2300 muffler location

[RickeyB]

What are the pro's and con's of muffler location?? I have heard 14" from the collector but would like to know the purpose be hind that. I'm using a 9" muffler (if you could call it that) and 3" pipe

Thanks,
Rickey

[Racedad]

84Dave provided this information to this board years ago and I convinced he's right on the money.

I'm counting on him responding soon here to your question.Follow his advice, he is a gentleman and gracious to share what he knows.

And get yourself a copy of Pipemax, favorite software I ever bought and well worth the cheap price.

[84Dave]

Pro's & con's of muffler location? With the right type of muffler, which can act as an 'expansion chamber', and its location from the ends of the header primaries inside the collector, the positive-pressure 'compression' wave from a 'just-fired' cylinder traveling down the header becomes a negative-pressure 'expansion' wave inside the muffler. That expansion wave immediately travels back up toward the engine and arrives at, and helps further evacuate the chamber of the 'previously-fired' cylinder, which is on the overlap cam cycle. So....... header primary & tailpipe lengths/diameters, and muffler location matter considerably. A BIG x2 on RaceDads recommendation of Larry Meaux's PipeMax software. PipeMax is moderately better/more accurate than the formuli I presented here many a moon ago. Why? Because the software requires a few more ACCURATE engine parameter inputs, versus the formuli I once used extensively. And accuracy is everything. Keep in mind the ole 'garbage in/garbage out' software concept. Go to www.maxracesoftware.com to acquire PipeMax. It's the best $$$ you'll ever spend on your race car. Whether a 4-cylinder Mini-Stock or a NASCAR Sprint Cup V-8. The best 'muffler' to use? Rules permitting, and enough room under the race car, use a FlowMaster 40-series Race SINGLE CHAMBER, installed BACKWARDS. The internal volume of the FlowMaster is sufficient to establish a good expansion wave from the compression wave. Yes.... the FlowMaster flows better installed backwards, although the 'noise' reduction is slightly less. But it'll pass the 95dB noise level test required by many race tracks. -Dave-

[4b316]

Dave,maybe you answered this befor but would it be better to run a muffler(flowmaster 40) or none at all,just straight pipe off the header?3 inch right now,turning about 6400 with stock cam and EFI

[84Dave]

If your Rules dictate that no 'muffler' is required for your track/class of racing, run an open pipe. The pipe exit into an open atmosphere can provide a good 'expansion chamber' for the production of a good negative-pressure wave back up the pipe. However, if running an open pipe, the pipe end should have a generous exit flare. It's a natural fact that a piece of circular pipe simply cut off squarely is somewhat of a restriction @ the exit. The flare dramatically reduces/eliminates the restriction. Also...... your engine appears to be close to 'stock'? Using PipeMax software for exhaust dimension calculations, you may find that a 2.625"/2.75"/2.875" exhaust pipe is recommended off the header for your engine. The 3" you're using may not provide enough exhaust mass velocity @ lower rpm to develop good Torque for you @ some specific/required rpm. Unless your engine is close to 3500cc capacity...... or larger. -Dave-