Critique my suspension and tell me what works for you

Discussion in 'Race car chassis tech' started by 436'd Skylark, Apr 25, 2019.

  1. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Guys- help me get my car to hook. My best 60' was 1.75. I'm stuck between bogging off the line or cloud of tire smoke.

    The car- stage 2 470, autogear M22w, 9" with 4.11s. 28x10 Mickey Thompson bias slicks with the recommended compound for a manual trans.

    3850 lbs with fuel and me in it..

    Front suspension- no sway bar, 90/10 shocks, tall spindle conversion with stock springs. The car is kind of high in the front- maybe an inch or two.

    The rear suspension-
    QA1 adjustable uppers, poly bushings
    Edelbrock boxed lowers with rubber bushings
    Factory control arm braces.

    New moog springs- stock replacement
    New stock rear shocks

    No sway bar of any kind

    The best time was 12.05@116. 1.85 60'

    Best 60' was a 1.74

    If i leave at 3k it noses down. At 4k it blows the tires up.

    I have a small budget to work with this year. I'm confident the engine is making enough power but i need to get that to the ground.

    Where should i spend the money and what is working for you? I've been eyeing Moroso trick springs for the front..

    Any input appreciated.
     
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    If you are bogging, and you cross the traps at the optimal RPM, then it is a factoring of launch RPM+1st gearing+driver.

    You need to have high enough RPM to have the torque to move and keep you moving, and the proper gearing that the car is multiplying torque smoothly and continually. If you have too little gearing, the car will launch but fall out of the torque band and that inertia is wasted. Think of swinging a bat, you want it coming forward and through the entire swing with the same "force" over "distance", other wise it results in a bunt.

    If you are spinning, it is too much torque and to high a gear, so the force breaks the tires loose, you then either slip the clutch or pedal the car and loose that inertia.

    There are exceptions, and "driver" can have a greater effect than changing parts/spending money.

    Practice launches at different RPMs and get the best consistent launch, then look at how effective that launch dialed in is working and then you can figure what to change mechanically.

    Change one thing at a time and test various launch RPMs.
     
  3. Julian

    Julian Well-Known Member

    You have video of the car... Side.,. rear tires.. at various laucul RPM? With no rear sway bar, you sure the body isn't twisting and unloading?
     
  4. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I have no video. It does squat to the right rear some, as expexted. Should i bite the bullet and order the anti roll bar?

    The goal is to leave at 4-4500 rpm..
     
  5. Jim Rodgers

    Jim Rodgers Well-Known Member

    Trick front springs which should lower the front. Buizilla has some for sale.
    Battery in trunk.
    Passenger rear air bag with 10-15 psi.
    Adjustable rear shocks.
    Lubricate front and rear control arm bushings.
    Use locking nuts on F/R control arm bolts and just barely snug them. Dont tighten them and bind the arms from moving freely!
    Use light weight distributor advance springs.
     
  6. moleary

    moleary GOD Bless America

    What is the first gear in your transmission?

    HRPartsNStuff is a solid component fore the rear and affects the entire vehicle suspension.

    https://www.hrpartsandstuff.com/

    Why do you feel lauch RPM needs to be 4-4500 rpm?
     
  7. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    First is 2.52 or 2.56.

    I can loosen up the front arms. I'm definitely losing range of motion with the front sitting to high. I can do that all at once with the front springs
     
    Last edited: Apr 25, 2019
  8. moleary

    moleary GOD Bless America

    My best 60' & 1/4 mile ET and MPH is about what you have, but my launch gear was crippled with the M22 that had 2.20 first gear * 3.7rear gear =8.14 launch gear. Not good. I was in fist gear forever. I upgraded to the M23 now is 2.99 first gear *3.7 = 11.06. I expect much better 60's now.

    I also put her on a diet for the track and have changed from 15*8 steel wheels on all four corners with BFG 245/60/15 on the front, w/ Dog Dish Hub Caps - Race Slicks are Mickey Thompson 29x9x15, tubed and screwed to Speedway 15x8 Steelies and doggies. Now going to run on Super Tricks and 4" fronts.

    You should confirm your trans first gear. I'd be surprised it is over 2.20 but if it is, 2.52*4.11 = 10.35 which is good. If it is 2.20 *4.11 = 9.042 which is not optimal at all.

