bbc gone backwards

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by PROMOD63, Jan 15, 2017.

  1. PROMOD63

    PROMOD63 Member

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    i have a 10.5 car that i help with it ran 4.60 with a junk littlefeild on it its a 521 the guy decides to replace the blower because it was worn out he calls and talks to Don Hampton and buys a 1471 from him it makes about twice the boost but the car slows half a second so they send the fuel system and the ignition system to Spud and have it all gone through with no better results so we have the engine apart and didnt find a thing inside except the front pistons and black as cole and the rear are clean which made me think ... they had to remove the setback plate to put this blower on and it is a open bottom blower bolted directly to a BDS intake so it is 6 inches further forward than the littlefield was which had a pie shape opening anyone have any clue what we have wrong ? the only thing i found at the track was the engine made about 48 lbs of boost and we could never seem to get it to lean out i dropped the pill to where i thought it would hurt the engine and the plugs looked new
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    If the plugs look new then you are way rich. Do you use a weather station and adjust your main pill for changes in density altitude? What was the DA for Spuds fuel setup? Spuds tuneup is probably a little rich just for safety and he expects you to dial it in. In case you don't have a weather station and how important it is. For every hundred feet of DA change needs one size change of the main pill. So if Spud gave you a tuneup for 1000 ft DA and at the track it is 3500 ft then you are 25 sizes too rich.
    Also you say you dropped the pill. Are you saying you made the pill size smaller? If so that made it richer.

    http://www.dragstuff.com/techarticles/reading-alcohol-spark-plugs.html
     
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    Last edited: Jan 15, 2017
  3. PROMOD63

    PROMOD63 Member

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    He sent it for 3200 ft we do use a station and adjusted it per the guide at first then I started leaning it out ( putting in a larger number) and still was never able to get it to burn the plug off any I went so far then I quit because I knew I was way off from baseline so I thought it might be putting the plug out and sent the ignition in but he said it was strong the only thing I have found is the different look on the pistons in the front 4 cylinders....... I have been looking around at Hampton blowers they seem OK but I don't see much use of them in outlaw type racing mostly Street and natistalgia racing ?
     
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  4. weld_everything

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    Was the cam or its timing changed? "Twice" the boost and won't touch the plugs doesn't jive but if the cam was moved it could make screwy numbers and poor performance.
     
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  5. Mike Canter

    Mike Canter Top Dragster

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    What type of Mag are you using? And how much timing advance is there total? Also talk to Spud about what is happening with the fuel system. Are you sure you don't have a poppet in backwards on the pump loop or a high speed leanout. That will make it run real rich.
     
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  6. Bjs344

    Bjs344 Member

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    I didn't think anybody had built a competition blower in the last 20 years with an open bottom?? Just because it makes more boost doesn't mean it's moving more air.
     
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  7. greenracing

    greenracing New Member

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    what Bjs said ^ If the LIttlefield was on a setback plate, it was probably a retro. So you took off a HH retro and put on a standard helix open bottom? Send the "worn out" blower to Mert's (or Gerardot's or ....) and have them go through it, you'll be further ahead.
     
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  8. PROMOD63

    PROMOD63 Member

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    the poppets are marked and have been checked ,its a 44 mag,we have ran from 28 to 34 deg timing I found nothing wrong with TDC or cam timing when I took it apart I am strongly leaning tword the idea that this blower just isn't what we need... as for the old blower I sent it to DMPE and they said throw it away it would cost more to fix than to replace this car was running and we did nothing but replace the blower we didn't even take the valve covers off
     
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  9. Critical Mass

    Critical Mass Member

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    We are all assuming you set the butterfly opening gap and the BV up correctly?
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    Well if all has been checked then it is time to call Spud. If it is that rich then you are not giving the blower much chance to prove anything.
     
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  11. PROMOD63

    PROMOD63 Member

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    talked to Spud first he said the ignition was bad so we sent it in when we found nothing he suggested the cam was wrong but its the same cam we had bullet make for it and it hasn't been messed with I am thinking I need to have this blower looked at by a third party
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    Regardless on what blower is sitting on the motor you should be able to adjust the fuel flow to show burn on the plugs. If you can't then the motor is never going to make power. Do you have a fuel flow meter on the motor? Are your plugs gapped at .015"? I can't believe that Spuds fuel tuneup is that wrong. The blower is making boost so it should run. Regardless on how the poppets are marked take the pump loop poppet off and look into the end that has the oring that goes towards the pump and see if you can see the end of the poppet down the hole. Also check the bypass the same way, the oring end should go towards the jet holder and you should see the poppet down the hole.
     
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  13. jay70cuda

    jay70cuda Member

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    Do you have air fuel math channel on your Racepack. What's about boost on the 2 step with fue flow. When I got my new fuel pump from rage I hooked everything up jut like my waterman was. Well it was wrong. His bypass do the management block was blocked off while the engine was running. But when you pull the shut off it put fuel to the management like t was working. Needless to say it was flooding the engine and no changes seemed to work. Just a dumb over sight on my part cost me tons of grief. Flipped the lines around and bang. Mean and lean jut like the system was flowed
     
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  14. PROMOD63

    PROMOD63 Member

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    but taking into account that the fuel system has been ran before and after spud worked on it it seems to me that it really cant be in the fuel system unless he missed it and we have too
     
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  15. altered boy

    altered boy Outlaw Altered

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    i'll never understand this whole 'had it flowed' thing. i have my pumps flowed to make sure they don't change over time. but we don't race flow benches.

    sean belt... metal mafia aa/fa
     
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  16. Mike Canter

    Mike Canter Top Dragster

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    I understand what you are saying because unless one knows the expected boost then it is pretty hard to give a tuneup that is right on or close. You would have to guess the boost then make a tuneup that is rich to get it down the track then modify the tuneup. Or you can by a fuel flow sensor and Jetsize and flow the system every run but if you don't have any of that and not much experience tuning then it is faster and safer to get the whole system flowed so you can get a baseline that can be adjusted after a couple of runs
     
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  17. jody stroud

    jody stroud ZOMBIE Top Dragster

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    A flowed fuel system ensures that all of the components are matches and tuned. A stock bypass pill usually does not actually flow what the number stamped on them shows. Also having the system flowed will show any cavitation in the fuel pump that will not necessarily show on a graph of fuel pressure. Some people get lucky and hurt nothing by bolting on parts and heading to the track, others burn up a pile of shit trying to figure it out on their own.
     
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  18. nitrowannabe

    nitrowannabe Member

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    Look who posted that. They run an iron Chevy Fuel Altered on 92%. They do dry hops. Obviously not listening to anybody . A bunch of great you tubes. Great show guys.
     
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  19. PROMOD63

    PROMOD63 Member

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    DMPE says that the pistons look different because the blower is getting so hot it is cooking the charge before it gets to the plug according to him this open bottom blower is way old technology and will never work
     
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  20. jay70cuda

    jay70cuda Member

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    SO how far is the set back? Also wouldn't that be a fuel setup issue? Like there should be more fuel going thru the blower? Those blowers did work. They just don't make the power a delta opening high helix makes.
     
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