|
Post by flipflopoo1oo on May 14, 2015 9:12:35 GMT -6
Go with about 80 bite and 52-53 cross and left if you can with tightening the left ft. and a more level chassis if heavy left built car-- move the rear weight to lower right if to balance rear traction but keep it low as to not making it happen as with a 4 right rear throws it as does to little air in the right rear-- The last guy converting spent two weeks with me in private post and then went to the front from a usual tenth or 11 place finish -- 3 of five is the norm of wins after the switch so don't give up until perfected as you are not getting my points correctly! Don't just move things with out knowing why and how it works as a whole with the rest-- as this spring fighting the other or thee importance of preloads in spring combos that have to be correct ft. to rear corner to corner to keep movement to a minimal to hold bar and pound settings at the track surface with pull bar applied and thrust angles adding to that if too positive -- mostly when rolled-- most four bar j-bar cars have to have a 4 degree neg angle on left lower to make this set-up work! J- bar lower is even with lower pinion location on most !!! To low it binds and too much angle holds the left down when out of gas and lifts suddenly when on the throttle and turning and giving rise to radical change when you want to be smooth going in or starting off the turn! When correct you can coast in and around faster than on the throttle sideways all the way threw-- keep the car straight -rear steering with g-forces and turn the front little as it rolls straight ahead with no drag! Its a sunday drive on Sat. nite when right! Be sure your ready for faster!!! Most need a gear change with improved corner speeds so don't blow it at the flagstand!
|
|
|
Post by mchizy on May 14, 2015 16:58:13 GMT -6
Ok Champ Old School set up This is a 2009 Harris chevelle sub b mod 3 link had a ton of steer in car know it looks like is under steer cant believe it before my left rear spring was loose when hiked up now it has a lot of wt on it I CAN NOT BELEVE THIS BUT SET UP CAR LIKE YOU SAID AND PUT IT ON THE SCALES AND THIS IS HOW IT CAME OUT WOW THANK YOU It just came off the scales car with out driver 1 1/2 lower ft left 1/2 lower LR Springs in 550 lf 750 rf 200 lr 175 rr 7 deg pinion ang. J bar 4 deg 6.8 Left link 8.7 right link total wt2513 class b mod usra 2550 min with driver 2762 # lf 523# RF 497# LR802# RR 692# left %52.7 Cross 51.7 Rear % 59.4 wt 2513 150 # lead low left with driver left 54.9 rear 60.4 RF LR Cross 50.4 wt 2762 LF 609# RF486 # LR 907# RR 760 # ps only have about 3" shock travel RF left front spring is loaded up thanks let me know what you think
|
|
|
Post by flipflopoo1oo on May 15, 2015 2:08:40 GMT -6
SOUNDS PRETTY DAM CLOSE!! if LOOSE COME OFF OF THE LEFT FRONT!!! if TIGHT GET RID OF LEAN IN FRONT TO ONE INCH! j-BAR IS MEASURED IN INCHES UP AND SHOULD BE 3-5 OR 7 INCHES HIGHER AT FRAME MOUNT THAN DIFF! OFSET MADE IN IS SOMETIMES LEVEL!! tHE CROSS NEEDS HIGHER AND LEFT A BIT LOWER!!! rEAR RATES A BIT HIGH TO THE FRONT SPRINGS THAT NEEDS TO DO ALL THE WORK FOR YOU!!!
|
|
|
Post by mchizy on May 15, 2015 6:35:52 GMT -6
Thanks My j bar sorry is 4" angle up to chassis rates are due to the Wt you had me add 150# to rear low left have to move some Wt right and forward or remove wt car is 150 # heavy We are getting close didn't understand if loose and tight thanks Going racing tonight hope car turns haha thanks a lot
|
|
|
Post by flipflopoo1oo on May 15, 2015 19:03:38 GMT -6
Never had a car work with my set-up with out weight low left and rear but missing something in left ft. lean causing it to be off a bit! Will think on it a bit and go over post again in time!!!
|
|
|
Post by bluestreek on May 18, 2015 11:20:52 GMT -6
I'd like to know how the races went for Mchizy.
|
|
|
Post by mchizy on May 18, 2015 18:52:06 GMT -6
Started ok till I had to get on brake mid corner then back to gas went right to wall then back to infield
|
|
|
Post by flipflopoo1oo on May 18, 2015 21:55:38 GMT -6
Better back up and re-read as to settings and springs fighting for control- how much left rear and cross to keep from hiking! With so much left rear poundage and throttle drag or quick transfer to the right rear to jerk it right or hiking that steers it left on the throttle-- if front springs are too soft for the rear! The front should have control so that the caster twist of the frame can control pounds and steer instead of the rear bars! Hike throws it all out the window as all angles change to power and drag limits! Have a four offset on the right rear kicking the J-bar to extremes and running the left rear under adding major steer along with taking away all right drive as to a balance of rear traction! You just have to calm it all the way down to drivable and let nature do the things it does best! Left bars overcoming the right side with side thrust from too much j-bar angle is where most problems start-- that's why God made pan hard bars first!!!!
