converter/racepak question

Discussion in 'PSI Superchargers Tech Questions' started by CjRedden, Apr 20, 2014.

  1. CjRedden

    CjRedden Member

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    ok so hopefully I can get some questions answered and going in the right direction. last 2 years ive been running an 8-71 on a 526 bbc at 28%over in a top sportsman nova running 7.50s generally with 1.09 to 1.13 60' times. we put a racepak in the car last year and made about 40 runs for the season.

    my questions/concerns coming from a friend who showed my wheel speed graph to his tuner who was a former pro stock guy.
    launching the car at 4k rpm on the 2 step. 1/2 second into the run wheel speed was at 2317 and engine rpm is up to 6283. then the wheel speed and rpm drop at .42 seconds in we are back at 1821 rpm and the engine at 6086.

    it seems to spike up with the wheel speed and brings the motor back down and flat lines the motor and the wheel speed drags back down.

    this tuner we had talked to seems to think it seems to be blowing through the converter which he thinks is too loose. does this sound right? any advice on to this. he also thinks this may be where excessive heat is building up in the converter which we had a few major issues overheating the fluid.

    what also concerns me is the racepack according to the first move of the driveshaft is at 2.13 g's of force on the g meter. so I started the run at the driveshaft movement. which is also 5800 rpm approximately when the 2 step is set at 4k.

    hopefully I can get some help and answers. I could probably sit and ramble on about this for hours and question it. thanks for reading my rambling
     
    #1
    CjRedden, Apr 20, 2014
  2. BUTCH

    BUTCH Member

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    Converter help

    Call Marty at Chance Converters, he can help, he will look at the racepac and let you know whats going on, 316 542 9869

    Good Luck
    Butch
     
    #2
    BUTCH, Apr 21, 2014
  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
    Staff Member

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    spin

    Without looking at the graph, it sounds like the tires are spinning either from hitting them too hard early or bouncing off the wheelie bar hard and unloading the chassis, resulting in the spin. After the spin, the car settles, takes a set, hooks the tires.

    If the engine rpm is going back down with the driveshaft rpm that early in the run, hard to say the converter is too loose.

    If you can post a picture of the racepak graph, it would be a lot easier to diagnose. If you click the image icon to the bottom right of the smiley face in the top of the edit text options in the box you type in, you can upload a picture. Most newer computers have a 'snip' tool that can be found in the accessories folder in your start menu. Just open your racepak, use the snip tool to crop the screen then save as, then post the picture on here as an attachment.

    I also have a tutorial on how to post a picture in the classifieds section.
     
    #3
    Will Hanna, Apr 21, 2014

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