Is it possible for a blower to…

Discussion in 'PSI Superchargers Tech Questions' started by Bjs344, Oct 9, 2021.

  1. Bjs344

    Bjs344 Member

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    Take a 1000 hp to spin?

    kobelco 14-71 std helix with minor dmpe mods.

    At 20 over it should be moving 1500 hp worth of air and making 40 psi of boost.

    it makes the right boost number according to my data.

    If I put 1500 hp worth of fuel to it, it makes 750 hp and just barely colors the plugs (assume 2 lb/hr/hp and 4.1 target. Ya I know, that’s a lean target but at 3.5 it makes even less power)

    if i put 1200 hp worth of fuel to it, it makes 850 hp and burns all the plugs to the top thread.

    If I put 1000 hp worth of fuel to it it will make 1000 hp for about 1 second before it torches the heads completely off.

    The blower case never gets hot on a run, but I don’t measure iat yet.

    is it possible for a blower to be bad enough to soak up 600 hp more than a normal blower or almost 1000 hp total????

    I’ve changed converters twice and rear gears once but the power just isn’t there. Different heads, cam. 50% through the blower up to 80% through the blower. I can make the plugs look exactly how I want on every cylinder with no problem.

    Only oddity is the right side idles WAAY lean even if I flood it with the barrel valve. Actually only 2,4, and 6. 7 and 8 are so far at idle they’re hard to keep lit.
     
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  2. jay70cuda

    jay70cuda Well-Known Member

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    I've ran Dmpe stuff a bunch and it was always good. Sounds like you got an electrical issue.
    Both heads grounded to the coil ?
    44 amp mag?
    Maybe we need some details on your setup to better help
     
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  3. Mike Canter

    Mike Canter Top Dragster
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    What engine is this blower sitting on? How many cubes? If you take the blower belt off and turn the blower by hand how hard is it to turn?
     
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    Last edited: Oct 10, 2021
  4. Bjs344

    Bjs344 Member

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    326” LS.

    stock coil on plug. Same basic motor made about 1500 hp with a turbo on top.

    Ive verified timing all the way to 7000 rpm, but it could be off by a couple degrees. Sounds great all the way to 9000 rpm. I wouldn’t say it pulls, but it definitely doesn’t nose over or misfire at all. Super crisp and clean above 7000.

    I’ve had timing all the way from 18 to 28. Most guys with this combo underneath a turbo run 18-24 degrees total although I’ve heard of maybe one at 30 degrees. 65cc chamber that I softened just a little. Small dome. About 10.5:1 compression.

    I’ve flogged this thing to death and blown it up or torched the heads about 8 times both on the chassis dyno and on the track. It just won’t make any power unless it’s dead lean and even then it’s hundreds of horsepower shy.

    I was going to just start adding 2 degrees at a time yesterday until it blew up but it lifted a head while making dismal power at 28 degrees.

    I tried turning the blower down and only making 30 psi in case blower speed was getting too high, but the power was down about like you’d expect for giving up 10 psi of boost.

    I’ve had it stal anywhere from 6000 - 7800, shifted it anywhere from 7500-9000. All about the same.

    I think Ssi has a blower dyno so maybe I just need to get it up there? Or call Davenport, but not sure I have the blank check for his help.

    i didn’t actually get the blower from dmpe. Got it from an offshore guy who had the email from dmpe where it had been sent in a long time ago. The case has been machined on the bottom in front of the rotors so somebody worked on it.

    almost forgot, Mike, it spins super easy by hand. I figured since it’s making 40 psi like it should be at 20 over, why bother restripping? I have an Ssi high helix that’s even looser and it ran great on my bbc stuff. I was planning on putting the high helix on this deal just to see (wouldn’t be class legal) but I’d have to cut the dash bar out.
     
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    Last edited: Oct 10, 2021
  5. WIDEOPEN231

    WIDEOPEN231 Member

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    IMO do not get over hung up on numbers. Boost is just a referance tool. Lots of things play into it. Valve size,cam design ,head flow and temp of air coming out the blower.
    I understand the x amount of fuel for x amount hp.Are you taking into account that the reason you put fuel thru top is to help cool the blower? It also gets less fuel out becuase when you are cooling it some is vaporized(for lack of better wording).
    Some times you have to listen to the motor and screw the math or to use word thats popular now days.Screw the science. If you want to run x amount fuel and its rich.Add blower thats why the pulleys have bolt holes. If rules limit blower over drive thats where you have to lean it some. Tune motor by what it is doing and what it wants not what some formula tells you what it should want. Just a old guys opinion.
     
