Steering Ratio ??

Discussion in 'PSI Superchargers Tech Questions' started by backmotor, Dec 19, 2007.

  1. backmotor

    backmotor Owner/Crewchief/Test Pilot

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    What is the typical steering gear ratio for a funny car ?? My car seems "twitchy" at higher speeds, we run a rack and pinion setup, not sure if that's just the way it is, or if it's the wrong ratio, thanks all, Mike
     
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  2. jim phillips

    jim phillips ta/fc

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    do you know how to align the front end properly on that shorty dragster you have put an 1/8" to 3/16 of toe in make sure you tires are the same pressure and check your wheel bearings a rack and pinion should be as smooth as any thing else and if your going real fast it could be the driver the rack is slower steering than whats on a funny car the sterring box ( spe )we use on the funny car is 3/4 turn each way lock to lock you probley have more than that with a rack but it still should be stable of the other end
     
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    Last edited: Dec 19, 2007
  3. altered boy

    altered boy Outlaw Altered

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    don't know how this applies since your motor is in the 'wrong place' on my altered (10.1-E car) we run a rack and you have to use a slow ratio and long steering arms. just my $.02 but if you have a 'dragster' rack it won't work
     
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  4. backmotor

    backmotor Owner/Crewchief/Test Pilot

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    Jim, not dragster, it is a funny car, yes front end is aligned properly, even took the "stagger" into account, and we run 1/8" toe in, have tried more and less, seems to make it worse, also more air in the front tires makes it worse, seems best at 30 psi, it seems like we need to slow down the steering (agree w/ altered boy), was looking for actual ratio, like 15:1, I think its 18:1 now, had chassis built, came with that rack, was not a problem until we got it over 125 mph in the 1/8th mile, Thanks for the advice, please keep it coming :D here is recent pic: [​IMG]
     
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  5. hemi altered 378

    hemi altered 378 Blown Altered

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    call Scott Weney at S&W and ask him what to put in it.........or you could call SPE, them make nice boxes.
     
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  6. WJ Birmingham

    WJ Birmingham New Member

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    +1 on the short dragster.

    It could simply be 'squirly' because of the design. You've changed the weight distribution of the chassis, and I've never seen a chassis like that before, nor has anyone I've shown it to.

    If it's 'squirly' now, I'd hate to see it at a faster speed. 115 in the 1/8th is barely a 9.0 qtr.

    You'd be well off to have your chassis builder go over it with you before you become a new NHRA statistic.
     
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    Last edited: Dec 20, 2007
  7. jim phillips

    jim phillips ta/fc

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    what do you think it would be like at a 190mph in the 1/8 mile i dont want to be rude but isnt it just a bracket car with a funny car body on it good luck
     
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  8. Eric David Bru

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    Jim,

    Please PM me with your contact information and I will hook you up with a chassis builder that specializes in cars like yours.

    EDB
     
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  9. Eric David Bru

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    Does the car seem to over/understeer?

    Do you have any kind of steering damper?

    EDB
     
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  10. backmotor

    backmotor Owner/Crewchief/Test Pilot

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    quote Jim "i dont want to be rude but isnt it just a bracket car with a funny car body on it good luck"
    Yeah right, was purpose built as a top alky funny car (A/Fuel to be exact) 10.1 E certified, BBC-Lenco-w/Clutch, we run on a 7.50 index with the "Southern Classic Funny Cars" group. Ran as altered for five years, just kind of lived with the twitchy feel, but I was considering putting a friend into it, and I want her to be safe and comfortable. Was just asking what steering ratio other funny cars use, since adjustments have not really changed it. Eric Bru --no damper, seems like move the wheel a little, car moves a lot, like when I shift gears (Lenco 2spd) makes it wander. Here is pic in altered trim: [​IMG]
     
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  11. JP

    JP Member

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    Hi, well here is my opinion.

    1. Considering that you sit so close to that rack , could it be that you have too much angle on the steering and therefore something could be tight or even too loose?

