w1964bgta

Has anyone ran the Dynatech split-flow muffler? reason being as I have had the opportunity to look at the (exhaust table) that IROCTHE5.7L put on this site (thankyou)and decided that I'm in need of a 4" sewer pipe for an exhaust. And I found this DYNATECH available in 4" inlet and 4" outlet for $95 and change and is much more economical than the other that I found (BORLA) at $189.99. Are these any good (the dyna-tech muffler)? And if I do get this muffler should I put it as close to the 3"Y possible, that SLP supplied to me w/the headers? I read somewhere that I should put the muffler further up in the exhaust and not in the back, is this true also? If so I can route out the exhaust before the rear axle and save$

brutalform

I was always under the assumtion, that, the further back the restriction (muffler) is, the less impact it has. You might not need the 4"dia. as the mufflers efficiency, not the pipe dia. is usually where the problem is. You can still have a 4" system, with a less than optimal muffler, and still be down on power. I found this article you might be interested in:



http://superchevy.com/technical/engi...t/0505phr_exh/

w1964bgta

Oh my ***, that was a very informative article but it did not tell me where to put the resonator (muffler) but everything else I think I got. Tail pipe length doesn't matter just don't dump it under car or yer car becomes reonator. It didn't deal w/single exhaust though. Should I go to duals? Now that's mo money!! Is it not? So as long as I have proper cfm flow on muff I should be ok, anyways I liked the what you gave me and thanks for the tips on my TQ arm bushing mount as it is off, thanks!!!!!!!!!

brutalform

Alot of states, have inspection laws, that say that you must have the pipes exit the body. Here in Pa. is the case anyway. If I were able to dump my exhaust, say, before the rear axle, things would would have been so easy for me.

BTW, What kind of engine, do you have, I mean, as far as power goes?

w1964bgta

I wonder how ford trucks get away with their exhausts dumping out before the axle in PA? Ahh, re-read thread and (out of the body) is the key. I believe that I'm going to be in the 450-475 hp range maybe a little more or less. That's what engine builder (MOTORCITY MUSCLE) said, we'll see when I get to a dyno this summer, making some sick comp. ratio 13.83-1 miight as well say 14

brutalform

Yes, as long as the exhaust tips either come out the sides, (before rear tire), or right out the back. They can not end somewhere under the vehicle.

Here is what I am currently running. I have Hooker L/Ts. Then a Mufflex "Y" pipe. Then it channels into a F/M cat back. I changed the F/M muffler, for a Dynomax UlltraFlow. The muffler change netted me one MPH, and one tenth, at the track. The ONLY thing that I really am concerned about with my system is, where the end of the Mufflex"Y" ends, to where the catback begins. I have a 4", to a 3" reducer collar there. If I drop my entire system at the track, my problem is is the change valid? I mean would the car pickup because of the system and muffler not there? No way to tell if the funneled 4" into the 3" is the problem, over the 3" system, as a whole. Im not going out and purchasing a Mufflex 4" system, just to not pick up anything. I hope this made sense? My engine made 500 hp, and 570 lb.ft. on the engine dyno.

w1964bgta

From what I've been able to decipher from the article you sent is that yes, that would be a problem: 4"to3". That part was on the 1st pg. of article I believe. Re-read that article maybe I'm wrong but I think I understood it correctly. But didn't get where I'm supposed to put muffler or (resonator) as author calls it. Do you know flow #s for the dynomax? I figured I'd need in the neighboorhood of 1050CFMs of flow using the 2.2 x hp rule in article.
http://superchevy.com/technical/engi...t/0505phr_exh/

brutalform

IIRC, the flow #s for the UltraFlow single muffler, (3" in and 3" out), was somthing like 1130 CFM.

w1964bgta

hey, thanks for those CFM #s brutal. I refigured my #s and came up with 1100. And from what I read that smaller reducer collar, 3" from the 4" IS hurting you, how much? I couldn't say, wish I could. What RPMs are you turning? I think that dropping your cat back wouldn't help at the track (too much back pressure)at the collar, killing scavenging properties no matter what length collectoris being used.