Converting a Performer manifold and TBI to TPI...

[David Sagers]

Steve

I was trying to do the same thing a while back, the injectors in the 
Edelbrock TBI to multiport conversion, according to an Edelbrock tech, use a 
very small voltage or (ohm? can't remember the difference right now) so that 
the TBI computer which is made to drive two injectors can drive eight 
injectors without frying the computer or the injectors.  I seem to remember 
that the injectors are smaller in diameter than stock units so they won't 
fit in a factory GM EFI manifolds.  Currently the injectors come in two 
sizes, about 20 lbs per hr and the larger 29 lbs per hour.  Edelbrock says 
the they successfully run a 502 BBC with the big injectors.

The conversion kit includes a card that requires you to give them a lot of 
info about your engine, cam exhaust, etc... so they can provide the right 
chip.  That is if you engine is stock or pretty close, otherwise they will 
direct you to someone to make the chip for a bigger cam or what ever you 
have that is outside of what they will sell over the counter.  Liability, 
emissions and all those other concerns prevent them from selling chips that 
work with modified engines.

If you are really good at drilling you can make jig to hold your manifold 
and drill it for injectors, then either weld or epoxy in the bungs to hold 
the injectors.  Force Fuel Injection   http://force-efi.com/  sells these or 
you can pay to have Force make the conversion for you, about $600.  One 
thing to consider is that if you are going to use a solid fuel rail all of 
you injectors must be at the same angle and at the same height. If you look 
at the runners on a Performer, or any other dual plane intake, intake you'll 
notice that runners next to the head are various heights.  Consider a 
Edelbrock Torquer intake as all the runners next to the head are about the 
same height.  Even though the Torquer is a mid range RPM intake,  the EFI 
will really tame it down and you'll have some very strong low end power and 
throttle response.  About a year ago I read an article in a 4 wheel magazine 
that described using a Torquer converted to EFI on a rock crawling jeep.  
The bottom end power was very strong as the EFI does not depend on air flow 
to draw the fuel out of the carb.  If you use the Performer, consider making 
your ow fuel rails/lines out of some high pressure fuel line.  Another 
option is something I saw in the PAW catalog.  I think it was a Weiand 
intake that is made to be converted to EFI. It has the pads and the fuel 
rail towers cast in and would save you a bunch of time and money.  You'd 
still need to drill and weld the injector bungs.  Cost is about $250 from 
PAW.




Date: Sat, 23 Oct 1999 00:03:51 -0400
From: "Stephen R. Cauffiel" <cauffiel at erols.com>
Subject: Converting a Performer manifold and TBI to TPI...

Hey guys,
	I think I remember a thread recently (here or on the Third gen list) about 
drilling an Edelbrock Performer manifold for TPI injectors and running a TBI 
with injectors removed as the throttle body...  Am I smoking crack?

I know that Edelbrock has their $2000 version of this, but if I could afford 
that...  This would work with the TBI harness, wouldn't it?  You would have 
to rewire it so that the left injector wiring fired the left bank of TPI 
injectors, and the right injector wiring the right bank...

Has anyone done this?  Would it work?  If you could burn your own 
chips/reprogram the computer to compensate for changes...  Would this work 
on a 383 SBC?

Please, unless you are going to stroke me a check, don't say "Just buy the 
MiniRam/SuperRam/HighDollarRam and call it a day."  If I could afford stuff 
like that I wouldn't even be asking this kind of question...

Thanks for any help,
Steve

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