stack size recommendations

Me personally I like the look of 8 inch stack. What kind of truck do you drive?

 

Personally i like the look of 7" the best .
Not to big or not to small. Just right!

 

I had a W9 with 7" pipes, no muffler or resonator, sounded real good. Had an Acert in it, which is quieter than a single turbo though. I like the look of 7" pipes the best too, not to small, not to big.

 

B model CAT's are quiet as a rule. 7's will give a deeper tone but won't really be any louder. That said I like the look of 7's and 8's bigger than that becomes gaudy lol.

 

hard to say iv. iv seen some trucks that are over the top in every way 400 lbs of chrome 200 chicken lights with 10 inch stacks that look good. a less over the top truck with 8's can look kinda silly imo. as far as being loud if you don't want loud put in a under the cab resonator or a resinator in the pipes to help quiet it down. anything straight piped is going to be loud. bigger will give a deeper tone where smaller will be a little harsher sounding

 

There's a coal bucket 'round here with stacks as big around as a 5 gallon bucket. Looks ridiculous, and is counterproductive. You want the exhaust to be large enough not to restrict flow, but small enough to keep the gasses flowing efficiently. Too large, and flow velocity decreases...and since flow velocity helps with scavenging, going too big makes it more difficult for the engine to breathe in as much on the intake.

5-6" works fine on a 728ci Mack. With more cid, a 3406 would probably be fine in the 6-7" range. I don't think I'd want to get much bigger than that, though. That light puff of black smoke as you take off or shift gears ought to be shot up into the air as a nice column...looks good like that. It should NOT be lazily puffed out like a pile of burning leaves, which looks rather pathetic.