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Author Topic:   4 Bar/Z link handling bug
uforacing51
Member
posted June 19, 2003 10:28 AM
Well, Here goes
I just purchased this car and am working with Harris and the former owner to get it handling. What it is doing is this:
On entry into the corner everything seems fine, but about halfway through the corner the car shoots the front end up the track and becomes a stinker to drive off the corner. It just drives up the track to the wall, like someone is pushing the left rear corner of the car.
So far, this is what I have:
LF 650 lb spring 45 bilstien 3.25 RH
RF 800 lb spring 55 Bilstien 3.50 RH
LR 325 spring (in front of axle) 94 AFCO shock 1.75 RH
RR 150 lb spring 95 AFCO shock 2. RH
52% Left, 51% Cross, 57% rear.
l60 lb diff in wheel weight across rear. Both bars on the 4 link had some angle in them but I moved the lower one back to level. I put the swing arm lower too it was in the middle of the three holes.
Harris is suggesting I get the wheel weights closer together and the former owner was adament that the 325 lb spring in the LR is too much.
Any opinions?

[This message has been edited by uforacing51 (edited June 20, 2003).]

Geffy95x
Member
posted June 19, 2003 10:39 AM
Get those rear springs a little closer ,with that kind of spring rate you will push like a dump truck .I would try it at 175# or even at 150# on the LR.


nvracer
Member
posted June 19, 2003 10:39 AM
I agree with him. 325# spring is to much. Most people here run from a 175# spring up to 225# spring in the LR with a 150# to a 200# RR spring. Having a LR spring of 325# will make the car drive to the wall under throttle. Hope this helps.
Good Luck


uforacing51
Member
posted June 19, 2003 10:51 AM
I thank you for your responses, it does drive to the wall, thats for sure. I also did change the LR spring to a 250 last night and have a 200 to take with me to the track in case the 250 proves to still be too much. I am anxious to try this and see if the car is faster in the corners. I was told that if the spring is in front of the axle, it loses its rate. Is this something that anyone has heard of? (Like a 300 lb spring acts like a 225 lb spring)

[This message has been edited by uforacing51 (edited June 19, 2003).]

BigBlueFord
Member
posted June 20, 2003 07:50 AM
I agree with what the the other guys are saying about the rear springs. 25# to 50# of split across the rear seems the best. Your RR 150 and LR 200 will probably be your best option.

You might also try lower your RF we're currently running LF 600, RF 650. Seems to help with a push. We were running LF650 and RF 700.

Think about this way, driving off the LR will force the nose of the car towards the wall. So, less LR and more RR will try to turn the nose towards the in-field.

Another little hint. A little longer wheelbase on the right side will reduce push.


Good luck


rocketwildone
Member
posted June 20, 2003 08:07 AM
Stiffer spring in the RF than the LF will make the car tight.It will keep the LR loaded more.I think it would effect the car going in as well?Most people i talk to seem to run softer spring on the RF than the LF.Just like the Late models do to get the car to turn.


wfoondirt
Member
posted June 20, 2003 10:29 AM
You've got way to much spring in the lr, unless it is mounted way inboard or something wierd. 225-250 should be in the ballpark. If it still has a push with the softer lr you might want to try a little more stagger. I ran as much as 4-6 inches when i ran a 4/z on some tracks. The reason l/m's run softer rf's is to get more travel on lr and thus more roll steer, which works also but isn't ideal. Moving the bottom bar up a hole will add some roll steer and may help the car turn in the middle, but i doubt anything will help till you change the lr spring.


uforacing51
Member
posted June 20, 2003 11:47 AM
I think you all are on the right track, I suspect I have too much spring in the RF also, the car came to me with two 650 lb springs in front and I thought that wouldn't work. Seems todays thinking is smarter than old school. I have a 700 and the other 650 to put in it, but its loaded and waiting for tonights action. I will take the springs and change at the track. BigBlueFord, thanks for putting it in a format I understood. I am getting closer to having that thing going alot quicker, now all I have to do is develope myself as a driver.


hasben
Member
posted June 20, 2003 02:16 PM
panhard bar only needs about 10*angle in it . use a long one.if you are running a 4-z try a 50 lb split in springs. dirt works sais to start with 300&250 in the rear.cant remember what harris recommends.have you set the leed?on my #43 car(a harris)we stretched the left side half an inch to get it to quit tailing out so bad comming off the corner.


