I need asphalt circletrack help!!

Shocks, Springs, Brakes, Frame, Body Work, etc

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72firechicken
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I need asphalt circletrack help!!

Post by 72firechicken » Mon Aug 27, 2012 1:31 pm

I RUN A 3100LB LIMITED LATE MODEL SPORTSMAN WITH A CHEVELLE CLIP AND REAR LEAF SPRINGS. 1/3 MILE ASPHALT TRACK LOW BANKS PROGRESSIVE BANKING, 6*,9*,12 DEGREES. MY CAR WAS ORIGINALL A 4 LING THAT WE HAD TO CONVERT TO LEAF SPRINGS SO I INSTALLED CRYSLER LEAFS. MY BROTHER AND I HAVE TRIED OUR BEST OVER 1.5 SEASONS TO GET THIS CAR GOOD AND JUST CANT SEEM TO GET IT DONE. WE HAVE OUR ROLL CENTER CLOSE, CAR IS SQUARE, I FEEL WE HAVE OUR BASICS DOWN PRETTY WELL AS FAR AS CASTER, CAMBER, TOE, FRONT, REAR ROLL CENTER, LEAVES ARE INSTALLED WELL AS FAR AS I KNOW. AND WE HAVE BEEN GETTING DESTROYED OUT THERE. WE RUN A 602 CRATE CLASS.

I HAVE LIMITED EXPERIENCE AS A DRIVE ABOUT 2YRS HOBBY STOCK, 2YRS IN THIS CAR.

OUR FRONT END COMES AROUND WELL AND DOESNT PUSH BYT WE JUST CANT GET GREAT TRACTION OUT OF THE TURNS LIKE OTHER GUYS, NOR CAN WE DRIVE IT IN NEAR AS HARD AS OTHERS. WE WOULD JUST SLIDE OUT OF CONTROL. TO ME IT SEEMS THAT THE CAR IS ALWAYS BEING PULLED TO THE ALL BY THE LEFT REAR, SEEMS TO HAVE A LOT OF BODY ROLL EVEN WITH A 300LB SWAY BAR LOADED WITH 3 TURNS. MY CURRENT SPRING FROM THIS WEEKEND ARE 800 EVEN IN FRONT, 200RR, AND A 175LR. I KNOW WE CAN SWAP THE REAR SPRINGS TO HELP REAR BITE. WE HAVE TRIED TON OF DIFFERENT SPRINGS ON ALL 4 CORNERS ON UP TO 900 LBS, WE CAN GET OUR CAR OK BUT I COULD REALLY USE SOME HELP ON SPRING RECOMENDATIONS.

I HAVE SEEN SOME INFO THAT RECOMENDS WHAT SEEMS CARZY TO ME OF 1400RF, AND A 900LF SPRING SET UP. I HAVE TRIED MY BEST AND DONT KNOW WHAT ELSE TO DO HELP!!!!!! [-o< [-o< THANKS.

englertracing
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Re: I need asphalt circletrack help!!

Post by englertracing » Wed Aug 29, 2012 10:04 am

I'm no asphalt guy
But make sure the car isn't bottoming. They handle like piss with the rf on the bumpstop
I would try a big right front spring.
Your probably off on scale weights.
And is your front roll center all setup?

72firechicken
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Re: I need asphalt circletrack help!!

Post by 72firechicken » Wed Aug 29, 2012 11:16 am

Im pretty sure the r/f is ok we check our shock travel, but i will check this car seem to roll like crazy, last race it was rollling so bad all thru the turn we had our sway bar loaded some had about a turn in it. This car has been my nemesis!! It has always seemd to really be hard on the outside edges of the right tires, sometimes turning them blue. we run a hoosier 700 grooved slick. We also have never been able to get the rear of this car too hook up well on exit not like other guys,I always have to baby the throttle.

Rear leaf springs have been a real challenge for us, it is TOUGH to get rear grip. tight now we have the 200 on rr, 175f l/r, and have went lower 175rr,150lr. on the scales rear bite would be in the negative unless weight is added to lr. Seems like if we wanted to run that setup it we require about 0 stagger. The fastet guy in our class can fire his leaf spring car into the corner and is so fast it seem like he practically rebound off the track and head down the straightaway. Ther is NOOO way i could fire my car into the corner like that we would go into a 4 wheel slide.

This class is a limited late model class, the fasted car seem to be running a conventional setup, Of course his car was built and all done up by a pro chassis builder that has the track and his leaf spring cars down.

RCJ
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Re: I need asphalt circletrack help!!

Post by RCJ » Wed Aug 29, 2012 12:50 pm

Work on corner entry first.IS The car tight or loose on entry.How are you using the brakes,trail brake,letting the car roll in,braking hard etc...Most leaf cars like to be run real tight in the middle to have good forward bite.If the driver can drive a tight car it helps alot.
Myself I would start with 200l/r 175 r/r ,160lbs of bite,208/78 linear bilstein on the r/r, 2'' of stagger

72firechicken
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Re: I need asphalt circletrack help!!

Post by 72firechicken » Wed Aug 29, 2012 3:50 pm

Car is loose on entry, there have been times we can have had the car tightend in the rear but we ran a pretty high cross, but the car doesnt like that and won turn as well in the front, and wasnt as good as others. we have had a very difficult time balancing this car. my car is very finicky and it inly take little deviation from a certain line you must run to try keep speed up all you have to do is bobble a little bit and your thru 2-3 tenths slower, drive it too hard and it will slide up the track.. sometime i wonder if I did the right thing by using the crysler leafs. the car that is whipping everybody is a camaro/leaf car and is waaay fast.

