Shape of Acceleration Curve

[SVX10]

Well, I think I'm gonna get the front pipes off my parts car and put them in with pre-cats installed. The power gain is obviously minimal since nobody who has done it can attest to a huge difference, and it makes the 3kRPM resonance worse. I'd rather trust the engineering capability of the engineers that probably spent the better part of a year tuning the exhaust

[SVX10]

Well, last night my roomate swapped out my modified primaries for stock primaries including pre-cats. Driving it to work this morning, I can say the following:

Sound amplitude/volume is lower, but not reduced to the point where the exhaust sounds weak. Just sounds more refined

Engine revs more smoothly to higher RPM (but still not redline). Whereas the power seemed to hit a wall at ~5800 rpm before, it now pulls strong to ~6300 rpm

Low end torque and general throttle response are improved.

As of now, I'm pleased with the change. Who would've thought that going back to stock would be so gratifying? Just goes to show the importance of matching all components for a specified RPM range. The engineers made sure it all matched in stock form, so doing modifications like I did just screws everything up.

I've got a little road trip starting tomorrow during which I'll put a good 1500miles on the car. We'll see how I feel about it after the full trip. It will involve some high elevation driving, too, so I might be able to get some ideas as to what role the MAF voltage plays in all of this.

Mat

[GreenMarine]

Originally Posted by Earthworm

It's not the engine that's surging...it has to do with the drivetrain. Mine does this too except I call it lurching

I wonder if it has anything to do with the carrier bearing on the driveshaft?

Mine does too