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Author Topic:   car won't stay on bottom in turns
washeduptoo
Dirt Maniac

Total posts: 155
posted August 10, 2005 10:12 PM  
We are running a 4lr-2rr. Spring on lr on bc behind and rr spring on top of housing. Car appears to skate up from bottom on dry slick and cars pass up under him. Do yall think this is a case of not enough side bite or driver going in too hard or maybe some other problem. The driver talked about the car wouldn't turn in the feature until he got off the brakes. Something changed from the last time we raced with almost the same track conditions. Another question I have is, put the rr spring behind clamped what would this change? I have read in the archieves about some of it, makes car tighter, axle rotation when off the gas more forward bite off the turn. Have I got this correct? Sorry to be so much trouble just trying stay up front when we have the lead. Thanks

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted August 10, 2005 10:43 PM  
In the PM I sent you I didn't know you had the RR on top. I haven't ran mine with it on top so I can't say what it will do. But if I were you, I'd try putting the spring behind. What you read about the axle rotation, is right. With the spring on top it removes all the axle rotation effects from the spring. That can be good for some drivers and not for others. Try the RR behind, then if it still has no sidebite, try adjusting your panhard bar. But I feel the spring move will most likely fix it.

[This message has been edited by FlyNLoIMCA17 (edited August 10, 2005).]

washeduptoo
Dirt Maniac

Total posts: 155
posted August 11, 2005 07:05 AM  
Are most of the 4-2 running with the rr spring behind? You could be right if that is the case. I'm having trouble understanding where the side bite went from the last time we raced under almost the same track conditions. I'm wondering if a spring went away or something or maybe we need to lower the j-bar both sides to induce some more side bite. I'm not wanting to remove all the parts, because our bc doesn't have a place for shock or spring, unless we replace it. Keep the input coming and thanks for all the help.

dluna
Dirt Freak

Total posts: 334
posted August 11, 2005 07:25 AM  
I was having the same problems w/ my 3link on entry. It would never bite on the RR, so I would have to wait until it stopped sliding, then get in the gas.

I went up 50lbs on the LF spring and put the RR spring on a coil-over behind. Made a huge difference.

washeduptoo
Dirt Maniac

Total posts: 155
posted August 11, 2005 08:19 AM  
You just gave me an idea, I know that is dangerous, but we're going to put the rr on a coil-over behind on bc. I guess it is alright to run rr on coil over and the lr on slider behind? Please let me know if yall see any problems doing this. Thanks for the idea, because I did not want to cut all that stuff loose on the rr.

i8uracing
Dirt Roller

Total posts: 18
posted August 11, 2005 09:20 AM  
I run the RR on a coil over behind. I had to change my upper shock mount however. It took 4 races and 3 shocks to realized the rear end was rotating enough off of the gas that it was binding the upper coil over bracket on the chassis mount. Just something to look at.

On a real tacky track the spring on top works good but when it dries out I think the spring behind is the ticket.

madnik18
Dirt Full Roller

Total posts: 40
posted August 11, 2005 11:28 AM  
with the rr spring behind, floated.. be the same as the rr spring clamped behind..i know that indexing is in play when floating.. so when the car is rolling over does the spring compress or decompress when floated?
thanks,

andykmod
Dirt Freak

Total posts: 351
posted August 11, 2005 01:26 PM  
I have been running the 2 link on my car with the spring behind and shock in front for the last 2 weeks and like it if i could get it to turn off the corner, it's just to tight from center off, you gotta steer the car away from the wall by letting off the gas alittle. I like the way it rolls on the rr and has more forward bite then the z-link did. I'am going to run a little more steer in it this week and a little less bite and see what happens.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted August 11, 2005 07:11 PM  
andy, try taking some bite out of the LR not sure what u have but the 4-2 doesn't need much LR bite. If that isn't an option try decreasing the LR bar angles.

donslink1
Dirt Freak

Total posts: 318
posted August 11, 2005 07:56 PM  
Locking that BC on the right rear will change how your pull bar works too, with the BC floated the rearend rotated in the BC on the rr, Now its will rotate on the bolt where your link bolts the the BC. SO your pull bar will get less travel which will afect the lr spring if it is clamped in the front, Which ours is so I will stick with the z-link, Good luck guys
also your wheel base changes alot as you get on the gas and when you get off the gas.
because it is not rotating in the BC.
as the pull bar pulls the rr moves back as the chassis hikes the rr moves back.
as the chassis drops the rr moves forward.
the more pullbar angle the more movement you get. something to look in to!!!

donslink1
Dirt Freak

Total posts: 318
posted August 11, 2005 08:02 PM  
unless you take your upper link and flip it to the front and mount it to the lower link and keep it floated, the 3 link will tighten the car up through and out because it takes dynamic bite out of the right rear as the car rolls in the corner, which the z link gained dynamic bite in the rr.

andykmod
Dirt Freak

Total posts: 351
posted August 11, 2005 08:37 PM  
I'am going to try 35lbs lr heavy and change my rear spring to a 200. I was running 50lbs of bite and a 175 spring.

flyin353
Dirt Full Roller

Total posts: 49
posted August 11, 2005 10:09 PM  
too much LS% will make the car "skate" in the center.

washeduptoo
Dirt Maniac

Total posts: 155
posted August 12, 2005 09:13 PM  
Installed c/o on rr and scaled the car with 66# lr bite, the lowest I have seen this car. Going to give it a shot Sat. night. Any of yall ever heard of clamping the lr shock giving more forward bite? The best of luck to all that race this weekend.

