[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: engine decision's... I have made up my mind.

To: "Brian Wagner" <scirocco_88_16v@hotmail.com>
Subject: RE: engine decision's... I have made up my mind.
From: "Scott F. Williams" <sfwilliams@home.com>
Date: Mon, 6 Aug 2001 16:53:16 -0400
Cc: <scirocco-l@scirocco.org>
Importance: Normal
In-Reply-To: <F50N3rYE77ZwLeTJdy1000117c6@hotmail.com>
Sender: owner-scirocco-l@scirocco.org

It isn't the back pressure that makes more torque. It is the proper port
velocity and properly tuned acoustics in the exhaust system. A shock wave
blasts out of the combustion chambers with each exhaust pulse. Once it hits
an obstruction, a bend, or other pulse, the wave then reflects backwards and
pushes any unburned fuel and air mixture back into the combustion chamber.
This also promotes greater chamber fill and thusly more low-end torque.

Someone educate me about the burnt valves thing, though. I forget why that
happens. Is it because you've got oxygen hitting red-hot metal?
______________________________
Scott F. Williams
Account Manager
GENUiTY - Eastern Region
100 Wall Street, 10th Floor
New York, NY 10005
Voice: 212.416.1745
Cell: 917.648.2256
Fax: 212.618.5160
scott.williams@genuity.com

