Coochas

Hi All,
One of the things I plan on doing this winter is to change my Fabspeed Maxflo exhaust out of my spec boxster. The current exhaust has two heavy cans and two sport cats. I think there's a lot of weight to be saved back there.
If I went with a typical race exhaust (see pic below) would I run into the 89 dB sound barrier which some tracks like Limerock, LCMT, and Calabogie impose?
Does having a set of bolt on bent down tips really make a difference on the sound meter?

I could just get rid of the sport cats and keep the mufflers although this would probably only save 15-20 pounds.

Juan Lopez

The trick is to bend it away from the sound meter

Qwickrick

Consider a plan "B" in case that doesn't work. That's why I went to detachable supertrap mufflers.

Coochas

Do you use this kind Rick? Do they really quiet things down?

U4EEAH

Lime Rock is now 84db !!!!!! Many factory stock cars cannot meet that, GT3s, Corvettes etc. Even losing the cats might put you over that unreasonable number. Any system louder than stock should be designed to include add ons like the super trapps for LRP. I would like an experts opinion on the impact on engine life such restriction causes.

Tom W

From what I've seen trying to pass sound at Laguna Seca ...

The tips with a bend only help if you are borderline. Taking a car that's normally 98 db and slapping alternative tips onto it and expecting to pass at 92 db is not going to work.

The supertraps can help but they are really restrictive.

I have no direct experience with the Maxflow, but comparing your suggested exhaust to what I've seen, there is no chance in hell of it passing an 89 db limit. I normally run twin Phase 9 mufflers and they are about 98 db. To meet the 92 db limit at LS, I remove the Phase 9's and add an old 911 'banana' styled muffler and it just passes (and it saps tons of power due to it being more restrictive than the exhaust the car is tuned for).

Deadeye

What a shame. A fine old track becoming the new electric car track.

GT3 Techno

https://rennlist.com/forums/porsche-...tailpipes.html

Coochas

Hmmmm, this is all food for thought. I think I'm going to buy a dB meter from Radio Shack and do things in increments. If anything, I'd like to get rid of the sport catalysts since they are heavy. Maybe with the twin Fabspeed cans I have, the dB will still be OK.

I could do a cat bypass pipe and do before and after sound measurements. I'll be sure to report if I end up doing this.

Qwickrick

I'm using the center of the three supertraps shown...Remember, I don't have cats and I have Fabspeed mufflers and so far so good.
LRP uses a POS Radio Shack sound meter.........must have cost them $29.00 if not on sale

BostonDMD

LRP, nice track, but it pains me to say that it is not worth the trouble to go thru the
all the stringent sound restrictions.........

We might as well race on bicycles over there.............

Coochas

Thanks for the link. I didn't find that one in my search.
Thx Rick.
It IS a bummer Paolo. LCMT and Calabogie have similar levels that are enforced.
I'm going to NJMP next week for the first time. Apparently their restriction is 80 dB measured 1 mile from the track with all the cars running! Interesting.

Matt Lane

Limits may be the same (not sure), but I've had no trouble with running Supercups at Calabogie without turndowns. Hoping for continued good luck on this!

PS - and removing LRP from my list of places to visit, at least as a driver...

Best,

Matt

Lawrence_P

As an aside, Lime Rock's noise restrictions have not changed. For muffled events it is 89 dB. Also, their noise meter is pretty good, but whether or not a car passes depends in part on weather, since humidity does not help if you are close to the limit. That accounts for a lot of frustration, since mufflers that are OK in June may not be in August.

Gary R.

I can swap out my muffler in 5 minutes, if you had a simple system like mine made up you could do the same and have it for Limerock or any other tracks that ding you in the future. I agree it sucks, but to not run on a classic track like Limerock, especially given the shape it's in now, is just crazy. Any muffler shop can make it, get a 2-in/2-out Magnaflow and bring it to them. Most likely less than $250 all in. And quit yer cryin!

And I was told it's 89db up on the main road and 91db on the track, but that seems to change depending on who you talk to.