Spread-Bore TBI
01-20-2006, 01:15 PM
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Car: 71
Engine: 406
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Spread-Bore TBI
If this has been covered somewhere else, please direct me. I've been searching.......
I'm kicking around the idea of a spread bore TBI setup....It would consist of a spread bore intake machined to accept injectors on each cylinder. I'd have to run the proper injectors (> 12 ohm from what I found).
Anyway, the TB would be an old rochester quadrajet gutted out. Adapt on a tps and make some sort of IAC (possibly where a high-idle circuit was on a computer controlled quadrajet?????....not that familiar.....).
The advantage would be for driveability. At cruise, you're running off the small primaries, but you kick-er in the guts & it opens up the secondaries.
I think I'd try to use a 7747 ECM. I think it'd work with some tuning because when you open the secondaries, the MAP sensor will recognize it and fuel could be tuned accordingly.
What do you guys think? Could it work or am I retarded?
Open to suggestions
-Mike
I'm kicking around the idea of a spread bore TBI setup....It would consist of a spread bore intake machined to accept injectors on each cylinder. I'd have to run the proper injectors (> 12 ohm from what I found).
Anyway, the TB would be an old rochester quadrajet gutted out. Adapt on a tps and make some sort of IAC (possibly where a high-idle circuit was on a computer controlled quadrajet?????....not that familiar.....).
The advantage would be for driveability. At cruise, you're running off the small primaries, but you kick-er in the guts & it opens up the secondaries.
I think I'd try to use a 7747 ECM. I think it'd work with some tuning because when you open the secondaries, the MAP sensor will recognize it and fuel could be tuned accordingly.
What do you guys think? Could it work or am I retarded?
Open to suggestions
-Mike
01-20-2006, 11:53 PM
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What you are suggesting would work fine but it wont give you any advantage. The CCC qjet can be gutted and used as a cheap TB on a 7525 intake. I wouldn't use a dual plane as each of the runners are a different size and shape. The small primaries are to enhance booster signal at the carb. You don't need this with EFI. So the motivation for doing a small primary and larger secondary comes down to cost. carbs are cheap when compared to huge TB's
HTH
John
HTH
John
01-21-2006, 10:03 PM
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Car: 84' Monte
Engine: 350
Transmission: 700-r4
Axle/Gears: ferd 9" posi 3.50 gears
What your suggesting is nothing more than a home brew multi port setup. It's been done before, heck there's even an entire board for DIY EFI intakes on this site. Cruise around there and see what guys are doing. Most start with a cheap older single plane intake, do the injector bungs, and then adapt some sort of cheap TB. A 454 TB without the injector pod will flow enoug air to support over 450 HP, so that may be your cheapest and easiest solution. TPS and IAC already there and ready to go. You'll want to use a 730 ecm though, TBI injector firing strategy isn't the best for a MPI setup. No matter what you do DIY chip tuning will be key.
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