    2. If that is not the trouble then just put more "laid back angle" on your spindles my s&w funny car has 20* ready to run. My promod had a wierd feeling and adjusting from 11 to 15 cured it.

    3. Looking at your photo, DONT YOU THINK, THAT NOSE IS TOO HIGH???
    seems to my like 5-6 inches and then with that firewall there where does the air goes? Also if indeed you want to think is a funny car then with that nose beeing so high you have NO down force.

    Just my comments and hope it helps!
     
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  12. jim phillips

    jim phillips ta/fc

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    look i wasnt tring to be rude and im soory if i hurt your feelings but be real you can call IT what ever you like but you would never be able to run tha car in TAFC in nhra or ihra im sure its fun for you as drag racing and if you didnt know A FUEL MEANS NITRO INJECTED AND IT LOOKS LIKE SOMEONE CUT THE FRONT END OFF A DRAGSTER MADE IT A SHORTY AND THEN YOU PUT A FUNNY CAR BODY ON IT AND STICK YOU HEAD OUT OF WHERE THE MOTOR IS SUPPOSED TO BE NOW AS FOR AS YOUR CAR TO EACH IS OWN YOUR GOING A LITTLE OVER BOARD POSTING ALL THOSE PICTURES OF IT BUT WHO KNOWS IT COULD BE THE NEW WAVE OF THE FUTURE REAR ENGINES FUNNY CARS REMEMBER THEY LAUGHFED AT DON GARLITS WHEN HE PUT THE ENGINE BEHIND HIM IT WASNT LONG TILL EVERY ONE HAD ONE AGIAN GOOD LUCK ON THE STEERING IT GETS SMOOTHER AT 200+


    PS TAKE THE WING AND THE TAIL RUDDER OFF AND PUT SOME WEIGHT ON THE NOSE
     
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    Last edited: Dec 21, 2007
  13. Eric David Bru

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    Agreed, get that body down to the ground as close as possible... If I recall correctly, the rule is 3" ground clearance from the front to 12" behind the spindles?

    A steering dampener might be the ticket, does the wiggle occur at the same time as the shift?

    EDB
     
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  14. backmotor

    backmotor Owner/Crewchief/Test Pilot

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    My feelings are not hurt :D I actually find it amusing that you don't like my car. But it is and always was a funny car (not because I called it that) but because it was built by a reputable chassis builder and came certified for TAFC (10.1-E) not with that body obviously, was not shortened, or modified out of a dragster, and yes I know A/Fuel is nitro injected, was built to never run a blower, We just run alky injected for now, its only a 7.50 index that our group runs on. I agree the nose is high, the pic with the vette body is only a test fit, not quite closed all the way, ground clearance will be 3.5 inches. Caster is 15*, yes the wiggle comes right when I shift.
     
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  15. Eric David Bru

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    Check into the steering dampener, contact Scott Gaulter (Nitro Madness) or Rapid Randy Baker, I believe they had to run one a dampener on the AA/FA.

    Ground clearance sounds good.

    EDB
     
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  16. jim phillips

    jim phillips ta/fc

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    Does It Shift On Its Own Are Do You Shift It Tring To Rule Out If You Reach For The Shifter You Might Be Moving The Whell And Does It Settle Down After The Shift Are Does It Make Any Moves When Slowing Down You Would Be Surprised At How Many Drivers I Have Seen Move The Steering Wheel When Shifting Not Saying You Do That Just Asking And When You Find Out What Causing It It Will Be Some Thing Simple After Looking Back On It And Saying I Should Have Known That Ps Its Not Up To Me To Like Your Car As Long As You Do Thats All That Counts But Im A Drag Racer I Dont Want To See Anyone Struggle With A Problem I Have Had My Share I Fought A Steering Problem All Last Year It Was Aligned Up Wrong It Has A 2" Stagger And Instead Of An 1/8" Of Toe It Had 3/4" I Had Asummedit Was Right When I Bought It And It Is Pro Built Also It Would Almost Shake The Wheel Out Of My Hand So After Many Night Check Every Thing Else And It Still Done It I Started Back At The Front Of The Car Took The Fuel Tank Out Of It To Check The Alignment And Guess What I Found The Alignment Was Wrong The Whole Time And You Know What Else It Was The First Thing I Thought Of The Very First Time I Drove The Carbut Thought Naw The Builder Knew What He Was Doing So See It Was Something Simple The Whole Time Keep Looking You Will Find It Good Luck
     
