Fuel Injection vs Carba

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Grand Poobah, Dec 28, 2009.


  1. Grand Poobah

    Grand Poobah New Member

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    Hey guys,
    I have had this question on my mind for a while, and I thought I'd ask everyone's opinion here.

    I really like the classic muscle car look, with the air cleaner mounted over the engine. However, I also like the efficiency and power output of fuel injected engines, so I was a split on what engine to put in if I were to do a restomod on an old engine.

    What I'd like to do is take a 302 (not a Boss, the Windsor) and stroke it to 331 cu and possibly convert it to a fuel injected setup, but I wouldn't like to lose that classic look and feel.

    I understand there are fuel injection kits, but I wonder if anyone has used these and what their thoughts are.

    btw, I know this is a bit blasphemous, but here is a modern (2005+) "Hemi" engine that has an aircleaner/intake mounted on top of the engine.

    http://i207.photobucket.com/albums/bb289/teh_Mac/allardmkii_la_033.jpg

    I'd like to hear all your thoughts, thanks. :)
    #1
  2. Tanus

    Tanus New Member

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    you can get FI set-ups with throttle body that goes in the same spot as a carb, with a air filter on looks basicly identical to a carb. cant remember the name of the company(s) that makes them.computer is even mounted to manifold for a very simple instalation. google "universal fuel injection"
    #2
  3. rebel65

    rebel65 Member

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    there are a lot of posts about this, powerjection 3, fast ez efi, megasquirt makes one too like minisquirt? i don't remeber. use the search button for those topics
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  4. Grand Poobah

    Grand Poobah New Member

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    Thank you for the input guys, Tanus, that sounds very promising, I'll look there next.

    Cheers :D
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  5. D.Hearne

    D.Hearne Banned

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    Build the 331, use an EFI style cam (wide LSA), run it with a smaller than recommended carb (500-600 cfm)and a good electronic ignition system and you'll have EFI performance with the simplicity of a carb setup.
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  6. Grand Poobah

    Grand Poobah New Member

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    Thanks, that sounds awesome! I know this sounds shallow, but how will it look? Will it retain that "cool" look with the air filter on top?
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  7. D.Hearne

    D.Hearne Banned

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    Yea, but this will look even better ;)

    Attached Files:

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  8. Grand Poobah

    Grand Poobah New Member

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    That is very interesting. So it looks to me (I'm an incredibly noobish person when it comes to this sort of thing) you have three carbs on top, and then I imagine your EFI system is somewhere on the block.


    If you don't mind me asking, how do you have an EFI setup with carbs? If you're referring to Electronically Fuel Injected, aren't the two mutually exclusive?

    And when you say performance do you mean power output or MPG improvement over the others?

    And btw, it does look incredibly cool. :nice:
    #8
  9. rebel65

    rebel65 Member

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    he doesn't have efi, he said efi performance with carb simplicity because it will have good throttle response witht he small carbs / good milage and electronic spark, if you want EFI but carb look look into the fast ez-efi, and powerjection 3, and search for those and other options will be in those posts : )
    #9
  10. Grand Poobah

    Grand Poobah New Member

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    Hey rebel, thanks for the clarification, unfortunately, the ez-efi offers fuel injection conversion, but it takes away from the carb'd look--that's what member Blue Oval Man said.

    However, in this thread:
    http://www.stangnet.com/mustang-for...ection-delivers-easy-carb-efi-conversion.html

    Don's Bolt has two pictures, and he still has the Air Cleaner, which to my untrained eyes is the definitive "carb'd look," that I was looking for.

    A little more searching reveals I have stepped upon a pandora's box--there seem to be several major ways of fuel injection vs. carb'ing--very interesting stuff all around.

    Thanks for the heads up rebel.
    #10
  11. htwheelz67

    htwheelz67 Member

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    Yes you can get close to efi response with a well tuned annular booster carb BUT you dont get the fuel economy, smoother idle, instant cold starts, instant correction for altitude and weather and if you want to make changes you dont have to take the carb apart and change jets and gaskets you can just hook up the laptop, also many systems let you control your ignition timing and curve.

