Two 75 Imperial Questions -- Vinyl Top Removal and Cam Profile

["John M Bittner" <jmb@xxxxxxxxxxxxx>]

Joe, It all has to do with flow dynamics. One could 
try to explain it with several pages of mathematical
formulas and equations, but in plain English you need
need to visualize what is happening.
 During the combustion process the spent gases are sent
out the exhaust system under pressure in pulses.
As the pulse of gas passes down the pipe it creates 
a flow which in turn creates a vacuum in the pipe
after it passes. This vacuum helps to pull the 
next load of exhaust gas from the next cylinder that
fires after it. You can probably start to realize
that the length of the pipe and the timing or RPM
of this flow process is critical. The H pipe
helps to propagate this flow pattern at low RPM's
by alternating flow paths down two separate pipes.
 It is amazing how much a well tuned set of pipes
can increase the horsepower and torque of an engine.
John

> -----Original Message-----
> From: mailing-list-owner@xxxxxxxxxxxxxxxx 
> [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of Joe Bachan
> Sent: Thursday, February 05, 2004 4:55 PM
> To: mailing-list@xxxxxxxxxxxxxxxx
> Subject: Re: IML: Two 75 Imperial Questions -- Vinyl Top 
> Removal and Cam Profile
> 
> 
> Pardon my ignorance but how does tying the two exhaust
> pipes of a dual exhaust system together with an 'H'
> pipe improve performance?
> joe
> --- dardal@xxxxxxxxxxxxxxx wrote:
> > Quoting Brad Hogg <roadhogg@xxxxxxx>:
> > 
> > > Regarding the H pipe.  My muffler guy suggested if
> > he were to convert my
> > > single exhaust car to dual that he would use
> > everything as is ans simply add
> > > a second pipe to the right side.  He would just
> > create a cut out in the
> > > elbow of the...
> 
>