Re: Throttle Body Update

From: Andre Mauboussin (andrem@cyberramp.net)
Date: Wed Jul 23 1997 - 09:59:12 EDT


jaallis wrote:

> > over the past several quarters we have had several 3.9 customers
> send us
> > their changed out V8 tbis to exchange for modified MPI 3.9s as they
> did
> > not like the performance with the v8 they put on. soft bottom ends,
>
> > poor in traffic performance, stock worse than modified 3.9s.
> >
> > we milled 1/4" off an intake runner and measured it on a superflow
> 600
> > set on a 420 scale. the monometer showed NO movement of the fluid
> > level... ie, no cfm gains! imo, based upon extensive work in the
> > manifold and tbi area the milled runner may give some gains at WOT
> with
> > a built engine, but for the "regular" guy... it will be a costly
> > exercise with little or no effective gains. there are other ways to
>
> > wake the 3.9 and it IS easy to get it to out run a stock 5.2 or a
> 5.9...
> >
> > to say you will get significant gains with above referenced info
> from
> > the mag article is a misrepresentation of the facts..., ioo
> >

In the magazine, RC Performance Engineering was talking about milling
the entire length of the protruding ridges of the manifold runners
(about 3-4" NOT 1/4"). This should make for a significant flow increase.
They also suggest reducing the plenum volume by adding fabricated plenum
boxes. I have no doubt that a 1/4" milling wouldn't do much of anything.
Has Jules tried milling the entire ridges off and dynoing the results?
I'm sure RC Engineering (who build and race magnums professionally) have
documented the results. Until Magnum Performance actually does what
these people have suggested and tests the results, they should quit
criticizing their claims. Oh yea, you can ask Karl Moltzan how much
improvement he got with the MP throttle body and $500 1.7 roller rockers
Jules sold him. NONE! When you call MPI, keep a tight grip on your
wallet. JMHO.

Andre Mauboussin

 



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