Anyone know of a good low restriction muffler and where to find one at???

 

Flowmaster claims theirs flow better than a straight pipe and are fairly quiet but nobody posts anything about them - I think they are high $$$ and nobody buys them. Craig

 

The Donaldson and the aero muffler are most popular on here.. Just search them. The hushpower has supposedly made more power than straight pipe as well

 

Yeh, Hushpower is what I'm thinking of. I think it's made by Flowmaster. I wonder if the hp keeps going up if you use more than one Hushpower! Craig

 

I run the Aero, and have installed quite a few for people... You wouldn't be dissaponted if you go with that one..

 

How does a muffler with bends / baffles flow better and make more HP than a straight pipe?

Those statements defy all laws of physics.

Straight pipe=less friction=greater velocity=faster expel of exhaust=more HP

Those claims are retarded.

 

whaaaaattttttt?

 

What year truck do you have ? I have an '05, and I just replaced the muffler with a straight pipe, kept the cat. It is not too loud, and it has to flow better than any muffler like Festus said.

 

I like my 40" Nelson, 4" straight through. Got mine from the local Cummins store for $67 Cdn.
Not obnoxiously loud like soe after market mufflers, nice low tone, not much louder than stock, sounds nice when you punch it and no drone.

 

My exhaust is factory 3.5" size pipe I believe. Can I get similar results by simply replacing my muffler with a good aftermarkert as I would get by replacing my entire system with a 4"?? Note, I'm not after sound, just efficiency. Thanks.

 

So the stock muffler is somewhat restrictive? Generally speaking, with diesel its better to have free flowing exhaust as opposed to gas engines that need some back pressure?

I hate to mess with mine and make it worse. I already did that once with a flowmaster on a Montero a while back. That was a mistake

 

Its based on aerodynamics and scavanging effect. Thru specific placement of baffles they can increase the velocity of the exhaust... I don't know if they really do, or how much, but it is possible.

Donaldson 40" M085171, has the best flow, over 3K CFM, that I have seen.. And only $65 at ryderfleetproducts.com I have one and it works great.

 

Now, I'm not going to profess I was an honorable physics student and I will always stand to be correct. Maybe it is possible.

However, here is my logical way of thinking: Any exhaust flow that has to bend around a baffle, especially numerous baffles, must create some type of friction. Friction slows stuff down, thus less flow. Molecules of air moving within molecules of air create friction even.

Personally, I need proof rather than some company just using this as a marketing tool.

JMHO.

 

Probably has something to do with the baffles creating an air vortex that allows other air molecules to slip by at a higher rate of speed, like a conveyor... Supposedly a truck with an open bed and tailgate up will get better mileage than with the tailgate down. Air trapped in the bed allows air currents to flow from the cab over the trapped air at a different pressure, just guessing.....I'm no scientist. But I would agree that a straight pipe makes more sense.

 

I run Flo-Pro Twister Race muffler and really like it.

http://www.flopro.com/DPmufflers.htm