Exhaust System & Intake Question

[Gregg]

I just picked up an 86 XT GL and absolutely love the car. I had a used down-pipe welded onto the exhaust yesterday so that the car would pass inspection, but am going to be having some more permanent exhaust work done in the near future. Ive orderd a 2" Ravin muffler from the local Midas which I will use to replace the stock muffler (which is a bit loud), per the reccomendation on the EA-82 performance info (Ravin has a muffler with basically the exact same numbers that SubieMech inidcated). What I want to know is should I go ahead and replace the system from the Y-pipe back with a 2" system (scrapping the cat in the Y-pipe and replacing the second cat with a 2" high flow 3-way)? Or would that not really help the car, performance wise?

 

Also, is there any way to route a cold air intake duct to that huge open space between the radiator and the front fender of the car? I could put some mesh there and mount a cold air behind it if there was any way to run the piping from there to the filter in the engine bay.

[JonOfScio]

everyone says "cats steal HP" and some people say "Hi perf. 3 way cats don't steal that much" so if you want to stay legal and not have to worry about the restrictive y-pipe cat, the 3 way isn't a bad idea.

 

If your car is turbo, then a 2" isn't a bad idea. but if it's N/A, I say stay with stock diameter. (which I think is 1 7/8? it may be 1 3/4)

 

Oh, and if your car has an o2 sensor, you might want to consider having the 3 way cat with an 02 sensor option, and moving it pretty much up to the front.

 

As for the forced air induction, I think someone inventive could work something out.

[Caboobaroo]

I was planning on doing a cold air induction on my wagon. I was gonna use some exhaust tubing and have it bent at a muffler shop. So yes you can do it, but you have to figure out where the bends are gonna be and what size you want, etc. Then just buy a K&N filter and pop it on the front of it

[Gregg]

I was considering the Weapon-R system, since they include a pre-filter in the ram funnel and place the Dragon filter at the end of the piping, inside the engine bay, along with a heat shield.

[samo]

I have a Weapon-R Dragon filter on my 'Roo. Not bad. Used it for about a year on my old car and just switched it over when I sold her.

 

Definately not the best for off-roading, though, since it likes to get dirty fast. I'd recommend a cotton-element filter if it's going to be out in the mud.

 

If you really want the best, the HKS Super Power Flow has time and time again been proven to be very non-restrictive, yet good-filtering.

[Alliturken]

On my recent cross country trip in an 86 turbo, I replaced the brand new cold air intake setupwith the stock box/K&N immediately after arrival on the east coast. Why? The one I had made at a muffler shop just before the trip, similar to what you have in mind, is steel. It soaks up lots and lots of engine bay heat. It got so hot we could not even touch it most of the time, and we could sense that it was sucking hp at times. Throttle response was KILLER, though, most of the time. Anyway, off it came. What did work extremely well on the car was a new crossover pipe, larger diameter than stock and no cat.....freed up the higher revs of the engine immensely. 2" exhaust from turbo back also did the same, made a big difference, even if it sucked up a tad of torque at low rpms.

 

I may try the intakeagain using pvc pipe or something that wont soak heat so much.

[Marck]

If it is a turbo, than you want to go with a 2.5 inch (not a 2 inch) diameter exhaust.

[Alliturken]

I have 2.5" on my WRX, but I though it to be awfully big for the 1.8 running only 7-8 lbs of boost. So I went with 2". Downpipe is 2.5, narrowing to 2, though. And it any case, like I said, it freed up the higher revs immensely.