More newb ?? pump size/HP

Discussion in 'PSI Superchargers Tech Questions' started by Compresser, Apr 9, 2019.

  1. Compresser

    Compresser Member

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    I'm going to start off with a quick layout of my car and current situation.
    Blown 540 BBC Fast EFI. 235" RED
    Car started out with TBS 10/71 and a #1 Hilborne pump and 8 160# injectors.
    Ran a best of 6.80 @ 200 MPH blower at 27% OD 11 PSI
    Did not qualify at Vegas last November so bought new HH 14/71 blower, manifold and setback plate from BDS and good 110 enderle pump 13GPM new 220# injectors.
    8 injectors in hat with two .025 jets in back of blower running off of fuel rail pressure.
    With the new setup car will not go past 30-40 feet WOT before the engine quits.
    I initially found a plugged fuel filter, thought that was the problem. No help with new filter. Removed the filter no help.
    Thought high fuel pressure could be shutting off the injectors. Installed 130 PSI bypass before fuel rails. No help. Lowered bypass to 80 PSI no help.
    Sent pump back to enderle. came back 13.1 GPM @ 4000
    So I'm down to checking if cell vent size is adequate. Currently vent is 3/8". Also my tank only has a #8 AN outlet to the pump which I have installed AN#8-#12 fitting to get to the pump.
    Distance from tank to pump is 12"

    So to all the resident experts on this forum:
    Is 990 pump to small? for the higher 20PSI boost I'm now running.
    Is the tank #8-#12 causing that much of a restriction?
    Is the 3/8 vent part of the problem?

    Thanks in advance
     
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  2. sammy christian

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    you're 3-400# low on injectors.
    miles off.
    and if those are bosch/siemens running as high as 130psi, you are risking catastrophe, can blow the bodies apart.
     
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  3. kosky racing

    kosky racing Comp Eliminator

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  4. kosky racing

    kosky racing Comp Eliminator

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    Need at least a#12 to the pump off the tank
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    I agree with Mike Kosky, you need a large supply line from the tank to the pump. Also need larger tank vent. Don’t know if that will fix your problem but they are still needed
     
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  6. Compresser

    Compresser Member

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    Sammy, this is great info.
    I as told that the 220# injectors would support up to 1600 HP on alcohol as well as 150PSI. Maybe the 1500HP# was figured at the higher PSI?
    Looks like I will have to drop back blower OD for the time until I can make room for more injectors.
    Thanks again for your reply
     
    #6
  7. Compresser

    Compresser Member

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    I'm in the process of building a larger tank that will have the outlets sized for this application.
    Old fittings and vent was for a belt drive 01/2 pump feeding a single alcohol carb.

    One last question here.
    How much HP will the 990 pump at 13GPM support?

    Thanks again for all of the help from all that have replied.
     
    #7
  8. Bjs344

    Bjs344 Member

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    I think my 990 is a little on the weak side. I have used most of it but not all on a bbc with decent conventional heads and a good 14/71 at 43% in average air. 6.2x @ 2050 lbs.

    How do you know it’s a fuel problem??
     
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  9. Compresser

    Compresser Member

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    BJS In my first post I missed stated the pump. It is a 110 that flows 13.1 gallons.
    I'm not positive it's a fuel problem. Just putting this out there to try and get some real world experience/advice.
    I do not think it is ignition as engine does a burnout without a miss, goes on the TB without a miss. Launches hard without a miss, It just quits. Back off throttle then roll back to WOT, car takes off and then quits.
    It does not lay over it quits.
    On my last outing it did go a bit further than 60' on the first run and recorded a 1.03 60' time.
     
    #9
  10. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    I have never heard or seen anyone running FAST EFI successfully on a 14-71.

    Not saying it can't be done, but it sounds like you are low on pump and injector size.
     
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  11. Compresser

    Compresser Member

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    LOL, Will please describe successfully. how about successfully with a smaller blower?

    I know from others experience with the EFI that MFI is faster.
    My goal is to be able to run in the 6.50 range. 6.50's will get me into pretty much any div7 T/D field for the next couple of years.
    6.50's is pretty much my budget limit.
    I'm 69 years old this year and don't have that many racing years left so this is kind of my last big swing for the fence deal.
    For what it's worth I like the challenge and the interaction here getting ideas and new knowledge.

    I just ordered a couple of new fuel rail blanks and a step drill to make a second set of fuel rails for an additional set of injectors.

    Thank you once again to all that have contributed with their thoughts and experiences.
     
    #11
  12. Ray Hadford

    Ray Hadford Member

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    # 12 fuel line and at a minimum... .5 ID tank vent minimum. .. If you have a stainless braid or flexible hose fuel line ....... be sure to put a spring inside the suction supply line leading to the pump.

    We fought a collapsing main fuel line for a full season with a nitro funny car in 1972. We got lots of backfires and ugly stuff. Sometimes it did exactly what you have experienced. We were able to recreate the problem in the shop with a vacuum pump.

    Earls has the stainless springs. This also holds true for all dry sump supply suction lines.

    Real cheap insurance...

    Ray H.
     
    #12
  13. Bjs344

    Bjs344 Member

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    Same combo with a 110 pump, same main pill, and less boost went 6.50s all day. Weather came once in and it went 6.37 shutoff but it was definetely burning the fuse on that pass.
     
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  14. Sascha Mecking

    Sascha Mecking New Member

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    Sorry to hijack an old discussion here:
    The 1600 hp would work on a N/A engine and going Lambda 1 at 43 psi base.
    The 220s you can probably crank up to 320 lbs/h at 100 psi base.
    That would give you: 320 x 8 (cylinders) x 0.8 (duty cycle) x 0.6 (Lambda at 4 to 1 A/F because of the heat created by the blower) = app. 1230 hp only those 8 injectors will safely support on a blower engine - minus power to drive the blower.
    It's not your supply - you're out of injector.
     
    #14
  15. swsc4133

    swsc4133 Member

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    Compressor. Had a friend with a very different combo in a blown dragster chase the exact same issue. It would launch and just die about 150 ft or so. Lift and roll back into it and it would fly for just a few seconds and die. After months of chasing the problem it came down to the main fuel line to the pump was collapsing (closed) and shutting off the fuel the he motor at wide open throttle.
     
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  16. Compresser

    Compresser Member

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    Update on my engine shut off at the launch. Freaking EFI!! After lots of $$ spent it was a $10.00 15 amp relay.
    Operating voltage for the injector harness and O2 sensor are controlled by this relay.
    I wired a very bright LED into that relay output and sure enough the light went out when the engine died. Apparently the relay would not stay latched from the acceleration of the car.
    I replaced the relay plus mounted it facing forward so inertia would help keep it latched.
    After getting all of the tune up back to original from the start of this year 6.65 206! in Las Vegas.
    It did lean out and blow a head gasket at the last 100 feet but that is pretty easy to fix after all I have been through.
    While replacing the head gasket I'm fitting port injectors into the intake. That should brink the AFR back into range.
    Thanks again for all of the suggestions.
     
    #16
  17. Sascha Mecking

    Sascha Mecking New Member

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    Don't feel bad. I know somebody who took off his "god damn EFI that always shuts down" only to figure out the very same power relay causing this would also shut down his then later mounted MSD 8 dual coil :)
     
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