HarrisMod#30
Member
posted June 22, 2003 03:36 PM
The weather "experts" here in Montana have been saying we are in a drought. It rained out for the 3rd time in four weeks at the speedway friday night. I did get to run a couple of laps of hot laps but on a somewhat heavy track. As dirtywrench points out, it does swing the back end around a bunch, but I attributed that to the conditions and then didn't get to run on a good track. HarrisMod30, I will try that, the track is 3 tenths of a mile flagstand to flagstand and those springs are really close to what I have now, I have a 200 so I will try that also. Mod52, the panhard bar has alot of angle, umm seems like it was 1 down from top on frame and on the bottom on rear. I will double check when I get home and get back to the post tonight. Hasben, thanks for the info I will print this and keep it in the racing folder, I believe that with all of the things you all have posted and the Harris factory I am really close to getting the car handling as well as it has since I took ownership of it a year ago. Thanks

[This message has been edited by uforacing51 (edited June 23, 2003).]

uforacing51
Member
posted June 30, 2003 02:21 PM
Hey, 2 nights of racing this week, I had the same problem thru all four races, a loose car all the way thru the corner. Both tracks went dry slick but from what I saw, nobody else was having the same problem. the rest of the cars out there were all running good. I spun once on each track from gassing up too quickly. I don't think the car is far off, but I just can't get it to hang on enough for me to feel comfortable with gassing it up all the way.


BigBlueFord
Member
posted July 01, 2003 07:18 AM
Sounds like you're making progress. Went from a push to being loose. Now you kinda have a range to work in.

How about an update on how your car is setup, springs, shocks, corner wieghts, panhard bar, stagger, rearend square or lead/lag, etc.

uforacing51
Member
posted July 01, 2003 11:39 AM
This week I tried a 200lb spring in the LR,
150 in the RR,
650 in the LF
800 in the RF

45 bilstien on LF
55 bilstien on RF
94 afco on the LR
95 afco on the RR

I have the corner weights in front of me now:
650 LF
485 RF
735 LR
643 RR
I will also add the angles on the bars as I have an angle finder now.
The Panhard bar is at 8 degrees down from frame to rear.
Torque Link is 17 degrees
Swing arm on Zlink is 10 degrees up
Rear bar on z is 9 degrees down to frame
upper bar on 4 link is 17 degrees up
lower bar on 4 link is 6-7 degrees up

The stagger is even on the front and 2.5 inches on the back. The rear end is sguare and centered. the tourqe bar is out of adjustment as I noticed last night that the spring is floping around. rim offsets are 2in. on the RR and 4 in. on the LR. Thanks for the advice.

[This message has been edited by uforacing51 (edited July 02, 2003).]

BigBlueFord
Member
posted July 02, 2003 11:57 AM
I can't really help much with the 4 bar setups. We run a swing arm.

But, you might want to consider increasing your cross. It's only about 48.5% now try raising it to 51%. That'll tighten the car up some. You may end up going even higher on cross, 52% - 53% isn't unreasonable. When adjusting the cross I'd suggest putting turn is the RF, LR and taking the same amount of turns out of the LF, RR. Based on the springs your running you'll probably want to only put a half turn in the fronts to a full turn in the rears. If you've got electronic scales you can do it by weight, 10# heavier RF, LR and 10# lighter LF, RR. That will maintain your ride heights.

Keep us posted on our progress.

Good luck! ! !

[This message has been edited by BigBlueFord (edited July 02, 2003).]

