Exhaust question

[ginsu417]

I have a 1G. It's the 1.8L turbo in the gallery (yes, very uncommon...) this isn't a motor-specific question anyway. I'm still running the stock exhaust even after the turbo install, and frankly, I think it's time to open the hole up. I don't want anything too much louder than the stock setup, and I personally would like to maintain the stock look and sound but I do want the performance gains of a larger system. Would a 3" cat-back split to two 2" dual-out with small 2-tip mufflers give me what I'm looking for? And what type of mufflers? I really want this sytem to be as quiet and stock-looking as possible... Helps confuse the vtec-heads before they get thier ass handed to them

- Kalani

 

[doug]

My opinion is that, if you don't want loud, go with a 2.5" all the way back-- it's good for at least 12s, from what I've read. I have a 2.5" with no cat and it's not loud at all. And I have a straight-through muffler with just a 3" tip-- doesn't draw any attention to itself. I've heard a 3" version of the same company's (RnR Racing) exhaust and it was definitely louder. The only difference besides it being 3" was that it was on a 1G AWD.

 

[kylemoto]

Hello Ginsu.


So, I'm not the only one out there in DSM land that wants a quiet exhaust. So, some tips and observations on exhausts:

-jdoug is right; a 3" pipe will be louder than 2 1/2 all else being equal. This, of course, does not mean that 3" diameter pipe is automatically too loud!

- mufflers: for good flow (i.e. HP) you want thru flow designs, not reverse flow. Anytime you can visualize gassses being forced to change direction, thats not good.

- more on mufflers: high flow ones will have either louvered pipe or perforated pipe. Louvered: like louvers on fenders, they stick up in the airflow, absorbing noise. Bad part they tend to take more power. Perforated pipe - think pipe with holes in it. This design makes pretty good power since there is little restriction, but can be noisy too.

- tips: I'm glad you don't want the cop attracting mega tip.

- cat: lots of so called high flow stuff out there, Random Technologies seem to have clean and high performing. Believe it or not cats also deaden noise.

- pipe. The law here is mandral bent, always! Never go press bent.

So, my engineering for a high performing, quiet system: 2 1/2 inch pipe from the turbo outlet back. Use a high flow cat, located as near to the downpipe as possible. For a muffler, a 3 " ID louvered type will be pretty quiet compared to anything else. For the tip section, the resonator from the TEL turbo models will get you a nice stealthy twin tip.

So go softly now and stomp those V-Tech 'ers!

Kyle

 

[ginsu417]

What I wanted was something REALLY quiet. Stock-sounding. Even a 2.5 is significantly louder than stock on any motor. But from what I understand, what deadens most of the noise is not your pipe size, it's your muffler and muffler outlet size. So here's what I was thinking. 3" from the cat back to a Y pipe. From the Y-pipe I'll run 2-2.25" pipes back to some stock 300Z TT mufflers. Those are made to flow enough for a TT 300Z, so they should support my setup. The reason I want to go dual-muffler is because having TWO mufflers in parallel should flow as well as a single muffler, but the gasses will be moving slower, and spend more time in the muffler where the noise can be absorbed. Does that make sense? Am I crazy? I want my car to be a silent killer. That car that just glides away without making a sound... leaving your mustang at the light... hahaha

 

[InferiorWang]

I've been wondering about that exact same thing recently. I dunno if anyone here has done it. You could try it and tell us. I am very glad to see others that want there car to sound VERY quiet. Great for being a sleeper with all them hondas and there loud weed eater exhausts.

 

[BryanK]

I, too am very interested. Let us know how it turns out. It looks like you'll have to do a lot of custom work with this, but try to keep in mind that mandrel bent is always better.

 

[ginsu417]

Yes. I will let you know how it turns out. I need to get some cash first. And of course, mandrel all the way

 

[fr33b1rth]

What i would do is get/make a 2.5" downpipe, and with your skills that shoudn't be too much to ask. High flow cat from the place that is bending/installing the pipe so you still get the warranty. Have them run 2.5" to the cat, then back to right before the "axle". From there have them make a custom y-pipe (more like a "t") that splits one towards the drivers side, and one toward the passenger side. You are going to need another kind of silencing device on your exhaust in addition to the mufflers. They will offer you either glasspacks or resonators. Resonators quiet high-pitched noises (ringing, buzzing and such) while glasspacks quiet through the entire RPM range. i've had my straight through muffler on my 1.8 without a glasspack, and it was painfull. With the glasspack it's a quiet as when i had the silencer in, without it. Have them put a glasspack on both sides of the "t" right after it. Get the glasspacks from them also as they are cheap. Get one no shorter than 6" and make sure that you can see straight through it. Don't have them route the pipe over the axle like the stock exhaust. There is a hole on both sides of the car in the frame. i know for a fact on the passenger side, but i think i remember seeing it on the drivers also. My exhaust is routed through there, as it ends up to be a shorter and more direct route. From there the muffler is your choice, but i would like this on in this conf on your car:
http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=756

Hope i helped you, and the car should be near silent with all this. If it isn't, you can always add another glasspack right behind the cat.