track noise restrictions, how to quiet challenge car down?

[Hammink Performance]

Hi Guys,

We have some tracks in my country with crazy noise restrictions, one with 90dba, and one with 85dba.

Our Coyote powered Challenge car does 105dba with already modified side pipes (no cats) and open air filter (cai, kind of).

Who knows what to quiet the car down?

[Jeff Kleiner]

I've been nailed before also. Don't know how the measurements are being taken at your tracks but here they measure sound with the dB meter placed 50 feet from the track at 3 or 4 feet high. With our sidepipes pointing out rather than back or down as on many cars we are sending sound straight into the meter and often go over. Although I haven't tried it I have heard that some have had success by turning the outlets to point straight down. Doesn't really alter the noise level per se but disperses the sound waves before they get to the meter.

Jeff

[johngeorge]

weld on the 5" supertrapp disk to the end of the exhaust, and double up on the disks, instead of 12 discs, run 24 disks. Mark Dougherty did this mod on my car, will post pics after this weekend.

http://www.supertrapp.com/product_sections/cat.asp?CatID=27

[CHOTIS BILL]

Meeting sound requirements is kind of a strange task. A Mazda rotary will drive by with such a vial blasting that all of your senses are numbed and it makes you sick to your stomach but will pass sound with ease. Yet when I would go by the sound meter with my GSX-R1000 at 12500 sounding like angles singing I would be black flagged. Very strange indeed. Turning the exhaust down has worked for some people and also putting a flat plate a few inches from the outlet has also been used. Some have tried wrapping all the exhaust pipes on the meter side but I don’t know if that helped or not. Another source of sound the intake. I have heard that a set of open Webers will produce 75 dba by them selves. Where the meter is placed can also make a difference. At Laguna Seca thy put the meter in a box surrounded by concrete walls on an uphill stretch which make everything in your favor against you.

Good luck,

Bill Lomenick

[FFRSpec72]

I have 1 track that has a 95 db limit, most of the others are either 100 or 103 db. The issue I have is that it cloudy here quite a bit and thus we get sound that does not get a chance to dissipate. So I have been using a flexible exhaust insert (this is so I can get the insert around the curve in the end of the exhaust), I use it when I need it and remove it when I don't. It's a 12" exhaust augur (summit racing) that has been cut into 3 parts (and tapered to fit into muffler part of the exhaust) and then reattached with springs, and it slides in the end of the side pipe and bolts into the side pipe. So I'm running the challenge car upgrades and stock exhaust, when running inserts I can be below 93 db and I loose about 10-15 hp.

20877

[Hammink Performance]

Hi Guys,

Thanks for all the imputs, really appreciate that!

We have tried different mufflers on the side pipes allready, turning the tips down, or in before the rear wheel all don't help. Turning them down only seemed to make it worse, because the sound bounced of the tarmac straight in to the pole with the microphone.

The supertrap and augur look interesting, I think I will research those some more.
Looking forward to see the installed pics.

Thanks again!

[FFRSpec72]

There is thread about the augur here http://www.ffcars.com/forums/17-factory-five-roadsters/290847-flexible-exhaust-insert.html#post3287354

[Hammink Performance]

So from all the forum posts the Augur's seem to drop at least 10db, anybody know what the Supertrapp do? I contact that manufacturer and he said the supertrapp usually only do a db or 2.

[68GT500MAN]

Karen had a company called Raptor Racing here in Fresno make her some mufflers for the coups she runs. PM me for the phone number if you want to give them a call or check out there website.
Doug

[fisherste]

We have a 50 foot 90 DB limit for auto X in San Diego. I run supertraps with 8 plates...mount the supertraps (weld or rivet) to a bent 8-10" long tube (just less ID then the side pipes) and insert that into your side pipes. Use a long bolt horizontaly to secure at the end of your side pipes. Yes you will have a hole in the shinny chrome. For auot x the down side is width...the car is about 5 inces wider, but i do get the db around 88 to 89 and a little more low end torque.

[Hammink Performance]

68GT500MAN, thanks will check out their site.

fisherste, sounds good, what engine are you running?

[Mark Dougherty]

sorry
I do not have any numbers on the supertrapps. The thing I like about them is they are tuneable for sound. if the sound is to high just remove a couple discs.
And yes I know loose power also.

[Hammink Performance]

But is there a noticeable drop in sound lever? Because I doubt you would notice one or 2 db

[Mark Dougherty]

yes a very noticeable drop in sound

[Hammink Performance]

I think I lean more to the supertrap, because I would asume it takes more sound away. Maybe even go crazy and combine the supertrapp with the augur

[John55]

I think I lean more to the supertrap, because I would asume it takes more sound away. Maybe even go crazy and combine the supertrapp with the augur

Freek,

I also think this is the good way to go, have some experience with these mufflers on dirtbikes, remarkable diffence.
And last but not leats, you should be able to find Supertrapps at almost every motorcycle dealer, you'll have to modify anyway.

CU soon,

John

[STLMARSHALL]

When I installed my new engine I did under hood magnaflows 2.5" ID and no sidepipes. Last fall at a national autocross event I was measured at 92 DB when a roadster at the same event came in at 103 DB.

http://i464.photobucket.com/albums/rr2/mmarshall01/LS1%20conversion/DSC_2887.jpg (http://s464.photobucket.com/user/mmarshall01/media/LS1%20conversion/DSC_2887.jpg.html)

[Hammink Performance]

Looks good, but in the roadster that's where we have our catalytic converters.
Would be cool if they sold these mufflers in the length of the side-pipes

[STLMARSHALL]

You could weld 2 of these together. They are small but still a real muffler, not a glass pack.

http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=11403

[John Crawford]

Do you know what kind of money this cost and did she lose much hp

[STLMARSHALL]

Do you know what kind of money this cost and did she lose much hp

I assume you are asking about Karen's Raptor pipes?

Start here:
http://www.ffcars.com/forums/21-ffr-type-65-coupe/277093-update-karens-raptor-side-pipes.html

http://www.ffcars.com/forums/21-ffr-type-65-coupe/239980-2010-coupe-25-hours-12.html

[Hammink Performance]

This is what we ended up doing, I'll post results as soon as we have tested them!

217612175921760

[Martin]

Any update on this?

Martin



This is what we ended up doing, I'll post results as soon as we have tested them!

217612175921760

[Hammink Performance]

So far so good on both Dutch tracks, still a bit to loud, but they don't wave the black flag at us no more ;-)

[FFRSpec72]

So far so good on both Dutch tracks, still a bit to loud, but they don't wave the black flag at us no more ;-)

Its so nice to not have to worry about going past the sound meter and being able to concentrate on driving

[lsxsean]

Try a super trap

[skullandbones]

So far so good on both Dutch tracks, still a bit to loud, but they don't wave the black flag at us no more ;-)

If you're not "black flagged" what's the problem? Can the track still sanction you without black flagging you? Or do they just say don't come back until it's so many dbl quieter?

Thanks, WEK.

[Hammink Performance]

They don't black flag us because we are close enough, and we are "customers" so to speak. The problem for the track is that they have to obey the law of the city. If the citizens complain, and the noise data gets checked, the track could be fined. If that happens than yeah worst case scenario could be that we could not drive the car anymore until it's quiet enough.