I participated in a HPDE this past weekend and I ended up being the only car at the track asked to take a noise test... which astounded me. Regardless, I suppose it was for good reason as I ended up being 1.5 dbs over the 99 db limit as this particular track.

My car currently has a catalytic converter and Burns stainless muffler, with 2.5" piping. But the piping hangs low enough that I am not sure I can fit an additional resonator to reduce engine noise.

Ive been contemplating ways to drop the noise a small bit. Has anyone here used a tailpipe silencer to meet noise requirements? Effectiveness? Any downsides besides the obvious?

 

i have a supertrapp disc only muffler... works for noise... but kills alot of power

thats surprising ur car hits over 100db with a cat and burns muffler

how far is the meter....

 

You could always do a down turn type muffler. I know some guys in ST* class do that at certain events.

On my A'PEXi N1 exhaust on my 00 Civic Si I used to run the silencer that came with my exhaust. I think Sport Compact Car also did some testing and found it only dropped hp by about 5hp.

 

It was measured 30ft behind the car. I was surprised too.

 

Thanks, I was hoping for some info like this. I found a silence by DC that is supposed to work with mufflers with a 2.5" tip:




I have no problem taking a 5hp hit. Did SCC comment on the effectiveness in decibel reduction? Another concern I have is the silencer messing with the air/fuel ratio...

 

wow 30 ft .... thats super strict

i would try vclamp with turn down and just turn it away from the meter that should be good for couple DBs...

 

30 ft is a bit close. On most RR courses the distance is 50 ft from the track at any given point on the track..
Look at one of these CC inserts / baffles.

http://www.carchemistry.com/shop/ind...oduct_list&c=3

They are usually run in a cat delete section inside the delete section.
I have the Redshift MS LCA exhaust that dumps before the LCA and downturns in toward the center of the car.
With out the insert the car is quiet enough. But with courses like Laguna Seca where the levels can be as low as 93-92 db the insert makes it even more quiet...
I dont feel any loss of power either. Of course I cant vouch for anyone elses exhaust set up but it works for what i have.
Its an option and those are nice to have.
Nobody likes the noise police.

 

Interesting. One of those 3 disk units looks like it might quiet the system more than the DC silencer above... and may not be as restrictive.

However, currently the only place in my exhaust system that isn't welded is the header/cat connection. And since I am running a cat, this silence would not fit in the upstream portion of my exhaust. I suppose I could place it in the tailpipe like a regular silencer.

Do you see any fluctuation in air/fuel ratios when using this insert?

 

nope no fluctuations... Chris and James at Redshift did their homework on these units.
The two disk is what i have ....

 

thats dumb why do tracks have noise limits??????

 

Fantastic. I will pick one up for use at an event on the 23rd of May. I'll be installing it in the tailpipe rather than the testpipe, as the car has a cat... but I'll report back as to the effectiveness.

 

Proximity to houses/metro areas. They would not have gotten permission from the city to build the track had they not put restrictions on the noise level.

 

I can't comment on the silencer, but just wanted to share a personal experience. I was the only car to get black flagged noise in my class during quiet hours at a NASA event at Road Atlanta in March. I was running 3" piping and two Burns mufflers with a turn down that dumped just before the passenger side rear wheel.

 

updates what did you end up doing?

 

ive got an r crew exhaust and i need to get a silencer i keep getting tickets do any silencers fit ??? any suggestions