chief63

Hi guys,

Just got my MHP long tub headers installed with an X-Pipe. Since I'm tracking the car, I'm taking decibel level recordings myself.

Here are the results so far (more mods to come):

Measures taken at 15 feet from the rear, reving up to 5000 rpm (trying not to punch the throttle pedal too so smooth reving)

Stock: 89.7
MHP LTH with X-Pipe: 106.4

Overall the car is very loud when accelerating above 3000 rpm (and starting the car) but I'm very far from 125db that other guys recorded on the Dyno.

Next step is installing a silencer and maybe cats. My target is to be below 100 decibels. As it is now I can't race at most race tracks!

Will also get some videos up soon.

I hope the info helps and I'll keep the thread updated.

alrasheed1991

enjoy !

BAD430BENZ

you can't race at most tracks ?

chief63

Damn your car is loud! Good stuff =)

Yes at 106db at 15 feet, any race track (lapping - not drag) near a village will pretty much black flag you if they don't already have a sound check (which I would fail by a long shot)

Most have a 92db limit, what will vary is where and how they calculate it. For example in Canada, Calabogie is 92db at 15 feet, Tremblant is 92db at about 50 feet (which is like 102.5db at 15 feet at 5000rpm) but that is taken on a straight at full throttle so I expect the car will be louder.

Here is a good site I found to calculate DB equivalence depending on the distance. http://www.sengpielaudio.com/calculator-distance.htm

My objective is to bring the car to 100db@4600rpm at 15 feet. I hope it can be done.

b16

Yup, most tracks have sound limits. Laguna is the most strict here. People usually lift when passing the sound station.

GL!

MRAMG1

Sadly even Beaverun has a sound limit, 96dba.

And most if not ALL SCCA events have sound level requirements now.

Keep in mind guys, this ISN'T drag racing.

cptdaz

Must be a Canadian thing. Decibel restrictions are rare in US tracks. The most I heard is Laguna Seca which has a 92db noise limit.

Merc63

What kind of X pipe are you using, any pics? Or vids?

MRAMG1

You would be surprised my friend, as MOST raod courses now have limits. Think neighbors that have complained to local gov, *****ing and moaning, and soon, guess what, NOISE LIMITS.

Happened two years ago at Beaverun

jakio

Are you saying we can't lap no more??

b16

Not as rare as you think, others are just not so brutally enforced like Laguna.

DB limits for Thunderhill, Infineon and Buttonwillow are 103db

chief63

It was sent last minute free of charge, no idea but I'll ask. It's not the mhp SS one that I know for sure...

chief63

Just ordered the Akrapovic Titanium slip-on exhaust from ACG San Diego. It will tone down the sound big time!

Will post my results here.

cptdaz

Been to Beaverun couple of times, and never got checked for decibel limits. My Arrow pipe is pretty loud but I'm sure I've seen (or heard) some louder ones.

I know NJMP has been under pressure from Milleville, but last I heard there's was no limit.

cptdaz

I was referring to tracks outside great socialist republic of california.

b16

lol, fair enough. We do have the best race tracks in the country though.

c63canada

so even stock the c 63 is close to the 92db limit of some tracks. wow.

chief63

Yes. If you punch the throttle too fast during soundcheck you'll sometimes hit 100db, stock!

I remember that at calabogie, the soundcheck guys would not believe that my exhaust was stock and that loud...

I'll also make sure to post videos of the before and after Akrapovic exhaust.

PS the car is crazy fast with the long tube headers and updated tune vs just tune only, I'm very impressed.