Aight i'm getting ready to do my exaust I'll most likley do RB headers but my question is I'm in SC so no emistions law and I'm wondering if i can just get rid of all my cats and just run strait the the mufflers and if it will benifit me me or hurt me.. And if so should I go true duals or 2into one headers.. 86na thanks

 

Since you have a 86 it will hurt you, you will need to have enough backpressure to open up the 5th and 6th ports.

 

If your on a budget just go with a streetable header and presilencer setup for the 86-88 and any cat-back you can afford. But otherwise I would say true duals all the way.

 

do you really need a presilencer? i mean of course it'll be pretty loud, but if you have a normal catback (not something like n1's) and just put in straight pipe instead of the presilencer, it wont be too bad... well it wouldnt be too bad for me, its all opinion

 

A straight pipe won't open up the ports since it doesn't even have a fitting for the split air. Besides the pre-silencer is designed to not even restrict flow much if anything at all.

 

i keep wondering about this..

i thought it was the s5's that needed the pipe hooked up for the aux ports to open, but the s4's didnt... is that true? cuz i had a presilencer on with no piping hooked up to the air pump, but i didnt notice a very big difference in power after hooking it back up, so does that mean my ports were wired open? how do i check that?

 

S4's use backpressure to open up the ports S5's use the air pump.

 

so does that mean that s4's dont need the pipe hooked to that cat? cuz in his profile it says 86 n/a, so is the cat or presilencer necessary still?

 

S4's need back pressure from something be it a cat or silencer.

 

ah ok, so the fact that its there works, even though the airpump isnt hooked up to it

 

If you have the air line hooked up they will work. Otherwise you need some other method of actuation. To me the presilencers are great.

 

I was wondering I have a 87 n/a I have an exhaust with stock manifold and only one high flow cat going into a y pipe back into 2 hks dragger high flow mufflers does this affect my backpressure and how can I check that I mean I put it on and really couldnt tell a difference

 

Usually if you have a cat and its hooked up to the ports it should work.

 

So it shouldnt affect backpressure

 

No your car just probably sounds like some honda

The cat-back doesn't really matter when you have a cat. The cat is the huge restriction.


Santiago

 

i have a jdm turbo 2 s5...i put the acv blockoff plate and the split valve block off plate and i eliminated the airpump..and i gutted my cat...does this mean my 5 & 6 ports are not opening?do i have to do something to open them?am i losing horsepower?

thanx for the help