Re: porting, polishing & chroming intake manifold

["jtrealtywebspannet" <jtrealty@xxxx>]

Porting and polishing will only work as part of an overall plan. It is 
used in the larger context of what is called "blueprinting" an engine 
i.e. making it as close to exact specs as possible, closer than the 
ordinary production tolerances. As such you do ALL breathing surfaces 
including the heads, and the exhaust manifolds. What goes in can only 
go in as fast as what goes out permits so you must work on BOTH sides.
Another point to consider, in some cases a rough surface creates a 
boundry layer that promotes mixing keeping the air fuel mixture 
turbulent so that droplets don't settle out in different runners. 
Making it too smooth inside might actually degrade performance. This 
is where many parts are made and tested on flow benches to see what 
actually improves things. Keeping crossection small also keeps airflow 
high which improves the inertia of the air flow. This is really no 
area to tinker in unless you are ready to spend $BUCKS$. A slip of a 
grinder and you wasted a part and it is really easy to go too deep too 
fast in aluminum. Polishing the "Y" pipe inside won't have any effect 
as it only carries coolant. The PRV-6 engine seems to be a very finely 
engineered SYSTEM so improving 1 thing will have a minor effect.
David Teitelbaum
vin 10757 




--- In dmcnews@xxxx, Soma576@xxxx wrote:
> In a message dated 3/1/02 10:45:56 PM Central Standard Time, 
Whalt@xxxx 
> writes:
> 
> 
> > BTW, I'm also considering a different design for the throttle 
spool cover
> > that would fit UNDER the Y-pipe. The OEM one just looks like it 
doesn't
> > belong there and unbalances the symetry.
> > 
> > Walt 
> 
> Walt, 
>