I got a catback right now. It's an apexi N1 3" turbo exhaust.
I do not have a turbo but that is wat came with the car. I was looking and am probably going to get headers.

With a full exhaust about how much hp do u think it adds?

Mods i got are, accel wires, intake, and not really a mod but 300zx fuel filter.

**Edit**
Also this

 

The AVG. on a CAT back exhaust systems is 2 HP, not chp your just shifting the power band. 300zx fuel filter........Well... NOTHING GAIN.... Accel wires NOTHING gain......
Focus on big engine gains for the price you paid for that CAT back you could of purchased a 64mm TB and gotten a 5HP gain or a 70mm at a 7hp gain.
Look into coolant bypass, FREE mod. Pop the ceramic out of the CAT FREE mod. EGR block off FREE mod
Look into cams.......
Look into engine management...
Don't believe the hype on name brand CAT backs, I paid $225 for a Pacesetter and got the same gains.........
On a 3" exhaust your losing power, not gaining power you need back pressure to regulate HP and torque. My exhaust is only 2.5".

 

its emissions stuff. juss take it all out if you want. im removing all my emissions stuff

 

I alread got the catback. I was looking at cams but they are expensive. Catback was already installed. I was just wondering what a full exhaust would add. What is a 64mm tb? I'm confused.Thanks for the help though

 

TB stands for Throttle Body, the stock TB is only 60MM, increasing the diameter increases HP and TOP end power.

 

intresting, how much do they run for?

 

I thought I seen somewhere that there was a 15whp gain with a 3" exhaust on a stock ka24de... I might be wrong though... I felt a gain when I put mine on... but you know a hell of a lot more about these engines than I do...

I got 3" because I plan on going turbo anyways, but i'm doing suspension stuff first..

 

header will give you 9-12hp usually on a NA 4 banger.

 

... I thought it was like 2whp?

 

Nope, especially if you still have the Catylitic converter. NO way will you see a 15WHP gain from any type of a CAT back, now if you take out the CAT, MAYBE.......
It's not just about the engine it's about transfring heat/exhaust down a pipe "thermaldynamics"...........

 

That is only a 5-7WHP gain depending on the flow of the header.

 

A 1986-93 FORD mustang TB in 65MM from Professional Products is 50state street legal and bolts right to the mani of the KA, and SR..........
Expect to pay around $175 to $265.......
Slight modification to the throttle linkage needs to be done....

 

I'm pretty sure with a 3" on a ka, i've read in alot of places, you still gain but it's mostly in the high range. I've also read that you do loose low end.

 

but i know u know alot so i'm not doubting you

 

Yo Vinnie, imma go KA24DE-T in about a yr or so. i got my KA24E in my 89 rite now. I got the head shaved/polished/etc. and imma get a 3" Apexi N1 cat-back, now will a testpipe (eliminates cat with 3" pipe for those who dont kno) be any good? Also, should i get a Pacesetter header for my KA24E or just wait till i have KA24DE-T and dont bother buying a header for the KA24E?

Thanx in advance