So, Fuel injection...

Discussion in 'High Tech for Old Iron' started by 70redbird, Mar 5, 2018.

  1. 70redbird

    70redbird Mongo

    Been a few years since I've really looked at doing anything to the 'lark... was in texas and away from it for almost 2 years, and before I left the 870 street avenger in it was starting to act up. It's idling high and dying really easily, and I've also noticed on really good pulls the motor will cut out and die around 70 mph, and take a few seconds before it'll fire back up, I'm thinking it's emptying the bowls. The machinist who built my motor said that when he had it on the dyno, it did a lot better with his 1050 (I believe it was) and my peak numbers were done with his carb and not my 870. Either way, it's all moot.

    I'm sick of the black magic of carbs and their flighty ways. I'm looking at putting one of the fuel injection kits on it.

    I have an aeromotive electronic fuel pump with a regulator
    my motor peaked around 540 hp on the dyno with a better carb, not sure if that was the best it can do.
    I have an MSD 6 (I believe) box on the car, I'll call summit to find out for certain.
    This is NOT a daily driven car, performance is my greatest focus, but I wouldn't mind being as practical as possible without really sacrificing power.

    I've been perusing the threads here, and it seems this market is changing fairly often, at least relatively speaking.

    I'm seeing that the MSD isn't a popular choice, that FI-tech and Holley are the more popular ones.

    Would the FI-tech kit for up to 600 HP be the solid choice? If not, what would you recommend?

    control center?

    Are the self tuning systems better now, or should I get something that needs to be dyno-tuned, how much HP or efficiency are we talking about versus cost, as dyno tunes aren't cheap, and finding someone knowledgeable can be difficult down here in the Florida Panhandle.

    Any input is appreciated
    Last edited: Mar 5, 2018
    TrunkMonkey likes this.
  2. Bens99gtp

    Bens99gtp Well-Known Member

    Not sure how big your motor is, but at only mid 500hp, I really can't see a 1050 being a great carb on that me that is way too big. A good rule of thumb formula is
    CID x RPM x V.E. / 2820 = CFM

    This is a little different than the older formula due to fact that new carbs can pull and shear full at a much lower inches of water.

    A .9 Volumetric Efficiency( ve ) is a good setup where 1.1 would be a full tilt, balls out , block splitting setup.

    So assuming a 464, common build, and 6000 RPM redline that comes out 888cfm. I ran a 1000cfm main body that flowed 987 on my 10.90 iron head 11.5:1 motor.

    So I think your carb is close to right size......I know some think carbs are black magic, and vodo, but they are actually very simple predictable things........

    That being said I believe your issue is in the tune up or overall condition of the carb, not the fact it has a carb on it. Sounds like a vacuum leak, maybe some float settings, or trash in the floats causing lack of fuel to the carb.

    As far as fuel injection goes, I have never put on one, and can't recommend anything over what I read, but it can be a good way to drop a couple g sometime
  3. 70redbird

    70redbird Mongo

    Well, everything I've been reading purports that they can increase power, DO increase mileage (which is always a plus), and get rid of the need to constantly adjust every time the weather changes or altitude changes. I'm sold on the idea of getting one of the conversions, I just want to make the right choice in which one I get.

    I'm thinking the Holley Sniper 4barrel should do the trick, but Holley's site says it's 800 CFM... I don't have the slightest clue what VE my motor is, it's a 462 iirc (.30 overbore from stock), about 9.8:1 compression. The next step up seems a bit steep of a price increase.

    Seeing that FI-Tech isn't as desirable because of their support compared to that of Holley.

    Is the sniper self-tune good or just decent?
  4. gs_jimmy

    gs_jimmy Well-Known Member

    I'm currently in the middle of doing this swap. Doing it for the exact same reason that you are listing. I went with MSD Master Kit 2900. From a price stand point on a fairly stock engine this was the more complete kit. There are still a few pieces that you do need to source out.

    Reading your engine specs above, the cam is going to be the biggest hurdle. The MSD system is already compatible with your MSD ignition system. This system is self learning, but does have its limits. I also looked at the Holley and FItech systems, they were just going to have me spending more out of pocket to get things up and running on an otherwise stock Stage 1 engine.

