New Member, Muffler Question (CMod)

Hello fellow CMod competitors,

I have been wanting to try CMod for several years, and I finally took the plunge. I just purchased this 1983 Reynard FF1600 (former autocross car, currently set up for road racing):


Previously I had an STX car, so there is going to be a *huge* learning curve for me. I have already learned a lot from this forum, so thank you very much to everyone who contributes.

I have a question which I am hoping someone can help with. I did some searching but could not find anything conclusive.

The car currently does not have a muffler, and I am trying to decide what size I need. I have had great experience working with Coast Fabrication in the past, so I plan to buy from them again (they also make the Burns mufflers).

Our local site has a very strict sound limit of 90dBA measured at 75'. My question is what size muffler do I need?

Here are the three options available for a 2" pipe:
3.5" O.D. x 14" L = 91 in^3
4.5" O.D. x 11" L = 140 in^3
4.5" O.D. x 18" L = 230 in^3 (custom size)

Obviously the biggest muffler would be the most effective, but I don't want to go any larger than necessary for cost and packaging reasons.

Does anyone have any first hand experience with Cost Fab / Burns mufflers who can make a suggestion?


Thanks in advance,

Dave T
New to CMod

New Member, Muffler Question (CMod)