exhaust and autocross

[Topless]

Hi all (long time, no post....)

I have a Q for you. What is the stock exhaust diameter for LT1 (1992)? I bought it with a KBD 3" system on it. I thinking of redoing it, but at the same time, I want start autocross this year. I have heard that my 3" system will bump me to another class.

What's the deal? Advice/suggestions please.

Oh, the reason why I am going to rework it is due to drone. By my self I can put up with it, but it is difficult to carry a conversation with passengers. I have tried having a balance tube installed where the pipes "Y" at the back, but didn't help. I would like to kill drone and get performance. I know it is hard to do both, but I have found a good exhaust shop around here, so I am up for some custom work.

thanks

 

[92ghost]

Hi Topless. I have a 92 Coupe that I have had for 2 years now and as far as I know it is completely stock. I measured the outside diameter of the pipe going into the muffler and it measured 2 3/4 inches. Like I said, as far as I know it is completeley stock. IMO, the stock diam. exhaust is plenty big enough for just about anything accept highly modified engines.

 

[Topless]

Thanks. the 3" is nice, but I need to get rid of the drone at 2000. If I have to, i might go back to 2 3/4.

I just don't want to be pushed up in class at autocross for exhaust. That whole learning curve thing. I don't want to be in with people that are going to severely out drive me on the first day.

 

[WhalePirot]

Take a look at where your tips are relative to the rear bumper. Perhaps some short extensions will extend them, and the noise, enough to be a simple and inexpensive fix.

Some are happy with the DynoMax mufflers; I am pleased with the Flowmasters.


Mike

 

[chaos on wheels]

As to the racing legality, talk to the people in charge of your local auto-x or get a rulebook. The rulebook will detail what you can and can't do to your car in each car class. Part of the SCCA's rulebook is online. The paragraph on exhaust is paragraph "E": http://www.moutons.org/sccasolo/Rules/stock.html#s1310 .

I have Borlas and the x-over y-pipe and the tech people always classify me in the stock class.

Auto-x is a ton of fun!!

 

[Topless]

Mike....My tips extend out past the bumper a bit. Should be enough to keep it behind the car. In fact, it sounds a lot different from the back than it does from the sides.

I will check out the web site for the info on exhaust for Solo. BTW..what size pipes are you running on your "X" and Borlas? How loud is it inside? That is one of the setups I am considering.

 

[RubyDropTop]

Last month I took my stock system off the car and replaced with the one in my sig. Stock system is 2 3/4".

 

[chaos on wheels]

I'm using the crossover y-pipe that's in all the catalogs, I think it's made by Walker. I didn't measure the pipe size, but it's probably the same as stock. It really did cut down the resonance from the Borlas. However it's only listed to work on L98's (up to 1991). So that might not help on an LT1.

-Jason.

 

[Topless]

Yeah, i tried having a balance piece welded where the pipes split, but it did not help on mine.. Oh well

I might go back to 2 3/4....don't know......