Cal Club Autocross Forums

Will Kalman wrote:Has anyone tried running a muffler made for a much larger engine (like a flowmaster, etc for a V8)? I'd think that the backpressure would be very low, the weight would be minimal, and it might even sound pretty good (i.e. less of the typically piercing Honda sound).

Will,

We are using this because it was laying around the shop, I get teased for it all the time. We are acutally in the middle of putting another one on before next weekend.

The weird thing is, this setup blew sound barely 93.7, after making it longer and using a resonator and directing it towards rear lower control arm, we had a 98 db reading

"Everyone" can now have their own Db meter in their iPhone. It would be interesting to compare the "pro" model as used in San Diego vs. the iPhone one and my Radio Shack model. I'd LIKE to compare my iPhone meter and the Radio Shack model that I keep loaning and "losing."

http://www.gadgetfrontier.com/

Sounds to me like the problem is San Diego Region and not the exhaust noise.

Oh yeah... Everybody's car got much louder... Right.... Hello? Must have been the sunspots.

Jeff Wong wrote:

Will Kalman wrote:Has anyone tried running a muffler made for a much larger engine (like a flowmaster, etc for a V8)? I'd think that the backpressure would be very low, the weight would be minimal, and it might even sound pretty good (i.e. less of the typically piercing Honda sound).

Will,

We are using this because it was laying around the shop, I get teased for it all the time. We are acutally in the middle of putting another one on before next weekend.

The weird thing is, this setup blew sound barely 93.7, after making it longer and using a resonator and directing it towards rear lower control arm, we had a 98 db reading

i liked the ebay exhaust!!! LMAO you should run that at the tour.

Jonathan Lugod wrote:

Jeff Wong wrote:

Will Kalman wrote:Has anyone tried running a muffler made for a much larger engine (like a flowmaster, etc for a V8)? I'd think that the backpressure would be very low, the weight would be minimal, and it might even sound pretty good (i.e. less of the typically piercing Honda sound).

Will,

We are using this because it was laying around the shop, I get teased for it all the time. We are acutally in the middle of putting another one on before next weekend.

The weird thing is, this setup blew sound barely 93.7, after making it longer and using a resonator and directing it towards rear lower control arm, we had a 98 db reading

i liked the ebay exhaust!!! LMAO you should run that at the tour.

Don't be hating on the ebay exhaust when it looks better then your ghettofied custom discount tire, magic muffler exhaust

Reijo Silvennoinen wrote:Do they ever get the sound meter calibrated? Sounds like quite a few people were having problems that weren't before ... maybe the common factor is the sound meter itself or an incorrect placement?

R

It's professionally calibrated and dated. I think annually.

Jay W

Jayson Woodruff wrote:

Reijo Silvennoinen wrote:Do they ever get the sound meter calibrated? Sounds like quite a few people were having problems that weren't before ... maybe the common factor is the sound meter itself or an incorrect placement?

R

It's professionally calibrated and dated. I think annually.

Jay W

When taking readings from the sound meter, is it only valid when the car is directly in front of the meter? I know our car lined up with the sound meter only read 90db, when we passed the sound meter is when we acutally got the violation.

hey look i'm Jeff Wong's Idol... i guess he likes listening to Abba also...

Jon "Fernando" Lugod

Jonathan Lugod wrote:hey look i'm Jeff Wong's Idol... i guess he likes listening to Abba also...

Hey Hey...Simmer down you two, don't make me pull over and stop this car. :mrt:

Next I'm going to hear that a Prius playing ABBA on the stereo set the DB meter off in San Diego....

"Breakthrough Muffler Technology"

http://autospeed.com/cms/A_111103/article.html

Jeff Wong wrote:

Jayson Woodruff wrote:

Reijo Silvennoinen wrote:Do they ever get the sound meter calibrated? Sounds like quite a few people were having problems that weren't before ... maybe the common factor is the sound meter itself or an incorrect placement?

R

It's professionally calibrated and dated. I think annually.

Jay W

When taking readings from the sound meter, is it only valid when the car is directly in front of the meter? I know our car lined up with the sound meter only read 90db, when we passed the sound meter is when we acutally got the violation.

I believe the most recent supp regs are here....

http://www.sdr-scca.com/solo2/docs/2009 ... Reg-R1.pdf" onclick="window.open(this.href);return false;

The reality is there isn't always a good place to put the meter and lots of things can affect the reading... Pretty much any ST class car and higher (SP, SM, M, etc...) that's near full prep (intake, header, hi-po cat/no-cat) has the potential of going over sound... Many stock class cars with aftermarket exhausts will be over (Elise, S2000) and some bone-stock cars (F355, I guess a C6 based on this weekend). Come prepared or risk the chance of packing up early.

