Siamesed Runner TPI Questions...

[Bruce]

Naaaa,
IMWO, it varies on a case by case evaluation.
For a new guy TBI will always be easier to build from the ground up.
For a very large displacement engine, MAP is the answer, and cam/rpm will
guide my response.

5+7 are mute in my opinion, most of the problems for them are cross
fire/ignition.
On a wet manifold, ya there can be problems, but generally at the higher rpm
levels.

I'd watch getting too short of runner.
Heck, I advocated the connected runner idea for a long time now,
What I would do if I were you is start measuring things out for the plenum
volume and see where you are
Bruce




> This thread over here too?
>
> Its not for everyone... but it is possible to extend the range of the TPI
> more to popular liking...
>
> Think of how the siamesed runners shift the curve. Now say "what if" the
> runners were siamesed all the way down?  more shift. Now... hmmm.. what if
> the siamesing was extended all the way INTO the base?  no need for large
> runners or a ported upper intake now... cause you're drawing from 2 runers
> simultaneously!  reversion is a concers, especially with #5 stealing fuel
> from #7 in the cycle of things but cam overlap management can help here.
>
> Here is Mike's URL with dynos of some different TPI intakes.. including
the
> siamesed-base.
> http://www.eecis.udel.edu/~davis/z28/winter01/dyno/
>
> again.. not for everyone... just another idea for the mix.. complete with
> dyno data.
>
> Oh.. the siamesed-base dyno will be re-done soon. A problem was found with
> the motor setup and is now repaired.. the dyno comparisons illustrate the
> mod well enough (a zero dollar mod I might note) .. but the next set
should
> show more of an appropriate comparison. stay tuned! ;-)
>
> -Dave Z
>
> 89 Iroc - '730 - 383 large tube MAP TPI, ZZ3 cam ,dry NOS 50 shot.
> 12.79 @106 / 12.08 @ 112.   www.delanet.com/~tgp
> 92 25th annev convertible  305 / T56.  268 mph in a perfect vacuum.
> ----- Original Message -----
> From: Bruce <nacelp at bright.net>
> To: <gmecm at diy-efi.org>
> Sent: Tuesday, May 29, 2001 5:15 PM
> Subject: Re: Siamesed Runner TPI Questions...
>
>
> >
> >
> > > Researching EFI updates for 71 Vette with 406/400. 218 @ .050 110 LSA
> flat
> > hyd
> > > cam with TFS Twisted Wedge heads and headers etc, currently a
> well-dialed
> > Q-Jet
> > > and Performer dual-plane (hood clearence). Power peak is at 5200 rpm
and
> > the
> > > torque peak is about 4000 rpm.
> > > So, since TPI stuff is cheap I was wondering how siamesed runners
would
> > effect
> > > the power curve?
> >
> > Just the oem stuff.
> >
> > > A stock or big tube TPI (with big manifold base) will kill power over
> 4500
> > rpm
> > > with a 406ci, but I'd think that the siamesed runners would behave
more
> > like
> > > the shorter runners of the Lingenfelter/Accel Super Ram as they're
> > partially
> > > open etc. What do Ya'll think?
> >
> > Still no plenum volume.
> > If you happy with what you have how about, a TBI?.
> > Maybe a  Weiand 7527, or 7546 manifold, then up grade one of them to TPI
> if
> > you want to progress further.
> >
> > > Would a Big Manifold Base/TB Siamesed Runner TPI set-up be able to
> support
> > a
> > > 406ci through 5600 rpm?
> >
> > Would be a real push to even try
> > Bruce
> > > TIA...
> > > Doug
> >
>
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