Speed density adaptation?
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Speed density adaptation?
Hi, I am trying to install a mid-80s EEC-IV speed-density setup on an older Ford truck. I have figured out that I prob have a system with only a 50mm TB and 14-lb injectors, which will be clearly inadequate for the motor its going on.
My q is, can I put in 24-lb injectors and a larger TB and have the SD EEC-IV computer recognize it? I know that SD is relatively intolerant of radical cams, etc, but Ive never seen a question on larger injectors addressed specifically.
Thanks in advance!
My q is, can I put in 24-lb injectors and a larger TB and have the SD EEC-IV computer recognize it? I know that SD is relatively intolerant of radical cams, etc, but Ive never seen a question on larger injectors addressed specifically.
Thanks in advance!
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thanks for the input. I bel its from a mid-80s Tbird, since the computer code is '8KC' which shows 14-lb injectors as stock. The injectors are orange tipped with a gray body.
It is to go on a 347 motor, and Im sure IF they are 14s, they are inadequate. I dont want to lean out the motor dangerously or whatever, thus my question. Id buy 24 lb injectors, but I dont know if the comptuer will recognize it, even if I got a MAF conversion harness
Advice? TIA!!!
It is to go on a 347 motor, and Im sure IF they are 14s, they are inadequate. I dont want to lean out the motor dangerously or whatever, thus my question. Id buy 24 lb injectors, but I dont know if the comptuer will recognize it, even if I got a MAF conversion harness
Advice? TIA!!!
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From: Concord, NC
You might have 19lb injectors - they have orange tops - but still might be a bit small for a 347. I think 14's have gray tops. If you got a MAF conversion harness, you could get a MAF computer, yet you'd still have to get a chip for the 24lb injectors. I think 24's are a good idea for the 347 for sure, but since the computer is calibrated for 19lbs (mass air computer) it would still need to be chipped to make it work properly - it would run rich otherwise. If you could find a computer from a '93 Cobra, it is already calibrated for 24 lb injectors, and you'd be able to run a stock calibration air meter. It would probably run very well that way. I'd definitely try to find a newer computer, as it will probably help you out performance wise. It is certainly possible to run it on speed density with a chip to account for the modifications.
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thanks for the info. If, by some miracle, I got the 14 lb injectors working with the smallish TB I have, whats the worst that could happen? I guess that at some point (RPM) the small injectors would 'max out' on their duty cycle and the engine would nose over at that point? Or would the motor being to run dangerously lean from that point on up the tach scale?
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I believe that you have a 58mm throttlebody. In 87 they went to a 60mm on the Stangs.
yellow tops are 19lb, white tops are 14lbs, If you go Mass-Air, you can order a 73mm MAF calibrated for 24lb injectors.
I was thinking that FRPP sonld the complete 24lb Cobra conversion kit with a 70mm MAF, 24lb injectors and correct PCM. I could be wrong though.
yellow tops are 19lb, white tops are 14lbs, If you go Mass-Air, you can order a 73mm MAF calibrated for 24lb injectors.
I was thinking that FRPP sonld the complete 24lb Cobra conversion kit with a 70mm MAF, 24lb injectors and correct PCM. I could be wrong though.
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Lead Driver
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From: Concord, NC
I believe they do sell the kit you mentioned, but it's around 600 bucks for the kit. I would not recommend getting a recalibrated air meter - I've had a bad experience with one trying to run 24lb injectors for my MAF swap (mine was calibrated for 24 lb injectors).
Lead Driver
Joined: Nov 2002
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From: Concord, NC
Apparantly mustang guys run those recalibrated things all day long without any problems, but for some reason, it just didn't work on my truck. I'm more partial to Pro-Flow, since they include new electronics with their mass air meters that are calibrated for each individual application.
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Interesting. The advice Im getting from other sources seems to say that I will need to convert to MAF in order to have the computer recognize changes in the airflow/injector size. A bigger issue is apparently that since the SD system was programmed for a 302 and not a 347, the VE map/curve and values, etc will be off, so it prob wont run any better than a carb.
I may have to pitch the computer and start with MAF.
I may have to pitch the computer and start with MAF.
Lead Driver
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From: Concord, NC
The harness you have should be a good backbone for the MAF computer. You'll have to move a couple pins in the computer connector of the wiring harness, and add a few more wires to it, but it isn't too hard. You'll probably be doing a lot of wiring to get that harness in the truck anyway, so this wouldn't be much more. MAF computers are always on ebay - most common computers are A9P for automatics (non-electronic) and A9L for manual transmissions.
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You can get the speed density to work with a custom chip. I have dont have a stroker motor but I am running a 306 with 11 to 1 comp., windsor heads, E303 cam, BBK shorty headers, BBk throttle body, and an Aeromotive fuel press. regulator. I had hypertech burn me a chip to match and it runs great. Its a 92 F150