One afternoon at the track = melted muffler packing...

750hp · #1 (**permalink**) 07-03-2003, 07:10 AM

For the racers that are required to run their cars to a decibel limit - what type of muffler packing do you use that can stand up to a weekend of racing? My nice, deep sounding pipes almost sound like open headers since I took the car to the track and burnt up the muffler packing. The pipes run hot enough to turn gold and blue out on the track, but the worst part is when I get to the hairpin corner after the 165mph back straight. On deceleration, there are flames about 1 foot long that flow from the pipes. Looks good, but kills mufflers...

The only muffler material that I can think would work is stainless steel wool, but is this an effective material for keeping the car under track noise limits?

I plan on also using spiral inserts on the street, but removing them for the track.

Thanks for any help,

Craig

casaleenie · #2 (**permalink**) 07-03-2003, 07:51 AM

casaleenie · #3 (**permalink**) 07-03-2003, 07:53 AM

What, if anything, can be inserted into a sidepipe to reduce the amount of noise???? Short of cutting and installing baffling is there a product that can be slid up the exhaust as a quick fix???

John Hannaford · #4 (**permalink**) 07-03-2003, 09:26 AM

Some guys like these. I think Summit carries them too.

http://www.speeddirect.com/Products/...c_inserts.html

Roger Upton · #5 (**permalink**) 07-07-2003, 11:23 AM

You can use a metal baffling system. You would have to cut the turn out or the collector off the side pipe to install them. Or worst idea purchase a new set of side pipes made this way.

By any chance is fuel running out of the back fuel bowl vent tube under hard braking causing the flames. And a lean condition the rest of the time causing the excessive heat. Chrome side pipes will turn colors ceramic does not have that problem.

Roger

750hp · #6 (**permalink**) 07-08-2003, 05:38 AM

Roger - I think I'll end up fitting a metal spiral system, as well as repacking the perf tube mufflers. I'll use stainless packing, rather than the "heat sensitive" glass packing this time....

The stainless pipes look as though they have simply got hot from prolonged high rpm, high load conditions. On the street, they don't get anywhere near as hot as the day at the track.

I have an aftermarket engine management system. The guy that tuned my motor is one of the country's top engine builders / tuners. His main work comes from our premier motorsport category, and the theory there is to run the cars as lean as possible for maximum horsepower, then feed a little extra fuel during deceleration to cool the cylinder walls. I think he's done the same thing with mine on decel, but fattened up the mixtures to cope with the supercharger.

Here's a small photo of Max Wilson (the ex-CART guy) in one of the Aussie V8 Supercars.

BevanWright · #7 (**permalink**) 12-08-2003, 01:43 PM

750HP I have a variety of mufflers in my sidepipe. From the collecter back there is a louver tube inside the sidepipe wrapped in a green sound deadening material. (it was from the factory who make a lot of mufflers for HSV Commodores in NZ) It is better at sound deadening than the standard packing, and resists heat better. I believe the stainless will survive but does not reduce noise as much. At the end of that section my car has a supertrap muffler, which allows you to 'tune' the noise by removing baffles, you reduce the level of noise. I dont know how bad these are on power, but, I had to do this as I was over 100db and we are only allowed to be 95 (measured from right angles from the side of the race track under full acceleration.

The best noise I have had was when at Ohakea airbase their was no noise restriction and I ran the car with open side pipes, man it was loud - but sounded awesome at full revs. (like a McLaren race car)

(I cant work out how to add a picture here - but if you look at my picture in the aerodynamic aids thread you will see my sidepipes.)