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Old 04-22-2009, 04:59 PM   #28 (permalink)
semtex
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Quote:
Originally Posted by wstar View Post
Are you sure that the low-rpm torque loss wasn't just from ramping the throttle in? On my DD run, I don't really trust any of the numbers under 3750 rpm or so as I'm pretty sure the engine wasn't solidly WOT until shortly before 4K. Even then, the way my torque doesn't really peak up until about 4250 is suspicious (this may have been lag between hitting WOT on the pedal and the engine really starting to breathe like WOT).

Given the data we have so far (including yours), I think it's fair to say that the headers aren't great bang per buck (and especially aren't good bang per installation hour), but I have a hard time believing we really lost torque on them given the graphs and the unknowns.

There's also the ECU consideration. The headers may provide better gains under good tuning (or not), we'll have to see.
Even if it was from ramping the throttle in, why would it show a loss? The throttle had to be ramped in the last time as well, right? I don't know. I'll tell you guys my driving impression so far though. I can notice the loss of torque on the low end. I mean, before the dyno, I kinda suspected it, but now I have confirmation. But paradoxically, it feels quicker once I really get into it, which I guess is where the hp gain comes into play. Sound wise, I'm still undecided as to whether I liked the way my car sounded before the headers vs. after. To be 100% honest, I do not feel that this was money well spent. I'm actually toying with the idea of having my stock headers put back in. But then that's another $750 out of my pocket, right? So I probably won't. Plus you're right about the tune. It'd be premature to rip these out until I see what a tune will do.
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