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T3: Re: intake manifold polishing


On  5 Mar 98 at 8:13, Big Al wrote:

> Well, I figure that since most race teams have just as much research behind
> them as Gene Berg, and they race to put bread on the table (kind of a "no
> win, no eat" situation), and they stive to polish intakes and ports to
> improve these odds, there is probably something to it.
> 
> The question is, would there be an advantage?  Our 54hp (or some odd with
> modifications) engines probably would not have much effect. Am I right Jim?

Good air flow brings advantages to any engine.  It is essentially 
"free" horsepower.  I think the only real debate here is which 
approach here really works.  I suspect that there are many variables 
and that it is hard to generalize.

As to what real racing teams do, I suspect that they never publish 
anything that they feel confers any real advantage--at least until it 
is already so widely known that there is no loss in doing so.

> >Just because something is obvious doesn't mean that it is true.
> >Actually, I'm not sure of this either, I don't own a flow bench and
> >have no experience with one, but I got this information from someone
> >who owns and uses one.   His feel for these things is usually good.
> >I don't recall if Gene Berg had any comments on this.  He's usually
> >done his homework, too.
> >
> 
> And I thought he offered ported and polished VW heads...

Or was that just ported intakes, and possibly polished combustion 
chambers and exhaust ports

> Air (and fuel) volume is a contributing factor to HP's.  This is fact, not
> just conjecture.

Agreed
 
> >> Rough pipes decrease the flow velocity of the air which makes the engine
> >> starve for fuel mixture right?  I can see the "rough causes mixture" in
> >> theory, but if this is so, wouldn't VW have added a texture to the pipe?
> 
> VW did their research too.

Yes, but they also had pricing constraints.

> >> And for polishing the exhaust manifold... Where?  Do you mean the interior
> >> of the heater boxes? I am unclear as to the location you mean.
> >
> >This comment was general.  In our VWs I agree that there is no need
> >for any polishing in the heater boxes because the pipe ID is already
> >smooth, but there is some advantage to smoothing the interior of the
> >exhaust ports in the heads.
> 
> Now this is an interesting idea. How much lower head temp (ballpark) could
> one acheive by doing this, and as you stated "The fact that someone wants
> something doesn't mean that there's an advantage to it. "  is there an
> advantage?

I'm pretty sure there is some advantage, I just don't know how much 
or even if it is noticable.
 
> I would suggest to John that if he wants to clean the interior of the
> intake, use a bottle brush attached to a flexible extension shaft on a
> power drill and (although somewhat blindly) work it through the intake to
> remove corrosion and or debris.

Or get them bead blasted while they are disassembled.

Jim
-
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************


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