Clemson Sports Car Club

So basically I am not happy with the design/price of basically all Miata exhausts. So I am going to be making my own. I am planning on the design being like the ISC racing one.


Simple and functional. I am going to be trying to use minimal bends and 2.5" tubing since I am going to later on do a supercharger. Right now the plan is to use Burns stainless tubing and u-bends. For the muffler I am thinking the magnaflow XL 3 muffler. Mainly because I like the sound from them plus it is of good construction. Good price too. Once my car is for track only ill put on a burns stainless one, but they are pretty expensive. I was just wondering what other thoughts you guys have on the subject.

I would leave the exhaust off the car until you are ready to do the blower as its really only going to increase noise and decrease performance at that diameter on a relatively stock car.

The ISC exhaust is about as simple as it gets, I think you have a good model for your own creation.

Scorke

supercharger is gonna take a while to save up the money, plus I have to do the clutch and flywheel first. Plus the car is really quiet, It needs some sound for how quick it is. I figure the muffler would give it decent back pressure instead of being straight through. I am probably going to build a header before the supercharger as well.

don't worry about a muffler... the turbo will smooth the pulses out enough...

I am not going to max power so I would rather have the response of the super. So basically I wanna use the muffler as my restriction in the system for the time being since ill be NA, then when I get the super I'll put a straight through in it's place.

Also I am thinking on 18gage but think I coul dget away with 20gage. light weight is another thing I am going for. Oh and I am not planning on having a resonator either, think that is a problem? No cat is a given.

run aluminum piping.

burns' stuff is way overpriced.

their muffler is a joke as far as muffling ability.
i'd only use when your rules require a physical muffler.

PM me, i can give you 4-5 links to places that sell piping, bends, etc for making your own exhaust and header.

i wouldn't worry at all about backpressure, it's mostly a myth with a properly designed header.

I wouldn't run aluminum. Ti would be sweet but $$. I know burns' stuff is costly which is why I was surprised how cheap I could make an exhaust even using their prices. I mainly like the burns muffler because of how light they are. I am a sucker for quality as well.

Good spec miata's use a 2.5" so I am not worried about that.

PM sent.

the springfield dyno exhaust is what every spec miata uses now. SSM uses the mazdacomp, which is considerably quieter. If you haven't heard what a miata exhaust sounds like that is that unrestricted i highly suggest you find one. they are VERY loud.

I know it is loud, which is why I am putting a muffler on it. I was just using it as an example that a 2.5" would be fine for my NA motor.

It's really annoyingly loud man I would really recommend you don't do this, with no cat and no resonator they sound horrible.

Scorke

This may not be your final solution, but it will get you by for the time being:
I made mine many years ago, and it is still doing fine. My muffler cost I think $79 at Advance Auto. It is a dual-parallel-tube, straight thru SS glasspak. See details here.
http://www.cardomain.com/ride/137977

JD

JD, I never knew there was a time before you had the supercharger. I can think of your miata without one.

My basis for my thinking is that our Racecar has a straight through exhaust with no cat and no resonator. Just a magnaflow muffler and it sounds pretty good and this is on the Street ported 12A. Would a resonator under the car really make a difference?

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Maybe a cat back. Keeping the cat would keep it quiet.

The cat does help the noise a lot.

I found that resonators don't change the loudness of the exhaust but change the sound dramatically.

Scorke

The resonator is really an anti-resonator. You can get a bad drone at certain rpms without one.
JD

At least with my mustang, 90% of the muffling was done by the catalytic convertors. When I put an offroad x-pipe on (basically a cat delete with a crossover) it was unbearably loud for daily driving.
This is in the car, with mufflers and windows halfway up. Was much louder in person, as you can imagine.
http://www.youtube.com/watch?v=XxS_3myCOhs