Borla S-Type vs. Lime Rock Park Sound Limits?

[climbiterp]

Hi everyone, was wondering if anyone knew about if my GT with the Borla S-Type catback is going to legitimately pass Lime Rock's 88dB limit on exhaust noise. I figure if a GT350 can be run there then I must be alright...right? No other modifications to engine or exhaust.

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[Cindy42]

My Borla S type has recorded sound measurements of 87 to 93 at 50 feet from edge of course at a point of full throttle. (otherwise, SCCA Solo rule measurement) Weather seems to be a big factor. Once, it was rainy drizzle and I got to 95. Typical nice weather is 87-89. Not sure how far away the track you speak of is measuring, but that gives you a 50 foot measure.

 

[climbiterp]

Replying here in case anyone finds this thread in their research: I was far from the loudest car at the track day. I didn't even see them sound check anyone, and one car was a stock car with a VERY loud carb'd V8 (it was lovely to listen to all day). The Spec Miatas they have for rent are just as loud if not louder than my car. You're definitely safe at Lime Rock with stock headers, I can say that.

 

[melwff]

climbiterp: what day of the week was it when you saw no noise checks, a Tuesday?

From: Skip Barber, Georgia Blades and Scott Mayo

As you know, exhaust noise has always been an issue at Lime Rock Park. We operate under a 1959 Court Injunction that stipulates: the number of weekends (10) that we can run unmuffled; other times we aren’t restricted (Tuesday afternoons); the decibel limit for all other track days; and bans Sunday track use. There have been no changes in the injunction and we don’t anticipate any court ordered reductions in noise levels. But we have growing criticism from some of our neighbors; some of which is justified:

1. Significant manufacturers like Porsche, Mercedes (AMG), and Ferrari are building street legal cars that at high speed and full throttle are “on the edge” of our required decibel limit. Given the right atmospheric conditions they go over the edge

2. There has been a major increase in the number of small manufactures building great track cars that are too noisy “out of the box”

3. More and more of our track users have cars in these two categories

4. The Skip Barber Racing School has steadily increased its use of “noisy” Miata’s rather than relatively quiet single-seaters

5. There are a small number of SCCA race cars, mostly Porsches that turn up at multiple club events for “cheap” practice. They almost always need to “test” their “improved” exhaust systems, making too much noise in the process

For 25 years the track set a limit 1 dB level below the injunction requirement to be safe and never exceed the mandated limit, unless the exhaust system broke. Cars were checked while stationary, before going on the track, 1000 RPM below the redline, and theoretically never got on track if too loud. There was no on-track testing to check for compliance as there is now. Porsches had the most trouble complying and it was common to have a Lime Rock exhaust system.

Over the years the 1 dB margin has vanished and on-track testing has replaced stationary checking. A common scenario is that a car runs 4 or 5 laps; is too noisy; comes in to correct the problem (often with steel wool); goes out again; the steel wool blows out after a few laps and it takes a few more laps to get the car in. Then the process starts all over and by the end of the day the car has run multiple noisy laps.

And now we have more complaints.

We are going to deal with this proactively:

· We are going to reduce the total noise

· We are going to have a sound engineer calculate the total reduction

· We are going to tell the town what we have done and we are going to stick with it

We are NOT:

· Going to court to try to change the injunction

· Going to complain about the injunction

· Going to criticize the states motor vehicle laws or the measuring system

· Going to make the economic argument that the town needs a viable track – they know that

We want to stand in front of the town and say:

1. The total noise is down_____%

2. All quiet days are quieter

3. Even the biggest professional race, the American Le Mans Series, is down 2 dB

We are going away from a “one size fits all” dB limit; assigning every club a limit we think is reasonable in terms of cost, impact on performance, and effect on entries. We know “reasonable” doesn’t always mean “easy” or “cheap.” The new limit, effective immediately for your club, PCA is 88 db.

The two big problem groups are the school’s Miatas and some Porsches, regardless of what club they run with. The school is fortunate – they have a new sponsor, Borla, who is building them all new complete exhaust systems. They have already tested under 83dB, their new limit at Lime Rock Park. This is a tremendous reduction – they have been running 88-89 dB, and they use the track more than 100 days each season.

Not so easy for some Porsches, so all Porsche clubs go down 1 dB; but we are going to rigidly enforce this. This 88dB limit is for non-race Porsche days – not for Porsche cars regardless of what club they are running with. So a Porsche limit would be:

88 dB Porsche Club Day

105 dB Porsche Race Day

87 dB BMW Club

86 dB PDA non-race

88 dB SCDA

88 dB Lime Rock Drivers Club

105 dB Tuesday afternoon Test & Tune

PLEASE don’t let anyone come for testing or a club day with an unchanged car that was too noisy last year. This isn’t about “beating the system” by short shifting or lifting off the throttle while being checked. This is about lending real meaning to the phrase, “We’re all in this together.”















Old 04-01-2011, 09:49 AM

 

[climbiterp]

It was a Monday all-day event, actually. I'd found that letter as I was feverishing googling, hoping I hadn't wasted $400 on a track day spot haha

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