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  6. Bjs344

    Bjs344 Member

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    Chris, if I was on your side of the fence, I would agree with you 100%. But if I extrapolate from where I’m at now, I would need about 6000 lb/hr and of fuel and about 90 psi boost to make 1500 hp. Same motor made close to 1500 with a turbo around 40 psi.

    In hindsight, I should have left the fuel up closer to 3000 lb/hr when I started turning the timing up, but the plug was so cold I though I could take away a little fuel too.

    So, has anybody ever seen a blower rob hundreds of hp more than normal?? Whether due to assembly error or anything else? I’ve knocked it off the intake twice, but it always spun ok afterwards. Any way I damaged it without any visual signs or binding?
     
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  7. jay70cuda

    jay70cuda Well-Known Member

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    Knocking the intake off is extreme lean conditions. A barrel valve isnt perfect but it dumps a lot of fuel during the transition from trans brake to wot. Not many people have made efi work on blower. Maybe talk to Jon at resolution racing. He ran it for a while and I'm sure he could crunch fuel numbers with you.
     
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  8. Mike Kern

    Mike Kern Member

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    First thing I'd look for is if the rotors are in backwards. With the snout pointed at you (and looking at the inlet) the rotors should make a V shape (V for Victory), If it looks like and A, you're an A($$hole).
     
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  9. Bjs344

    Bjs344 Member

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    No efi here. All my numbers are based on spuds calculator plus the pump flow sheet.

    I knocked the blower off because the ports weren’t opening fast enough. I understand why it happened now. I can explain but don’t want to start an argument about that in this thread. Didn’t have data the first time but the second time I had a pressure transducer in the port distro and it was very obvious what happened.

    no victories here but I do have a v in the rotors. Actually woke up in the middle of the night a few weeks ago and went out to the garage to verify.
     
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  10. Bjs344

    Bjs344 Member

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    Something else I just thought of.

    last week i stall checked it in the driveway before putting it on the trailer. 7900 on the button and climbing. Motor wasn’t ice cold but it wasn’t warm.

    changed nothing, took it to the track, warmed it up. Did a decent burnout. Air is maybe a tiny bit worse. It goes 7000 on the button.

    the blower case doesn’t get warm but is it possible something happens to it as it warms up to completely mess up the airflow??

    something else I hadn’t thought of: when the motor is relatively cold I can flick it to the moon in neutral. By the end of the day it just wants to labor until I give it a bunch of throttle. Didn’t even realize it till just now, but i think it’s been that way for a long time, maybe ever since I put it together.
     
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  11. kosky racing

    kosky racing Comp Eliminator

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    something stupid ----but could there be tape or a covering on the manifold opening -seen clear tape covering blower discharge and openings- also on manifolds!
     
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  12. Bjs344

    Bjs344 Member

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    Lol, that would be a good one. I’ve had the blower off no less than 20 times since I started this deal a year ago so I don’t think I missed anything being taped up. But it just about has to be something almost that stupid.
     
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  13. MaineAlkyFan

    MaineAlkyFan Active Member

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    Two thoughts... Heat seems to be a factor, maybe when the case or rotors heat up something is binding? The blower dyno would show up some kind of heat induced mechanical loading.

    What else changed when you went from turbo to blower? Plumbing. Wires. Ignition. We chased a lean cylinder for a while that was perfect except during the run. Ended up being a nozzle line with a pinhole in the inner jacket of the hose. Tested & looked fine, but during the pass, fuel pressure would balloon up the inner liner & restrict flow. Maybe something like that on another system that happened to change at the same time as the blower swap.

    Chris Saulnier - Team Tigges
    Mechanic Falls ,Maine
     
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  14. Bjs344

    Bjs344 Member

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    Ya, I definitely need to get the blower looked at and on the dyno.

    the turbo setup wasn’t mine, I just bought the motor and bolted on a blower intake. But there’s dozens of combos just like that turbo setup out there. Any hillbilly with a laptop can make 1500 on these things with a turbo on it. All the turbo guys say it’ll never run with a blower on it. Unfortunately I think this is currently the fastest 14-71 Ls in the world, but that’s just because it’s the only one that’s been down the track.
     
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