Turbo? Supercharge? Cold Air Intake? Leave it well enough alone?

[Cuckoorex]

OK, I dropped in a K&N hi-flo filter and…

Well, the car runs pretty much like it did before. No real difference that I can tell. Oh well.

[Madd_Maxx]

@Una Persson

<snip>Pumping or volumetric efficiency, which is something controlled by intake and exhaust processes, generally only leads to an increase in potential power, unless the engine is already so poorly designed that flow stratification is causing mixture problems and impacting combustion efficiency. I sincerely doubt a port fuel-injected post-1980’s vehicle has those issues.<snip>

I agree with almost all of your post. On my particular truck however there was miles of tubing that was part of the intake system that was actually a drag on the engine. Acceleration wasn’t as crisp as the air had to travel further and in no way straight before reaching the MAS, and ultimately the ports themselves. I ended up taking out half a dozen peices of plastic tubing that were part of the stock intake, some of which are shown below and replaced them all with two straight plastic tubes with a silicon sleve between the two. You can check out some of the before and after pictures here NissanOffroad.net, click on “How To Guides”, Frontier/Xterra, Airbox modification or K&N.

Note: I am in no way affiliated with this site at all, its just one I frequent when having problems with my vehicle.

[Cuckoorex]

OK, maybe I spoke too soon. The old Alero does seem to have a little more pep, which is especially noticable when accelerating from 30-50 mph; at the very least the engine response seems smoother or more consistent. Maybe it’s just a placebo effect, I guess. Unfortunately I didn’t test the Alero’s acceleration times prior to the installation of the K&N filter, so I can’t prove that performance has improved. It sure feels like there’s at least a slight improvement.