Old Muffler Comparison

[Steve Wood]

Some of us old guys are always ranting about how sorry Flowmasters are and why they don't work on our cars because they are built for tuned exhaust pulses whereas our cars don't have much in the way of a systematic pulse because the turbine wheel chops up the pulses so the Flowmaster tuning does not work.


I suspect that is more sounds good, but is less filling when it comes to science.  I think the reason they don't work as well is they are restrictive as hell.  IF your car makes enough power to make restriction a problem, then there are far better mufflers available.  If you make 200 hp, then the restriction is not a problem.


Below is an old chart that compares some various mufflers for flow and noise.  Note that UltraFlo, Maxflows, Magnaflows, Pypes, are all basically the same design inside so I think any of the straight thru types that do not have louvers hanging down in the exhaust stream will probably perform basically the same.


 

[larrym]

Good stuff!

[Charlief1]

I had that chart at one time and then the puter crashed. Thanks for posting it again Steve.

[Steve Wood]

I think they did one on three inch mufflers as well

[Charlief1]

Since I'm going with a single 3" I'd love to have that one as well for comparison if you can find it Steve.

[Steve Wood]

I will look for it...  here is an interesting article that takes some reading http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/index.html

[Steve Wood]

On a NA engine, the rule of thumb is 2.2 cfm of flow per hp....not sure if that applies to FA, or not.  My guess is that it does not because we are shoving the air out the pipe with the turbo.  After all, we see 700+ hp on a single 3"

One square inch of area equates to 115 cfm ~ for pipe flow.

[Charlief1]

Thanks for the link Steve. It brings some interesting theory to the table for my headers. I will hopefully be welding the new ones up this weekend.

[Steve Wood]

Vizard really knows his stuff and is good at explaining it.

[phil_long]

This might be a dumb question, but how did they get 101% for the dynomax ultra flow, and what's the difference in the "welded" version versus the regular dynomax?

[phil_long]

Ok, so thats actually two dumb questions combined into one.  :-)

[Steve Wood]

The welded one has all the seams welded up instead of being rolled, or crimped like the normal muffler.  I think it is supposed to be stronger and last longer. 


I can only guess that the 101% could be attributed to a tuning effect that sucks a bit more air through.  One percent is probably in the range of error for the bench.

[phil_long]

Ah, got it.  I was always under the impression that most exhausts were welded.  Guess not tho.  Thanks for the info

[Steve Wood]

Look at a pic of the two mufflers mentioned and you can see the difference