> -----Original Message-----
> From: owner-scirocco-l@scirocco.org
> [mailto:owner-scirocco-l@scirocco.org]On Behalf Of Brian Wagner
> Sent: Monday, August 06, 2001 4:44 PM
> To: sfwilliams@home.com; Josh.Hignight@phoenix.edu
> Cc: scirocco-l@scirocco.org
> Subject: RE: engine decision's... I have made up my mind.
>
>
> BP is essential to the life of the engine, without it you will get burnt
> valves and a top end.
>
> Brian
>
> 88 16v
> 87 16v
> 86 8v (sold to neighbor)
>
>
>
> >From: "Scott F. Williams" <sfwilliams@home.com>
> >To: "Josh Hignight" <Josh.Hignight@phoenix.edu>
> >CC: "scirocco List" <scirocco-l@scirocco.org>
> >Subject: RE: engine decision's... I have made up my mind.
> >Date: Mon, 6 Aug 2001 16:27:15 -0400
> >
> >Okay, you got me there. Let's say that no *4-stroke* motor needs
> >backpressure. :^)
> >______________________________
> >Scott F. Williams
> >Account Manager
> >GENUiTY - Eastern Region
> >100 Wall Street, 10th Floor
> >New York, NY 10005
> >Voice: 212.416.1745
> >Cell: 917.648.2256
> >Fax: 212.618.5160
> >scott.williams@genuity.com
> >
> > > -----Original Message-----
> > > From: owner-scirocco-l@scirocco.org
> > > [mailto:owner-scirocco-l@scirocco.org]On Behalf Of Josh Hignight
> > > Sent: Monday, August 06, 2001 4:15 PM
> > > Cc: scirocco List
> > > Subject: RE: engine decision's... I have made up my mind.
> > >
> > >
> > > Umm, 2-strokes benefit from backpressure. Since most 2-stroke
> > > engines don't
> > > have mechanical valves, the back pressure helps to eliminate blow-by,
> >thus
> > > increasing power because it maintains that there is a mixture to
> > > burn in the
> > > chamber (Hence the reason my r/c car barely runs when the pipe
> > > falls off).
> > >
> > > But that's beside the point when it comes to dubs. Just thought
> > > I'd mention
> > > it.
> > >
> > > Joshua Hignight
> > > Student Services/Technical Services
> > > New Mexico Campus
> > > (505) 821-4800
> > >
> > >  -----Original Message-----
> > > From: 	Scott F. Williams [mailto:sfwilliams@home.com]
> > > Sent:	Monday, August 06, 2001 1:11 PM
> > > To:	jdbubb@ix.netcom.com; Neal Tovsen
> > > Cc:	scirocco List
> > > Subject:	RE: engine decision's... I have made up my mind.
> > >
> > > Let's kill the myth that backpressure helps an engine. NO ENGINE
> >BENEFITS
> > > FROM RESTRICTION IN THE EXHAUST SYSTEM! The reason normally aspirated
> > > engines may gain more torqe with a smaller diameter exhast,
> is because
> >the
> > > higher velocity in the system creates a greater scavenging
> effect that
> >in
> > > turn allows for cleaner combustion chambers, wich means more air-fuel
> > > mixture per stroke, which means more power.
> > >
> > > Zero backpressure is always the ideal. Complete scavenging and
> > > high exhaust
> > > velocity are always the goal.
> > > ______________________________
> > > Scott F. Williams
> > > Account Manager
> > > GENUiTY - Eastern Region
> > > 100 Wall Street, 10th Floor
> > > New York, NY 10005
> > > Voice: 212.416.1745
> > > Cell: 917.648.2256
> > > Fax: 212.618.5160
> > > scott.williams@genuity.com
> > >
> > > > -----Original Message-----
> > > > From: owner-scirocco-l@scirocco.org
> > > > [mailto:owner-scirocco-l@scirocco.org]On Behalf Of Dan Bubb
> > > > Sent: Monday, August 06, 2001 2:55 PM
> > > > To: Neal Tovsen
> > > > Cc: Patrick Bureau; scirocco List
> > > > Subject: Re: engine decision's... I have made up my mind.
> > > >
> > > >
> > > > somebody, please somebody explain this BS about lower backpressure
> > > > causing loss of power!
> > > >
> > > > Neal Tovsen wrote:
> > > > >
> > > > > > 2.5" Pipping finishined with stainless Remus or Borla
> Muffler.(to
> >be
> > > > > > decided)
> > > > >
> > > > > Did you mean 2.25"? 2.5" is pretty damn HUGE for a N/A 2.0L
> > > engine. With
> > > > > such a loss of backpressure, you might actually lose power.
> > > Since you're
> > > > > ordering the manifold/downpipe from TT, you could go with their
> >2.25"
> > > > > exhaust system with a Borla for a sweet full setup.
> > > > >
> > > > > Looks like a screamin' setup otherwise. Go for it!
> > > > >
> > > > > Neal
> > > > >
> > > > > --
> > > > > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > > > > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > > > majordomo@scirocco.org
> > > >
> > > > --
> > > > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > > > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > > > majordomo@scirocco.org
> > > >
> > >
> > >
> > > --
> > > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > > majordomo@scirocco.org
> > >
> > > --
> > > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > > majordomo@scirocco.org
> > >
> >
> >
> >--
> >Email LIST problems to: scirocco-l-probs@scirocco.org.
> >To unsubscibe send "unsubscribe scirocco-l" in the message to
> >majordomo@scirocco.org
> >
>
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
>
>
> --
> Email LIST problems to: scirocco-l-probs@scirocco.org.
> To unsubscibe send "unsubscribe scirocco-l" in the message to
> majordomo@scirocco.org
>


--
Email LIST problems to: scirocco-l-probs@scirocco.org.
To unsubscibe send "unsubscribe scirocco-l" in the message to majordomo@scirocco.org

Follow-Ups:
- RE: engine decision's... I have made up my mind.
  - From: Brian McGarvey <brianm@zbt62.eastnet.gatech.edu>

References:
- RE: engine decision's... I have made up my mind.
  - From: "Brian Wagner" <scirocco_88_16v@hotmail.com>

Prev by Date: RE: 16V top end clattering - impending doom?
Next by Date: RE: [theory] Exhaust size/restriction vs. power
Prev by thread: RE: engine decision's... I have made up my mind.
Next by thread: RE: engine decision's... I have made up my mind.
Index(es):
- Date
- Thread