Hello,

SPA rules regarding mufflers:
A proper muffler must be used but tuned pipes are not legal d. Pumps may be used but no oversized carburetors can be used.


What category would tuned mufflers (like Jett, Evolution new blue muffler, and the like) fall into?? Are they legal or not??

I ask because I initially assumed they were not allowed due to the fact that they do increase performance. Then I read where a guy won a SPA contest using one of the new Evolution blue mufflers on his new 60NX.

What do u think??

So you have your flame suit ready...lol....


like you said here is the rule from the site..........

3. Engines

a. Any side exhaust two cycle engine up to .61 cubic inches is legal
b. Four cycle engines up to .91 cubic inches with no air chamber or super charging or any kind are legal
c. A proper muffler must be used but tuned pipes are not legal d. Pumps may be used but no oversized carburetors can be used.

so if it said muffler on the package , I would think it would be legal.. I think there where a few used at the SPA Masters in 2010....

It is legal in CPA www.classicpatternassociation.com

Wave tuned mufflers are legal. Jett, Evolution, and Ultrathrust mufflers are a few that come to mind.

I got the OK from the SPA president. It was my P7 that ran at the '10 Masters.

Thanks,
Do u remember how much rpm you gained using the Evo muffler?? Also, what prop??

I'm kind of ignorant here, but what's the difference in function between a tuned pipe and a wave tuned muffler?

The short, quick answer is that they are similar because both boost power.

Tuned pipes can be "tuned" for a particular prop/rpm, thus you can produce more power if done correct. One disadvantage is they are bigger. Tuned mufflers are tuned at a particular rpm so you have to prop accordingly to get max power. The advantage is they are smaller.

As for the Evolution blue muffler, they say that its tuned for 15k+ (website says at or above 15k). That is why I am asking playntraffic how his setup performed (Evo 60NX with Evo blue muffler). I want to know how much (if any) of a boost he is getting over stock muffler. I believe he is running in the 13k range on a 11x6/7 apc prop. I'm thinking about trying this muffler on my Mag 52.

I have a more detailed information on tuned mufflers, so pm me if you want to know more.

It is like night and day. The evo motor with the stock muffler has midrange problems. The evo tuned muffler cleaned that up and raised the rpms about 1500. I was using a 10x7 on my kaos but changed to a11x6 for the P7. You have to get the motor up on the rpms or it doesn't run good. I am using 15% fuel because there wasn't much gain with higher nitro . Get the engine/prop combo to turn at least 15000 and it should run good. Check out the evo60 threads in the glow motor section .