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Author Topic:   help getting on the bars
nelson1m
Dirt Roller

Total posts: 15
posted May 15, 2005 11:02 AM  
I have a harris with a 4-link lr and a z-link right rear. 650lf 750rf 225lr 200rr, the lr is in front of the housing and the rr is on top. I am having problems getting the car to get up on the bars. I also run a j-bar with about 4" of rake, and the lr bar angels are 17 on top 5 on bottom. just need to get the car to roll over more. thanks

nyimcamod8t
Dirt Full Roller

Total posts: 67
posted May 15, 2005 07:52 PM  
I run a 2004 harris 4-z car. on ours we run a bilstein 1040 lr shock, really helped it jump up on the bars quicker. is the LR clamped ahead? i had run mine clamped ahead for the past year and always fought the car being tight when i pick up the throttle. last friday i put the LR behind on the cage and it made a night and day difference. now i can drive the car thru the apex without being tight and the car just launches off the corner. something you might want to try. also sounds a bit heavy on the RR with the spring on top, i would back it down to a 175, or keep the 200 and put it on the cage in front.

[This message has been edited by nyimcamod8t (edited May 15, 2005).]

nelson1m
Dirt Roller

Total posts: 15
posted May 16, 2005 02:51 PM  
Thanks I will give that a try, also do you ever mess with making ther bars on the z-link longer or shorter because i have never changed the length on those bars. thanks

nyimcamod8t
Dirt Full Roller

Total posts: 67
posted May 17, 2005 02:07 PM  
I played with different bar lengths last year. what i'm running right now is the 15" lower bar and a 20.75 upper bar. I ran it awhile last year with a 20.75 lower bar on it, wasn't bad, just slowed down the steer a little. It's always felt to me like the car drives better with the shorter lower bar on it. what holes are you in on the RR? most all of the time i run my lower in the third hole up on bracket and run the rear bar in the middle hole on the clamp.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 17, 2005 02:34 PM  
there are a few things you could try.

More bar angle on the LR upper bar.
softer RF spring
more jbar angle
stiffer RR spring

Ego Racing
Dirt Forum Champ
Total posts: 724
posted May 17, 2005 03:51 PM  
quote:
Originally posted by dirtbuster:
there are a few things you could try.

More bar angle on the LR upper bar.
softer RF spring
more jbar angle
stiffer RR spring


Stiffer right rear spring will keep the car on the left side harder and not allow it to roll over to get it on the bars. On our cars we drop the right rear by 25-50lbs and it will get on the bars for you!

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 17, 2005 04:01 PM  
the idea was that with the stiffer RR it will plant it harder on entry creating more side bite and instead of the RR corner compressing it will keep the corner of the car up, and the LR will rise and try to roll over it instead of just using the weight transfer to compress the RR spring and the LR staying near static height.
I didnt beleive it either until we tried it, may work for some and not others.

Same with softer RF spring. It gets the car rocked over on the RF which will let the LR start to raise up.


GRTWallbanger
Dirt Maniac

Total posts: 196
posted May 17, 2005 05:01 PM  

 
This is with a stiffer RR spring then LR.
Dont get me wrong, this car is way to tight and terrible to drive in traffic, but you asked!!!!!!!

Ego Racing
Dirt Forum Champ
Total posts: 724
posted May 17, 2005 06:44 PM  
The softer the right rear spring the more weight transfers to the right rear tire, If the car is tight through the corner we will raise the right rear up about 25# and try it again. This lets the right front stay down more and it helps free the car up.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted May 17, 2005 07:20 PM  
ah HA! I was discussing on another forum the stiffer/softer RR spring deal. According to Dirt Works and GRT's trouble-shooting guides the Softer RR makes the car looser going in. I didn't agree with that! Because the RR rolls over more therefore transfering more weight to the RR. I put a softer spring on my RR and it tightened the car all thru the corner. Anyone else agree with this???

HarrisMod#30
Dirt Freak

Total posts: 353
posted May 17, 2005 07:32 PM  
GRT you must have a lot of angle in the lr bars? Just curious, I know you guys race on a short track but does the car loose bite toward the end of the straights? I know when we get to much angle the car looks exactly like that but the car looses bite toward the end of the straight away on a half mile.

[This message has been edited by HarrisMod#30 (edited May 17, 2005).]

A&M Motorsports
Dirt Maniac

Total posts: 117
posted May 18, 2005 05:03 AM  
quote:
Originally posted by FlyNLoIMCA17:
ah HA! I was discussing on another forum the stiffer/softer RR spring deal. According to Dirt Works and GRT's trouble-shooting guides the Softer RR makes the car looser going in. I didn't agree with that! Because the RR rolls over more therefore transfering more weight to the RR. I put a softer spring on my RR and it tightened the car all thru the corner. Anyone else agree with this???

