harrydirty

Did a search but no luck on this topic.......

What do you track guys do to pass sound on tracks that have sound restrictions? I'm getting my 07 Z06 ready for the track, but I'm guessing it will not pass sound at Laguna when I go WOT.

Suggestions besides short shifting?

gkmccready

What have you changed? Stock I would think it should pass sound. You can try the 90deg bends if you can get some that fit over your tailpipes (or inside them). You can also add Supertrapp discs to the end of the 90deg bends. Laguna likes to move the sound station throughout the day so you may find yourself having to point the exhaust out different sides for different sessions -- easier to just make the car quiet...

Crepitus

Found with the sprint cars; A slash cut 90 pointed straight down helped a lot

harrydirty

My first track date with my Z06 will be at Laguna at the end of this month, so I have no experience with it. I have heard from others that when the valves open up on the exhaust that it will not pass at Laguna, so looking for some advice from others who have tracked stock C6Z06's at Laguna.

Thanks

C5inWV

18" mufflers really don't affect HP and help control sound. My LS1 made 108dB w/ 12" mufflers but is usually below 100dB w/ the 18's

DarkMastyr

I've seen stock C6Z06 get meatballed for sound at Laguna. Is there a way to just brace the flaps closed so that they don't open up?

96solo

This what I did to get through the San Diego Nationals 93 dB requirement with a C5 Z06 with kook headers, X pipe and B&B bullets.
It measured 99 dB before, the 89 dB after adding these temporary pipes. I had diverters made my Burns stainless, then in 3 hours had Budget Muffler, San Diego make this out of half of a stainless BMW 5 series bullet muffler.

Go laugh! it worked well!

davidfarmer

turn downs help a lot...you can get 90deg elbows at many local shops, or Summit /Jegs. I agree that mechanically wiring your secondary's should would help, and probably only cost you a few HP. Better than being black flagged. It's just a vacuum system, so safety wire would probably do the trick.

Last C5

This got my Borla equipped C5Z passed at Laguna. Not pretty, but effective . . . .

harrydirty

Those pipes look like a solution I'd like to consider.....I see the welded nut, but how does it attach to existing pipes? Do you drill a hole in the underside of the exhaust pipe just aft of the tips and bolt the "elbows" on? Where did you get them made?

also, I'm a bit confused by their orientation.....they seem to be pointed towards the passenger side of the car, which would correspond to directly pointing to the sound shack at the exit of T5 at Laguna.......shouldn't they be pointing the opposite direction or am I missing something?

thanks

Last C5

Yes, you drill a small hole in each pipe just forward of the weld on the tips. Doesn't hurt a thing and most systems have a hole for drainage back there somewhere anyway.

I had them made at a local muffler shop. At least I had the pipe cut and bent there. Only cost $6 each. The hole and nut I did myself.

You're right, the orientation was for Portland International but they worked fine for Laguna even though they were pointed at the sound shack. I'm thinking about building another set with less of a bend, shorter, pointed straight back, and slightly down. Simply removing the use of the bell on the end of the Borlas makes a world of difference.

harrydirty

Updating this thread............I've successfully run many 92db Laguna track days with my stock c6z, but got meatballed on the latest day, which was 90db (I was tagged at 92.2db). I understand many available track days will be 90 db days in the future, so I need to find a solution. I'm not willing to alter my exhaust tips in any way nor mar them, so looking for someone who has successfully implemented exhaust tips on a c6z.

meldog21

Here is my Laguna pipe. I had it made recently and used it this past weekend Dec 1,2. It got my supercharged LS6 with headers down to 90.5 db. Not pretty and it weighs about 15 lbs, but it doubles as a cannon for shooting cantaloupes out the left side of the car, or as a rear bumper for demolition derby.









Sorry I don't have any close ups handy. It is basically a big pipe with four inlets that go over the stock exhaust tips, closed on the right and open on the left. I drilled holes in the bottom of my stock tips and riveted it on, I also added a safety strap made of picture hanging wire in case it tried to get away.

Dog

Last C5

Here is my newest attempt at adjustable sound levels. Running all the plates with washers in between each plate (basically wide open) I made 102 db at Thunderhill with no difference in power.

By removing plates you quiet the car, but at some point you will lose some power.

harrydirty

Mel, where did you have that setup made and cost? Does the inside of the Laguna pipe inlets have something to prevent marring your exhaust tips?

Charley Hoyt

I was dealing with this issue earlier this year when I went to Laguna. The attached thread shows a great way to electronically keep the exhaust butterflies closed all the time. It was easy and it worked perfectly. I ran all day without sound issues.


http://forums.corvetteforum.com/c6-z...5-seconds.html

meldog21

Chris at Bay Muffler in Mountain View(he is a racer guy with several short track cars) made it for $150. I wasn't worried about scratching my exhaust tips so there is no protection. I guess you could put something like exhaust wrap between the Laguna pipe and the stock tips.

Dog