Tuning Help

Discussion in 'PSI Superchargers Tech Questions' started by RLPRACING, Feb 10, 2009.

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  1. RLPRACING

    RLPRACING Member

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    Need some help getting this thing into the 3's. 260" wheelbase, 1900 lbs, 402 sbc with 14-71 HH Littlefield, 20% over making 35 lbs, Gerardot injection, MSD 10, powerglide, 10" converter, 4.10 gear
    Best pass is 4.25 @165. Had a lot of trouble with tire shake and nothing seemed to work. Moved the batteries to the rear, changed front wing and took almost 50 lbs off front tires. Now it does a nice wheelie, no shake but no faster. That was our last race so we didn't get to work on it more.
    Now to the dyno, made a bunch of 7500 rpm and under pulls, playing with timing, fuel. Made 1679 hp and was still going up but I don't think it was going to make much more with that setup. You could wear out a motor trying different things. Changed the main 50 hp, changed timing 50 hp, it was crazy. Highest EGT 1090, half the cad burnt off the plugs, and it was so fat the dyno O2 probe only worked on one pass.
    So now go to this link for lots of graphs and let the suggestions begin such as what to do with the converter.
    http://s252.photobucket.com/albums/hh18/rlpracing/
     
    #1
    RLPRACING, Feb 10, 2009
  2. BLOWN INCOME

    BLOWN INCOME tafc

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    Check your p.m.
     
    #2
    BLOWN INCOME, Feb 10, 2009
  3. jim phillips

    jim phillips ta/fc

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    more wheel speed leaving try to keep the front down if shaking its under powered look at the plugs you might need to lean it down a little are maybe put a high speed on it lean it down . down track
     
    #3
    jim phillips, Feb 10, 2009
  4. Mike Canter

    Mike Canter Top Dragster
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    According to your data logger you are down on boost in high gear. You only get up to 7200 engine RPM at the finish line, no engine rpm means no blower RPM and therefore no boost. Look how slow the motor is to come up in RPM in high gear. The 4.10 gear is making too much load on the motor. Since you are running 1/8 mile I would change your rear gear so you can get that engine to pull more in high gear and get up in RPM so you can make boost. You should consider at least a 4.30 gear and see what happens.
     
    #4
    Mike Canter, Feb 10, 2009
  5. RLPRACING

    RLPRACING Member

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    Yes the rpm's do not recover after the shift. I was wondering if the converter was too tight. By loosing it up, won't it do the same as a gear change?
     
    #5
    RLPRACING, Feb 11, 2009
  6. Mike Canter

    Mike Canter Top Dragster
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    I don't think loosening up the converter is the right way to go because it will overheat the fluid. A 4.10 gear is just too much for the motor to pull. Even for a 1/4 mile car with big power a 4.10 gear can be too much to pull. We use a 4.71 gear in our 1/8 mile car with a Lenco. A 4.30 or 4.56 will also get you rpm up faster right after launch and make boost faster but the big deal is making that motor recover after the shift and RPM.
     
    #6
    Mike Canter, Feb 11, 2009
  7. Ken Sitko

    Ken Sitko Super Comp

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    I think you'll be happy with a 4.71 gear as well. If it shakes, you'll have to adjust the clutch a bit. Also, make sure you didn't accidentally put 2 main jets in the barrel valve, that would make it really fat all the time.
     
    #7
    Ken Sitko, Feb 11, 2009
  8. Mike Canter

    Mike Canter Top Dragster
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    Ken, one way to keep check on accidently putting two jets in the BV is to paint a red ring on the jet tool so with one jet the red ring is inside the BV. With two jets the red ring is outside the BV and will be a warning for most people unless you suffer from CRS. Then it don't make any difference what you do (lol)
     
    #8
    Mike Canter, Feb 11, 2009
    Rich AA/FA-FC likes this.
  9. craig moss

    craig moss Member

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    pills

    I hate to admit it but I have done that at the lake drinking beer shooting the bull.:D It is easy for me to get side tracked .
     
