NickHolt Posted May 17, 2004 Report Share Posted May 17, 2004 THR Late Model Competitor Richard Norman (#40) shared this diagram of an exhaust system that he has available at a substancial discount for all teams competing at Thunder Hill Raceway this season. He recommends using either the Howe or Coleman muffler with this system. By the way, this is the system that is on Bobby LaFont's Street Stock that checked out at 91 dB on Saturday. Norman's #40 Late Model also met the 96 dB requirement at THR last Saturday. Anyone interested in more information should call Richard at 817-431-8900 or email him at NormanRacing@aol.com. Not everyone is willing to share this sort of information. Hats of to Richard and Bobby LaFont for sharing. I really hesitated to put this up since some might think it's an ad for Norman Racing, but the benefit to race teams and Richard's willingness to share this system at his cost seemed to me to outweigh any potential loss of advertising revenue to TSZ. Nick Holt Link to comment Share on other sites More sharing options...
TTR73 Posted May 17, 2004 Report Share Posted May 17, 2004 Hey nick is there any way you can post the db results so we don't have to put it on the trailer if we were over? Chris- TTR Crew Member #73 ss Link to comment Share on other sites More sharing options...
NickHolt Posted May 17, 2004 Author Report Share Posted May 17, 2004 TTR73 - Chris, We used two dB meters last Saturday and we took readings at two different locations. Then we exchanged meters at the same two locations. There was a 2 dB difference between locations but no difference between the two meters. We are very comfortable that the meter is accurate but we have a decision to make about exactly where all future dB measurements will be taken. For example, some cars were 96 dB at one location and 94 dB at the other location. So, we are very hesitant to publish this data until we determine where all future dB readings will be taken. That being said, there were some cars that were significantly quieter than others and we will be contacting those who were either borderline or over the limit (very few cars were actually over the limit, but there were several LM and Street Stocks that were borderline). So far all the Hobby cars passed with flying colors. Once we have decided which loaction will be come the standard for all future dB tests we will feel much more comfortable about sharing the information with each team. In the meantime teams should do everything possible to make sure their exhaust systems are as quiet as possible since we will be monitoring very closely until we are sure all cars are under the 96 dB limit. Nick Holt Link to comment Share on other sites More sharing options...
Banker36 Posted May 17, 2004 Report Share Posted May 17, 2004 Nick, My Dads car was 97db. He said hes gunna go ahead and put a coleman muffler on it but does he still need to cause what you just posted sounded like yall arent sure of where the db spot will be. Isnt the coleman muffler gunna be required next year? Thanks, Matt Banker Link to comment Share on other sites More sharing options...
Chuckman Posted May 17, 2004 Report Share Posted May 17, 2004 Matt one thing to think about is as the weather changes you may have a variable of a few DBs.If you were 97 I would shoot for 91 or 92,just something to keep in mind. Link to comment Share on other sites More sharing options...
NickHolt Posted May 17, 2004 Author Report Share Posted May 17, 2004 Matt (ss36_tams37), In light of the extra effort the track is making to control noise, I would think that we will measure at the more sensitive spot and not where the readings were a bit lower. But, unless Brian and Jim decided today while I was out, a final decision has not been made as to the exact location we will be taking the measurements. A couple of other things you might want to be aware of: I took lap times while we were taking the dB measurements to determine if all the cars were under full acceleration. We noted that a few cars may not have had the pedal to the metal last week. The 36 car was not in the "sandbagging" group. Also, the wind was coming out of the North (from the neighbors towards the track) instead of from the South (from the track towards the neighbors). Once the weather pattern changes, the wind will typically be from the Southeast which should increase the level of sound traveling in that direction. So -- bottom line -- I'd do everything I could to make sure I was in the low end of the scale, not on the high end. Nick Holt Link to comment Share on other sites More sharing options...
Bandit Posted May 17, 2004 Report Share Posted May 17, 2004 The only problem I see is that it dumps under the car. Link to comment Share on other sites More sharing options...
Truck99 Posted May 17, 2004 Report Share Posted May 17, 2004 Bandit, our rules require the exhuast to dump under the car via a turndown. Just curious, what problem do you see with dumping it under the car? Thanks, Chase Link to comment Share on other sites More sharing options...
Banker36 Posted May 17, 2004 Report Share Posted May 17, 2004 Alright Nick thanks for the verification. Link to comment Share on other sites More sharing options...
lbeaver087 Posted May 18, 2004 Report Share Posted May 18, 2004 they sould take the readings in the back straight of the track because ti is the side closest to the homes , and about the dumps under the car this is where the cars are being so loud you have a big open area under the car reverbing under the car makeing it loouder. just me two cents. Link to comment Share on other sites More sharing options...
