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Thread: RPM launch chip?

  1. #1
    Senior Member MASTER BUILDER
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    RPM launch chip?

    Im running a swing arm with a long stroke 572, 3.89 rear, 1.80 trans, 33.5 tire,4500 stall. I know this is consertave, but doing 1/8 mile seat time now. Ran 5.31 @128 with 1.18 shorts. Still have 1 inch of throttle left. QUESTION? How far below the actual stall do you set the chip for hardest launch? Thanks, lot of smart people on here.TC

  2. #2
    Senior Member RACING JUNKIE
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    Every combo reacts different, I've had some that liked 100 below stall and some that are 2500rpms below on the launch. What kind of car is this in ? 4500 stall seems very low to me for this combo.
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  3. #3
    Senior Member MASTER BUILDER
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    chip

    David thanks 4 the reply, see u on here a lot.Its a worthy swing arm. Have been running a 4400 chip. Wasnt a lot of time to test everything. Yes conserative, crashed the 27 wheelstanding roadster twice. Came back with the new digger.Just working our way back,thanks TC

  4. #4
    Senior Member RACING JUNKIE
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    I understand, I was thinking when you said swingarm you were talking about a dragster. I've found on all my bbc stuff in my cars that 4000-4600 launch works very well for being consistent yet fast. I think you combo would be a lot more consistent with a higher stall convertor. I now run a 6800 stall spragless and launch at 4400. If you need any other info on anything feel free to PM me.
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  5. #5
    Senior Member RACING JUNKIE
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    Wow. That stall is way off. My guess is 6200-6800 would be a better place for you. Is it an 8 inch or 9 inch convertor. Sounds like you are driving right thru that convertor. What carb, cam, etc. We launch our swingarm at 4400-4600. It is a 548 with a 5800 stall single 1050 alky carb. It runs short time of 1.16 and runs 5.0's 4.90's with a 6600 shift. Where you shifting at?

  6. #6
    Senior Member MASTER BUILDER
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    I,ve got a mullis 4-link my daughter drives, same size motor 34.5 tire 4.30 gear we launch at 4800 and have 1.09 60'.


    Steve

  7. #7
    Senior Member MASTER BUILDER
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    stall

    ''thanks again, i knew the stall is too low. this is a 4.5 x4.5 572 12 yr old shafiroff combonation. dart funnelram with a book 1150.dart 360 with super mod porting. cam is a c rane 791/731 with intake [email protected] and [email protected] on the ex.He recommended a 5500 stall. I ordered a bte 9'' with the 4500 stall because i didnt want the violence we had in the old car just starting out. max rpm for this combo is 7000. i dont understand how you can run a 6400 or up converter on a 7000 motor. i know yall know yall stuff, yhats why im here. also, were still on 3/4 throttle, but are ready to turn it loose as he gets a little more seat time. i also went with the 3.89 for the 4.5 stroke because most of the 4.25 stroke guys seem to run the 4.11?

  8. #8
    Senior Member MASTER BUILDER
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    shift point

    shifting at 6400, didnt play with that yet.

  9. #9
    Senior Member RACING JUNKIE
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    Re: stall

    Quote Originally Posted by topcat572
    ''thanks again, i knew the stall is too low. this is a 4.5 x4.5 572 12 yr old shafiroff combonation. dart funnelram with a book 1150.dart 360 with super mod porting. cam is a c rane 791/731 with intake [email protected] and [email protected] on the ex.He recommended a 5500 stall. I ordered a bte 9'' with the 4500 stall because i didnt want the violence we had in the old car just starting out. max rpm for this combo is 7000. i dont understand how you can run a 6400 or up converter on a 7000 motor. i know yall know yall stuff, yhats why im here. also, were still on 3/4 throttle, but are ready to turn it loose as he gets a little more seat time. i also went with the 3.89 for the 4.5 stroke because most of the 4.25 stroke guys seem to run the 4.11?
    IMO your motor all out in a worthy (which is light) should go 4.8's easily. I may have went with the 4.11 gear just to get it in the powerband. when you are ready to turn it loose I would shift it @ 7000-7200, and get a 6000-6200 stall spragless convertor 9" and your good to go.
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  10. #10
    Senior Member RACING JUNKIE
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    I agree with Dave except on the spragless convertor. Have not been a big fan of them but I know Dave has had exceptional luck with his. To each there own. I think the gear is a little much as well and suggest the 4.11 gear.

    The cam that is in our 555 is a Reher Morrison uses. It is an Erson custom ground cam. Duartion is 284/298 and lift is 808/765 at 112 center. It will be a 7/4 swap set up. Your cam could be a little bigger but is a decent application.

    Your heads may want to see a little more RPM to work the motor. I am sure Dave is suggesting more RPM at the shift point for this reason. Even at 7000-7200 that is conservative for that head. What size header are you running? I would think the 2 3/8" should be what is on it.


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