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  1. #1
    FEP Power Member
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    Default Converting carb to fuel injection

    Anybody actually do this conversion? I'm just starting to research and see there a re a few manufacturers like Holley, Fi-Tech, Edelbrock, Summit, that offer a kit. Any input or advice will be appreciated. I've got a 1985 GT with stock motor and carb (78,000 miles). Is it worth the price of the conversion or do I just get a better aftermarket carb? Car is used for cruising around and will not go to track.

    Thanks,
    Joe
    Last edited by Boomer85gt; 08-29-2019 at 07:23 AM.

  2. #2
    FEP Power Member richpet's Avatar
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    I am going this route when I install my motor. The ease of turn key and go regardless of temp outside, potentially better power and economy... yup.
    83 5.0 GT. Quicker than it looks! 10:1 (or just over) 306, Motorsport a332 cam, 140A alt, t5 conv, 8.8 w/ 3.27's, Edel rpm, alum rad, very worked e7's, Holley SA carb, etc... SOLD IT!!!!

    Now an 1981 Granada! .040 over 302, Edel E-street heads... Currently building a 347 because, why not?

    "Never underestimate the power of stupid people in large groups"

  3. #3
    FEP Super Member 84StangSVT's Avatar
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    I’ve done it to my 84 GT. When I get a few extra minutes, I can explain the ins and outs of the conversion. I used the FAST EZ-EFI system.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

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  4. #4
    FEP Senior Member E2ZZGLX's Avatar
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    Bone stock cruiser...just get your Holley gone through and enjoy
    Current keepers...
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  5. #5
    FEP Senior Member BMW Rider's Avatar
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    I'm using the MSD Atomic EFI and integrated ignition on mine. It took a little bit of time to fully dial in the settings, but it's really working well now. Much less grief than trying to tune a carb on a non-stock engine. For a stock engine, I'm not sure if the work and expense is warranted versus just running a good stock carb.

  6. #6
    FEP Super Member erratic50's Avatar
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    There are advantages, especially in locations where it gets cold, to running a multi-port fuel injection over a throttle body based EFI.

    The problem -- fuel pooling on throttle body injection based combos when the engine is cold. And I don't so much mean cold like 50 degrees I mean cold like zero or -10 or -20 degrees.

    I remember all too well dealing with a 360 degree highrise intake on my 351W that had a cam and D0OE heads. The bitch was a runner when she was warm, but getting her warm was a CHORE. I should have had a block heater or simply not tried to run that setup on daily!

    I would have raw fuel dumping out the duals that you could light on fire on the ground and it would still pop out the carb and quit as the mixture went "lean".

    Why? Liquid fuel doesn't burn nearly as well as atomized fuel. A cold runner turns into a drowning wet runner almost instantly as fuel falls out of atomized state back to liquid.

    Dual plane intakes are not quite a tough to deal with in cold weather at single but there are tuning things to consider there. Also there still is no replacement for having a nice flow of fuel atoms spraying in every intake port right as the intake valve opens. Well, except direct injection but you may need some luck retrofitting that on to a motor that was essentially designed in the 1950's!

    My opinion is swapping to EFI is GREAT, but going to a factory style multi-port setup has strong advantages for a car driven daily in cold weather.

    For a garage queen or occasional use, probably tolerable to run a throttle body EFI and call it good.

    For the ones doing the real work, go to a factory MAF setup and tune with a Moats QuarterHorse with Binary Editor (BE) or if 30 year old electronics doesn't thrill you then go to a full after market ECU designed for plug and play with factory style multiport injection hardware.

    And with the after market stuff you might like Speed Density with a wideband better than MAF honestly.

    Any way you cut it, don't go too crazy on cam. If you go too far and end up with too few degrees of LSA you're going to hate it. The practical limits with MAF is around 110 LSA if memory serves me correctly, but you get a lot better throttle response and torque production when LSA is kept at or above 112. More boost friendly anyway.

  7. #7

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    Have you considered going with a factory 5.0 mass air setup? I’m currently updating to an EEC-V from a 2004 Grand Marquis and will tune using a quarterhorse and Binary Editor. But if you are looking for something simple and user friendly then I would lean towards Holley sniper EFI. Definitely worth the reliability and driveability imo
    Last edited by NotchoJones; 09-17-2019 at 08:34 PM.

  8. #8

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    You know what I like about carbs? Nothing. EFI is better in all respects,especially port EFI. I could have converted my car to carb when I put the motor in but, naow, just naow. I made the factory EFI off the donor work. It was all there and free.