NickHolt Posted May 18, 2004 Author Report Share Posted May 18, 2004 lbeaver6, they sould take the readings in the back straight of the track because ti is the side closest to the homes , We do indeed take the readings on the back straight, behind the signs that are out near the fence. Nick Holt Link to comment Share on other sites More sharing options...
hray Posted May 18, 2004 Report Share Posted May 18, 2004 lbeaver6 You would probably be right about the sound if you didn't have a turndown. The turndown causes the sound to disperse in all directions making less noise in any given direction. 2 years ago we had IMCA type exhausts on our car which didn't meet the db criteria. We added the IMCA cone type mufflers (the type that go inside the collector) and still didn't meet the db level. We then welded brackets on the collector with a circular metal plate slightly larger in diameter than the collector diameter and positioned about 3"-4" away from the end of each collector (to make a barrier - like the pavement with a turndown). It worked and we raced with them until we got our mufflers installed. About the turndowns, they stir up all kinds of dirt and dust in the pits and make a mess of the whole underside of the car, not to mention the carburator, valve train or Q/C rearend gears of your pit neighbor whose trying to work on his car. Yes, we're installing a turndown, but I don't like them; especially at a track like SAS or CCMS. Their pits are the pits----yuk! yuk! Link to comment Share on other sites More sharing options...
Bandit Posted May 18, 2004 Report Share Posted May 18, 2004 The turndown down does stir up alot of dust. It also introduces carbon monoxide under the car were it can leak in. There are down force reasons that also apply. If you can meet the rule and exit the outside of the car, they should let you run it. Running till 1:00am does not help the noise problem either. Link to comment Share on other sites More sharing options...
Jason Posted May 18, 2004 Report Share Posted May 18, 2004 They were done pretty early this past weekend. Link to comment Share on other sites More sharing options...
lbeaver087 Posted May 19, 2004 Report Share Posted May 19, 2004 hray , what iwas saying is that the turn down even they face the ground it still hits the ground and then it goes right backup in the big open area under the car and makes it louder than what it was ratted at . now you can tyr this cause mi have in the past you put on a set of flowmasters with or with turn down start the car or truck you use it will be very loud , then run tail pipes to the back of the car or truck with or without turn downs its not as loud ,i did this with a 71 ford 4x4 .i ended leaving the tail pipes on becaues it was too loud i could not even hear the radio when it was under the truck. louis Link to comment Share on other sites More sharing options...
UMSCHEIDRaceServices Posted May 19, 2004 Report Share Posted May 19, 2004 lbeaver6 Your thinking of the noise inside the truck, we are talking about the noise at 100 foot from the racing surface. of course the noise will be louder if your sitting on top of the turn down. the exhaust on a racecar where the body is acting as a sound barrier makes it quitier at a distance. This is what THR is concered about with the neighbors I think i see your point. J.C Link to comment Share on other sites More sharing options...
lbeaver087 Posted May 19, 2004 Report Share Posted May 19, 2004 jc , your right too but i have seen it in race car too , i have been to race tracks from texas to all over southern and northern cali to washington state and all had to use mufflers at these tracks . louis Link to comment Share on other sites More sharing options...
hray Posted May 19, 2004 Report Share Posted May 19, 2004 One thing the NASCAR Busch and Cup cars use is an exhaust pipe called a 'Boom Tube'. It's a flat tail pipe that exits on the passenger side (but it can exit anywhere). They actually work like a muffler but cause no back pressure. We looked into them for our car last year. Dr Gas makes them but they are VERY expensive. If used in conjunction with a spin type baffle muffler you could get the db level way down with very little loss of hp. Only question is, How expensive do you want to make this sport? I say do it like tires. Let the track find 1 or 2 mufflers, based on performance and price, that work on any class car and mandate all cars run the same ones. Then all you'd have to check is the traveling series for db level. Link to comment Share on other sites More sharing options...
KELLY83 Posted May 20, 2004 Report Share Posted May 20, 2004 Anyone have any problems yet with the turn downs that point straight down to the ground? BEWARE!! I tried this once and the force of the air coming out lifted the car into the air like a jet or rocket engine would. I was hovering above the track once I got up to 7,000 rpms. I'd come out of the corner.. hammer down and as I got towards the flagstand the car would lift into the air. Then when ya let off it slams the car back down and it make for a tricky corner entrance... still playing with the right springs & shocks for the touch down. Link to comment Share on other sites More sharing options...
NickHolt Posted May 20, 2004 Author Report Share Posted May 20, 2004 Mind if I have a look inside that engine Kelly83? Maybe we could adapt it to the THR clean up truck and never have to blow the track again -- if we could keep the pickup on the ground, that is. Nck Holt Link to comment Share on other sites More sharing options...
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