I was looking in the rule book on exhaust for the 600 and it looks like it says 6.5- ANY MUFFLER MAX 90 DBA. So as long as it meets that 90 dba it should not matter what lenght your muffler is. I just received a 12inch muffler and someone told me it had to be 18 inch. Does it have to be 18 inch?? I wouldn't think so since 90dba is what matters not length plus your muffler is more vulnerable at a longer lenght. Does it matter what lenght?
ET92 said
Mar 26 10:19 AM, 2009
Tate,
This may be one of those instances where it is really up to the track owners discretion. I know in the past Paul has tried to "spec" several different muffler combinations to minimize noise (and i'm not entirely sure that all 600's were passing the 90db threshold last year).
Perhaps Paul can provide clarification for the 600 class if he intends on making everybody use the same muffler, or if he will allow anything that comply with the NMSA 90db rule.
Eric Turner
mike said
Mar 26 10:20 AM, 2009
sometime during the season last year paul changed his rule to the longer mufflers, gave everyone a couple of weeks to switch over. sometimes the tracks have a different rule than the club, (that is why we try and correct the rules at the winter meetings)
tate said
Mar 26 12:06 PM, 2009
Thanks for the reply guys. Now I guess I will wait for Paul to answer to the question. I can't see any benifit in running a longer muffler if the dba is the same or less on some shorter muffler. Thanks Tate
tate said
Mar 26 8:14 PM, 2009
I went to MPS where Paul and the gang were doing dynos and DBa tests on alot of different muffler set-ups for this up coming season. We put my 12 inch muffler on there and it wasn't close to under 90!!! I got fooled on this one I bought. It's going back!!!!
This may be one of those instances where it is really up to the track owners discretion. I know in the past Paul has tried to "spec" several different muffler combinations to minimize noise (and i'm not entirely sure that all 600's were passing the 90db threshold last year).
Perhaps Paul can provide clarification for the 600 class if he intends on making everybody use the same muffler, or if he will allow anything that comply with the NMSA 90db rule.
Eric Turner
sometime during the season last year paul changed his rule to the longer mufflers, gave everyone a couple of weeks to switch over. sometimes the tracks have a different rule than the club, (that is why we try and correct the rules at the winter meetings)