RCJ
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Re: I need asphalt circletrack help!!

Post by RCJ » Thu Aug 30, 2012 12:45 pm

If cross made the entry good and you know cross will help forward bite start looking for something to make the car turn in the middle.Bump steer ,excessive ackerman,does the roll center move to the right and up once the chassis roles over?iF all of these are good look at your wheel travel to decide if you need to stiffen the rear or soften the front.

72firechicken
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Re: I need asphalt circletrack help!!

Post by 72firechicken » Sat Sep 01, 2012 2:55 pm

Checked my roll center and it goes to the right 1.3 inchech and down .5 inch. static roll center height 3.7 and 9.7 to the right. I dont know how to determine where to place it for my car though. I checked ackermann with some plates and mine is near 0 ackermann at 10* turned left. I made my own turning plates and they work awesome!! I set the bump at one time though we are limited at what we can do as far as modifications, right now i have my stock parts on, bump isnt real bad with the stock parts.

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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sat Sep 01, 2012 5:18 pm

How much:
Corner weights ?
Wheel travel ?
Stagger ?
Wedge ?


Too much rear brake will make it loose IN.
Last edited by Unkl Ian on Sat Sep 01, 2012 5:22 pm, edited 1 time in total.
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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sat Sep 01, 2012 5:20 pm

72firechicken wrote: I checked ackermann with some plates and mine is near 0 ackermann at 10* turned left.


WHY ?

Tires are supposed to Toe Out in a turn.

How much static Toe do you run ?
Please help make Speedtalk a Troll free zone.

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Re: I need asphalt circletrack help!!

Post by 72firechicken » Sun Sep 02, 2012 2:32 pm

This is a chevelle clip, with leafs.

My car is a 68-72 chevelle clip, leaf springs in the rear (crysler style) we have to run a spool in the rear.

3100 lbs
camber -4.5rf,+3lf,
caster +1Lf,+ 4rf,
1/8 toe rear weight 51.6.
1 1/8 sway bar
rear spool
48.8% cross 49.10 with sway bar.
weights
left 57.1%

Stagger when warm 3.5. we pulled some out this race and tried it. it helped some



WHEEL WEIGHTS
898lf
641rf
921lr
719rr

HAD ABOUT 300 LB WEIGHT ON LR SOME IN FRONT OF THE AXLE A SOME BEHIND.

RIDE HEIGHTS

REAR HAS 1.50 INCH LOWERING BLOCK/RR HAS A 1 INCH LOWERING BLOCK, UNDERSLUNG.

4. 00"lf
5. 1/4"rf
4 1/8"lr
4. 1/2"rr

SPRINGS

800rf
800lf
200rr
175lr


tires are hoosier 700 8 inch grooved
tire temps after 6 lap practice had to get to pit stall and then check them

FRONT
/|\
142 147 152 | 157 156 160
|
|
LT----------------RT
|
|
|
155 158 156 | 196 197 186
|
REAR


AS FAR AS ACKERMANN WE BETTER DISREGARD MY POST AS FAR AS NO ACKERMANN I JUST REMEMBERED WE HAD EXCESSIVE TOE WHEN WE GOT TO THE TRACK, CORRECTED IT BEFORE PRACTICE, SO MY ACKERMAN CHECK WOULD HAVE BEEN INACCURATE THIS I WILL RECHECK.

Unkl Ian
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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sun Sep 02, 2012 8:06 pm

72firechicken wrote:
FRONT
/|\
142 147 152 | 157 156 160
|
|
LT----------------RT
|
|
|
155 158 156 | 196 197 186
|
REAR
Lets start with tire temps.

The center of the tire, temp, should be the average of the inside and outside shoulder temps.

LR is pretty close.
RR looks hot, which tells me the car is loose.
You could use a touch more camber in both fronts.
Please help make Speedtalk a Troll free zone.

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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sun Sep 02, 2012 8:16 pm

72firechicken wrote: Stagger when warm 3.5. we pulled some out this race and tried it. it helped some

WHEEL WEIGHTS
898lf
641rf
921lr
719rr
I'm assuming those weights are with the driver ?

What happens when you take out Stagger, and add more Wedge ?

57.2% left, you need more wedge. A lot more.
That will help the RR temps, and enable you to pick up the throttle earlier.

70% left, you can run 50% cross weight. Not at 60%. IMHO.
Please help make Speedtalk a Troll free zone.

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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sun Sep 02, 2012 8:32 pm

Try this:

LF 770 ---- RF 770

LR 1050 --- RR 590


It will hurt LF temps, but help RR temps.
Please help make Speedtalk a Troll free zone.

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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sun Sep 02, 2012 8:38 pm

For Ackerman, I would want to run more than stock,
so the wheels Toe Out in the middle of the corners.

Bump Steer should be close to zero.

I'm not familiar with those tires, but 3 1/2" Stagger sounds too much.

I would take out the preload of the sway bar,
and jack all the weight with the jack screws.
The tires only know how much weight is on them.
Please help make Speedtalk a Troll free zone.

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Re: I need asphalt circletrack help!!

Post by Unkl Ian » Sun Sep 02, 2012 8:39 pm

How much shock travel, in compression ?
Please help make Speedtalk a Troll free zone.

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