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 Lime Rock and mufflers? 
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Joined: Sun Jan 05, 2014 11:06 pm
Posts: 43
Location: MA, Boston Metro-West
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Guys, my race car is finally done and I'll get my hands on it next week at LRP.
I've heard horror stories about getting black flagged for noise violations there. I've also heard that the noise requirements differ per club and event. Does anyone have advice on noise limits they've encountered at LRP, whether or not to run a muffler permanently, and what kind of muffler to put on the car?

Car: Elva Mk6, Ford pre-crossflow 1600 (1500 head/1600 block). No muffer, just a brand new stainless header and straight pipe. It's probably slightly louder than your typical Formula Ford.

Event: 1st one for the car will be the VSCCA event at LRP next week.

Thanks all.

John

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John Feng
Massachusetts


Fri Apr 25, 2014 7:34 am
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Joined: Sat Dec 14, 2013 11:13 am
Posts: 225
Location: Pittsburgh, Pa
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John,

I recalled seeing a similar post about this on another forum, and it appears that was you over on ApexSpeed .

Looking at a few recent events at LRP on MotorsportsReg, the sound limits seem to be sort of all over the place - anywhere from 86 dB to 105 depending on what type of event is there. Unfortunately, I can't immediately find any kind of supps to pass along from the VSCCA.

So, best bet is to get a confirmation on what the limit is from VSCCA, and make sure you have a muffler solution of some sort. If you're concerned you will going to be over sound, or in this case - aren't aware of the sound you'll even make yet - ask sound control to pass along your readings across an entire session so you can correlate to your lap times. If you're turning really great lap times but flirting with/over the limit, you'll just have to back off. Sound is tricky - I worked for a while with SCCA on sound and it was one of those necessary evils of racing. I think we all love the sounds of our own cars, but if the neighbors aren't happy, then no one gets to race.

Hopefully it won't be too humid/wet out, which tends to keep the sound closer to the ground and louder. Those with more experience with your car/motor setup, and LRP sound can hopefully provide some insight - and there are more than a few VSCCA racers here who likely have first hand experience with this. Some tracks will allow you to get dinged and attempt to correct it before sending you home; given the rather special circumstances of LRP, it may be a one and done. But, experienced racers can tell you whether that's the case at LRP.

Good luck, and have fun!

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Ian
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Fri Apr 25, 2014 10:44 am
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Joined: Sun Jan 05, 2014 11:06 pm
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Location: MA, Boston Metro-West
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Ok, due to the good advice here and on apexspeed.com, we've decided to fit up a real muffler that's removable for unmuffled tracks/days. Unfortunately, with the motor at the back, the only option is going to be a 90 degree elbow with the muffler running laterally across the back/lower part of the car. Not going to be pretty, and no doubt it'll have substantial backpressure (not a great concern). I suppose I should be grateful that LRP is the only place I need to worry about (and not even every event).

John

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John Feng
Massachusetts


Fri Apr 25, 2014 7:28 pm
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Joined: Mon Dec 30, 2013 10:26 pm
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John,

Why not fit a Supertrapp? I have the kind with the fiberglass pack inside, and have never needed to add the baffles at Lime Rock. This one may be too large/long for your exhaust, but the short one that just has baffles should do the trick without requiring you to re-route the exhaust.

Mark Palmer


Sat Apr 26, 2014 8:42 pm
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John:

I deleted your duplicate post. I agree with Mark. Look into SuperTrapp. They have tunable circular baffles and are pretty short.

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Mack


Mon Apr 28, 2014 12:44 pm
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Joined: Sun Jan 05, 2014 11:06 pm
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Location: MA, Boston Metro-West
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Thank you for the advice. Turns out this is a moot point because the car was no where close to being ready. List of issues and to-dos the length of my forearm, many of which are show stoppers. So I missed the LRP event , and the car still isn't done.

But there is about 10" -12" for a muffler that goes straight back. So the 10" Supertrapp or a similar from Burns or coast fab will fit as long as I don't need a second hanger to support added weight. The burns muffler is only 1.76lbs!!

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John Feng
Massachusetts


Tue May 13, 2014 8:13 pm
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