Dale, as you have heard on here a million times, body roll does not mean weight transfer. If you have a real soft spring on any corner it only compresses and does not absorb the dynamic chassis weight like a slightly stiffer spring. I like to keep my cars as flat as possible so the tires can do their work properly. There are hundreds of things that determine the spring rates that the driver likes, the track likes and so on so forth. To me smoother if faster and more consistent but if you can drive a 3 wheeling car and you like it go for it. JMO

------------------
Artie Perilloux
A & M Motorsports

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 18, 2005 07:50 AM  
Ego,
I guess we'll just have to agree to disagree because I feel just having a softer spring does not increase weight transfer. We went through this last year on our car, the RR wasnt sticking yet gettting 3-4" shock travel. increase the spring and suddenly the car started sticking better. shock travel decreased but finally got to the point that the car was tight in. We changed nothing else during that time so the actual weight transfer was nearly the same based on panhard, ballast height, track, etc, just how much of it got put to the track was the difference.

If you look at like a Mastersbilt setup sheet, when the track slicks off and you need more sidebite and on the bars easier they soften the Rf a bunch and stiffen the RR. That way the car rolls over, the stiffer RR gets more of the load than before, planting that tire and the softer RF compresses furthur allowing the car to rock forward and down on the right which then lets the LR get started climbing. Just the opposite when tacky, stiffer Rf, softer RR.


[This message has been edited by dirtbuster (edited May 18, 2005).]

Ego Racing
Dirt Forum Champ
Total posts: 724
posted May 18, 2005 09:47 AM  
quote:
Originally posted by FlyNLoIMCA17:
ah HA! I was discussing on another forum the stiffer/softer RR spring deal. According to Dirt Works and GRT's trouble-shooting guides the Softer RR makes the car looser going in. I didn't agree with that! Because the RR rolls over more therefore transfering more weight to the RR. I put a softer spring on my RR and it tightened the car all thru the corner. Anyone else agree with this???

We have pictures of our late model qualifing on a 1/2 mile track. With a 225 RR the car was pushing really bad and wanted to pickup the left front. We raised the trackbar, changed front springs, changed bar angles and nothing helped. We switched the RR to a 250 and the car loosened up and the left front only came up about 4 inches.
If the stiffer spring would allow more roll then you would stiffen the right front to get the car to turn, you dont you soften it.
More roll will not create more side bite unless the roll center of the car moves farther to the right during the roll, If it moves farther the weight added will be more as the center moves to the right side of the car.
The sofeter right front will allow a car to raise the left rear sooner as a chassis works on the diaginal plane. This allows the car to turn and not push.
GRT's setup sheets use a 225lb RR as a base line, a 250 for banked or High speed tracks and a 300 for Very tacky high traction tracks.
The setup change from a baseline to a slick track is to add rear % and change the right front from a 350 to a 325 and allow you to go to a 300 to get the car to turn on a slick track.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 18, 2005 10:04 AM  
Sound like the car was tight coming out, in that case a stiffer RR will loosen the car and keep the LF down, but getting in a stiffer RR will take more of the transferred weight from the left side and pin that tire and the car will try to pivot around it more. If you go to soft on the RF and too stiff on the RR you will tighten the entry to where the RF cannot steer the car because the RR has take too much of the transferred weight. Thats why it works well with a 4 link setup because the LR steer makes up for it and the car still turns, and at the same time gets started on the bars.


If you look at GRT setup help matrix, it says if your car is loose on entry you 'stiffen the RR spring or soften the RF'. Same thing if your car is tight on exit.

[This message has been edited by dirtbuster (edited May 18, 2005).]

rocket36
Dirt Freak

Total posts: 209
posted May 18, 2005 03:14 PM  
like many adjustments, there are times when you can get to a point where the opposite result starts to apply.
just this past season we were having continued troubles (turn entry push) with our late model on one particular track (3/8 mile, banked, tacky, momentum) we talked with the guys at rocket quite some (as well as steve hendren on this forum), and eventually they put us on thier "big right rear spring" setup which has the stiffer spring on the right rear. normally they recommend this deal when side bite is more important than forward bite, but in our circumstances, it freed the car up alot and made the car much faster, more consistant, and easier to drive.
i think it depends alot on driving style and comfort as well as track shape.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted May 19, 2005 05:18 PM  
I talked to Zero about this and he set me straight LOL!! From the way he explained it a stiffer RR will tighten entry. It made sense.

I guess my deal was that the car may have been unbalanced or just not to my liking and when I changed the spring it fixed it to where I could drive it. I guess I gotta watch out for that type thing because it could really mess me up in the long run.


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