Stock Hellcat Exhaust Manifolds VS. Kooks Longtubes - Any Power Gains?

[ostmike]

Unscientific testing on the same car, same dyno, same tune.

 

[Jack_Toepfer]

If 150* to 170*ECTs are worth 40 wheel… how bad is it at 200*?

 

[ostmike]

If 150* to 170*ECTs are worth 40 wheel… how bad is it at 200*?

I have to be honest and say something doesn't seem right here. This is why we repeated the hit (did two total hits) at 150 degrees just to confirm. I think the test would have been more informational if I would have done a second hit at 170+ degrees and if the same WHP was obtained as the previous 170 degree hit I could stand by the results and answer your question with more confidence.
What I can answer with confidence is the power gain with the headers in before/after tests at 150 degrees.
To avoid confusion we probably should have left the 170 degree hit out of the video but left it in so everyone could see what we saw and come to their own conclusions.