Chambered Muffler Eliminators

[jimmers]

On the Mid American Motorworks site it says that these are not street legal? But from reading posts on here many people say that they are. I am considering these myself because i want a nice tone. I watched mad mics videos that he posted and i love the sound. I just have a stock l98 and was wondering how they would sound? I dont want it to loud but i really would like it louder then the quiet stock sound i have now. I want people to know that a corvette is coming!!!
Also by using these will there be any performance lose? It would increase horsepower because there would be no mufflers right?
Also, if i where to go to a muffler shop and get them to put a straight pipe would it sound the same?
Any info will help!!

[78SilvAnniv]

Originally Posted by jimmers

On the Mid American Motorworks site it says that these are not street legal? But from reading posts on here many people say that they are.

They are advertised as non street legal and I don't think anyone who has them claims they are legal, they just have them and enjoy them.
I love my chambered exhaust, it makes my 78 sound like a muscle car. You should see a small increase in hp/torque because it is able to breathe/flow better, but I don't think you'll find any dramatic hp increases, the sound increase is phenominal though! I had perma-grin for hours. They were installed in the winter and I drove around with the windows down, grinning, just to hear them.

Straight pipes vs. chambered... straight pipes the sound just rolls right out of there with little backpressure. I feel that chambered tumbles the sound into a throaty roar and provides a little more backpressure while still allowing increased flow.

I'd be interested in hearing if you decide to purchase and install. I'll BET you'll be grinning!
Heidi

[jwilliams]

jimmers,

First question I have is does the system accomodate the O2 sensors? I know my 89 has a sensor or two in the exhaust system. Car won't run right without them. Secondly, it appears that system eliminates the cat's. Car will not pass any emissions inspections in any state if the vehicle is subject to one. I have the muffler eliminators on my car. It is used strictly for autocross so my seat time is limited and the car spends most of its time @ full or near full throttle. With the muffler eliminators (I still have my cat's) the car does resonate at cruising speeds. A friend of mine has an 89 as well that is strictly autocrossed and he has a turn down on the end of the cat. The resonance in the cabin is horrible to the point he couldn't even stand it for a 60 second run on the course. He has gone to a full face helmet to help cut down the noise.

I think you find that very few people on CAC are running the type of setup you're looking at. You may want to give Corsa, etc a serious look. Chevy small blocks typically do want some exhaust backpressure to run correctly. The stock cat's provide that. I wouldn't run my set up of my car was a daily or weekend cruiser. For the price of the system you're looking at you have options that I think you'll be happier with. The sound of my car with the muffler eliminators and the cat's is okay, but full systems sound better. I run what I run for purposes of weight reduction. By the way the biggest restriction on our cars isn't the exhaust, it's the tpi set up which was actually designed by gm for the 305 motor.
Good luck,

Jay

[Vettefan87]

All he is talking about is removing the mufflers, and putting on straight pipes with chambers in them. This in no way will alter anything the O2 sensor would relay back to the ECM. My car only has one O2, and it just monitors what the engine's emissions are. I know for LT1 cars there is one after the cat, but I am not sure on his. Your car will still pass emissions unless you remove the cats, or it is running really rich for some reason. I am thinking about them too, but I don't know if they will provide me with enough backpressure, since I am running open exhaust.

[jwilliams]

Vettefan87, my bad, I thought he was looking at the full chambered system from mid america designs, did not the chambered eliminators they offer. When I put my eliminators on these were not offered. I am not a huge fan of the way the standard eliminators sound, as I said I only did it for weight savings reasons.

I will be curious to see how jimmers likes the sound of the chambered eliminators. Jimmers, I asked my local muffler shop if he could duplicate the eliminators for less than $120.00 which is what I paid for mine and he said no.

Jay

[Vettefan87]

It is okay, I wasn't sure if I read it wrong myself. Aren't the chambered ones 199 though? With open exhaust I know my car will be loud, but I love that sound, all I am worried about is backpressure

[jwilliams]

Vettefan87, I do know that small block chevy's need some backpressure, exactly how much I'm not sure. What I have been told is that typically running a full open exhaust will not give best performance for a small block chevy. I can tell you that just running the eliminators or a turn down off the cat creates a lot of resonance in the cabin that is not tolerable. This is especially true with the turn down off the cat. When I drive my car I am wearing a helmet. MY friend's 89 with a turn down off the cat (nothing else beyond the cat) is horrible to the point he bought a full face helmet to autocross with. For $200 it might be worth trying the chambered eliminators to see if you like it. The chambers will probably help with the resonance that is real noticable around 2200-2500rpm. My car is loud, but I'd say it lacks a real low rumble, especially at idle. At idle you almost can't tell it has no mufflers. You might want to read an article on this site by Hib Halverson. He did alot of work to build light powerful exhaust fora ZR1. It's an interesting read on the workings of an exhaust system. If I was driving on the street I'd probably look real hard at the corsa systems too.

Jay