i have an 89 gxl fully stock...i am going to the shop next week to get a full exaust set up. i am planning to order headers, and a catback apexi n1 exaust...i was wondering how much of a result will i get from this set up 1/4 mile wise, & if i get the pipe custom made what size is recommended...i just bought this gxl. thanx

 

2-2.5 inch. You mention nothing of a race pipe or presilencer or even a cat. This could make a big difference in power output. I would say if you loose the cat you'll pick up 15-20 horsepower with headers and staight through to the tip. Which should put your GXL in the mid 15s. With the cat you'll be looking at 8-12 horsepower and a high 15.

No, I don't have any dyno charts but I've seen enough.

 

the set up is going to be str8 pipe all the way, no cat. header back.

 

if i bridgeport my gxl, how much hp might i gain from it with that set up? 1/4 mile wise what might i be running?

 

if you were to brigde port your motor...you will gain about 20-30% on horsepower....which is a hell of an increase...

 

how will that affect my gas mileage? a little, bad, horrible?

 

if you want all out bad *** exhaust, chaeck out the mazdatrix racing exhaust, headers, dual 2" pipe all the way back, no cats just presilencers and mufflers. this is a pretty expensive set up thiugh, I got it on mine 2 years ago, love it, sounds awesome(even though some people on this site don't like my tips) get flames, cool!
i don't know of anyone else on here with that exhaust to give u a second opinion but i love it

 

I have the M-trix dual as well (kind of), and I love it. I used to work at a metal shop, so I bought the m-trix dual header and a set of RB mufflers, and fabricated the rest of the tubing (mandrel bends) and presilencers myself. I've had it on my 7 for like 6 years with no problems.

Definitly the best system for an NA.

 

i have never had my car dyno, Mark S, how much power do u think it gave you?

 

I run the RB Header, RB Presilencer, and N1 single. The other day, from 40-120, I stuck (my front right wheel to his back left) w/ a modded 97 Trans Am (and yes, he was racing. In fact he cahllenged me). Nothing more than the exhaust and I forgot to wire open my ports after I put the engine back in, so I wasn't running as well as I should. The full exhaust is a veru nice upgrade.

 

nice job Rico, i love hearing about rx's keeping up with displacement monster.

 

I haven't either, but it was definitly quicker than the RB single presilencer I had on before it. I read a post on here once where mazdatrix actually answered an inquiry on that subject. Said they saw a 32hp increase on an s-4(bone stock), but assumed it would be less on an S-5.

It is quite pricey, though. $for$, a downpipe and presilencer would probably the best way to go.

Law of diminishing returns...

 

whats the difference between a dual and a single...does dual mean there is 1 can with 2 tips on it or...2 seperate cans on each side of the car like the stock exaust.

 

the dual exhaust has two 2" pipes all the way, one from the front rotor and one from the back rotor. there is a pre silencer on each pipe and then a muffler at the end of each pipe, no y pipe.