Rustic Posted May 28, 2007 Posted May 28, 2007 http://www.carchemistry.com/shop/index.php?action=category&id=1&subid=1 I was curious if any of you have tried these... or any product similar. Last year at the Autobahn I got the black flag becasue my exhaust was too loud. I was using a Dr. Gass boom tube system with X-pipe. I thought I could carry a pair of these in the trailer... and if I trip the Db meter again I could stick them in between my header collector and the rest of the system. Quote
nape Posted May 29, 2007 Posted May 29, 2007 Never used those but instead of boom tubes, clamp turn-downs on so you can turn them away from the meter or at least down. Or, in a more Macguyver fashion, take a soup can, cut a hole in the side of it, then screw it to the tail pipe to muffle the sound. Doesn't look the greatest, but I believe it was at Autobahn that I saw someone do that last year. Also, which side is the meter on at Autobahn? I didn't know they had one. Quote
jeffburch Posted May 29, 2007 Posted May 29, 2007 I've always heard if the turndowns point toward each other at a 45 or so they can cancel out noise. Dunno. jb Quote
Rustic Posted May 29, 2007 Author Posted May 29, 2007 I don't think there is a way to use turndowns unless I get rid of the boom tubes. Same for the soup can... not place to stick it. Maybe I'll just try one of these inserts in my header collector: http://www.schoenfeldheaders.com/mufflers.htm Quote
swhiteh3 Posted May 30, 2007 Posted May 30, 2007 I'll add one more idea to the list of ghetto tricks that can used at the last minute to "make sound". At Waterford Hills, where the 75db limit (at the property line) routinely sent home cars every time a cloud rolled over, we developed all sorts of ideas. Obviously, the pointable turn-downs were on just about every car, because it seemed like a day-to-day thing to re-tune them. The other popular idea was to have some SS window screen, hose clamps, and steel wool. Pack some steel wool in the exhaust, put a piece of the screen over the exhaust outlet, and secure with a bandclamp (although safety wire also works well). This becomes a "tuneable" solution by adding or removing the steel wool. It's not pretty, but to this day I keep all the appropriate parts with me, just in case. Quote
LMan Posted May 30, 2007 Posted May 30, 2007 75dB?????? Can you even have a conversation in the paddock? Quote
Members Jim P. Posted May 30, 2007 Members Posted May 30, 2007 I always get the "Roebling Special" exhaust: - x-pipe with both tubes exiting the passenger side Most of the tracks we go to test on the driver's side of the car Quote
Gfaules Posted May 31, 2007 Posted May 31, 2007 I always get the "Roebling Special" exhaust:- x-pipe with both tubes exiting the passenger side Most of the tracks we go to test on the driver's side of the car Regarding most tracks testing on the driver's side, that is NOT the case in Northern California and some even test on both sides and or are mobile. Having had LOTS of experience with sound issues both at Laguna Seca and Thunderhill I can tell you that noise monitoring has many variables especially the weather, temperature and even night time driving versus day time. For example, many cars that pass noise levels during the day in the 25 Hours of Thunderhill find it impossible to pass sound after dark. It not only cost them time in the pits but sometimes even the race because during the race you ONE TRY ONLY to make it right or get booted. The bottom line is that you need to know exactly what level is acceptable at each track as well as all the above. It's a double edged sword since if it's too quite you are probably losing HP. Quote
swhiteh3 Posted May 31, 2007 Posted May 31, 2007 75dB?????? Can you even have a conversation in the paddock? Yup. It's measured at the property line, which is farther away from the track surface than most places test. It's another classic case of racetrack has been there forever, idiots buy cheap property next to race track, build houses, then file lawsuit - and win. What a country. The property line measurement is done because that's was the result of the lawsuit. They have a certain number of "free" days per year (like 6 or something) that are used for historic races, etc. On weekends they can race as long as the track as a whole meets the 75db liimit. No cars on track from 10am to noon (approx) on Sundays. Oh, and on weekdays, no "racecars" on track - even if they do meet sound. It's just stupid. Because it's measured at the property line, it's sometimes hard to tell just what car or cars are contributing to the noise violation. Also, you pass by the noise station twice, once going in each direction, which makes it hard as well. The steel wool technique has been a common one used to keep people from having to go home mid-weekend when the cloud cover rolls in. Again, because the measurement point is so far from the cars themselves, reflections play a massive part in meeting sound, and ambient conditions, including clouds, can completely change things. Quote
mikef Posted June 1, 2007 Posted June 1, 2007 Those work well, almost too good, I took them out and used the perforated cone type, they were easier to get in and out. Quote
tonycook Posted June 1, 2007 Posted June 1, 2007 http://www.carchemistry.com/shop/index.php?action=category&id=1&subid=1 I was curious if any of you have tried these... or any product similar. Last year at the Autobahn I got the black flag becasue my exhaust was too loud. I was using a Dr. Gass boom tube system with X-pipe. I thought I could carry a pair of these in the trailer... and if I trip the Db meter again I could stick them in between my header collector and the rest of the system. I have used those with decrease in the sound but do not know if they cost any power. Quote
ST#97 Posted June 11, 2007 Posted June 11, 2007 just lurking here but does anyone know if Mid Ohio has noise limits? I would guess not but never know... We have one track with 105db limit and I am running Xpipe and no mufflers...nobody has ever said anything to me but I do have a meter in the trailer.... Thanks! Quote
ST#97 Posted June 11, 2007 Posted June 11, 2007 which track is that? MSR Houston! Am I the only one that ever reads the paperwork we are given at the track?! Quote
ST#97 Posted June 11, 2007 Posted June 11, 2007 i've always read them, and i never seen it. IT was part of an instructor package from a NON NASA event. Listed it as "track rules". 105db is pretty darn loud...but you never know what someone will get on to if they have sand in their... Quote
Glenn Posted June 11, 2007 Posted June 11, 2007 i've always read them, and i never seen it. IT was part of an instructor package from a NON NASA event. ... well how was i suposed to have known that? Quote
ST#97 Posted June 11, 2007 Posted June 11, 2007 i've always read them, and i never seen it. IT was part of an instructor package from a NON NASA event. ... well how was i suposed to have known that? You are a director now...you should be ALL Knowing!!! But you should already KNOW that!!! Quote
Glenn Posted June 11, 2007 Posted June 11, 2007 i dont know what aint passed on to me. i do read minds, but only at work. Quote
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