I'm having trouble finding a good exhaust setup for my 98 prelude, it seems like there are only 2.25" headers for these cars, but i'm looking for a good 1 piece 4-1 header with a 2.5" collector, a 2.5" high flow cat and a 2.5" cat back, anyone know where to find some of these, it was so much easier to build an integra

 

You could always have someone weld on a 2.5" collector. Talk to local exhaust shops and you can probably find someone to do it on the cheap.

2.5" High Flow Cat will produce a very slight increase in power. I've been told to go with the stock cat, or catless. No point spending almost 300 on a carsound cat for 1 horsepower.

2.5" Piping - KTeller. I went with KTeller piping for $160 shipped direct from them. Fit great, sounds amazing (22" Magnaflow Resonator in factory resonator position and Thermal R&D single inlet, dual outlet muffler.)

I'd also recommend a resonator. I'll try to get side by side pics of my car with 2.5" all the way back from the block, resonator, and nice thermal muffler versus his 2.25" mandrel bent with megan racing muffler and no resonator. A) slightly quieter, B) adds a nice growl to the car... mine also rumbles and pops as the motor winds down.

Hope that helps... hit me up if you have any questions on my setup. Header is DC Sports 4-2-1 with 2.5" collector btw (I know I know... I'm going with hytech eventually and couldn't afford it at the moment because I did suspension and bushings this year as well)

~Peace

 

I got my 2.5" exhaust from the collector all the way back customed.

 

Kteller is probably the place to get piping, then choose your own cat, resonator(s) and muffler as desired and get it all welded together (I think the kteller kit includes a couple flanges).

I would argue that an aftermarket cat is just fine; trying to find a used OEM cat that is 2.5" will be difficult, probably not flow as well, and likely be more expensive than an aftermarket one. My carsound (magnaflow) 3" cat was $110 and has been fine and not thrown any codes (OBD2).

 

KTeller Kit comes with 1 exhaust flange where it meets up with the catalytic converter and 5-6 pre-made hangers. The exhaust is a slip fit design so it also comes with 2 clamps to hold them together as well as the welds you put on.

Personally, I'd take the first straight section of pipe, add a resonator in there and retrieve 22" of stainless, then have your shop fabricate a test pipe for you out of it. I'm currently running the OEM cat with the openings widened to 2.5" (ghetto rigged) and I'm just getting a test pipe next year. What year is your car and what are your emissions laws like? I never have to pass smog again in IL.

~Peace

 

Yeah, thanks for the advice, I never thought of having a new collector welded on, ill probly go with some ebay piping and play it by ear, I think since I'm lucky and although stationed in oklahoma which sucks, they have no emissions laws and neither does alabama which is where ill be going home to, I think I'm gonna start it out with no resonator and see how it sounds then if I want it a bit quieter ill find one to splice in