    I think you need to look at the powerjection system, its a self tuning (but you can also tweak it with a laptop) high pressure TBI system disquised as a carburetor, I bought a powerjection 1 used which I havent installed yet but it also controls ignition, the new powerjection 3 has the computer and everything built right on the throttlebody (mine has a seperate computer) any time now they will be releasing the powerjection plus which is a powerjection 3 with ignition control.....heres the links....

    Professional Products Online

    http://www.professional-products.com/pp_EFI_catalog_112007_web.pdf

    Retrotek - Home

    You can find deals on the powerjection 1 systems, I got mine for 1300.00 the polished billet one.

    The only carbs that have came close to efi for me are the demon annular and the 4100 but EFI ROCKS and actually the new systems like the powerjection and ez-efi make more power than a carb, usually mpi makes a little less but more torque and drivability TBI used to be a comprimise between carb and mpi and used about 15psi fuel presuure, the new systems use 45-60 psi high pressure injectors which atomize the fuel so much better and a carbed intake (wet flow) which provides a slight intercooling effect and wide band 02 sensor and they work killer. The further away the injector from the port the more power you make. Modern efi cars have injectors close to the port for emmisions and simplicity but look at any efi race car and the injjectors are further away from the port.....the better atomization of fuel the more power you will make.
    #11
  12. D.Hearne

    D.Hearne Banned

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    Of all the above, only the altitude correction is true. Weather changes ? B.S. Cold starts? B.S. Fuel economy is only partly true. But who's going to drive their classic enough to care ? Tuning those three carbs took all of an hour.(and that was changing jets in all three) And that was 6 years ago. Ain't touched em since. They're no more trouble to tune than hooking up a laptop.
    #12
  13. D.Hearne

    D.Hearne Banned

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    That's a 3 carb setup with Holley 250 cfm carbs. No EFI there. The ignition is a stock Ford Duraspark. Throttle response equals any EFI system. MPG? they pulled down 16 mpg highway @ 70 mph with no overdrive in my 89 Ranger. 14 mpg in the Comet with it's C-4 transmission. The Ranger had a Toploader 4 speed. No overdrive in either vehicle. Cold starts are no problem even with no choke (all that's long since been removed) Give it a single pump shot, then baby the pedal a minute or two and it'll idle on it's own. The 5.0 currently in the Ranger is an Explorer 5.0 topped with a Ford A321 intake and Holley 570 carb. Also, no choke there. Cold starts & idle down to 25*F with no babying of the pedal, again the secret is the EFI cam grind (Ford's F4TE hyd roller) and a good electronic ignition system (it's got a Crane XR-1 in a points distributor) Both have been extremely reliable, tuneups go 2 years or better between plug changes. And no carb adjustments once the initial tune is done.
    #13
  14. htwheelz67

    htwheelz67 Member

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    I have been messing with carbs for 30 years, years ago on my 351w I tried a 4100, carter 625, holley 600, then a holley 4010 I spent hours and hours and had an old edelbrock a/f meter and tuned that carb to perfection I then took it to a carb guru and had him dial it perfect, I even passed CA smog with it.
    I found an old analog 670 cfm holley projection with closed loop box in my local paper for 300.00 this was about 1990. It was my first taste of efi and instantly my 268h cam idled way smoother, this unit was adjustable by turning knobs from the drivers seat....choke,idle,acc pump,mid and high, after messing with it for about an hour my butt dyno felt about 20 hp and 20ftlbs over my well tuned carb, it had almost too good of throttle response as I would chirp the tires with a light stab of the throttle it actually got some getting used to. My fwy mileage used to be 14-15 at best with the carb, it was consistanly 19mpgs with the efi and I got 21 on a long steady 120 mile cruise. The emissions also went down as well as I had a buddy that would bypass the visual and just do the tailpipe inspection, The efi absolutly blew away my carb in performance and economy. I later upgraded heads and to a hyd roller and the analog was not up to the task so went to a projection DI and it ran great, I later decide I was going to a 408 and sold the efi and went back to a carb, I used an edel 750 and tuned it to perfection but it was not even close to the efi, I switched to a 650 speed demon and it was excellent out of the box, faster and better response than the edelbrock but still not as good of drivability and MPG's as the EFI. I will bet a tri-power intake and 3 carbs work excellent as that gives you drivability and power BUT how much is a tri power and carbs? I bet about the same as a powerjection or more, the only carbed setup that I know of that works like efi is the cross boss or the new Barry Grant Badman which is an improved version of it. I have a BG mighty demon 750 annular on my 408 now I also have a wideband a/f gauge and it is pretty spot on, I am going to dyno test it and then install the powerjection and dyno it again and I will post the results, both the carb and efi are 750cfm but really flow about 900 cfm, this will be interesting........I can tell you you cant really feel 10 hp but you can feel 20.
    #14
  15. D.Hearne

