need sidepipe options to get the decibel level down

[jeffnolan]

I was at Laguna Seca yesterday and ran afoul of the sound monitors. The limit for the track is 90 decibels (I think Sonoma is 92) and while I could pedal the car by the sound station between turn 5 and 6, they still called me out on other parts of the track. I really enjoy track time but if I have to drop to 4th gear and manage my way around the track, I might as well take my driving buddy's advice and "get yourself a GT4 that you can track and also drive to work."

I'm looking for sidepipe options that will help me manage the sound output. I don't mind giving up some horsepower in the tradeoff, I have plenty of power to spare in this car so trading some off to be able to hammer it on the straights and out of the corners is a fair trade.

[saltshaker]

Look at classic chamber mufflers
Jon

[spdbrake]

I'm looking at the Flowmaster Slimline 30". Mainly because its Stainless and will match my current setup, Quieter, Flows better, and I can get rid of the Heat shields.

A chap over at FFR site made a great DB comparisons video of 4 systems.
[ame]https://www.youtube.com/watch?v=ZZJ1oi9jJxc&feature=youtu.be[/ame]

[x96535]

I have the exact opposite problem. I want mine to be louder! Good luck with your search. It seems from the video above that the Flowmasters should be a good option for you.

[Steno]

I have done the slimline 30" change out on my FFR and it's great. Great sound and you'll never need to buy mufflers again!

[moore_rb]

X3 on the Flowmaster slimlines... They are the quietest, low restriction sidepipe mufflers you are going to find.

Expensive, yes, but if noise reduction is your primary goal (without killing HP), then you will not find a better sidepipe muffler.

and, as an added benefit, the insulating wrap is a thermal barrier fabric, so they don't get nearly as hot, either... great for the backs of your legs.

Here's a link to another discussion where one of the California guys switched to the Slimlines on his ClassicRoadsters:

Question about rattle in CR sidepipe


Now, if you want a much cheaper muffler option, that will reduce DB, but will also kill off 50-80 HP, then go to Jones exhaust, and order a set of their turbo-tube mufflers - these mufflers have a pair of opposite flowing internal baffles that shave off about 30Db in all RPM ranges, but the internal baffles are only 1.25 inch diameter, so they flow like absolute crap... Not recommended

[cycleguy55]

I'm currently running a Patriot auger insert in each 3.5" side pipe.



By all accounts the Flowmaster Slimlines are quiet and efficient. Those will be my next mufflers unless somebody comes up with something that's equally or more effective AND efficient - all at a lower price point.

[xlr8tr]

Hey cycleguy, how did you find the augers worked? I have a set for my 460 but havent gotten around to installing them. I'm currently running 3" straight thru pipes, perforated core, 4 1/2" body. Love the sound but its LOUD

Originally Posted by cycleguy55

I'm currently running a Patriot auger insert in each 3.5" side pipe.



By all accounts the Flowmaster Slimlines are quiet and efficient. Those will be my next mufflers unless somebody comes up with something that's equally or more effective AND efficient - all at a lower price point.

[cycleguy55]

Originally Posted by xlr8tr

Hey cycleguy, how did you find the augers worked? I have a set for my 460 but havent gotten around to installing them. I'm currently running 3" straight thru pipes, perforated core, 4 1/2" body. Love the sound but its LOUD

Augers work well, but the sound is a bit less mellow than some folks like - I guess you could describe it as a bit 'tinny'. I suppose that's what you get when you're relying on sound waves bouncing off flat steel plates for attenuation! It's worth noting there are certainly some views out there that augers cut HP at higher RPM.

I had to slightly bend the auger plates to get a snug fit in the side pipes to eliminate the rattles - snug enough that I then had to use a heavy hammer to drive them in. Before that I had a pair in each side pipe that were too loose when first installed. That caused them to rattle under certain conditions (e.g. throttle closed, engine braking) and that drove me crazy. I tightened them up and re-installed them but found them too quiet, so I pulled one auger out of each side pipe.

Between the hollow centre core and the gaps between the plates there doesn't appear to be a lot of dampening at idle, but I don't mind that. Sound levels are quite tolerable under steady state cruise, but not so quiet when you're on the throttle. IOW you can use your right foot to adjust the volume - perfect for Cobras.

[xlr8tr]

thanks, im gonna give them a try

[jeffnolan]

Thanks. I emailed Eric and Classic Chambered and he has been really helpful. The Flowmasters do appear to be the best option. I would also like to fabricate an adjustable turnout so that I can avoid blasting the sound station. The GT3 guys were running angled exhaust tips out the back of their cars to beat the sound police. Good idea.

[cycleguy55]

Originally Posted by jeffnolan

Thanks. I emailed Eric and Classic Chambered and he has been really helpful. The Flowmasters do appear to be the best option. I would also like to fabricate an adjustable turnout so that I can avoid blasting the sound station. The GT3 guys were running angled exhaust tips out the back of their cars to beat the sound police. Good idea.

If you haven't already done so, consider v-band flanges and clamps to allow rotation of the turnouts. Loosen clamp, rotate, then tighten. Simple.

[jeffnolan]

thanks, you saved me from making my own!

[BAsque1]

[url=http://www.fireflyperformance.com/] talk to Ron Roberts you cannot go wrong.

[Thor maine]

I was always thinking about doing electric cutout's just after the muffler in the sidepipe and then going to a couple of flowmasters and out back exit. Nice and quiet then at the flip of a switch ROCK AND ROLL BABY!

[Rare Iron]

In the movie, at 2000 RPM it's still 100 dBA's on the quietest setup. How you going to shave off 10 more on a track? These race track decibel limits are just plain stupidity. Next they'll be limiting airports & Air Force bases to certain decibel limits.

[Dwight]

I replaced my side pipes with the 3" Classic Cobras with the louvers turned the correct way to scoop the air.

Buy the longest pipe you can fit onto your car. Turn the tips up to keep from bouncing the exhaust off the pavement.

Before I changed they could hear me a 1 1/2 miles away. Got a picture of a cop that pulled me over when he hear me four block away in a neighborhood of three story houses. He did not write me a ticket because he only "heard" me.

After the change I had no problem easily talking to my passenger at highway speeds. Quiet but had a heathy rumble at idle.

Dwight

[jeffnolan]

I'll never get to 90 but if I can get down from the level it is at now I can 4th gear roll by the sound station and still enjoy the throttle in other parts of the track. The problem I have now is that the decibels are so beyond the limit that any throttle anywhere on the track is going to get attention. If I can get down to 100 I'll be in the range of the Porsche GT3 cars and not stand out.

Originally Posted by Rare Iron

In the movie, at 2000 RPM it's still 100 dBA's on the quietest setup. How you going to shave off 10 more on a track? These race track decibel limits are just plain stupidity. Next they'll be limiting airports & Air Force bases to certain decibel limits.

[KDubU]

Slimlines are the way to go.

[MKS427]

Google "Breeze Automotive Quietpipes". Contact them, I do not know how quiet they are.