    Have you measured your range of travel? Measure at front fender from ground up to opening lip with car on its front suspension, then jack it up just until front wheels are just off the ground and measure again, subtract the two numbers. Mine is just over 6". QA1 double adjustable coil overs, GW tubular arms and no front sway bar.

    Rear is UMI Adjustable Upper and Lower rear control arms, Flaming River double adjustable rear shocks, MOOG 5401 rear shocks, HRParts-N-Stuff Rear Bar.

    Car leaves great and looking to do better this year with the changes.

    This was last year.
     
    Last edited: Apr 25, 2019
  9. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Mark- the gears in the trans are the m20 ratios cut at the m22 angle. M22w set from autogear.

    The 12.05 was with 3.42s..

    Last year with the 4.11s i couldn't get a clean pass in with the two times i went to the track. The 4.11s did get me th 1.75 60'
     
  10. moleary

    moleary GOD Bless America

    OK, 2.52 first gear so launch gear ratio is in the good range.

    Do you have video of launching to see what's happening?

    What cam / power range is your engine? What RPM were you thought the trap light?
     
  11. hugger

    hugger Well-Known Member

    Just be glad its spinning and not wheel hopping like a muther,...
     
  12. hugger

    hugger Well-Known Member

    Viking shocks,....a double adjustable shock is the best way to control suspension motion and load,...that and and a HR bar would be my approach. Stay away from the Sphon bar it's a huge hassle the HR bar is trouble free installation and will solve alot of suspension issues
     
  13. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I'm not looking to dissect the engine in this thread. I want to focus on the chassis and how to make it work better. Like I said earlier the power is there I need to get it to the ground. Honestly it's so inconsistent at the line it's not worth discussing what to do with the engine.

    No videos at this time, looks like thats in the future.

    I was hoping more folks would discuss their combos.
     
  14. cjeboyle

    cjeboyle Gold Level Contributor

    Check your instant center. I’m by no means an expert so read up on it. I know you aren’t getting wheel hop which is good but a set of no hop bars will move your instant center back which will help put more down force on the rear tires when you launch.
    Cliff
     
  15. hugger

    hugger Well-Known Member

    Just aren't but just a handful of guys that run a 4 speed successfully, our black car is and its probably 600hp or better, but we haven't put any real effort into running it. Engie runs his GSX a fair amount and runs mid to low 11s pretty consistently I'd message him. Otherwise a forum like "Class Racer" will be of more use imo. An automatic suspension setup is a good bit different than what's needed to make a 4speed work. My orange car would pull the front a few in on the street and I'd be glad to tell you what I done nothing special just expensive ha, but hearing what works from a 4speed guy would serve you better

    I recently went to a Ram dual disc clutch and it appears to be much easier to regulate the application of power. When I run my dads car I do no burnout and slip the clutch its been a 1.75 ONCE in 20yrs ha,..but I've only ac6ran the car maybe 20times
     
  16. moleary

    moleary GOD Bless America

    The Only reason I asked about your engine is trying to understand your launch RPM and why you are targeting 4-4.5k.

    I’d focus on your rear suspension. Out of curiosity, what clutch are you running?

    Its hard to hook our Stick cars but it’s very doable, just put money in the right places.

    Best of luck to you man.
     
  17. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I'm running a dual friction. It's held up great. I tried slipping it once and that was a disaster.

    My goal of leaving at 4000 plus is more of goal than a necessity with this engine. If i can get the suspension to work at that level in theory i should be able to consistently leave at a lower rpm. Like i said it bogs at 3k and frys the slicks at 4k. I think somewhere between 3500-3800 is the sweet spot.

    I think the trick springs and a bag in the right spring we'll be my start. The HR bar is not in the budget right now. I'm tied up in my scout resto..
     
  18. hugger

    hugger Well-Known Member

    Keep in mind with the trick springs , they do a great job of transferring the weight but do nothing in keeping the weight there, that's where double adjustable shocks come in.

    With springs alone you will unload the suspension within a few feet and then knock the tires off
     
  19. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    The 90/10s aren't enough?
     
  20. hugger

    hugger Well-Known Member

    They transfer great but like the springs have no real way to keep it planted, Calvert 90/10s are much better than your standard issue 90/10
     

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