So I need a muffler to pass inspection, so no straight pipe for me!!! I was thinkin about a 3" Thrush type glasspak to get me by till I can afford to finish fabbing up the stacks. Anyone know how this sounds on a 91.5 cummins with 3" exhaust? Worth it, or should I try to fab up a "dummy" 4 inch chamber to look like a muffler. If I don't get help soon, I'll just go and try stuff out for myself. Thanks, Jeff

 

You might try www.sourceautomotive.biz

Rip Rook sells a "sneaker" muffler... Looks like a muffler so you can pass a visual.

 

A smart man, like me, would devise a muffler with flanges on both ends, and a like-sized section of straight-pipe with matching flanges.

When being inspected, simply swap the flanged section for the flanged muffler.

When you get your credentials, and all papers are in order, slip the straight pipe back in.

If made well, the whole swap shouldn't take over a quarter hour.

 

Love the intro

Good Idea too.

 

If you put on a glass pack it will sound like a straight pipe in about 3 to 6 months. All that carbon fills the holes.

 

I seen test somewhere online between glasspacks and a high flow mufflers and the mufflers accually flow better numbers than the glass. Something to do with tubulance and harmonic distortion disrupting the flow.

 

great call all, I WANT straight pipe,, but I got to get around the man. My old inspection boy went the way of the dodo, so I need to cheat the system .Plans now to fab uo a fikie muffler to look real, and thats it for now

 

A turbo technically counts as a "sound suppression device"

 

that is tru but i don't thing "the man" will agree

 

You don’t even need to add flanges, just use the band-type clamps. They’re about $10 to $12 each at NAPA.

 

I guess it depends on what state your in. I just get farm plates so I don't have to get inpections.

 

Do like Boatnik said. Put on the glasspack and wait a while - you will have a straight pipe in a few months when the fiberglass gets clogged up with soot.

 

Thanks wanna and boatnik, that was my plan, striaght pipe sound with the muffler look for "the man"... for now, muuhahaha

 

Yep! That is why I got a muffler for an 8.3 Cummins in a school bus. Four inch on both ends and egt's only raised a little. But my egt's are to high anyway. Just got to watch the gauge.

 

Actually The man has it stated in the FMCSA guidelines. And since state cant overturn Federal, it should be legal. Here it is:


Subpart E — Measurement of Noise Emissions; Stationary Test

§325.91 Exhaust systems.

A motor vehicle does not conform to the visual exhaust system inspection requirements, 40 CFR 202.22, of the Interstate Motor Carriers Noise Emission Standards, if inspection of the exhaust system of the motor vehicle discloses that the system

(a) Has a defect which adversely affects sound reduction, such as exhaust gas leaks or alteration or deterioration of muffler elements, (small traces of soot on flexible exhaust pipe sections shall not constitute a violation of this subpart);

(b) Is not equipped with either a muffler or other noise dissipative device, such as a turbocharger (supercharger driven by exhaust gases); or

(c) Is equipped with a cut out, by pass, or similar device, unless such device is designed as an exhaust gas driven cargo unloading system.

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