Re: Back pressure

["Billy T." <btylaska@onramp.net>]

no!  ha ha!

LORI ROSE wrote:

> REMOVE MY NAME
>
> -----Original Message-----
> From: Matt Zajac [mailto:MTZajac@beloit.com]
> Sent: Monday, January 03, 2000 3:25 PM
> To: jettaglx@igtc.com
> Subject: Re: Back pressure
>
> Hi Bill
> Thank you for explanation. The only thing that I don't really understand is
> why backpressure is impoortant for low end torque. From what I've heard so
> far is that too low backpressure will hurt low end torque. Perhaps you can
> help me with this.
> Thank you very much.
>
> Sincerely
> Matt Z.
>
> >>> Bill Hussey <vfrboy@home.net> 12/28 4:38 PM >>>
>     Backpressure is when your exhaust system doesn't release as much air
> as the engine is putting out.  Like dripping oil into a funnel ... the
> funnel doesn't flow as much as the larger-necked quart of oil bottle so
> the oil builds up in the reservoir.  Same thing as air .. if the exhuast
> can can't release enough, the gases build up and cause a pressure.  As
> pressure builds, it pushes back up the exhaust system ... thus the term
> "back pressure".
>
>     As pressure increases inside the exhuast system, it moves up towards
> the engine and stops air from coming in (not all of it of course, but
> some) ... this is why a restrictive exhaust system cuts power, because
> air flow, and thusly fuel flow once the EFI compensates, is cut.  Most
> engines only push enough air to cause back-pressure at higher RPM
> ranges, which is why you only get an upper-rpm power increase when
> throwing in a new exhaust system.
>
>     Diameter of the exhuast and header tubes is not the only factor
> either .. bend quality and smoothness is very very key.  If the inside
> surface of the pipes are rough or the bends are angled sharply, the air
> flow is distrupted and will slow down which will cause a "traffic jam of
> air" if you will, and again build up pressure.  Straight pipes with
> gentle bends and polished insides produce the best power, but sound
> louder than hell.  I'm going into a huge tangent now .. so I'll stop.
> Hope this helped.
>
> Bill
> '98 GLX
>
> Matt Zajac wrote:
>
> > Hi
> > Can someone please tell me what backpressure is?
> > All I know it refers to exhoust.
> > Thanks in advance
> >
> > Matt Z.
> >
>
>
> !
>
>
> !
>
>