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Thread: Injectors on siamesed intake ports

  1. #1
    Carb and Points!
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    Injectors on siamesed intake ports

    I am working on a 1952 Buick 263 cid straight eight engine. I am going to build my own intake manifold. This motor only has 4 intake ports. If the firing order is correct can I use 4 injectors and fire each one twice in a cycle to run all eight cylinders? Has anyone done anything like this before? Any help would be greatly appreciated!

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    Super Moderator dave w's Avatar
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    Your Buick 263 is an interesting project!

    Some background information that might be helpful:
    Port Injected 4 cylinder engines use an injector firing sequence of every 2nd Distributor Reference Pulse (DRP). I'm wondering if the 4 cylinder port injection system fires 2 injectors at a time?

    The V8 Port Injector firing sequence is every 4th DRP. The V8 Port Injector Batch Fire will alternate firing 4 injectors on each bank, cylinders 1,3,5,7 / cylinders 2,4,6,8.

    I'm not sure what will happen if a computer set to 2nd DRP injector firing sequence sees the V8 DRP's rate instead of 4 cylinder DRP rate?

    Maybe a V8 TBI system would simplify your Buick 263?

    dave w

  3. #3
    Fuel Injected!
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    That might work, but I don't have any experience in that area. You might be better off going with a batch fire setup. It might not be quite as efficient as sequential multiport, but it worked pretty good on tuned port engines. Using just 4 injectors should work out as long as they're properly sized. Hopefully someone else with more experience in this area can chime in as well.
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    Super Moderator Six_Shooter's Avatar
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    If we're discussing TPI type port injection, they are batch fire, meaning ALL injectiors fire at the same time. There are only one injector driver in those ECMs.

    Batch fire with 4 or 8 injectors will work just fine, as lonh as they are properly sized. Using 8 you might be able to get them aimed at the valve better than using 4. Alternatively using injectors with a tip thatbis used in 4 vslbe per culinder enhines might work out well, since they tend to have two orifices that will point one at each valve.
    The man who says something is impossible, is usually interrupted by the man doing it.

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    Fuel Injected! JeepsAndGuns's Avatar
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    Quote Originally Posted by Six_Shooter View Post
    Alternatively using injectors with a tip that was used in 4 valve per cylinder engines might work out well, since they tend to have two orifices that will point one at each valve.
    Cadillac northstar engines have injectors like that I think. Seems like I remember seeing some at the junkyard once.
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  6. #6
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    Quote Originally Posted by Panningbros View Post
    I am working on a 1952 Buick 263 cid straight eight engine. I am going to build my own intake manifold. This motor only has 4 intake ports. If the firing order is correct can I use 4 injectors and fire each one twice in a cycle to run all eight cylinders? Has anyone done anything like this before? Any help would be greatly appreciated!
    Hello,
    My boy had a 320 str 8 from his uncle and around 1988 he got a wrecked 351 v8 or a 460 v8 ford eec4 speed density rig from a junkyard. it was a federal 49 state setup, no air pump.
    The gas tank, fuel pumps, out -return lines and filter were taken. The the tfi remote module and distributor and eec4 were taken. the sensors temp, knock tps, load, etc were taken.
    The intake two hose plenum and airbox were taken.

    The 8 slot hfi ignition was welded to the buick shaft-housing and set to about 10 deg btdc. The throttle and input plenum were placed on the old carb mount and the thottle adapted.
    The starter was rewound for 12v and a ford alt w 5v center winding and its old regulator replaced the generator. The sensors were mounted in the right places and the knocksensors were jbwelded to cyl 2 and 7, then the eec4 harness was rewired to its sensors and resistors were placed in the air bypass-divert relay wires (same as in ford, had no airpump).

    Used the ford fuel tank and mounted 4 injectors in siamesed ports and hooked them to eec4 firing order 1-4, then used diodes in wires from eec4 to firing order 5-8.
    The rest of the 6v stuff was disconnected in the car.

    Turned on the 12 batt to the eec4 and the fuel pump ran 2 seconds and stopped, set its pressure at 25 lbs instead of 36 lbs from ford. cranked engine with bar to watch dist turn.
    Checked spark, it was hot from the tfi coil. Checked injectors and they had squirted in all 4.

    Hit the starter, and the damn 320 buick ran. checked in gear with brakes and it took load with power. used a dual scope to ck tfi spout and fi timing synced on cyl1 tdc and saw the advance move from 40 plus down to 10 at idle. The fi pulse for each cyl always started on the last of the exhaust stroke and stopped max halfway down the intake stroke.
    It appeared the eec4 sd sefi and the old 320 were happy with each other. checked o2 in collector 1 and it was 14.2-15.5, moved o2 to collector 2 (had 1 in each, but this eec4 only wires to one) and it was the same. We paid a 100 dollars for what we got, a little welding, and the rest fit ok.

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