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Tbi to mpfi conversion questions

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Old Jan 31, 2009 | 09:34 PM
  #1  
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Tbi to mpfi conversion questions

Me and a friend of mines working on building a hot 355 some where in the 450-500hp range. And he was telling me about an idea he had based on the edelbrock tbi to mpfi system. What he brought up was taking a ported victor jr 4 barrel intake running the base of a ported 454 throttlebody, a set of lt4 high flow injectors and fuel rails. How difficult does this sound like to get to work and what type ecm or pcm would it take to run it? Machining the parts are not an issue because he owns a machine shop. Any ideas or sugestions will be greatly appreciated, thanks. We're trying to get max performance with the lease amount of dollar's like everyone else.
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Old Feb 1, 2009 | 06:16 AM
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From: Austria
Car: 84 TA / 89 Formula
Engine: LS1 / L03
Transmission: T56 / 700R4
Axle/Gears: 3.73 / 3.27
Re: Tbi to mpfi conversion questions

hmm let me see if i got that right, so ..
#1 you're trying to do a setup that has TBI-style injectors on the TB and MPFI-style rails+injectors on the intake for a total of 10 injectors?

OR

#2 are you trying to do a dry-induction system and just use the 454 TB w/o any injectors, leaving the fueling to MPFI?

imho you can use EBL here as well since it supports mpfi (batch firing iirc).
here is the link: http://dynamicefi.com/EBL_PortMod.php

i guess that wasn't of too much help, i was just trying to clarify your enterprise for other readers
ownor
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Old Feb 2, 2009 | 11:48 AM
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From: Lake Jackson Tx
Car: 91z,97ws6,98fb,87&90jeep,05 yz250
Engine: 5.0tpi,5.7LT4,5.7LS1,4.2I6,5.7TPI,1
Transmission: t5,4l60e,
Axle/Gears: 3.42
Re: Tbi to mpfi conversion questions

i thinks hes looking at #2, keeping an eye on this as i was thinking of doing the same to my truck w a tpi unit i have on the shelf
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Old Feb 2, 2009 | 01:06 PM
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Re: Tbi to mpfi conversion questions

Yes I'm thinking of the secon option. A friend of mine got his engineering degree frome MSU and they built a supercharged fuel injected racing cart as an engineering project and he's been giving me some serious ideas on the mechanical side I just need to figure out what control system to use for the system.
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Old Feb 2, 2009 | 04:38 PM
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Re: Tbi to mpfi conversion questions

Getting the manifold "correctly" drilled(angle) is quite a science. I believe it takes sophisticated equiptment to do it correctly for MAX performance. Also some trial and error. Why not just buy the pre-engineered EFI manifold that optimizes efficiency? If you feel you are up to doing yourself it will require some serious study.

No reason why the GM TBI cannot be used less the injectors and pod. A popular TB is the LS series on a Edelbrock neck(just released). Then add cold air ducting. Or drop the TB on the 4 barrell intake as you stated. I think the preferred injectors are Ford (SVT?).
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Old Feb 2, 2009 | 05:26 PM
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Re: Tbi to mpfi conversion questions

But where would the fun be in that, we engineers are crazy like that. I really like the Edelbrock tbi to mpfi conversion for the gm trucks but can't afford the unit so we're devising a similar setup.
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Old Feb 12, 2009 | 12:48 PM
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Car: 1993 Caprice LTZ
Engine: 350 TBI
Transmission: 4L60 (700R4)
Re: Tbi to mpfi conversion questions

Interesting...I have been floating that idea around myself because I have a blower kit laying around and I wondered if the BB TB would flow enough. I think the CFM output on the blower I have is 750CFM and since the BB TB would be 850 CFM...then I thought it would be ok on top of an Edel. Victor or Accel MPFI single plane manifold conversion running with smaller heads. Sure would like to see this topic explored more...
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Old Feb 12, 2009 | 01:52 PM
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Re: Tbi to mpfi conversion questions

Blower output is rated on CFM of 750? My info (Procharger) has their blowers rated on PSI? I believe atmospheric pressure at sea level is 14.7. So a 750 CFM TB will flow that at sea level no boost atmospheric pressure. Add additional blower boost amount of 14.7 or another atmosphere so now 200 MAP 29.4 psi? I would think the 750 CFM is now see twice as much air flow if it is not a restriction. A restriction with size of 750 carb or TB would show as a MAP <200. Same with a normally asperated engine <100 MAP if restricted or up on elevation. Anyone agrees?
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Old Feb 12, 2009 | 02:07 PM
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Car: 1993 Caprice LTZ
Engine: 350 TBI
Transmission: 4L60 (700R4)
Re: Tbi to mpfi conversion questions

Hey there Ronny...

That's what they told me when I called Vortech...but they also gave me PSI ratings for a 305 10-12 and 350 8-10 and a 383 would be 6-8...but from what anesthes has said...on a 383 it would amount to basically nothing because its a much larger CID. I am only quoting what they told me. Basically the A-Trim I got is pretty worthless and if I use it...its going to need to get tradeed in for an upgraded unit like an S-Trim or a T Trim for a 383.
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Old Feb 12, 2009 | 02:33 PM
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Re: Tbi to mpfi conversion questions

Order the Procharger catalog. Makes for good reading. some nices photos of rides.
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Old Feb 12, 2009 | 02:59 PM
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Car: 1993 Caprice LTZ
Engine: 350 TBI
Transmission: 4L60 (700R4)
Re: Tbi to mpfi conversion questions

Originally Posted by Ronny
Order the Procharger catalog. Makes for good reading. some nices photos of rides.
I already have the brackets and such for the Vortech...sure would hate to change direction but if I don't use the Vortech...I'll probably just go NA.
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