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Thread: Do I Need to Upgrade ECU

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    Do I Need to Upgrade ECU

    I have a stock 1991 engine and thinking of upgrading to include ‘93 Cobra SVT intake manifold(I like the way it looks), 65 mm throttle body, 70mm air mass and 24# injectors. Exhaust is stock reversed manifold with FFR j-pipes and side pipes. Will I also need an upgradedd ECU to realize the full power benefit of these changes?

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    They don't make upgraded ECUs for that generation motor. That's the short answer. You could get a 93 computer, but if you have a matching Mass air meter to your injectors then you good to go.
    Some places will make a chip for you. Im no expert, but from what I have heard the chip just changes the timing.
    Mike

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    Ford Racing sold a kit that contained 24lb injectors, 93 Mustang Cobra computer and a mass air meter (not sure the size but bigger than the stock Mustang one) this what I have on my car, but I don't think it is still available from Ford. Might find one if you are lucky or go with Mike's suggestion.
    David W
    Mkll 4874 built in 2004
    Gen 3 coupe #16 registered 2018 painted 2019

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    These old school ECUs are both incredibly flexible and somewhat limited at the same time. Since they mainly operate off the O2 sensors along with the MAF meter calibration, they are really good at adjusting to more airflow automatically. There are steps you can take to fool the ECU into what you want, in particular changing initial advance, fuel pressure and a MAF with a different calibration. Beyond that, the ECU has a service port that can support a chip (either burnt or PC configurable). Finally, you can always junk it and swap the full ECU and/or the full EFI system. The only mod you mention that may require a new MAF calibration or chip is the injectors. There are folks much smarter than me that can tell you for sure.

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    Senior Member Mike N's Avatar
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    Quote Originally Posted by ptstew View Post
    I have a stock 1991 engine and thinking of upgrading to include ‘93 Cobra SVT intake manifold(I like the way it looks), 65 mm throttle body, 70mm air mass and 24# injectors. Exhaust is stock reversed manifold with FFR j-pipes and side pipes. Will I also need an upgradedd ECU to realize the full power benefit of these changes?
    Get a MAF that is calibrated for 24# injectors. That is all you actually need for the engine to run with the mods you listed. Mail order chips may sound wonderful but I wouldn't waste your money. Most of the gains can be had by dialing in a few extra degrees of timing. If you are running 93 octane you should be able to run 12 to 14 degrees of advance with no issues. Note that some aftermarket MAF meters have a reputation for causing idle issues. If you find that to be the case try rotating the MAF, that will sometimes correct the idle issue.
    Mike............

    FFR2100 - 331 with KB supercharger - T5 - 5 link rear 3.08's and T2 Torsen.

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    I'm not an expert here, but from what I've read, the biggest restriction is the OEM heads. I doubt the 24# injectors are needed, and probably the 65mm throttle body and larger MAF will not yield much gain. (but won't hurt). If I were you, I'd do heads first. I'm pretty sure the OEM ecu will be fine for your mods.

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    Not a waxer Jeff Kleiner's Avatar
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    Dave is exactly right; heads (and then camshaft) are the bottleneck. Bigger injectors and a different intake aren't going to be any benefit if you can't move enough air and fuel to support them.

    Jeff

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    Senior Member CraigS's Avatar
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    I would also caution against spending $ on your potential efi upgrade. I say that because I see more and more people w/ ecu problems. Some can be fixed by soldering in small electrical thingies to the mother board. Some can't and the ecu supply, at this point, is at best very limited and at worst, zero. Not saying to do anything right now, but I would hold off and be thinking about an upgrade to one of the new efi systems that mimic the looks of a carb.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

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    Pretty sure they make a tuneable EEC IV ecu now. Cant remember what tuner it is but my brother has one in his Vortec SCed fully build 88 GT.
    If in doubt......flat out-Colin McRae

    Coupe #485

  10. #10
    Senior Member Mike N's Avatar
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    Quote Originally Posted by TNcoupe View Post
    Pretty sure they make a tuneable EEC IV ecu now. Cant remember what tuner it is but my brother has one in his Vortec SCed fully build 88 GT.
    There are a couple of plug and play options for replacing the EECIV. I have one of the MS2 versions. Unless you have a thorough understanding of engine tuning it's probably not a good option.
    Mike............

    FFR2100 - 331 with KB supercharger - T5 - 5 link rear 3.08's and T2 Torsen.

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  12. #11
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    Thanks for all the input. I am running 14° advanced now and using 93 octane gas. Changing out heads is more than I want to get into with this project. I have a spare 1991 ECU rebuilt with new capacitors so will stick with that technology for now and will be sure that MAF is calibrated for 24# injectors.
    Phil: FFR 3121, Frame #2050, Mk 1.5, built 2002, 1991 donor with Blueprint 302 long block and 1993 Cobra intake, BBK 70mm T/B, no smog, power steering, T-5 and 3.55 rear.

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