Quote:
Originally Posted by hassmaschine
I actually think it's the 3 stage manifold that causes the high RPM power drop - not the throttle or something else. I dont think it's possible to make power over 6900 without a different manifold entirely - it's not airflow thats the problem, its the resonance of the 3rd stage. It's only tuned for a narrow band between 4500-6900, beyond that it actually has the opposite effect.
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I also think you are right, it would likely make the most absolute power at the upper rpms with a different manifold. Like a N54 manifold maybe.
But I am hoping there’s an improvement with the BBTB from where it is now and 3IM. I don’t want to give up the midrange I’ve got now with the 3IM to favor upper RPMs only since my car is a daily. Looking at that Big Bore Throttle Body dyno posted earlier in this thread there’s a nice bump from 6500 and up:
Like Marty is saying, I would love to pick up 5HP on those last 1000 rpms from 6500-7500. And there’s MILV’s and headers on here also which that dyno doesn’t show hopefully the mods all compliment the BBTB.
Here’s another dyno showing MILV’s with a 3IM posted by BPC in the MILV’s thread. This dyno doesn’t have the BBTB or the 7500 rpm redline, and it looks like they stopped the pull well under 7k RPM’s. The top end power bump from the MILV’s looks good too on this dyno. I think (hope) the mods will synergize somehwhat even though I want to keep the 3IM.