BigBlueFord
Member
posted July 07, 2003 01:05 PM
What's up? Have you run the car?



uforacing51
Member
posted July 07, 2003 01:41 PM
I decided to give the family the 4th because they have been really good about me racing and two tracks ran big shows against each other and I figured I wouldn't lose that many points because the track I run at didn't do a two night show for the big bucks. That is where all the fast guys went and I only lost 3 positions. Plus I discovered a slew of bent steering parts and have all new ones arriving today or tommorow. I will be at it friday and let you know what kind of luck I have. Thanks for all your interest.


rocket36
Member
posted July 08, 2003 06:34 AM
try lowering the bottom 4 bar angle.
when it is pointed up it will loosen corner entry as it is already in its arc pulling the rear end forward dramatically.


uforacing51
Member
posted July 08, 2003 04:30 PM
Harris suggested putting it back also, and moving the top one up one hole. going to try it this friday.


dirtywrench13
Member
posted July 13, 2003 09:34 AM
what type of torque link do you have and how does it mount and where?i have an afco type and it's on a grade 8 all thread with jam nuts on the axle mount,hitch pin and spacers on the front. front pointing across the center line of the car and adjust the fear to compensate for throttle push.1/16 of an inch at a time as you get it close.start it in the middle and go to the right,when the throttle push goes away start relaxing and enjoy the race!


uforacing51
Member
posted July 14, 2003 08:15 AM
Raced on Friday the 11th and the results were much better. I ran 1st in the heat for several laps before spinning sideways in 3&4 and losing the lead. I spun in the main but the corners were drasticlly different. 1&2 were awsome and the others were bad... just really bad. I looked like a drunk wondering around looking for a grove to run in. LOL anyway I just need a way to get the car to work better on the dry slick and thats about it. everything you all suggested worked well. anything else for the dry slick conditions would be apperciated. Geez I hate dry slick. Hey dirtywrench I didn't see yours till I put mine up, let me get back to you, I think its a harris or afco one. its alot to the left.

[This message has been edited by uforacing51 (edited July 14, 2003).]

uforacing51
Member
posted July 20, 2003 09:33 PM
Raced on Friday the 18th, runs ok in the heats but when the track goes Dry slick, it still could stand to be tighter. what can I do? I am out of ideas and getting fed up with the track?


dirtywrench13
Member
posted July 20, 2003 11:31 PM
dont forget the old stand by's like moving the tires left or right,pull the right rear under the car and stick the left rear out.adding a round or two can do it,or the angle on the panhard bar can be raised or lowered also.i'd try the side to side adjustment on the pull bar,go to the right just a little,about 1/8th of an inch.


BigBlueFord
Member
posted July 22, 2003 07:31 AM
I'd go with what dirtywrench13 said. Give it try and get back to us.

Did you get any details on your pullbar yet? Spring rate, etc.

spde
Member
posted July 22, 2003 06:06 PM
If you cann't get it hooked up on the dry let me know I'll sell you a new Pierce car. It will hook up when its dry!! Sorry I couldn't help myself. I try reversing the front springs 50-100# split. This will let the car fall on the rf. Then try softer shocks, all the way around. This lets the weight transfer faster. A heavier pull bar spring will hook up faster off, might try a 1200#. It works quite well. gl ltr kevin


#13 mod
Member
posted July 22, 2003 09:43 PM
The key to getting your car to "hook" is body roll. Remember you can over hook. Here is what I have found, if the track goes dry slick, or takes rubber try a #150RR with a 94 shock and a #175LR with a 93-5 shock. 77's on the front to slow down roll on entry. this has worked well for our harris mod. now on a heavy or rough high grove track, go with a #175RR with a 95 shock and #200 with a 94. 77 are still good on the front maybe try a 76 on the RF.


uforacing51
Member
posted July 23, 2003 09:40 AM
Opps, I forgot about the pull bar! I will get those today.


