My 70 Racecar Project

Discussion in 'Members Rides' started by Tyler Northcutt, Jan 8, 2009.

  1. carmantx

    carmantx Never Surrender

    This car has had air bags in the rear, and they add some height and stiffness. We will be pulling them out, and adding the rear drag bar, and changed the pinion angle with the adjustables. We will test in a few weeks.

    I am anxious to hear how your 4:56 gear does. Our car has 4:10's and is fine for 1/8th mile but too much gear for the quarter mile. So we are going back to 3:42's as soon as we can sell enough parts to buy the gears.

    We are hoping for low 10's and maybe a 9 second time slip some time in the future.
     
  2. Opa

    Opa Torque/a 8 piston figure

    The calculator and JW say that it will work.
    I will be going to the straps at 6700-6800rpm tops so with this motor that will be fine.

    What oil do you use, I can get Kendall GT1 20W50 here locally for a good price and heard also good things about this oil.
    I used Brad Penn last year but have to drive a long distance to get it.
    All the tractorpullers and autocross and speedwayers are using it even in the new LS6 alu chevy engines and revving it at 8000-9000rpm with out problems.

    Greetz

    Robert
     
  3. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    We use Valvoline Racing oil.

    I am going to be going through the traps below 6000 rpm. Which will be great, because anything past 5600 rpms with my motor is just wasted. My peak hp is at 5600, and the torque and hp curves down pretty steep after that.
     
  4. Opa

    Opa Torque/a 8 piston figure

    My peak torque (622) is at 4900 RPM and Peak HP is at 6200 (650HP) the HP just drops a little at higher rpms. So I think were looking good.
    Just have to leave hard at the start to plant the tires really good, then just hold on and keep it straight! :3gears:

    And oh yeah I must not forget to change my RPM chip in the MSD box for a 7000RPM one, there is now a 6400rpm in it. :grin:
     
  5. Bobb Makley

    Bobb Makley Well-Known Member

    your just planning on useing 4.56 in the 1/8 only is that right? you won't run those in the quarter mile at all will you
     
  6. carmantx

    carmantx Never Surrender

    Opa is going to run 1/4 mile I think he said. Tyler's going to 3.42 for 1/4 mile. 3.73 might work for now, but once he gets a little faster with this engine, 3.73 will be too much.

    We are hoping 3.42's still work ok in the 1/8th since most of the tracks around us are 1/8th mile.
     
  7. Opa

    Opa Torque/a 8 piston figure

    Yes, the 4.56 gears are for the 1/4 mile.
    Like I said it will be at 6700rpms when I cross the finish, my engine can make that rpm safely so no problems there!:TU:
     
  8. Bobb Makley

    Bobb Makley Well-Known Member

    OK just seems like alot of gear is all my old GSE car we ran 4.30's and 30 inch tall tires. we would run thru the traps at 6900 to 7000 I know the power is different but it just seems like alot is all.
     
  9. Opa

    Opa Torque/a 8 piston figure

    We will see when I make my first 1/4 mile at full WOT.
    I will post what she does then.
     
  10. Bobb Makley

    Bobb Makley Well-Known Member

    Cool I may be way off, just concerned about trap rpm is all. Good luck show those guy's over there what its all about :beer
     
  11. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    Got the new rear sway bar in the car.

    [​IMG]
     
  12. skierkaj

    skierkaj Day 2 Street Screamer

    Tyler,

    I've got a suggestion if you're up for a "test and tune". See what the car does on a launch, without the use of the airbag in the passenger side spring.

    I've heard claims (when using a H/R Parts bar), there's no need for an airbag to correct the "plant" on the rear tires. Since the bar your running looks very similar to the H/R Parts bar, I'm wondering if it's really true? :Do No: I do know that some of the H/R components are a little more heavy duty than some of the ones that I'm seeing on your car, so, I don't want to be held responsible for any breakage that occurs. :laugh: It's totally up to you, but I'd appreciate the input.

    I opted to use the H/R bar, but since my resto is sidelined for a bit, I'm wondering if I should invest in at least one airbag in the future.

    Also: H/R Parts recommends welding their lower brackets directly to the axle tubes (which I did on my car). Maybe it's to be sure the brackets won't move? I'm curious to see what your installation guide said.
     
  13. Opa

    Opa Torque/a 8 piston figure

    We installed the HR bar last summer, and yes you need the weld it to the axle tubes to be sure it will not move.
    And to make it easier for your self when you have to tighten everything up again.
    You will have to do that a couple of times, cause after a few runs things can get loose again, take special note of the axletubes bolts they need to be bolted up most of the time.

    And yes you do not need to run a airbag anymore, car will go straight from now on.
     
  14. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    There is no air in the airbag, I am going to take it out, just have not done it yet. :laugh:

    The spohn performance parts are just as tough as the H/R parts.
     
  15. BuickRacer69

    BuickRacer69 1320, Mark of the Beast

    That is a pretty sweet looking rear sway bar.

    If you do not mind me asking you, how much did that cost?

    Thanks Gary
     
  16. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    Gary,

    The bar ended up costing $395 plus shipping. Heck of a deal for such a great piece. It is 1-5/16" solid 4140 heat treated spring grade chrome moly steel.
     
  17. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    Taking the car to the track later today. Wish me luck. :TU:
     
  18. Opa

    Opa Torque/a 8 piston figure

    Good luck!

    And I bet you new ET time will be 10.41@123MPH
     
  19. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    it ended up running a best of 6.63 @ 104.85 in the 1/8th mile. i will do a calculation here in a minute to see what that is in the 1/4, but i think your pretty much dead on.
     
  20. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    10.45 @ 129 @ 3800ft. air density.
     

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