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Author Topic:   42% rear !!
timcsim7
Member
posted July 15, 2002 03:25 PM
if car pushes bad middle-out with 42% rear then increasing rear will make it push even more, there has to be something setup wise wrong. Give spring rates and shocks and what stagger/tire press. your runnin


timcsim7
Member
posted July 15, 2002 05:11 PM
Your springs shocks and air pressures all sound pretty close. I really dont see any reason you are pushing with 42% rear. It should be lighting the tires. Have you had it on an alignment rack? if the front end isnt workin as well as it could then its goint to push. on the left front run as much positive (top of the tire leaning out) camber as you can and still keep .5-1 deg positive caster. on the right front around 3-3.5 deg negative(top of the tire leaning in) camber seems to be a good starting point. caster on the right front should be between 2.5 and 5 positive for starters. set the toe out 1/4 inch. make sure the front end isnt binding also.

What is the competition running for cars? If they are running metrics then, Im sorry to say, you are pretty much ******* . Double check your rules (look into gray areas)and see if there is ANYTHING you can remove or replace with somethig lighter on the front or middle of the car. Gut the hood and doors if you can. gut the hood out. make sure to get rid of all hinges and latches. they dont weigh much by themself but it all ads up. get rid of any brackets that arent being used, maybe try to find an aluminum front bumper. the stock front bumper weighs way to much for the front of a circle track car. great for derbys, bad for circles. get rid of the stock bumper shocks too. if i remember right i think they weigh about 10-15# each. Get rid of the stock radiator support. run a piece of 1 1/4x1/8 round tubing between the front frame horns and mount the bottom of the radiator to it. Just getting rid of the heavy core support and getting a lighter bumper will help your overall and rearweight.
without seeing the car i dont know what else to reccomend for the diet.
get it back on scales. see how much weight you have to put right on the rear bumper to get 45%. that should be the absolute minimum for a dirt track. I run 210# right in front of the rear bumper with no problems. 300# seems to be the limit at my track before the pendulum effect starts to kick in. your track may be different. depending on how much you can strip off of the front end it may not take much to get 45%. 100# of of the front end will make alot of difference on the scales.


timcsim7
Member
posted July 17, 2002 09:28 AM
Sounds like you really need to lower the back end. Bigger tires aren't helping either.

However, something isn't right if you're not busting the tires loose every lap with 42% rear.

timcsim7
Member
posted July 17, 2002 12:23 PM
Are you sure the scales are correct????


timcsim7
Member
posted July 17, 2002 02:08 PM
are they electronic scales or grain scales? if they are electronic they should be real accurate. grain scales are usually pretty close too.

couldnt you use lowering blocks to lower the rearend? i dont drive streetstocks but i'd think lowering blocks and adjustable shackles would help changing ride heights. I know guys here use shims on the fronts to get car to scale out, IE: shim RF spring to help gain LR bite.

o5racer
Member
posted July 17, 2002 10:09 PM
Nah, hes got coils and a stock four link. dont bother with heating the stock springs they will just be short and you sill wont know the rate. did you get the full length rear springs or the short ones? on mine I used the short pigtail springs with no spacers. normal ride heights for montes and chevelles(pre '77 models) is 8 1/2 left, 9 1/2 right. on mine its 6 1/2 left and 8. when you lower the rear it puts more angle in the upper arms making the rear end lift up on the chassis when it twists back. BUT, you have to drop the rear mounts for the lower arms on the housing to make it work. if you dont the rear end will be pushing ahead and down on the chassis unloading the tires. lengthen the lower mounts on the rearend untill the arms are angled up about 5 deg with the front end higher.

moving the bigger tires to the front cant hurt. more tire to help it turn.

another idea i had. how well do the the brakes turn the car going into the corner? if the car isnt turning enough on entry it will throw off the whole rest of the corner. do you run a right front brake? if your rules allow it i would get rid of it. it might take a night or two to get used to it but it does help the car get into the corner.

I was just wondering about your competition. at my track its about 75% metrics. the two cars above me in points are metrics and the next five below me are metrics. its a pretty big disadvantage to run against them with an older car. the only thing saving me is the 3500# weight limit.

ryan
Member
posted July 18, 2002 12:23 AM
Go to a truck stop with scales or a local grain elevator/co-op and weigh it there if the totals come out reasonably close you should be fine. I was just givin you another thing to consider.


timcsim7
Member
posted July 18, 2002 09:52 AM
With that much spring combined with a sway bar it WILL push!


FirstLight7
Member
posted July 19, 2002 12:02 AM
Loose the sway bar!!!! It will help weight a little, but more importantly, it will allow the car to roll and transfer weight to the right side tires.


o5racer
Member
posted July 20, 2002 12:10 AM
with a 1200 RF and a 1000 LF you shouldnt need a swaybar. definatley ditch it.

are you allowed to shorten the wheelbase to the minimum? cutting it down to 108" will gain you a couple of percent.

another benefit of montes is the engine location. Stock V8 montes have the #1 plug even with the upper balljoint. thats almost 4 inches back from a metric.



timcsim7
Member
posted July 24, 2002 09:00 AM
try 225 lr spring instead of 250. that will loosen you up a little. also try around 2" rear stagger. you could also decrease the front stagger which would take some of the cross out.


stockcar5
Member
posted July 25, 2002 08:29 PM
you WILL handle better without the sway car.i was running about the same ad ihad a swaybad and it pushed almost all the time (i can believe i won a feature with that setup) i ditched the sway bar....100% better. sway cars can work but you need alot softer springs up front.


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