Hi Guys



I am new to the forum and I am trying to get my sandrail to be able to run under the 93 dB. noise restriction. I am currently running a 13b in my sand rail. What muffler/spark arrestor setup would you recommend?

 

we run 2 inline mufflers on the race car. one larger oval borla xr1 in the center and one magnaflow in the rear with a 90 deg turn down angled away from the db reader at the tracks. the car is quiet. i also run that same set up but with a 3.5 inch exhaust on my turbo car and the car is well under 93db

 

I didn't know that California had a Spark Arrestor rules, and thought Super Traps were just mufflers. For the record, they are spark arrestors required for use in Nationa forrests.



They have a muffling effect that can be adjusted by adding or subtracting rings from a stack of rings. Power wise it is a problem if you remove too many rings, the back pressure goes up.



So your primary muffler needs to be really effective. Years ago I bought a Borla racing muffler that is about 20" long, about 8" in diameter with a 4" center tube. In that center tube are 7 perf tubes that fill the 4" tube. There is no other muffler. The exit pipe just ahead of the right rear wheel is turned down 90 degrees. This is fine for 93dB or less at 50 feet and full throttle. I tried many other mufflers and combinations of mufflers, trying to stay under 95dB.



That measurement is an exponential curve, so 93 dB is way quieter than 95 dB. So I had a 3 1/2" Super Trap I could slip on if atmospherics changed and put us over the limit. Once I had the Borla we never needed the Super Trap again. Borla does not appear to make our muffler any longer. But similar (round) constructions are still in their catalog. Not many people ordering 4" tubes any more.



On a sand rail you could put a 90 on the end and point it away from the sound equipment. Aimed down at a 45 or more. Less reflection that way.



Note the heat tape. Very effective. Use only on stainless. Carbon steel will melt.



Lynn E. Hanover