LR Carry/ No Drive

[jonnywhoop52]

We run a 4 bar, lift arm UMP modified. We have 50 degrees of bar angle on the top LR bar, and we are maxed out on our bottom LR bar to put steer in the car/drive. After the feature I check tires with the bare hand method, the RR has nice even heat across it, but the LR tire is barely warm. I'm wondering if any of you have had this problem of possibly picking the LR up causing no drive out of it? Will shortening bar lengths help? Or taking more out of the limiting chain help? Have a handful of races before Nationals and want to get something figured out. Any help is appreciated

[racin6mod]

I have seen photos of modifieds with the lr off the ground but those were underslung cars. how the he11 can you get 50 degrees of bar angle in your car. I would say you have something way off to need that much angle. , what kind of j-bar or straight bar are you running and how long?

[jonnywhoop52]

I know people say that over 47 degrees you lose its effectiveness but we kept raising it to hopefully get more angle in it making it react quicker. I believe our bar is like 16" long, driver does not like j-bar. We have changed a lot from the start of the season, but we have had no help from our chassis builder, so I just am running out of ideas on where to go with this, only things I can come up with is shortening left side bars to react even quicker, and I'm not sure to put more slack in the chain or take it out?

[LITE-INN]

racewise.net

[MasterSbilt_Racer]

We run a 4 bar, lift arm UMP modified. We have 50 degrees of bar angle on the top LR bar, and we are maxed out on our bottom LR bar to put steer in the car/drive. After the feature I check tires with the bare hand method, the RR has nice even heat across it, but the LR tire is barely warm. I'm wondering if any of you have had this problem of possibly picking the LR up causing no drive out of it? Will shortening bar lengths help? Or taking more out of the limiting chain help? Have a handful of races before Nationals and want to get something figured out. Any help is appreciated

I hope 50 degrees is at full drop? Raising the lower bar is counter-productive to loading the spring.

[jonnywhoop52]

I appreciate the link LITE, but it doesn't really help since there's no tech help, and there's no sessions in the near future before the end of the season. So it is kind of irrelevant.

[jonnywhoop52]

yes 50 is at full drop. I thought lower LR put more steer in it and makes it react quicker since you shorten the angle

[MasterSbilt_Racer]

yes 50 is at full drop. I thought lower LR put more steer in it and makes it react quicker since you shorten the angle

If your spring is mounted on the birdcage on the backside of the rear, the more angle in the lower, the less spring loading you get from birdcage index.

[jonnywhoop52]

so is there a general way to get the LR to drive because it just has next to no heat in it after 20 lap features

[MasterSbilt_Racer]

You most likely do not have enough weight on the lr when racing around the track. Depending on how the car works, there are a million ways to do that. All have trade-offs.

You might need more leftside weight. More lr weight. Various spring changes and bar angle changes could get you there. Don't be afraid to look at all the suspension at the other 3 corners.

[jonnywhoop52]

we have a spring behind so would changing that spring to a lighter one in the LR help? Another thing is, is the chassis builder's car can run the bottom and be fast, our car has to be up top to be fast it does not like to stick on the bottom, and I know running the bottom is like having a job it sucks, but when we're getting beat because the bottom is fast we just kind of have to settle for a top 10

[LFMotorsports]

We have had this issue.... Guarantee not the same chassis because I have an odd ball. Easiest thing is to give me a call and I can tell you what we are finding, just with all the rain recent, have only gotten to try a few things that have helped. To much to discuss here.

Lance
cell #: 812-470-0063

[powerslide]

we have a spring behind so would changing that spring to a lighter one in the LR help? Another thing is, is the chassis builder's car can run the bottom and be fast, our car has to be up top to be fast it does not like to stick on the bottom, and I know running the bottom is like having a job it sucks, but when we're getting beat because the bottom is fast we just kind of have to settle for a top 10

post your static bar angles/lengths and springs/%'s and we can help alot more. Its really a shot in the dark w/o knowing that. On the LR spring it depends if its a stop and go track(LR setting down) or a momentum track(LR still up).

[racing_kid]

maybe index the lr b/c?

[jared1624]

sounds to me like the car is already way to tight. if i was guessing, with those extreme bar angles, the lr is at max tracion as soon as he gets on the gas which is making him think he has no lr traction. the lr has to be able to work, he is probably breaking the car loose when he gets back in the throttle and rear tires are spinning on corner exit

[Modlitefan0]

Tell the driver to go get a colonoscopy because I think he has a brain tumor. And than throw some bite at it like I told you a few months ago. Someone touched on it when they said not enough weight on the LR.

[JustAddDirt]

What Front stub are you running? Chevelle, Metric, Impala, Ford
What Spring rates on all 4 corners?
I would venture to say when the throttle is applied with those bar angles, the car jumps up so fast, I bet the LR tire comes off the ground, and becomes unloaded, and never regains traction. Also if you have that extreme of bar angles, I bet it has so much loose roll steer, it feels loose, but it is all roll steer. I bet if you dropped the Upper right 1 or 2 holes, and the bottom probably 3 holes, the car would probably have better traction. Lift-arm cars require more LR weight as well. 125 is a good start, but it may require more.

[johnny v]

masterSbiltracer hit it on the head....
IMHO:
Raise the LS % .... everything you do to it is a band aid if you don't get the LS and Rear %'s right for the track conditions your racing on...... LS weight gives you some push back when the car hikes up...giving you drive...another benefit is it loosens entry... Which almost every car needs , but drivers are too scared to admit.....Most don't want to learn how to correctly drive a 4 link car...

[jonnywhoop52]

talked to someone from BSB and I think he is right, I think we have a bind in our bird cages, he liked our scale numbers and bite, so he suggested going through the front end and making sure the weight is getting transferred to the wheel and go through our bird cages, we have absolutely no hike when turning left while just driving around. So we might switch bird cages and front lowers and go from there

[LFMotorsports]

Sounds like a good sales guy.... We "had" the same or very similar issue. Found the answer tonight during testing. Offer still stands with a call.