Exhaust Systems....Researched

[FalkenDrift]

"it has a nice throaty sound unlike thoses damn crx's and stuff that sound like pissed of bee's"

even more important "those damn crx's"


AMEN

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Domestics FEAR ME

[supra_91]

so since everybody is saying that a 3" is too big for a N/A, would it even matter if i put a high flow 3" cat in my 2 1-2" exhaust? is it worth it?

[supra_91]

and what about the research info done on the cold air? tell me......

[mrnickleye]

Well...I manage a smog test & repair shop here in CA. The high flow cat, like Magnflows (the brand of cats we use) will get you thru smog at least once. The specs are higher on our MKIIIs than newer cars. The high flow cats are just that, and many times the openess does not allow the cat to get hot enough to do its job.

I installed the 2 1/2" cat and piping all the way back. It seems to work fine. I am only 225 hp, though. My smog #s are very good.

Be sure to get a new O2 every few years. Cheap insurance for better fuel mixture ratio.

[mrnickleye]

As for cold air intake, I've read lots on the net, magazines, and forums. With the AFM like our n/a has, you'll end up putting a K&N (or similar) either directly onto the AFM (mine), or on the 3" pipe you'll use to run out front somewhere (behind the headlight?).

I ducted air with galvanized sheet metal up from the front grill to the opening for original airbox, behind headlight.

Then I made a plastic box to seal off the heat from under the hood from getting into the K&N.

You DO NOT want hot air going into the air cleaner, it cause HP loss !!!

[supra_91]

cool thanks for the info

[Isphius]

I have a question, does anyone have a before/after dyno sheet pic of a stock N/A before and after mods? I was thinking about buying a header and getting the whole exhasut done, but i dont want the car to be loud so I duno if its worth the HP gains/noise

[burton51m]

Originally Posted by mrnickleye

Then I made a plastic box to seal off the heat from under the hood from getting into the K&N.

what elese could i use to make a heat shield other than a plastic box?

[mrnickleye]

You could use sheet metal, but it does not insulate as well as plastic.
By box, I meant I boxed it in. I actually used a household trash can. I cut 2 pieces out of it, one for the top, and one for the side that is toward the radiator.

The bottom is already there, as is the fender side.
The back is best left open, as the AFM blocks enough off, and you need it open in the back to allow the outside air to flow better over the filter.

[Redtag20]

Originally Posted by mrnickleye

As for cold air intake, I've read lots on the net, magazines, and forums. With the AFM like our n/a has, you'll end up putting a K&N (or similar) either directly onto the AFM (mine), or on the 3" pipe you'll use to run out front somewhere (behind the headlight?).

I ducted air with galvanized sheet metal up from the front grill to the opening for original airbox, behind headlight.

Then I made a plastic box to seal off the heat from under the hood from getting into the K&N.

You DO NOT want hot air going into the air cleaner, it cause HP loss !!!

Of these mods, what is legal in CA? I really don't want to pay $50. or so for a stock rubber intake hose to replace the damaged on I have, if I can install a better flowing intake pipe from my air-box.