Racer X
Dirt Freak

Total posts: 256
posted August 13, 2005 11:47 PM  
Had the same problem tonight.Car would skate in 3 and 4 no matter what line he ran.We run the rr on top also I'd like to try it behind but don't have another slider so we are going to play with the springs. Wish me luck.

J 46
Dirt Full Roller

Total posts: 28
posted August 14, 2005 05:23 AM  
We lock down the left rear shock on are four bar car and it will give you forward and side bite if your bar angles are right .

bachshute
Dirt Maniac

Total posts: 118
posted August 14, 2005 07:16 AM  
lots of varables here but if the front springs are to stiff could cause the car to skate .

washeduptoo
Dirt Maniac

Total posts: 155
posted August 14, 2005 07:42 AM  
The car was awesome tonight. Started 7th out of 22 cars in the feature and ran down the leader withing 10 laps and was fixing to pass him coming out of 4 when caution came out. After several restarts, car tightened up on entry thru center, finished 5th. Very proud of how the old girl ran. Checked stagger on rear after race and it had grown 1/2 inch. Do yall think this caused the tight problem or was it the burn off of fuel? Would raising the rr bar up 1 notch help? Thanks guys for everything, it has been a long time coming with alot of hope and help from yall. Any input would be great. The drier the track got, the tighter it got.

[This message has been edited by washeduptoo (edited August 14, 2005).]

washeduptoo
Dirt Maniac

Total posts: 155
posted August 14, 2005 08:11 AM  
RacerX, if you would post the springs and bar angles, stagger, wheel weights, and stuff like that, guys on here will help you if you want them too. They have been a great help to us.

Racer X
Dirt Freak

Total posts: 256
posted August 14, 2005 12:32 PM  
Thats true alot of good help on this site.The car usually works good on a dry track but last night turns 3 and 4 were really tricky it was more like a greasy slick. We are trying to get a new power plant in this week so we will only make minor changes to the car,plus we will be the first feature on next week so it shouldn't be as dry.

washeduptoo
Dirt Maniac

Total posts: 155
posted August 16, 2005 01:26 AM  
With the car tightening up after running 10 laps and rr gaining 1/2 inch stagger, this should have caused the car to loosen up. This has got us confused as to what the problem is. The c/o can be mounted at an angle can't it? Looking for a bind somewhere and we only put c/o on and new spring on lr, I was thinking it had to be one of those things, or maybe that has been the problem all along and we just haven't found it. What do yall think?

boas51
Dirt Maniac

Total posts: 190
posted August 16, 2005 07:28 AM  
washed up,
did the track start to rubber up? maybe the track changed during the caution? maybe your driver changed during the caution? the rr most likely grew because of the tight in, which ussually leads to loose off, which abuses the rr and creates heat.
try to determine if the track changed during the race. if so how would it effect the grip/roll of the chassis? more grip may mean more roll, may mean spring change. check for binds also. less grip will be less roll/maybe less loose roll steer? etc. etc.

washeduptoo
Dirt Maniac

Total posts: 155
posted August 16, 2005 04:00 PM  
The track was changing during the race, but it never slicked off or started taking rubber, but it was drying out. I'm going to look for a bind and maybe put in on scales to recheck, if we don't find anything, we'll probably raise the rr bar up one and also probably check tire temps to see if that will tell us anything. We checked by feel but couldn't really tell. Thanks for your response.

mod52
Dirt Full Roller

Total posts: 30
posted August 16, 2005 10:33 PM  
I was zig-zag'n car back & forth under yellow once when a shock pulled a clamp up. Then it bottomed out on entry, during race. Pushed real bad. I would think this would be obvious though.
I think "51"s observation may be more in-tune w/whats happening in your situation.
As the track dries out, grip is gone & corner speeds slow. These conditions decrease dynamic weight transfer & roll. Less roll means less roll-steer.
Less wt. trans. means less wt. @ RF (needed to keep from pushing).
Now, one thing that doesn't decrease is the engines output. Throttle application adds to this by driving the LR (that has all that wt that didn't trans. to the right). At this point the driver has to drive hard through the push to get it to turn. This usually results in a loose-off condition, heating up RR. Hot RR grows 1/2" (same as 1 round in RR spring)that further resist roll at next corner entry.
If dynamics played a part in good handling early, then those dynamics must be achieved @ slower speeds. I've had better luck approaching setups w/in mind.

washeduptoo
Dirt Maniac

Total posts: 155
posted August 17, 2005 06:21 AM  
After reading it several times, I think I know what your mean. Because it doesn't transfer wt. the same, he will need to slow down a little more to be able to run thru the turns as he was earlier in the race? Would raising the rr bar help with this condition or do you have have another suggestion? It looks like the front link on the upper -A- have a slight bend in them, this might be the problem, will have to check caster/camber to see, how far it is off, before replacing. Thanks, for the time and effort. I'm still trying to learn the chassis stuff, so I can help them. Thanks again.

boas51
Dirt Maniac

Total posts: 190
posted August 17, 2005 08:05 AM  
raising the rr bar should help turn while on the gas. should ad rr bite.

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