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Author Topic:   WE STINK.....NEED 4-LINK HELP
JERP27
Dirt Roller

Total posts: 13
posted July 16, 2002 12:08 PM
We stink.....need 4-link help

I'm seeking the vast knowledge of the reading audience. I need help with our 4-link car. There has to be something that we are missing. Here is what we run: 1/2 mile high banked clay track that gets black by feature time. We are ok until it's gets black then we go backwards. Here's our set-up:
50/50 shocks on the front with 40/40 on the rear, 1000lb spring on the LF & 900 on RF, 250 on LR, 225 on RR and 300 spring on the lift bar. "J" bar that goes from the right side of the chassis to the left side of the pumpking.
Link's
LR:
-Top: 1 dn from top
-BTM: Btm hole
RR:
-Top: 1 dn from top
-BTM: Btm hole

The scaleing #'s are as follows: Race ready full of fuel
LF: 495
RF: 590
front%: 44.9
Left side: 52.6%
Right side: 47.3%
Cross: 56.5%
LR: 775
RR: 554
Rear Split: 55.0

3" REAR STAGGER, 1" FRONT

Chevelle front clip, the the LR spring behind the rear end.

This past weekend started 3rd and finished 12th, max rpm of 6600 with 5.00 gears. rear tire temps, 140's for LR and only 160's for RR, so he wasn't over driving the car.

Any help and or suggestions would be much apreciated.

28
Dirt Full Roller

Total posts: 36
posted July 16, 2002 02:33 PM
Why is he going backwards? Lack of forward bite? Too tight? No side bite?

JERP27
Dirt Roller

Total posts: 13
posted July 16, 2002 05:37 PM
No fwd bite and he is tight from the middle out. The fast groove at feature time is on the bottom and he can't run there due to a tight car. He is pretty good on entry.

28
Dirt Full Roller

Total posts: 36
posted July 16, 2002 05:58 PM
I think you have too much cross in the car. You say the car has no foward bite but with the good tire temps and high cross, it would seem impossible not to launch off the turns... but, when the car is that tight, you have to throw the car or break the tires loose with the throttle. You also lose your momentum when you have to slow in the turn for a tight car. All of this will make it feel like you have no forward bite. Take cross out and drive the car into the turns. On a slick track, we try and get the front tires to be equal weights. When you do this, your cross will match your left side %. Adjust your left side weight by using wheel offsets. As long as your fronts are equal in weight, your cross will always match what you do to the left side. My car works best with about 52% left/cross (without me in the car) Always have good bite and a very drivable car...even on the bottom.

I also took alot of the angle out of my bars to make the car drivable. You think you need to keep raising the bars to get the bite but usually we just dial ourselves out of the race because the car is undrivable. It is going to be hard to get the driver to believe that less angle and less bite is a good thing but if he tries it, I'll bet he will love you forever. Good Luck

motorsport 18
Dirt Full Roller

Total posts: 58
posted July 16, 2002 06:14 PM
is your birb cage indexed also you might try to use a clamp bracket or move pan bar just some things that i might try im going to be gone for a week on vacation so wont be around

dirtracer14
Dirt Freak

Total posts: 333
posted July 16, 2002 08:03 PM UIN: 23443678
What size motor are you running? It seems that 6600 on a 1/2 is pretty low and would not give throttle response very well making it harded to loosen the car with the pedal? And yes the cross seems high i have gone down below 50% some nights to get the car to turn. Just my 2 cents

JERP27
Dirt Roller

Total posts: 13
posted July 16, 2002 09:05 PM
We have been running a 406 but we are taking this week off to rip into the car and try some different springs and see what kind of #'s we get when we scale. When we start back up the following week we will have a spec motor in. We are planning on trying some new things, the driver is pretty much up for anything since we are out of the points and trying to stubble onto something so we can end the year on a good note.

Any help will be much appreciated!

tls88mod
Dirt Full Roller

Total posts: 40
posted July 17, 2002 10:25 PM
Your main problem is your front springs are backwards. If the left front is stiffer than the right front it makes a very tight condition coming into the corner.

Geffy95x
Dirt Forum Racer

Total posts: 78
posted July 18, 2002 10:30 AM
Cross is too high ,I had that much cross once when a crew member at the shop went the wrong way with all the jacking bolts(no scales) going from pavement to dirt setup, Went from the pole to 10th in 8 laps.

voodooracecars
Dirt Newbie

Total posts: 1
posted August 27, 2002 08:32 PM
I have to agree with 28...to much cross...i would just about bet your not having a true lack of forward your just having a heck of a time trying to drive the car off on the bottom. Would you be willing to try a oposite mount on your j-bar? i am afraid with the rite side mounted jbar if we detraction to much initial drive"dcreasing wedge" the he may have a devil of a time gathering the side bite to get the car to scotch up. I also agree with not over lifting your bars ...better ways to get drive than that. It has to many negative effects as well. unless you just wanna impress the girls doing wheelys...but irecommend doing that only in hotlaps...otherwise you look cool but you still lost...lol.....just my 2 cents....by the way what type of chassis?...i am not disagreeing with the other guy but if your getting in the corner good your front springs sound fine...middle off trouble would call for a spring reversal in my opinion

155fan
Dirt Full Roller

Total posts: 30
posted August 27, 2002 09:33 PM
Swap the panhard bar mount to the opposite side ! The rt. mount to lt. of the pinion plants the rt. rr. more and will hurt you on the slick , but the main problem sounds like too much cross . The reversed frt. springs don't bother me unless it's a momentum track thru the corners , not a flat stop and go which seems to like the reverse stuff . If you're carrying momentum thru the corners on a slightly banked track , it will try to just shove the rt. frt. in the ground creating a terrible push thus not allowing the car to turn and keep on the bottom . Stop and go drag race type of flat track , the frt. spring are probably not too bad . Sounds like too much stagger also on the rear when the track slicks up but maybe you're trying to free the car up to turn like that with your current push problem .

jreep
Dirt Roller

Total posts: 13
posted August 28, 2002 09:20 PM
you need to change your bottom bars. your cross is definetly to high but your are not utilizing the strength of the four bar. if you will move the lr btm bar up this will cause the lr to suck under the car. when your driver gets on the gas this action will put lead in the car and loosen up coming off the corner.

JERP27
Dirt Roller

Total posts: 13
posted August 29, 2002 09:54 AM
The car is a "Perfect Chassis", manufactured by a local LM driver. The last couple of weeks we have been going to a 3/8 "wedge" type of track. High banked, tight turns....a track that you need a lot of wedge. The car has been very good on entry to the middle but middle out we loose fwd bite and side bite. Any more suggestions? What spring should be on the lift bar? Right now we are runnung a 350lb and get about 2" of travel. Still have the "wierd" panhard bar in.

BD #13
Dirt Newbie

Total posts: 4
posted September 18, 2002 08:42 PM
Just a suggestion, I had the same problem and all I did was add 75lbs. of left rear weight when it came time for the feature, this made a major difference, I could stick the car to the bottom of the track and pass the cars that were running the upper grove. I am however running on a smaller track (3/8). If your running a panhard bar try switching to a J-Bar. Just a few suggestions.

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