Exhaust DB level

[R Walter]

WOW.....got tagged by the noise monitor last weekend in the Challenge race at Thunderhill....108 DB. Naturally
the monitor was located coming on to the straight away. Boy did that kill my lap time lugging my way by it.
Anyone with suggestions on quieting it down without killing HP. I assume a new set of side pipes are in order
but question how quiet they would be in comparison.....know of any replacement mufflers that would be better
or inserts?
Oh...I sure do enjoy driving the Challenge car with the new upgrades...what a difference!

Robert
"Last man standing" WestCoast Challenge Series
(Hopefully a short lived title)

[johngeorge]

Robert, when we ran Limerock (back then 89db, now 87db) we had made a custom insert out of supertrapp that you put at the tip of the exhaust
http://www.supertrapp.com/product_sections/cat.asp?CatID=27

At first we tried this: did not work
http://www.johngeorgeracing.com/gallery/albums/limerock06/LimeRockParkRace_8_5_06_016.sized.jpg

I dont have any better pic but this is what we did on my car, cut the tip off, and made an adapter for the supertrapp:
http://www.johngeorgeracing.com/gallery/albums/limerock07/limerock07_042.jpg

[johngeorge]

picture above in full resolution click here: http://www.johngeorgeracing.com/gallery/limerock07/limerock07_042?full=1

[Hammink Performance]

We also have the 87db limit over here. We installed new mufflers.
11385
11386

As you can see where the band clamp is we cut the stock side exhaust, we also experimented with smaller tips but this did not change anything.
The new mufflers dropt 12db, but we are still at 99db with the coyote motor and 4.6L 4into4 exhaust.

[vnmsss]

Tom Coon got tagged with a sound violation at T-Hill during an enduro as well. He had a set of aftermarket (Breeze?) pipes on, but they seemed to be killing HP when he did the upgrades, so he went back to the stock pipes. Not sure if he's run at T-Hill since the change. I believe Dave Standridge ran Supertrapps on his Challenge car some years ago, and he may have some ideas as well.

We just went with the Raptor Racing pipes on our Coupe, and it's under 95 dB....

Karen

Karen

[R Walter]

Well continuing to research the DB problem for the best solution. In looking at our rules for for the Challenge series, I've got a question...
can we cut out our existing muffler and install a longer muffler in it's place? Same shape but different internal "baffling". Not finding any
desirable inserts...minimal noise reduction at the cost of lots of hp


Robert
West Coast challenge Car #3

[Steve Powell]

I got busted at "The Ridge" (new track in Shelton, WA) three weeks ago. Our conference is max of 103 db. I had to put a Vortex cone in one side (the side where the sound meter was). Also got real close at Portland 2 weeks ago. Went 102.4 db. These numbers are with new stock side pipes and J pipes. I need to come up with something better or I'm going to get booted one of these days. What is weird is, Tony Nadalin has the same set up and he was below 100 db at the same track the same day???????

[Ultimate Track Car]

Here's what I did for Thunderhill:

First, if you've got the money, get V Band clamps welded on your sidepipes and buy an extra set of auger mufflered ones. With the V Band clamps you can rotate the pipes under the car and pointed toward the ground. This makes the sound travel away from the monitor, bounce off the pavement, and back and forth under the car before it is expelled. Also, buy some commercial grade metal souring pads and stuff them inside right behind the collectors (If you have V Band clamps), and this will also significantly reduce the noise. I have a 647hp 12:1 race motor and I was able to get it down to 90db at Thunderhill. PS Make sure you do not sit still in the car and idle for any length of time with the pipes turned inward and down. It will make you sick pretty quickly, but as I said, very effective.

[FFRSpec72]

I got busted at "The Ridge" (new track in Shelton, WA) I had to put a Vortex cone in one side (the side where the sound meter was).

I had to use that same Vortex cone last weekend (limit was 95db and I was 95.2 db), I think I need to find a solution over the winter, it may be to cut the tip off, put a 4" Vortex cone in then use the V band clamp to put the tip back on and then I can also turn the tip in any direction I need.