TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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I plan on doing a small build up on my TBI powered 305.
Heres the plan, gonna get a small cam, a few notches bigger than an RV cam, and put my set of 081s on for the heads. The one thing I need some advice on, is what type of intake.
I've heard hi-rises don't go well with TBI, I don't really need one since my power band only pulls to around 5200. Can't remember if TBIs work well with dual or single plain intakes.
I'm thining of going with an edelbrock Performer or Performer RPM, or maybe even a weiand stealth. LMK what you guys think would be best to go with.
Also, I have a friend who did a similar build up, with some minor chip work, its pretty mean. just wanted to let you know, that I already know that I'm not gonna get through this W/O some tuning. This thread isn't about the computer trouble, its about the intake, just keep that in mind. I'm prepared to deal with the chip work.
thanks for the help,
Kyle
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Thats My 92 RS
350 HSR, air foil, Full custom exhaust, K&Ns, 17" SS wheels, full polyurathane bushings, KYB Shocks and struts.
It has to do with plenum volume, it also allows all the cyl's to pull from both throttle bores, instead of 4 pulling from one, and 4 pulling from the other. Also, since the fueling is not dependant on the vacume signal like a carb is, you don't have the low RPM, and idle issues that are normaly associated with a single plane.
Q: instead of 4 pulling from one, and 4 pulling from the other.
my divider on the Holley Projection dual appears to be low enough to allow some flow of fuel across it? maybe 80% from "dedicated injector" and contribution of 20% from injector serving other cylinder bank? now keep in mind when the butterfly is 25% open that injecto(s) is spraying all over butterfly/shaft and i am uncerrtain how the fuel distribution ends up to be(EGT?). the Edelbrock dedicated TBI manifold. is it a single plane or dual plane?. i thought i read once that the performer carb unit is similar to the Edelbrock TBI? dual plane. with dreduded height on divider. or if you use carb manifold you could reduce its height? why would Edel and Holley not use a single plane base and configure it for dedicated TBI applications? i had 2 seasons of use with Accellerator(xram'd) and i believe the dual plane with longer runners runs better. but that may be partly due to xram adaptation not being the best engineered !
I can possibly answer a few, some I don't have a good answer for. I like you, am always trying to learn more!
1) Why holley/edelbrok use a dual plane. I would imagine that part of this, is who they are selling to. I would image a large majority of their customers, are running basicly stock motors, and don't have the ability to tune a chip. going to the single plane, I had to make DRASTIC changes to AE and the VE tables (the AE being VERY major). Running a stock chip, and changing nothing, but going to a single plane, I would image you would get a lean back fire on throttle tip in, and probably knock in the upper end. (again, judging on teh changes I made in my chip). I doubt that they are trying to make the 'best', but instead they are trying to make something, that people will get a bit of a power increase, and will feel good about their purchase.
There is some very good info, talking about injector height above the plenum floor, plenum volume, etc. also the advantages to drawing from both bores.
as usual. that makes sense. i am "assuming" these intakes used on mod cars. not often the case.
POI
i ran the single plane on stock 'puter' stock chip with mods listed phase 1. lean backfire you bet! with backfire, and some AE invoked with gas pedal it caught, and laid some rubber. other drivers thought i was an idiot. i was till the 7747 came in mail.