  9. #9

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    Quote Originally Posted by 4eyedblind View Post
    You know what I like about carbs? Nothing. EFI is better in all respects,especially port EFI. I could have converted my car to carb when I put the motor in but, naow, just naow. I made the factory EFI off the donor work. It was all there and free.
    Awesome, more carburetors for those of us who enjoy increased peak and average torque and horsepower, and potentially crispier throttle response and better fuel mileage with a dialed-in carburetor, using simple hand tools and a few dollars. How does one inexpensively dial out factory EFI's general mediocrity and it's deficiencies in those departments?
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  10. #10
    FEP Super Member erratic50's Avatar
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    Without fancy stuff you have plug gap, timing base anvance, and fuel pressure you can play with

    not to take away from a well dialed in carb ...... my 86 runs hard with EFI and sounds good while doing it

  11. #11

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    C'mon Fred Flintstone, general mediocrity? Even in the 80s, the 87 GT pulled off 300 lb/ft of torque and 15 more horses than the last carb version. Plus that car would start every day, any temperature, get 30 mpg on the highway and I sure don't find any trouble with throttle response on the SD 88 motor in my current toy, despite it's 31 year old engine wiring. Things have improved from that time in leaps and bounds. I guarantee you'd never get a carb to even start a Coyote, much less run it with all the advantages you describe, on 87 pump gas. Plenty of options to upgrade the factory 86-95 EFI if that's yer bag, cheap to expensive. I believe in working with what you have and, this is what I got (and what I wanted).

  12. #12

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    Quote Originally Posted by 4eyedblind View Post
    C'mon Fred Flintstone, general mediocrity? Even in the 80s, the 87 GT pulled off 300 lb/ft of torque and 15 more horses than the last carb version. Plus that car would start every day, any temperature, get 30 mpg on the highway and I sure don't find any trouble with throttle response on the SD 88 motor in my current toy, despite it's 31 year old engine wiring. Things have improved from that time in leaps and bounds. I guarantee you'd never get a carb to even start a Coyote, much less run it with all the advantages you describe, on 87 pump gas. Plenty of options to upgrade the factory 86-95 EFI if that's yer bag, cheap to expensive. I believe in working with what you have and, this is what I got (and what I wanted).
    Yes, very much so inside-the-box mediocrity as were/are off the lot. Greetings, George Jetson, lol. Does your automobile hover and fly, and is it true that now meals are all in pill form and you set that on your plate and only have to add a drop of water in order to chow down on a full course meal? lol ... Anybody who figures that "the last carb version" of anything offered was anywhere near the best that factory carburetor function can be, at the very least does not have all of the facts straight. News flash: Millions of vehicles have been starting any given day, any temperature, and got respectable/acceptable fuel mileage, for a very, very long time now... otherwise, continued sales of them would have ceased, and we'd all now/again be on horse & buggy, bicycle, etc. "Improved" is a matter of exposure, interpretation and opinion. Has technology increased? Yep, sure has. Has technology been distanced from the general public in general, who a good percent of them used to fully maintain their own automobile... distanced/detached by way of complication of a simple thing as well as much more expense to just own and operate an automobile daily? Also yes. Has there really been progress in the last say five decades. In my humble but experienced opinion, no, there has not been.

    "I guarantee you'd never get a carb to even start a Coyote, much less run it with all the advantages you describe, on 87 pump gas" - is not a bet you should take and/or bet largely on, because I'd certainly be game largely. Besides things being complicated and hidden, there's no voodoo in today's internal combustion engine (air pump) than ever was. Vacuum and airflow signal has not been somehow magically avoided now, and could still be very efficiently and powerfully provided for with a lowly carburetor supplying precisely what that engine wants/needs by way of demand... instead of that engine being inside-the-box dictated to what it wants/needs, and being force-fed that "tune" by "technology".

    I'd definitely be interested in hearing about the cheap options/upgrades that I am unaware of that allow somebody to get and go outside of the box.

    As do I, believe in working with whatcha got... and believe it or not, there are some "have not's" out here that wouldn't be able to own and operate an automobile at all if they didn't do everything themselves, learn what they need to if they don't know what they need to know, and pinch every penny that they can along the way. Pretty much anything newer than about the early '70's, and especially '86+, doesn't really allow that across the board for most any more. You have what you are able to have, and it's what you want. Good for you, Sir.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  13. #13
    FEP Power Member slow84lx's Avatar
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    The Jetson's are classic cartoons. Way ahead of their time. It's good to see that others remember them also.