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  17. G FORCE JUNKIE

    G FORCE JUNKIE New Member

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    Is it as squirrelly with the body on? Just some thoughts: Seems like that open front with the closed of sides would act like a scoop pulling every which way. I would fab a nose piece for it that would slide in those 4 open tube ends and lock with pins so you could remove it for the body, maybe like some of the altered noses with the built in canards!! The wing in the middle probably does weird things with the down force. Might drive better without it or move it back over the rear tires. Also you did you say it meets TAFC cert.? I might be wrong but I don't think it will tech even in advanced ET without helmet bars?? I know you said you only run a 7.5 index and you probably have enough power to get that done but your probably leaving a fare amount of HP on the table with that injector so low behind your brain bucket!! Still think it would look cool with a high helix and a tall carbon hat!!!
    Thanks,
    Kent
     
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  18. backmotor

    backmotor Owner/Crewchief/Test Pilot

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    Thanks Jim, yes I have to reach for the shifter, couple times I let the weight of my arm pull down on the wheel, and it darted to the left, I have to keep my left arm rigid when I use my right to shift, it is still possible I'm introducing the twitch, but it seems overly sensitive, that's why I asked about the ratio and think it might be too quick.
    About the body: ran it with no bodywork at all for a couple years (bare chassis) then went to side panels, big spoiler and shark fin, and it handled better. Now we joined a classic funny car group, and are adding the Vette body, this body went 5.70's @ 240mph on another car (alky funny) did not want to alter it too much aerodynamically so just trimmed for rollcage to stick thru hood, looks a little funky but it works, also it still has "some" resale value (still fits front engine car) the next body will be purpose built for our car(driver behind windshield)
    Yes the SFI has expired, needs helmet bars and very minor mods to recertify, was waiting to see if the dual ones become the norm or mandatory, before investing. Been running outlaw tracks til rules settle down. We don't run the altered body any longer, and are just getting going with the Vette body, we have no full runs with the Vette body yet, was trying to make sure we didn't have a chassis type problem before intrducing the body to the equation.
    PS Thanks for all advice, Mike
     
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  19. jim phillips

    jim phillips ta/fc

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    G-force Mad A Good Point About Enclosing The Front End That Would Just Make Things Better Aero Wise And I Dont Think Your Wing Is Helping The Way It Is Supposed To From What I Can Tell In The Pictures And I Think You Dont Really Need On From The Speeds You Going Right Now I Know A Lot Of Fast Cars Dragster Long And Short Ones That Are Not Running One In The Eighth Mile At 125 I Dont Think Its Nessicary Just Yet Home Made Wings Are Difficult To Build The Correct Way

    THE WINGS IS ANGLED UP IN THE FRONT THAT IS A NO NO THAT WILL CAUSE LIFT AND ITS NOT MADE LIKE AN AIR FOIL POINT THE FRONT LEADING EDGE LOWER THAN THE REAR EDGE
     
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    Last edited: Dec 22, 2007
  20. M gibbs

    M gibbs f/c matchracer

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    Wheels Up!!!??

    :Ddamm jimbo? you bored!!! MARRY XMASS YOU ALL!!! HO HO HO! Oh ya the steein deal? LOCK THE CLUTCH UP MORE, LEAN'ER OUT SOME MORE, CARRY THE WHEELS TOO THE LIGHTS. NOW THATS FUN!!!!
     
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