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4.3 TBI info

2K views 2 replies 2 participants last post by  DoubleVision 
#1 ·
Since I`ve been involved with cars I`ve always delt with V8`s with carbs, now I`m down to something new, a 4.3 chevy V6 with throttle body injection.
I don`t know a whole lot about fuel injection, but from what I`ve read I`ve learned some. Here`s a list of the parts I have:
Isky Hydraulic roller cam, 206 intake, 209 exhaust duration @.050, .450 intake, .465 exhaust lift, computer compatible, springs, locks retainers from isky that match the cam, Milodon double roller timing set, comp 1.6 ratio roller rockers, comp pushrods, Manley pro flo necked down 1.94 intake valves, heads are stock swirl vane reworked with new guides that I mildly pocket ported, edelbrock performer tbi intake, msd heli core plug wires, msd coil, speed pro 4 valve relief flat top pistons that I`m having balanced, a K&N air filter, TBI injector spacer, ported TBI body, vacuum controlled fuel pressure regulator, with bung for fuel pressure gauge, remanned and balanced fuel injectors. My concern is the computer, I don`t want to have to battle the "service engine soon" light, will I need a new chip? How much do I need to go up on fuel pressure? What else am I missing? I don`t plan to race it, I just want it to be a fast revving torque engine that makes decent power to 5000 RPM. I thought I should have used the smaller isky cam, but the techies at isky recommended this one. Any help is appreciated.
 
#2 ·
The biggest problem with the TBI computers that I have seen is that they don't like a big increase in airflow or too much cam duration. such as the addition of Vor-Tec heads or a lumpy cam. With the mildly worked TBI heads and the computer compatible cam you should be OK, although you may not reach the full potential of the engine without an improved chip. You don't say what kind of exhaust you will be using, headers may push you into engine light on territory.

tom
 
#3 ·
Thanks Tom. Since headers cost a arm and a leg I decided to stick with stock exhaust manifolds that I lightly ported, each runner has a lump right into the entrance that I smoothed out. the exhaust is 2 pipes running into one with a turbo muffler then back into 2 pipes that exit out the back. I`m running a 5 speed tranny, and a peg leg 3.42 rear gear that I plan to convert over to a limited slip unit in the future.
 
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