  14. #14

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    The words "carburetor" and "precisely" being used in the same sentence is quite funny
    Jack Hidley
    Maximum Motorsports Tech Support

  15. #15

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    Quote Originally Posted by Jack Hidley View Post
    The words "carburetor" and "precisely" being used in the same sentence is quite funny

    Even funnier was how much slower and smoother idling, and better and cleaner crispier throttle response and running overall... the real icing on the cake was nearly doubling the fuel MPG (last achieved 34 average on the highway) by removing fuel injection from a tired 3.8L V6 and installing and dialing in a 500 Holley that's originally calibrated for and often used on roundy-round rowdy-cammed V8 race cars.
    Last edited by Walking-Tall; 09-23-2019 at 03:18 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  16. #16

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    OP - it ain't worth the cost of admission. Originality = clean out all passages very well and refurbish the car's 4180. Simpler in the end with much better chance of the ability to clean passages out well = garden variety 4160 LIST-1850 or 80457 600cfm vacuum secondary picked up for basic peanuts, the older the better, and refurbish.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  17. #17
    FEP Power Member
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    Thank you all for the input and advice. I'm still investigating all the EFI systems out there but leaning toward just replacing the carb with newer model or possible refurbishing the current one. Car is just a cruiser. As with almost any thing on cars...it comes down to personal preference...and most of the time money dictates.

  18. #18

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    Quote Originally Posted by richpet View Post
    I am going this route when I install my motor. The ease of turn key and go regardless of temp outside, potentially better power and economy... yup.
    A *properly-tuned* carburetor with a working choke should start up just as good as any *properly-functioning* EFI system with a working computer. A daily driven vehicle equipped with a carburetor should only require one single pump of the pedal to set the choke on a cold start and the vehicle should immediately fire. As soon as it fires, you should be able to drive away without any hesitations or stalling in any weather condition. A warm engine doesn't even need that. A warm engine should start right up with only a turn of the key just as fast or even faster than EFI.

    Anything less than that and there is a problem somewhere.
    Last edited by RickFury; 10-22-2019 at 04:16 PM.

  19. #19
    FEP Super Member xctasy's Avatar
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    The cold and warm starting matters on carb engines are due to the way the old Duraspark II centrifugal advance system worked, with its delay valves, its TVS and other ways of tying into the EGR, AIR and that jazz. The throttle kicker, the AC kickers, and the special choke pull-down system, none of that was well understood.

    A carb with a proper modern ignition system like the CFi's TFi system used, with some kind of good air fuel ratio control when cold, would kick any EFi systems butt. The hot fuel handling problems were dealt with via a bleed off valve.

    The flood-tide to EFi has forced people only to look forward, not back on what worked.

    You can do it either way, your choice!

    After a diet of EFi cars that have fuel pump issues, I've gone back to Holley carbs. But I really like closed loop/open loop 02 monitoring for cold starts.

  20. #20
    FEP Senior Member 854vragtop's Avatar
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    By far, the best running carb that I've used on my '85 GT is the Summit 600 CFM vacuum secondary carb. Cold weather driveability is excellent. No hesitation. Just start, back out, and drive off. Mid 30's, Mid 20's, cold and rainy, no problem. The two 4180C's that I still have in a box were the worst, by far for cold driveability and hesitation. The Holley 1850 was a little better, but still not nearly as good as the Summit carb. I played with different pump cams, different shooters, different choke settings by limiting how far the choke plate could close, adjusting the 4 corner idle mixtures, etc. Float level and slop in the pump cam linkage were always set just right. The Summit Carb is basically a Holley 4010, uses Holley parts, and tunes exactly like a Holley. For the price, you can't go wrong. It uses a dual feed line, so you'll need to relocate your ignition coil if you get one. I moved my coil so that it mounts on my A/C compressor support bracket. You can also install a Holley quick change vac secondary spring kit on it.
    '85 Mustang convertible GT, 5 speed, 4V
    Stock bottom end, Comp Cams XE264HR-14, GT-40P heads w/ Alex's springs, Weiand 8124 Street Warrior,
    Summit Racing 600CFM carb, 8.8 Turbo Coupe rear end w/ 3.55 gears, '94/'95 Cobra brakes, '85 Town Car M/C, '93 Cobra booster, MM Panhard Bar, MM Strut Tower Brace, MM 4 point K-member Brace

    '68 Mercury Cougar, w/ '88 5.0L, 4V
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  21. #21

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    Quote Originally Posted by 854vragtop View Post
    ... Summit 600 CFM vacuum secondary carb. ... Holley 4010 ...
    Yep, the Summit units are clones of Holley 4010's, and Holley 4010's are an adaptation with Holley-specific features (accelerator pump housing and diaphragm and vacuum secondary housing and diaphragm locations, adjustable needles and seats, etc) of the good ole '50's-'60's Ford Autolite 4100 four-barrel... dead simple, reliable, like Autolite 2100 two-barrels... there still ain't nuthin' new under the sun.
    Last edited by Walking-Tall; 10-25-2019 at 11:15 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

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