Noise Levels

[Mikey Antonakakis]

Hey, I'm a member of the team at Columbia, and we need to get our car to pass the noise test. We run a cbr600f4i engine, and we had a stock muffler from a gsxr600 on there. We were at 120 db (outdoors) according to our radio shack db meter. It's analog, and probably pretty old. We were trying to figure out how to fix the issue, so we decided to try out some of the other mufflers we had in the shop. It seemed like our Vance and Hines carbon fiber muffler would actually work (we thought it'd be too loud before), so we tested it out and we were at 123 db in the shop (but the inlet of the muffler was not sealed hardly at all when we tested). We tried out the stock muffler again and it was at 120 in the shop. We weren't super accurate with the rpm, but our engine doesn't rev over 12500 anyways because of the tuning. It just seems like we're WAY over the noise level, even with a stock exhaust. I'm starting to think its our db meter. You guys have any thoughts?

[Mikey Antonakakis]

Hey, I'm a member of the team at Columbia, and we need to get our car to pass the noise test. We run a cbr600f4i engine, and we had a stock muffler from a gsxr600 on there. We were at 120 db (outdoors) according to our radio shack db meter. It's analog, and probably pretty old. We were trying to figure out how to fix the issue, so we decided to try out some of the other mufflers we had in the shop. It seemed like our Vance and Hines carbon fiber muffler would actually work (we thought it'd be too loud before), so we tested it out and we were at 123 db in the shop (but the inlet of the muffler was not sealed hardly at all when we tested). We tried out the stock muffler again and it was at 120 in the shop. We weren't super accurate with the rpm, but our engine doesn't rev over 12500 anyways because of the tuning. It just seems like we're WAY over the noise level, even with a stock exhaust. I'm starting to think its our db meter. You guys have any thoughts?

[Horace]

With absoltely no experience in mufflers and db levels I'd say buy a new db meter if you think that's the problem. From what you're saying $50 can save you a lot of time.

[Chris @ UML]

Mikey,

A couple things. Make sure that you can prove to the judges what RPM you're at when you go to the brake test. If you can't prove that you're at the minimum rpm level, you won't pass. If you still find yourself above the threshold after you figure out your meter, check out silencers at Summit. It's surpising though that you're that high with a stock GSXR muffler. We ran a CBR600F3 at VIR last week with a stock GSXR muffler and came in at 100dB. We sounded like a hybrid compared to the rest of the field.

Silencers

[Mikey Antonakakis]

Thanks for the help guys.

[Mike Sadie]

I just wanted to add that the RadioShack sensors are total junk. I have heard that Police have good sensors in an effort to screw street racers and people with whistle-tips.

Whenever the police have come out when we are testing they are really cool/interested in what we do. You probably could call them up and ask to use it (easier if someone knows a cop). They won't appreciate it if you call their toll-free number (911).