ok i have found a good deal on a 3 inch apex'i exhaust made for a turbo fc...mine is a non turbo fc...will it work? if not what needs to be modified?

also where the Y pipe starts, could i just bolt it up to that flange or whatever?

and if i used a 3 inch exhaust, and didnt decide to go with a header, just used the stock exhaust manifold, would i be ok.

thank you all.

 

If its just the catback unit it should work.

 

any other input?

 

A lot of exhaust systemf for an N/A are 2" . I had a nonturbo with a full 2.5" . 3" is too big IMO. You will lose exhaust velocity and the car will be less responsive in most of the rpm range.

Also, if your car is an 86-88 you need actual backpressure (i'm not even talking about exhaust velocity here) to actuate the 6 port induction system (some similarity to VTEC on a honda). Do a search on this... you need to find a solution for your auxilary ports or you will lose 20 horsepower.. The Racing Beat full n/a exhaust has a backpressure collector that will keep the ports working though.

 

so even with a stock header, that wont keep enough backpressure to open teh 6th port or whatever, just using the catback unit, from where the Y pip starts?

 

I use the apexi N1 exhaust on my 86 gxl. I just wired my ports open, so I dont need back pressure. You lose a lil low end but gain more in the higher rpm's.

 

you won't gain any higher rpm power, you'll just lose low end, this is my setup and it works for me but i want him to understand that wiring open the ports isn't really a performance mod since if you fab up a way to make the ports open at 3500-4000, your dyno charts should look the same as with the wired open only less low end. The 3 inch is ok, the less back pressure the better, sorta, a large pipe will shift you powerband up, to large and you could shift the powerband higher than the rest of the motorcan support. My advice, get the exhasut and search for other ways to open your 5/6 ports, or wire em open if like me and RotaryWeaponSE7EN you don't car about low end

 

A cat-back on a N/A without changing that bath tub of a manifold is a waste of time. Just go buy some good headers.

 

Wrong. You'll probably notice the biggest diffence from lossing your cats. But i ran a 15.2 in a s4 na with the stock header. i could have sworn most people here only get a few hp from a header. I 'd ditch the cats long before the stock manifold. Not that a header won't help but you'll gain more from a stock header back, ie; use the 3 inch your lookin at and replace your cats with a test pipe if you can or a least a high flow cat

 

You can use the corksport headers, they have a dyno of a 14hp gain. Not sure if its at the motor or wheels.

 

The NA and turbo Racing beat catback systems don't bolt up in the same spot, the turbo kit is shorter. The pipe diameter is different, obviously bigger on the turbo. I thought they bolted at the same spot, had to add some pipe to bolt it to my NA.

 

so but i am picking this up tomarrow. will the turbo onr bolt up to where the Y pipe starts, give or take some pipe?? or at least bolt up to the last cat..

 

I have a stock 91 NA S5 w/M/T. I'm looking at buying a used 2.5" GReddy Power Extreme Catback exhaust. Will the 2.5" diameter shift the powerband upwards? And also, will I have to make any modifications to the S5 auxiliary ports in order to not lose low-end power? The S5 ports are electronic, correct? Thanks in advance!

 

reviving old thread, also doing what moutainseven is doing. GReddy PE on s5 na okay?

 

It'll be fine.