CFM Continued...

[Bruce Plecan]

I tend to think other wise.  While not at the HP level we're talking here,
for my 355 SBC running a cross fire manifold with runners slight larger than
3/4"x3/4".  It will push a 3100 car into the 13.7s.
  While shortning the runners helped some, it was increasing the plenum
volume that really made the difference.
  I think the TPIs real downfall is that goofy plenum.  Other than the Accel
$$$$$$$ revised set up no one that I know of has tried reengineering the
plenum, in any other form to use the stock runners.
  The Accel part has always gotten good reveiws.   My contention is removing
the EGR, and lowering the "Belly" of the plenum, or raising the roof to get
a plenum that approches engine displacement.
Grumpy
     Gonna hit GP Dr Office later, and see if he has any better car mags.

> If a stock TPI runs out of breath at 4800 rpm on a 350, it will run out
much
> sooner on a 434, something like 3800 rpm.  My personal view is that it
> starts running out at 4000 on a 350 and 3200 rpm on a 434.  Just as your
> turbos are coming on, your intake will go out to lunch.  Using boost to
> cover up a poorly flowing intake or exhaust system works to limit the
> efficiency of the engine.
> I recommend a proper large flow passage intake system.  The tube ID should
> be approximately the same as your intake valve.  If you intend to run in
the
> 3000 to 5000 rpm range, the TPI tubes are OK for length, but too small a
> diameter.  If you intend to run above 5000 rpm, you need shorter and
larger
> diameter tubes.
> Don't forget, the only time you will be below 3000 rpm is in first gear
> where you will be traction limited anyway.
> Gary Derian <gderian at oh.verio.com>
> > Thanks to Ken, Todd & Gary for your answers regarding CFM.  Perhaps I
> didn't
> > ask the question correctly.   A stock TPI runs out of flow about 4800
rpm
> on
> > a stock 350 ci engine.  I'm looking for an EFI intake system for my twin
> > turbo 434 ci engine.