280zx exhaust

[Guest BillV]

I am getting ready for new exhausst on my 83zx, and wondered how some of you ran the pipes.

Is there room for duals, or would I be better off with a single 3" system? The car is getting a 383 next year, and I am going to run the exhaust to the six for now. Is there room for mufflers in the tunnel, or is it best to hang them in the rear? Any help would be appreciated.

[Brad-ManQ45]

I would use one 3" pipe - just like I did on my '83ZXT.

 

I used a Dynomax Muffler - straight through 3" oval cannister ~19" long.

 

This keep the car quiet - but that's w/a turbo ahead (and 3" cat).

 

You will probably need the biggest muffler you can get for the 383.

 

One downside, especially if you are NOT going to have a cat is resonance - big pipes can cause problems here.

 

For a normally aspirated 2.4-3.1 litre engine not much need to go over 2.5" unless turbo'd.

 

A lot of people are happier w/2.25" for na cars - better low end and quieter/weighs less.

 

Stock 280 ZXT's had ~2 3/8's"...

[Guest greimann]

There is room for 2 cats in the tunnel and a single 3" muffler at the rear. If you re going to plumb a system for the 6 first and later convert to V8, you might want to put a flange just before the hoop over the rear half shaft, so you can later plumb a twin system with the V8. Check out a picture in the mechanical details of my site below.

[Guest BillV]

Thanks for the reply. Why didn't you run dual pipes all the way, not enough room? I'm not going to use cats, so is there room in the tunnel for mufflers? I noticed you used manifolds, won't any headers work? I was planning on putting a flange on for easy removal when I have to get to the driveshaft.

[Guest greimann]

There is really no room for two mufflers at the back, unless you want to cut out the spare tire well and put one on the right side. Even though, snaking the pipe past the fuel tank and hoses would be a real challenge. There is really no room for mufflers in the tunnel.

 

I went with manifolds for two reasons: Easy smog certification in California and I have the steering box type of steering and there is simply no room for stock headers on the left side next to the box.

[Guest BillV]

I have the rack and pinion, will block huggers work with that? I thought there might be room in the rear for 2 small turbos on end beside each other, but they might hang down kinda low. I thought there might be room for 2 2" or 2 1/4" pipes where the stock one goes. Does anyone know the flow difference between a single 3" and 2 2 1/4" pipes? I know only one muffler hurts the flow alot.

[Guest greimann]

I think any kind of headers need to be tweaked to fit around the steering shaft. Not sure what kind of tweaking, but it is possible.

 

As far as duals all the way, you have to now decide on what you really want out of the car. My goal was to make the car a Corvette like sports GT that was civil daily driver and have good astethics and throaty, but not obnoxious exhaust note. In its present form I run 13.3 @108 mph on street radials. If that kind of car is what you want then stay with the single 3".

 

If you are racing mostly and don't care too much about having a loud car, then do what ever it takes to get two pipes and small mufflers out the back regardless of what it looks like. But it will be LOUD.

[Guest BillV]

I don't want it too loud, I have 2 Flowtech afterburners on my S15 383, and it isn't too bad, but it sounds a little raspy like glasspacks on acceleration. Does anyone know a sight that has flow numbers on different brands of mufflers? I had thought about a 3" in, dual 2.5 out like Chevy trucks use, or a dusl 2.25 in/out, but don't know if that restricts the flow or not.

[Lockjaw]

Dynomax makes a muff that has 2 2.25 inlets and outlets, and it is a pretty slim muffler.

 

I have a 280ZXT and I have a 3 inch system with no catastrophic converter and I have a Hooker Max Flow 3 in straight thru muffler. It is nice and quiet until I get into the boost, and then it has a nice sound. I have the 5 speed and run high 12's.

 

I have also read that one 3 in pipe flows more than two 2.5 in pipes, but the math does not bear that out.