A Prius with a well built system should easily be able to exceed 93 at 50ft

Wait, wait, wait...you're saying they set the sound meter up and used it when cars were moving toward or away from it? How exactly does that qualify as 50 ft? Unless I'm missing something, if the car's moving, it's going to be closer than 50 feet from the meter at some point during the reading unless they set it 50 ft off the course in a strategic location where nothing else could set it off. Wouldn't just be easier and more accurate to impound suspected cars, leave the car stationary, put the meter 50 feet behind the car and make the driver rev to full throttle? If stock cars are setting it off, I don't see how it was reading correctly, whether it was user/setup error or miscalibratation. But then I'm not a physicist, so I could be wrong.

Jason Uyeda wrote:
A Prius with a well built system should easily be able to exceed 93 at 50ft

Kurt Rahn wrote:Wait, wait, wait...you're saying they set the sound meter up and used it when cars were moving toward or away from it? How exactly does that qualify as 50 ft? Unless I'm missing something, if the car's moving, it's going to be closer than 50 feet from the meter at some point during the reading unless they set it 50 ft off the course in a strategic location where nothing else could set it off. Wouldn't just be easier and more accurate to impound suspected cars, leave the car stationary, put the meter 50 feet behind the car and make the driver rev to full throttle? If stock cars are setting it off, I don't see how it was reading correctly, whether it was user/setup error or miscalibratation. But then I'm not a physicist, so I could be wrong.

I'm not saying anything, just providing a link to the actual rules... However, given the guidelines, the closest a car should ever be to the meter is 50ft and that would be when you're directly in-front of it. Using my invisible 50ft string, I have a hard time seeing how you could ever place the meter in a position where 50ft wasn't directly in-front of the meter and have it be anywhere close to the rule or be safe for that matter.

The rule pre-dates me so don't consider this accurate, but the rule is there because the region almost lost the lot due to the neighboring homeowners complaining about sound. It was a compromise between us, the homeowners, the stadium, the city (not sure who all was involved) and is somehow tied (not sure exactly how it's worded) to our contract with the stadium. I highly doubt it's going to change (why risk it, the stadium is probably going to be torn down in a few years anyways) and people have been dealing with it for over a decade.

Has anyone ever gone out and measured how loud the Saturday evening Drag Races are at Qualcomm?

Mako Koiwai wrote:Has anyone ever gone out and measured how loud the Saturday evening Drag Races are at Qualcomm?

easily should be over 100 dbs. I know when i used to drag race there with my Z; I had a straight piped (no cats) inline 6 high compression all motor. There is supposed to be a sound restriction but i was never notified.

Jonathan Lugod wrote:heres mine
http://blip.tv/file/1856743" onclick="window.open(this.href);return false;
2nd Place
59.999

My fastest was a 59.6xx but got DSQ for sound

Thanks for the video!

Here's mine from that same course:

http://www.vimeo.com/3542319

Very good course - It was a really cool surprise to see something like this down there! :gpower:

Mako Koiwai wrote:Has anyone ever gone out and measured how loud the Saturday evening Drag Races are at Qualcomm?

Much, much, much louder then they should be.

Leonard Cachola wrote:Here's mine from that same course:

http://www.vimeo.com/3542319

Very good course - It was a really cool surprise to see something like this down there! :gpower:

Thanks Leonard!

Hope you had a good time, I sure did! Are you sore today? lol

Jamie Lessie wrote: Thanks Leonard!

Hope you had a good time, I sure did! Are you sore today? lol

Not as sore as I thought I'd be, but yeah I totally had fun and have been telling everyone at work today about my experience driving your car! :gpower:

more video.

http://www.youtube.com/watch?v=FMBN0YW4je0&fmt=18" onclick="window.open(this.href);return false;

Nothing says where you have to be. This sound is measured in 1sec averages ("slow" setting), which means the sound you're making as you pass the meter typically won't show up on the meter for 1+ seconds, which at 60mph is 80ft later.

Jay W

Jeff Wong wrote:When taking readings from the sound meter, is it only valid when the car is directly in front of the meter? I know our car lined up with the sound meter only read 90db, when we passed the sound meter is when we acutally got the violation.