    You will most likely need to get a new fuel tank and will most likely want to go with an in-tank pump. There are a few choices on how you do that. the FI in-tank pump, fuel tank is running about $225 on ebay.

    So far my system is not giving me too much trouble on the install, looking to mount the external fuel pump and do the last bit of fuel line plumbing. Then the system is "installed" less the wiring & firing part. MSD seems to have the customer support down, just not as tunable as some of the other systems available.


    1969 GS California
    455 Stage 1, TH400, 3.31 12 bolt, HEI, MSD Atomic FI

    1964 Nova, 454/TH400 & 9"
    Turbo Regal
    1976 Tube Chassis Vega
    2003 S10 ZQ8, 5.3 LM7, LS1 cam, 4L60E & 3.42 posi (my last build - sold in Dec)
  5. sriley531

    sriley531 Buckle up, this could get rough....

    I'm in the middle of a fitech Meanstreet 800 install. I'll have a full write-up/review in coming weeks.
    Julian and Harlockssx like this.
  6. 70redbird

    70redbird Mongo

    Any words of wisdom regarding the CFM? Is 800 enough for my motor, or would I need to go bigger?

    What kind of loss could I be looking at if I went with an 800 and needed say 900 or better?
  7. OHC JOE


    Hey bud
    What type of fuel filter did you run..
    I need to pick one out.
    I have my tank and pump set up from tanks inc.
    I plan on using the push lock style of hose.
  8. sriley531

    sriley531 Buckle up, this could get rough....

    Hey Joe,

    I'm using the C5 Vette filter/regulator/return combo that's so popular with the LS swaps. I too am using a Tanks inc tank and pump, and fitech advised that the pump I'm using (tanks inc gpa-6) has a flow rate higher than what the built in fitech regulator is meant to handle. Plus I can integrate this thing on the frame rail where I had another filter for the old setup, this making a clean simple install and a shorter return line.

    And summit (or many other places) sells fitting to connect the "quick connect" configuration to AN systems.
    Last edited: Mar 21, 2018
  9. OHC JOE


    Ok thanks I'll check it out
  10. Steve73GS

    Steve73GS 73 GEE YES

    Hello Jim/SRiley or anyone else running with fuel injection,
    I'm considering FI on a 455 build. Any feedback or comments, good or bad? Aside from the reasons others mentioned, any difference in performance? I've seen claims of "should perform better " but, I haven't actually seen anyone saying they've seen a noticeable performance improvement. Thanks.

  11. 1973gs

    1973gs Well-Known Member

    I have FAST ezefi and the only issues that I've had was a faulty map sensor right out of the box. It's lifetime warranty, but it uses GM style sensors, so I replaced it with a GM sensor. What I don't like about the Fitech is the throttle body mounted ecm. Why would you want to mount an ecm where it's going be subjected to heat and vibration? I think that it's just cheaper to produce because they don't need to supply a harness. What I don't like about the Holley Sniper is the rubber crossover line between the two fuel rails, Do you want a rubber high pressure hose to leak on a hot engine? The picture in the Summit catalog shows it being a steel braided line, but I think it's an old picture because I saw one at a car show and it was just rubber hose. I've put 2400 miles on my Fast without any issues. The original Fast ezefi is in my opinion, the best looking because it looks like a carburetor. Summit has the ezifi systems for $900. You would have to step up to the ezefi 2.0 to have timing control, but for my application I felt that it wasn't necessary. With the Fast system, don't waste your money on the fuel pump and harness. The pump is very cheap and failed within 200 miles and the harness that came with the pump only had 18 gauge wire so when I installed a good pump, I had to run 10 gauge wire.
    Last edited: Dec 8, 2018
  12. 70redbird

    70redbird Mongo

    I'm still hoping to get some wisdom on which cfm I need to look at getting.
  13. sriley531

    sriley531 Buckle up, this could get rough....

