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Re: [oletrucks] tuned port injection

To: oletrucks@autox.team.net
Subject: Re: [oletrucks] tuned port injection
From: mark@noakes.com
Date: Wed, 24 Apr 2002 18:58:25 -0700 (PDT)
On Wed, 24 April 2002, Jon wrote


> Both TPI and TBI cannot handle a lot of horse power
> and torque.  If your 350 is over 350 horsepower, I
> suggest not going with either one if you get them off
> a production vehicle (i.e. late 80's Camaro).  I'm
> looking at running 450 + HP and around 600 pounds of
> torque.  Thats why I'm going to MPFI, which can handle
> up to 500 HP for small blocks.      
> 

Not true; I've personally driven a Lingerfelter tuned Corvette TPI that was 
dyno'd and
documented at 455 hp...lots of engine mods, but it was a TPI car.  The vette 
magazines
in the early 90's were full of TPI cars in the 400-600+ hp range.  However it 
is true
that the orginal TPI setup was initially designed for 305 instead of 350 and 
when they
went to the 350, it ended up with alot of low end torque and not much high end 
power due
to the original flow characteristics.  There's lots of ways and lots of 
aftermarket
parts to deal with this though.

> Sorry to say but it probably wont be that cheap.  If
> you get an existing setup off another vehicle you'll
> still probably have to reprogram the computer for your
> engine setup.  Running an already carb engine...I'd
> say stay with the carb until you decide to rebuild it.
> They maybe jump to the injection setup so that
> everything works right together.  It will probably
> save you a lot of time and agravation.
> 

Agreed almost no EFI conversion is cheap.

One of the reasons I like the mass air flow sensor-based TPI setup, even though 
it is
one step down from true EFI, is that it is more adaptable to engine variations 
like cam,
distributor changes, intake, exhaust, etc changes because it bases its lookup 
table on
measured mass of air into the intake.  This means that you could get away 
without a new
EPROM but not necessarily that it wouldn't  run even better with a custom 
EPROM.  Chevy
went away from the mass air flow approach for cost sake with the LT1 but later 
went back
to it.

Mark Noakes
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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