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Long TBI Question

Discussion in 'The Injection Section' started by mikey_d05, Jun 24, 2005.

  1. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    This question has only a margainal amount to do with trucks but it focuses on TBI which most of us have had at least some experience with.

    A friend of mine is sorta resto-modding a '72 Camaro. He came across a TBI 350 out of an '89 Sub for cheap. He has very limited funds so cheap is good.

    My first question is what would be involved in making the TBI work in a car like that?

    My second question is since this car isn't going to be seeing extreme angle or anything, would it just be easier to convert it to a carb setup and forget about fuel injection?
     
  2. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    The TBI is a pretty simple system. It won't take a whole lot to get it running in a vehicle that didn't originally have one. Couple things you would need to look into installing though:

    1) A VSS (Vehicle Speed Sensor) Maybe people disclude this imo, essential sensor when they do an install. It costs maybe 60 bucks for an inline VSS, and it only takes a few minutes to install (power, ground, signal to DRAC)

    2) A DRAC (No idea what it stands for) This thinger takes the VSS signal and converts it to the signal your TBI ECM needs, you can bypass the DRAC by getting the correct signal VSS right away (but I cannot remember at the moment if a TBI likes a 2 or 4 pulse per turn signal...)

    3) An 02 sensor. You'd need to install this into the pipe directly below one of the manifolds. If you have headers, you might need a three wire (heated) 02 sensor that is installed into the collectors. But with the 3/4 length headers a Camaro would have, it may not be a big concern as compared to the long full length truck headers most deal with.

    4) Fuel Pump. The TBI likes something like 15 PSI of pressure or so, which most mechanical pumps are not able to provide. You can buy either an inline pump, or a high pressure mechanical pump from Carter, Holley or something. If you go with an inline pump, you'll want to install it as close to the tank as possible, but still below the tank as much as possible to gain the use of siphoning the gas into the pump. Inline fuel pumps usually like to push fuel, not pull it. If you go with a high pressure mechanical pump, your supply line can remain stock, but from the pump forwards, you will need high pressure fuel lines. You'll also need to install a high pressure return line to the tank. Before you use compression fittings for anything, check your local regulations, in some states I hear compression fittings are illegal on fuel systems.

    The rest of the sensors should already be on the 89 TBI 350, but make sure they are all there, as the thing that really kills these swap's affordablity is being nickled and dimed on little things.

    Of course, there will be a couple of different modules and relays that will need to be installed as well from the donor vehicle, but if you use wiring diagrams from www.chevythunder.com you'll have no touble figuring all the wiring out.

    Overall, its a fairly easy swap. It will be a bit more expensive than a carb if your 89 350 is missing stuff, but they are reliable setups.

    Make sure you check out the soldering tips that are given on chevy thunder. I think they are in the Electrical section. Like the 3rd page or something. He shows an extremely good way of soldering wires together. Also, don't forget to get the high quality shrink wrap that has the sealant in it. They are far superior to the regular stuff :)

    The other thing to consider is why you are putting EFI in. If you are primarily going for gas milage, an overdrive transmission will be your best bet to large gains. EFI will typically get similar milage to a carbed engine under ideal conditions. Where the EFI really shines is when it comes to those not so ideal conditions, such as having your rig basically lying on it's side, or up 10 thousand feet from where it is typically driven, or if you live in a climate with extreme temperatures on either end (90 in the summer, -40 in the winter sorta thing)

    The last consideration is that of performance. If your buddy is looking for a monster of a car that beats the snot outta everyone with a monster high performance 350, then TBI is not right for you. TBI is senstive to engine changes. They depend on good engine vaccum to run correctly, as that is how they measure how much air is entering the engine. If your buddy is just looking for a maintenance free engine that will have a lot of low end torque, but not so much in the high end (aka, don't expect to rev much past 5000 rpm, if even) then TBI is perfect for him.

    Of course, if he is really good with electronics, he can always up the performance with a TBI throttle body from a 454. Its a four barrel monster that provides a LOT of fuel for a small block. You would most definitely need some serious programming changes, but you'd be able to build a pretty healthy small block with it.
     
  3. readymix

    readymix 3/4 ton status

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    Digital Ration Adapter Controller :D

    I learned that when i was recalibrating mine when i had my 98 with bigger tires
     
  4. Thunder

    Thunder 3/4 ton status

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    Besides all the stuff sirrea Classic said you will also need a TBI distributor. Regular HEI dist wont work with TBI. Also plumb in a fuel return line back to the tank. and of course a complete wireing harness for TBI.

    Personaly altho I like TBI, I would not want to put it in a 72 Camaro. I can see no benifit for all the trouble you would go thru to install it. IMHO unless you go MPFI just stick with a good carb. For all the money you would spend doing the TBI conversion you could buy some good performance mods on a carb car and get a lot better performance gains.
     
  5. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    I kinda figured the 350 would already have the dizzy, and that he'd get the wiring :)

    But yeah, for a Camaro, personally I would not stick a TBI on. Carb would be best suited in that case. However, its your buddy's car, and he can do what he wants with it, so I'm still willing to help :)
     
  6. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    Well, thanks for all the help. I'm gonna try to get him to go carb. Cuz if he went TBI I'd get roped into hooking it up. :D

    Seriously though...this car won't be seeing huge elevation changes or inclement weather or extreme angles or anything that I love my fuel injection for. He knows a lot more about carbs also so it'll be easier for him to tune and fiddle with. Besides, this motor probably won't last long since he drives with his stupid foot. Once again, thank you sincerely for the help, I appreciate it.
     

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