    #9
    craig moss, Feb 11, 2009
  10. mbaker3

    mbaker3 New Member

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    Mike,

    I'm OK with the CRS stuff, I will be 59 in a few weeks.:) I get aggravated because I can't even "find" the Jet Tool, let alone use it to install too many jets!:D:D

    Didn't mean to take away from the "jist" (SP?) of this post, but ................:)
     
    #10
    mbaker3, Feb 11, 2009
  11. Alkydrag

    Alkydrag Sr. Dragster

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    I'm with Mike on this one. Change the rear gear. It appears you don't have enough driveshaft speed. And after the shift, it went flat.
     
    #11
    Alkydrag, Feb 11, 2009
  12. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    gear

    considering a competitive TAD that runs quartermile only runs a 4.30 gear, you have way too tall of a gear for the hp and application. I would think a 4.71 or 4.56 would be more in line. You may have to pull some timing or play with launch rpm and tire pressure after the gear change to get it off the line, but it's not going to go much faster with that gear without a lot more hp.

    You can loosen the converter and see a marginal gain, but the bottom line is that's too much gear ratio for your motor, it's even too much for a 3300 hp TAD.
     
    #12
    Will Hanna, Feb 12, 2009
  13. RLPRACING

    RLPRACING Member

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    Thanks

    Thanks for the suggestion everyone. Now, somebody got a 4.57 gear for a Mark WIlliams 9.5????
     
    #13
    RLPRACING, Feb 12, 2009
  14. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    tire pressure

    how much tire pressure did you have in that first photo? the car has barely launched and has absolutely no wrinkle to the sidewall. seems like the tire pressure is way high. granted, you don't want it so low it's bouncing the rim off the ground, but you do want to work the tire a little.

    also, it's not out of the question for your guage to be off, double check your gauge against one or two others.
     
    #14
    Will Hanna, Feb 12, 2009
  15. RLPRACING

    RLPRACING Member

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    Your right there isn't much wrinkle there but by our gauge its between 5 to 6 lbs. Thats the area we tried but would have to get in our records to see exactly that day. Never had an issue with launch except at one track. Our tire shake was out at least 30 ft. We will try another gauge.
     
    #15
    RLPRACING, Feb 13, 2009
  16. Mike Canter

    Mike Canter Top Dragster
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    You should drop your reference limits by one pound and like Will said get your gauge checked against somebody that has a professional CSR type gauge.
     
    #16
    Mike Canter, Feb 13, 2009
  17. BLOWN INCOME

    BLOWN INCOME tafc

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    The old rule was (non-beadloc's) sitting on the ground,not under power,you should have a wrinkle and a 1/2 to 2 wrinkles..today with the different sidewalls this may not be the rule...
     
    #17
    BLOWN INCOME, Feb 13, 2009
  18. Outlaw68

    Outlaw68 Member

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    curious how many high speeds do you have on it??
     
    #18
    Outlaw68, Feb 14, 2009
  19. RLPRACING

    RLPRACING Member

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    Only one but I think it opens around 60 lbs which is very early.
     
    #19
    RLPRACING, Feb 14, 2009
  20. Outlaw68

    Outlaw68 Member

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    I think the convertor is too tight on the gear change. I dont know what stator you have but it looks too tight. I like them to drop about 800-1000 tops on the gear change your dropping the rpm 2000 rpm on the shift. Its not the GEAR, the convertor is your problem. When you knock the motor in the head like that it will never recover. But you might be able to put another high speed on a timer to come in there at the change, and dump some of the fuel off to get it to recover quicker.

    Thats my 2cents

    I have a convertor guy who would love to help you out if you need it. He has done more than a couple small block and big block blown convertors..

    If your open to it pm me..
     
    #20
    Outlaw68, Feb 14, 2009
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