BLKROKT

I'm getting ready for track season coming up, and am at a loss on what to do about these retarded db limits.

Right now, my exhaust is stock. The db limits at most of the tracks out here is in the 89-91db range - some tested on track. Limerock and Watkins Glenn are coming up, and I'd rather not be black flagged. Our cars stock are louder than that - I just don't get how these limits are at all reasonable, but what can you do. AND I just picked up MBH headers/mids (stock exhaust the rest of the way), so I know I'm going to be way way over.

What do you guys do to get by these limits? Turn-down tips to point away from the noise-detection side? Do the valvetronic exhausts work, and can they reduce the noise sufficiently? Old school steel wool stuffed in the tips? Lift off on the track where they measure?

Can I weld in another resonator, or is that just pointless.

I'm reaching for ideas here. Any?

Thanks

jrcart

A valvetronic type muffler bypass will be your best option.

BLKROKT

Thanks for the reply man. If the stock mufflers don't do the job, will the valvetronic be any quieter? I'm not sufficiently knowledgeable to know if the valvetronic mufflers, when the valve is closed, are quieter than the stock cans. Or can be made to be. Thanks.

C63TSgt

The valvetronic when closed is basically stock sounding with just a slightly deeper tone. Open is a different story, but at the moment I still have stock manifolds and secondary cats. About to remove the secondaries and hoping I gain some db with that. I keep considering cutouts where the secondaries are now and just go all out halfway down the track. I know Infineon dragway measures at the starting line so halfway I could flip them open and maybe even gain some horses on the top end. Have yet to hear a 63 with open headers basically. I bet it's just raw and awesome.

MaroonC63

I have a fully catless LTheader/valvetronic system. Valves closed is definitely way quiet than stock even with headers.

C63TSgt

This is good to know, I wonder what hellfire and brimstone would sound like with cutouts right after the headers.

snowmuch

Get a M4...

BLKROKT

This is what I was looking for. Thank you.
So you're saying, with the valvetronic exhaust AND LTH mids etc, the car is now quieter than stock with the valves closed? That's the ticket.

I am Jeff

When are you planning on doing the install of your LT's? If you have some time, we can meet up and compare the noise level of the different setups. I have 200 cell cats and a xpipe in my setup.

BLKROKT

Definitely man. They're not off the car yet, then being shipped. Couple of weeks, will let you know.

QWKSNKE

Noise limits at a track??? That is the craziest thing I have ever heard! Where are you located?

C63TSgt

I'm in the bay area, our limit at Infineon is 114db

Diabolis

Every single track that I've driven at in Canada and the US has them, although the rules vary based on their proximity to urban areas and times / days (no open / loud exhausts after 5 PM or before noon on Sundays for example).

Diabolis

A properly designed X-pipe will quiet it down somewhat and increase scavenging (i.e. give you even better flow) - but the key here is "properly designed".

P.S. 91 db does seen excessively low for daytime unless you're runnign on Sunday. That is the evening limit (5 PM - 9 PM) at most tracks around here, but on weekdays during the day it is usually in the neighbourhood of 101 - 103 db.