Lenco ratios

Discussion in 'PSI Superchargers Tech Questions' started by Iron Mike, Feb 6, 2012.

  1. Iron Mike

    Iron Mike New Member

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    Ok.
    540 - 2000hp
    14/71 big & Ugly

    I have the following ratios
    1.5616 & 1.4383

    Makes 2.246 first
    What should be second ratio 1.56 or 1.44
     
    #1
    Iron Mike, Feb 6, 2012
  2. Iron Mike

    Iron Mike New Member

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    Door car 2700
    4.3 rear gear
    34.5 17 16 tyre
    Triple clutch
     
    #2
    Last edited: Feb 6, 2012
    Iron Mike, Feb 6, 2012
  3. Dave Germain

    Dave Germain New Member

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    ratios

    I am not a door car expert but that seems like a lot of low gear for that much power. Have you ran the car with that set up before? I have seen guys that had the same question as your's do a track test to decide which gear set to shift when. On the air shifter cars they ran it one way- swapped the air lines and then ran it the other way. I suppose with a manual lever car you could just pull the other lever first? I have always preferred to shift the section closest to the motor first. Not because I knew something smart but it was just sort of a habit I got into. Once you ran the car shifting it both ways you could easily swap gears to do it however you wanted.
    I have seen lots of roots blown funny cars with less horsepower than yours running low gears in the 1.75-1.85 range. More low gear (higher numerically) is almost always a good thing (the car leaves and pulls harder down low) but it also makes them more susceptible to tire shake and spin. The tuning window gets narrower the higher the low gear
     
    #3
    Dave Germain, Feb 6, 2012
  4. Mike Canter

    Mike Canter Top Dragster
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    Dave is correct. You would do better with something down around 2.10-2.18 with a 4.30 gear with that size tire. Since you are running the 4.30 and those are the gears you have then I would try the 1.56 for a second gear. What you need is a first gear that when you multiply it by 4.30 comes out between 9.02 and 9.4. Your first gear comes out to a 9.67 which is a little steep. You are going to have to keep that launch rpm down.
     
    #4
    Mike Canter, Feb 6, 2012
  5. Iron Mike

    Iron Mike New Member

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    I also have an eight lug 1.3815. If I use that instead of 1.5616 that would make it 2.00 first. Is the eight lug an issue?
     
    #5
    Iron Mike, Feb 7, 2012
  6. Mike Canter

    Mike Canter Top Dragster
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    I assume that when you say eight lug you are talking about coarse spline. With your 2000 hp the coarse spline will work. We ran them for years.
     
    #6
    Mike Canter, Feb 7, 2012
  7. Iron Mike

    Iron Mike New Member

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    Yes course spline. But the floaters in the clutch pack are eight lug instead of splined
     
    #7
    Iron Mike, Feb 7, 2012
  8. Mike Canter

    Mike Canter Top Dragster
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    Wow that's an old one. Somewhere I have some of those steels. You could use that to test how the car works with that ratio. If it works then look around for a later splines type.
     
    #8
    Mike Canter, Feb 7, 2012
  9. Iron Mike

    Iron Mike New Member

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    Mike
    Thanks for you input. Yes box has been laying around for quite some time since I last used it in a sbc n2o engine. Was a 80s pro stock box. But did little work.
     
    #9
    Iron Mike, Feb 7, 2012

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