    Hi Steve,

    So here's my take on the Fitech system I installed. "Performance improvement" is pretty subjective. You'll hear guys argue they won't make power over a perfectly tu ed carb. I'm not sure I agree as a carb that tuned "perfectly" today may not be "perfect" a month/6months/year down the road with changing conditions, perhaps an elevation change, etc. So here's my observations. I replaced a very well tuned Holley with fuel injection. My Holley ran great, was initially tune on a Dyno and then repeatedly tuned in the car using a wide band o2 setup. It always fired right up, had no dead spots, etc. That being said, the Fitech created some VERY noticeable differences as far as the throttle goes. Cold starts are improved (though only very slightly as my Holley never gave me trouble with cold starts. A crank and two pumps would fire Everytime. Now I just don't need those two pumps). Where I noticed the biggest difference is throttle reponse. It's just way more snappy. Now I personally feel the car pulls harder as it's always adjusting to keep the afr just right. My afr with the carb was good, mid high 13's across all rpms under wot. But there is no doubt the fi is just a bit better. Free-revving (though not all that important) is quicker as well. I also very much enjoy the boatload of real-time feed back I get on engine info, and being able to datalog could come in handy as well. All things considered, I replaced a good running carb with Fi and have no regrets. It made a good running car run even a little better. Now that's based on back to back comparisons with my highly calibrated butt Dyno, so take it for what it's worth. But a lot of other well experienced car guys have ridden in my car many times, and all agreed it was a step up. Never caught 4th gear rubber with the carb, it happens frequently with the FI. Is it night and day, total world's different and turned a slug into a hypercar? Nope. Is it undeniably noticeable in how it runs? Yes. Just my experience, though a few others here I've shared notes with and have shared notes with me from their installs would agree.
    OHC JOE and 300sbb_overkill like this.
  14. Steve73GS

    Steve73GS 73 GEE YES

    Thanks a lot for the replies guys. Most of what I have read has been pretty positive although the fuel pump has been mentioned quite often, especially on some of the earlier installs, as well as possible limitations @ WOT and max HP considering some systems are 800 or so CFM unless you upgrade past entry level, which gets kind of pricey. At the same time, the better throttle response is mentioned by almost everyone. I suppose there are tradeoffs no matter what. Anyone using the Holley Sniper/Terminator?

  15. Ken Warner

    Ken Warner Stand-up Philosopher

    Most of the throttle bodies are rated around 1000cfm. More potential airflow from a throttle body than actually needed is not the performance killer it is with a carb as the loss of signal does not impact performance. Generally the biggest concern is that the unit has enough fuel flow to support your combinations horse power level.
  16. cruzn57

    cruzn57 cruzn57

    we replaced a Qjet, on my buddy's 454 GMC truck, with a Fitech unit.
    600 hp unit,
    used primarily for towing,
    motor is lo miles, ( under 10k) with RV style cam (262 dur)
    heads were cleaned up, and tri y headers, with T400, and gear vendors.
    starting, was instant ! down shifting is much less seldom,,
    and gas mileage........ previously was 8-9 towing, now 10-12,
    drive ability was 1000% improvement,

    what size (cfm) do you need? bigger is NOT always better,
    it slows air flow, which decreases good fuel mixture,
    it decreases the signal to the venturi and air bleeds ,
    which decreases HP !
    I'm doubtful your engine is above 90% efficiency,
    so using readily available formulas .... 722 to 938 CFM is what it calls for.
  17. Steve73GS

    Steve73GS 73 GEE YES

    Engine will be newly built so trying to decide whether to go carb or EFI and narrow down a couple of other things
    455 .030 or .038
    TA Stg 1 SE or TE, Level 1 or 2
    SP1 or SP2
  18. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    If you don't have headers now and plan on getting them, consider the SE Stage 2 heads that cost IIRC the same as the Stg 1 heads. They will give better ex. flow so you can run a single pattern cam.
    sriley531 likes this.
  19. Steve73GS

    Steve73GS 73 GEE YES

    Plan on getting headers and was considering Stg 2 but I was told I would have to cut the hood for Stg 2 (73GS).
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Stage1 and Stage2SE heads would be the same as far as hood clearance. The TE heads have a raised intake port and you have to use the SP2 taller intake, so for either of the TE heads, you'd have hood clearance problems.
    300sbb_overkill likes this.

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