Muffler Advice

LA,
Have only a few moments but I would like to comment.

I agree with David V. and so does Walker. They both like the 2.2 cfm of airflow on a bench per HP flowed at 20 inches of mercury I think it was. Whether it is 100% correct in all cases is unknown but it has been proven time and time again that restrictive mufflers hurt power and unrestrictive ones really do not.

Regarding crossovers, we saw lots of advantages with the true X as sold by Dr. Gas. I have no test experience with any others but based on how many of them are made, I can say they will not work as well and may even hurt power in many cases. I know his work. As far as location, seems to me after our testing that anywhere in front of the mufflers worked well but experts maintain it is better up in the front.

Many mufflers work great. Chambered ones tend to be louder and unless you bump the internal diameters larger than your incoming pipes, they tend to flow less. Also, anything with lots of turn arounds hurts airflow and three pass OEM-style mufflers tends to hurt high HP engines at higher rms.

One of the best we ever found for all around goodness is the long case Dynomax SuperTurbo. They have a good mix of sound and flow for good power output and nice driveablity and the longer ones, in most cases, tend to not resonate very much, if at all. The straight-through mufflers like UltraFlos and Magnaflows and Goerlich XLERATORS and many chinese knock offs also tend to let the engine run well and longer ones help keep the tone and sound level down depending upon the perforated pattern they have and the acoustic material that was used to pack them.

I certainly agree that Aerochambers do a good job of letting a lot of air through but, they tend to be a bit louder. A photo is below of one along with a straight through muffler.

More later.
Tom