Inliners International Forums General Discussion Hi Performance Split exhaust

I don't know if this helps, but here goes:

A very important factor of exhaust flow is velocity.
That's why the exhaust piping size (diameter) needs to
be matched to the available flow.

The other factor for street exhausts is the overall
volume of the system before the flow meets atmosphere.
The more volume of the proper diameter equals better flow.

The longer exhaust velocity can be maintained within the
system, the more power the engine can develop. This is
for street/muffled systems.

Think of this, a Harley Davidson exhaust diameter and length
vs. the single pipe exhaust of a stock 1960's inline six.

The trick in improving engine performance by exhaust mod's
is tailoring the exhaust to the engine's state of tune....

The only formula I have ever found that helps is this:
Most engines perform well with at least 2.5 times the
cylinder volume in the head pipe before the 1st restriction.
(Baffle).

One last "trick", remember those coffee cans over the
ends of zoomie exhausts on the old dragsters? The open
tube allowed the exhaust flow to enter atmosphere with
the least turbulence.

I hope this helps.