    D.Hearne Banned

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    What ignition system were you running with that old 351W ? As for the cost of my tri-power, it cost me $1100 shipped to my door. It was a year old, bought second hand. The same setup new, now runs about $1700 (Mustangs Unlimited) The 5.0 in my Ranger with it's 570 runs as well as the tripower. I've yet to have the chance to check the mileage (hopefully that'll happen this week) as I didn't have an operable speedometer with the Toploader 4 speed.(it's got an SROD in it now) The mileage of the 331 (when it was in the ranger)was checked without it, but on a measured round trip from my 06 Mustang. Bottom line is you can have most of your cake and eat it too with a carb. It just takes the right combo. It's all in the cam choice, ignition and a smaller than normal carb.
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  16. htwheelz67

    htwheelz67 Member

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    I was running a jacobs energy pak with a recurved dura-spark, I switched to an accell 300+ when I switched to the holley projection DI as the Jacobs needed a seconary trigger with the digital efi. I agree the smaller than normal carb works great but limits performance, my 408 ran excellent with my 650 speed demon, The low end was killer and great drivability, The 750 mighty demon annular blows it away past 2500 rpm, the 650 was great but only off idle to about 5000 rpm and then it pooped out.

    You are so right a smaller than needed carb will increase drivabilty and MPG's but at the expense of overall power, my experience is efi can give you both. I am sold on efi.

    You want the best of the best? This is the best for power......a marriage of efi and a carb, talk about atomization.......this is the best. I cant see any carb or efi that will beat this. I dont see any way to get better atomization of fuel. but you need a computer.......

    http://www.barrygrant.com/bgfuel/default.aspx?page=63
    #16
  17. D.Hearne

    D.Hearne Banned

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    The downside to EFI is when it goes wrong. If you don't know how or have the tools to fix it, it's going to cost you an arm and a leg to get it fixed. Multiple carbs gained their bad rep from being paired wth points ignitions "back in the day". 90% of what everyone thinks are "carb problems" are actually caused by the ignition system. The 3x2 works as well as it does due to the running on the center carb all the time with the end carbs being the secondaries. It's basically like a spreadbore carb, but with better fuel distribution. Something I'd like to try someday is Edelbrock's airgap 2x4 setup. but with two 2 bbl Holleys or twin EFI throttle bodies. Or maybe that BG carb you liked to with a pair on a tunnel ram intake.
    #17
  18. Grand Poobah

    Grand Poobah New Member

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    Well I have to say gentlemen (or ladies, but I'm assuming we're all males here) my mind has been both blown and educated.

    It seems that a carb is then a perfectly reasonable choice for balancing performance with mileage.

    I was wondering it'd be possible to get ~380 net horse power out of a stroked Windsor 302 (stroked to 331 ci) and yet achieve ~10-13 mpg avg.
    #18
  19. ForceFed70

    ForceFed70 That's why they call it "dope" Founding Member

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    EFI certainly has it's advantages. Yes, with a carb you CAN get NEAR the power and efficiency of EFI but you will not surpass it. AND, it takes someone who is very good at carb tuning just to get you that far.

    From someone who used to run a carb and has now converted to EFI: I will never install another carb.

    Check out my EFI conversion thread. Keeping the "carbed look" was one of my goals, and I believe I did a good job of it. 95% of people think it's carbed until I tell them it's actually EFI.
    http://www.stangnet.com/mustang-forums/593406-70nes-custom-efi-conversion-writeup-part-1-a.html
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  20. 65FBE2

    65FBE2 Member

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    Easy if you have the right tranny. I have a 347 around 400 hp with 3.70 rear gear a 2.74 O.D. and I get 18 mpg
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