits right now: Exactly as these dyno graphs show but with the factory midpipe installed. After that we will be testing the helmholtz resonator to band pass the 125hz drone spot and doing some more testing then returning for more dyno pulls and jumping back into working on our intake options.
Temp/Humidity data on the pulls shown is as follows:
Stock Pull A: 65.55F, 62% Humidity
Stock Pull B 65.86F, 61% Humidity
Stepped Header, OP/DP, Midpipe, Street Axleback: 81.64F, 27% Humidity
Now, don't forget, we're not done with the header development. We could call it a day right here and start selling them, but we're pretty sure that more power can be had. For SCCA competitors requiring a catalytic converter in the downpipe, we will still be testing a 4-1, Catted, Stepped design as well.
And we are very confident that the midpipe doesn't show much of any gains in this system. We will know for certain on Monday. Another thing to note, we have certainly seen exhaust system gains in other naturally aspirated systems behaving in an asymptotic manner, meaning that just because you get 10hp out of a header and 10hp out of a catback does not mean you get 20hp out of a header + catback. We are going to try to swap the factory axleback into the Header + Overpipe/Downpipe combo after getting the 'As run at the track this weekend' version of the exhaust dyno'd on Monday and see how much power is lost from that as well.
Jason