355 Challenge w/stock exhaust for Laguna?

Depends on weather. I can say that we blew over 105 dB on a humid 80 degF day running SCCA Touring 1 and changed to the "quiet" muffler. Dropped to 92 dBA same day.

This was not at Laguna, but Blackhawk Farms. Every other track, no issues what so ever with sound for the remainder of the season.

Bring both if you have them. You can also try fabricating extensions which direct the exhaust toward the inside of the track. Might be good for one dB drop in sound pressure.


Rob

 

You will be black flaged with a challenge exhaust. Go stock and don't even bring the challenge exhaust. However, if LS sees it in their hearts to let the Ferraris slide maybe you will be o.k. but you will be over 103db. I have a sound meter and I fail on the 348 at idle! The 103 db is 50 ft form the track and they have a roving meter too so you can't just let up at turn 5. If you want I can send you my meter and you can prove it to yourself.

 

Just a question to ROB...

Are you refering to the stock exhaust or the challenge quiet exhaust??

The stock factory exhaust is quieter than the challenge quiet that we run at Lime rock park.

Good luck to you.

 

LS's sound limit is at 92db between turn 5 & 6. Most people with laud note short shift in that turn to avoid the db meter tripping. Last time I was there a 360C got black flagged mid afternnon for tripping the meter.

 

You will definitely NOT pass with the "loud" challenge exhaust. The normal challenge exhaust will be ok. I used it on my 355 Challenge at tracks where sound is a big issue (some circuits 85db) and never got thrown off in 2 years.
As far as I recall, all 3 exhaust types (including road) are bolt on, although I only ever used the "standard" challenge exhaust.

 

Matt -

Laguna approved the higher limit for the National event this year. Noise limits vary depending on the event, they have a certain number of days per year they can go higher. I'm kind of surprised they "spent" some of their high-limit days for a Ferrari club event, but I'm glad they did.

Gary

 

The dyno tests I've seen done showed no measurable change in HP between a standard exhaust, a challenge exhaust and with/without the bypass valve.

 

Rob, pick-up an inexpensive SPL meter from Radio Shack...
Always a good tool to have!

 

Rob,

The stock 355 muffler should be just fine for the laguna track. We used the stock units for the challenge there and at lime rock with no issues.

The stock exhaust will not cause any problems with the ecu or overall running of the engine.

I would also make sure with the stock exhaust, that you have installed the original "intact" catyl. converters. This will ensure compliance with the db meter.

best regards, Jim

 

If there are different versions of the challenge exhaust, how do you tell which one you have?