Cal Club Autocross Forums

My bone stock, street legal exhaust might exceed the 100db limit at 50ft some times. It did it once last year at the Divisionals.

Given that the sound metering policies are fairly new, how do they work at a ProSolo?

When I'm staging at the line, I have to do 4 runs before I get back to the Grid, 2 left and 2 right runs in the morning, then 4 more in the afternoon, then 4 the day after. I don't know when do I get notified of a sound limit warning, and when can I get it fixed.

Thanks

Dude, just buy a quiter car.

Unless they've changed things from last year, consider each set of 4 runs to be like a single run at a Tour. You're not going to be notified of a sound violation until you're done with your four runs and are back in grid or impound.

Jason Uyeda wrote:Dude, just buy a quiter car.

Is that what they call the Lotus these days?

Rad_ Delgado_ wrote:My bone stock, street legal exhaust might exceed the 100db limit at 50ft some times. It did it once last year at the Divisionals.

Given that the sound metering policies are fairly new, how do they work at a ProSolo?

When I'm staging at the line, I have to do 4 runs before I get back to the Grid, 2 left and 2 right runs in the morning, then 4 more in the afternoon, then 4 the day after. I don't know when do I get notified of a sound limit warning, and when can I get it fixed.

Thanks

Does this mean that you are going to come out and play with us?

Unfortunately El Toro happens the same weekend of a major family event. However, I want to take the Fiat to Nationals, it has suddenly started to work a little better, thanks to Isley and Marshall, on top of my tedious testing sessions.

So, if the car breaks the 100 db barrier in any of my Saturday morning runs at a ProSolo, I can stuff the intake with foam and cotton for the afternoon runs and do my 4 runs as long as the modification is approved by the Chief Steward. In case it breaks the 100 db barrier once again (it shouldn't) I can still get an exhaust expert on-site and weld something to be able to pass sound on day 2.

Unfortunately, some car manufacturers are not reasonable with car modifications, Fiat is one of them.

In addition to stuffing the intake with Teddy Bear inner content, and making turn down pipes (or turn away pipes that don't change directions magically on day 2), what other measures are considered reasonable or accepted by popular demand to reduce sound? is upshifting to 3rd before the meter a valid measure? what about coasting by the meter station? Is there a slip-on muffler I could add without major weight sacrifices or the risk of damaging the stock exhaust or even worse the engine?

I don't have many options for aftermarket mufflers, they are all louder than stock, and they cost more than some National competitive autoX cars.

Thanks a lot

Rad_ Delgado_ wrote:So, if the car breaks the 100 db barrier in any of my Saturday morning runs at a ProSolo, I can stuff the intake with foam and cotton for the afternoon runs and do my 4 runs as long as the modification is approved by the Chief Steward. In case it breaks the 100 db barrier once again (it shouldn't) I can still get an exhaust expert on-site and weld something to be able to pass sound on day 2.

sound regs wrote:Redirecting the exhaust away from the sound meter between days is not a valid repair action and may be referred to the Chief Steward for action under 1.3.2.L.

I would think that welding something on the exhaust (assuming you mean a turn-down or away) on Saturday night would be a redirection of the exhaust and not a valid repair action. You need to start on Saturday with what you plan on running for the weekend.

would a hi-temp silicone elbow work?

or is the exhaust too hot?

Rad_ Delgado_ wrote:
I don't have many options for aftermarket mufflers, they are all louder than stock, and they cost more than some National competitive autoX cars.

Thanks a lot

Hmmm Hang 4 coastfab mufflers off the tailpipes?

http://www.coastfab.com/mufflers.html" onclick="window.open(this.href);return false;

I think this would be illegal for Rad. One is not allowed to make a Ferrari ugly:

Robert Puertas wrote:would a hi-temp silicone elbow work?

or is the exhaust too hot?

That should work Silicone is typically rated for 500 degrees F, so use a 45 to keep the end from getting too hot and an off-the-shelf hose should be fine over a 60-ish-second course. Or even better, use the hose as a coupler to attach an aluminum turn-down.
Also, there are even higher temp hoses that I've used for couplers to connect exhaust systems to chassis dynos / emission benches that tolerate exhaust temps with no problem.

Here are pictures of the stock muffler. Notice that the outlets located on the rear bumper are cosmetic, the real outlet is the 60mm thick pipe.

I was thinking that I could get a custom made L pipe with a clamp from the 60mm pipe to the outside of the bumper and then point it down. I could also attach one of those Burns 2-stage mufflers to that L Pipe, although at 5 lbs and 3g of lateral force they might bend my stock muffler or break my rear bumper.

I really want to run the Fiat this year.

more pics

Rad_ Delgado_ wrote:Here are pictures of the stock muffler. Notice that the outlets located on the rear bumper are cosmetic, the real outlet is the 60mm thick pipe. .

Could you fabricate elbows that locate in the cosmetic outlets yet guide and direct the flow out the back? Do you have access to the front side of those outlets from underneath or something where you could insert a bolt, or fit a clamp or something? That way it wouldn't mar the external view.

Or perhaps you could clamp a 60mm elbow to the actual exhaust pipe using a DynoMax band style muffler clamp. That's a split tube with nuts and bolts at each end to clamp down on two tubes, joining them. Dunno if your physical layout makes that doable.

Like this: http://www.summitracing.com/parts/WLK-33226/" onclick="window.open(this.href);return false;

Here's another thought. Weld extensions to the ends of your exhaust pipes that extend out through the cosmetic outlets. Now you've got something to clamp elbows or auxiliary mufflers to. Remove elbows for street use, and cut off tubes when you're done racing it.

BTW, I have a Burns 2-stage on my Lola and can't recommend it. It's four times the size and four times the price of the aluminum SuperTrapp it replaced. And only 1/2 dB quieter. The aluminum SuperTrapp would be much easier packaging for your add-ons. Not as high performance a muffler, but you probably have more power than you need. And if necessary you can remove plates mid-event to show compliance with "make a change". You could probably clamp SuperTrapps straight to the end of the extensions and let them stick straight back.