|
|
|
Post by mchizy on May 19, 2015 19:06:35 GMT -6
Thanks I am going to go with 650 Lf Ft 850 Rt I tried a 650 Lf But with 1 1/2 low Spring is all the way up Ride Ht set with driver in or out of car I had it last week with out driver with me in car it leaned way left I will set J bar at 3" ang. 150 lb lead low left thanks let me know
|
|
|
Post by flipflopoo1oo on May 20, 2015 21:50:04 GMT -6
Should be falling in close you may have to move a bar to the right rear but getting rear percentage to hook always helps until you pull both front wheels and have trouble steering!
|
|
|
Post by flipflopoo1oo on May 20, 2015 22:01:39 GMT -6
I use no forced roll by any means as to tucking the right side rear tire, j- bar angle or mounting lead high but do keep fuel tank toped off as to be able to control by settings and not let the track demand changes!!! My tank is right side and battery left rear! Weight on the cross just pivots and does not lift or hike! This puts the left rear as the pivot of the turning point of steer so if center it has no sling being so close in too--- no rotation outward! This also gives the left ft more control when adjusting-- think of it as all 4 wheels as having the same pounds as needed when rolled for equal 4 wheel traction in the turn to hold both ends in the turn at higher speeds-- setting even out when rolled as with bump steer keeping tires correct for ft traction in steer mode!!! Once there a simple turn of the steering wheel will change pounds at all 4 wheels and steer all 4 at the same time to make going to the front a easy drive!!!
|
|
|
Post by younggun on Jul 2, 2015 22:56:47 GMT -6
Alright, I found this discussion the other night and i have a few questions. First off i have driven a southern sportmod (stock 4 link rear suspension) for 6 years off and on (engineering college cuts down on racing) and my dad has recently purchased a northern sportmod (3 link). I've been trying to set it up for him and am fascinated by all the adjustment that can be made. I do have a few questions for flipflop though.
1.) What is the theory behind the 200 lb. split in the front? The most I have ever run was 50. With a southern if you get too heavy with the right front the car likes to skate coming out of the corner.
2.) Why does the pull bar affect the traction and how does it do so? What is the best angle to run it at? Currently we have a 14 degree pull bar angle. Is it because it projects your lift point further towards the front to pick more of the car
3.) This car has a panhard bar behind the rearend. Do you measure the pitch the same as a the j-bars and just compare how much higher the left is than the right and follow the 3-5-7 rule? We have been playing with the panhard bar and when the track gets really slick we lower it down and it seems to stick better, though, on a heavy track the low panhard bar creates a kind of jacking affect from what i felt.
All of my theories are speculation and im learning to feel the car as well as my dad cant seem to tell me what the car does so i have to jump in and find out myself (bummer!). When i roll through the corner on the bar the car feels like generates a lot of side bite and on corner exit it has forward bite but once you start going straight it feels like the car breaks loose and needs more traction. We race on 3/8 miles that get about as slick ass glass with a bit of sand and clay on the top.
Thanks for your help!
|
|
|
Post by flipflopoo1oo on Jul 3, 2015 11:33:26 GMT -6
The left front holds the car up freeing the right ft-- the lead mounted LL&R counter balances in the cross to do the same-- the weaker spring on lt ft is then preloaded to help roll and switch the cross to right rear when nosed and rolled to have more right drive to push the car left around the turn ===It has more pounds on the scales than right ft. something like 50 w/o driver and 150=200 with driver!!!. The lead LL&R gives left rear with out preloading it with the rt. ft. threw the cross untill nosed and rolled also!!!Rt. ft. is not preloaded by left rear!!!--The right rear is planted as the right ft. simply by lifting the throttle and thus can turn on a dime -- no roll needed to plant! I use G-force pounds instead of loosing right in the roll-- transfer and not roll to get there-- car is more stable and needs no hike to recover lost pounds of left rear! It only gains more on or off the throttle-- hooks a bit harder and faster with good transfer insted of loss in motion in roll!
|
|
|
Post by flipflopoo1oo on Jul 3, 2015 11:40:32 GMT -6
The back angle gives leverage if closer and pulls harder-- lifting is not holding pounds down so why go that far! The higher the ft. the better transfer to the rear. Level can work just fine if not needing to lift to change all the angles you have preset!!!
|
|
|
Post by flipflopoo1oo on Jul 3, 2015 11:56:43 GMT -6
Mounting gives way to a free roll center! each set up changes that spot!!! Car should roll in free off the throttle and not impede this smooth entry or change when on the throttle what naturally happens to upset where things are when working great!!! A pan hard needs 3-5 inches in height change a to b is best to hold the rear end under the car as designed and not to make it plant or roll if otherwise designed!!! A free car is a fast car!!!
|
|