Re: Mufflers

[Tom Harais <tjhemh@domain.elided>]

Tom:

2.5" because testing has shown that to be the best compromise size for low
back pressure, fit under most street vehicles and cost. Actually, I plan on
going to headers and they would most likely have a 3" collector. But,
bigger than 2.5" pipes on street engines is low or no back pressure but
doesn't help low end torque at all because it's TOO BIG. Smaller than 2.5"
results in uneccesary back pressure.

Somwhere on the web, I found a site that sold Walker Flowmasters real
cheap. It had a description of each model as in length, width, size of
inlet/outlet and offset and shape. It also had the data on back pressure
for the different mufflers and size pipes. 2.5" was the ideal street size
(for gasoline engines - diesels are another story).

The reason you have 2-1/4" so commonly is because that was the stock size
on Scouts. You won't find too many manufacturers using 2.5" pipe due to the
"extra" cost.

Tom H.