uforacing51
Member
posted July 26, 2003 08:52 PM
I can't determine what spring is in the tourqe link, however the former owner thinks it should be a 900 lb spring and a 90/10 shock. I ran the car last night and used 6.50 gears. what a difference! the car was turning before I got to the corner, I was able to power back up quicker and I didn't have to use the brakes as much. I was rapping the engine hard though and didn't like how much I was asking of the car, thinking of a 6.33 for next week. I am wondering, why does a different gear that pulls harder make such a difference in the way that the car handles? can anyone explain that to me... what an uplifting experience thou... two weeks ago I was ready to quit, now I am thinking we are closer to what we have been looking for. By the way the body roll was much different this week, like there was alot more, and I see how much difference it makes in how the car sticks in the corners. I felt that it would stick in either corner this week where last week the track conditions were the same and we couldn't get it to bite in one corner. this week we just didn't want to blow it up or I think we could have really ran well.

[This message has been edited by uforacing51 (edited July 26, 2003).]

dirtywrench13
Member
posted August 03, 2003 11:16 AM
well maybe i missed something or u never told us what size track u are running,or what tires u are using.we are on hockey pucks,1/4 mile,and using a 5.83 gear turning 6200 to 6800,and we wish we had a 6.10 or so.the engine comes to life at 6800.but theres no bottom end to it.(no torque) my best educated answer is that your engine has the torque and horses to carry the car, but your wheel speed was way too fast.changing gears allowed you to slow thi tires down enough to let the rest of the car do its job.it sounds like your getting close now,so slow your changes down to a little at a time, try a gear tonight, and a shock change for the feature possibly,depending on how the car reacts to the gear change.may even want to move the pull bar to the right a little to compensate for a throttle related push comming off the corner.patience is the key here!


uforacing51
Member
posted August 05, 2003 09:14 AM
Didn't make any changes for the night of Aug 1. I liked the way the car handled for the night so the only change I plan on making this weekend is the moving of the tourqe link. I am borrowing a set of 6.33 gears to try because the 6.50 seem like they are too much at times. Was hitting 6800 rpm consistently last friday. 406 engines don't like to hit that kind of RPM all the time. I am not sure when I will try the gears as too many changes will leave you wondering what fixed the problem. I ran with the leaders for 7 laps last week before they took off. I am also working with a really good driver to improve my driving.
Track is a 3/8 mile, we run Hoosiers. I have 650 in the car now and may try 633 soon.

[This message has been edited by uforacing51 (edited August 05, 2003).]

uforacing51
Member
posted August 07, 2003 10:30 AM
Found a small problem, two of the rockers had pushrods through them, hmmm, no wonder the engine wouldn't run at full speed and seemed to lay over... LOL


dirtywrench13
Member
posted August 10, 2003 08:46 AM
SOUNDS LIKE 6.33 GEAR SHOULD BE THE RIGHT GEAR FOR YOU,BUT WHAT KIND OF CHEAP ROCKERS ARE YOU USING?GOOD ROLLERS DONT COST MUCH WHEN YOU LOOK AT RELIABILITY.BE CAREFULL ON THE PULL BAR ADJUSTMENT,TOO MUCH WILL DIAL YOU RIGHT OUT TO LUNCH IN A HURRY!


uforacing51
Member
posted August 15, 2003 08:37 AM
Last week was a lousy weekend, nothing went well. Engine ran really good, so that was the only positive. Can't run roller rockers on a 406 here. I lowered the ride heights for this weekend and lead the right side by a quarter of an inch. Thats it and will let everyone know how it turned out.


uforacing51
Member
posted August 17, 2003 10:49 PM
Well, I am about to give up. I have not finished better than last of the running cars so far this season. I can not get a set up under the car that will work on a dry slick track. Every week I think I am doing something that should benifit the car and instead I spin the car and end up getting lapped and spend the rest of the race trying to just finish and save some face. I will most likely pull the rear in favor of something else that isn't so comlicated to get to work. I see others getting all kinds of bite on a track that goes dry slick all of the time and the same guys are winning every week. I give up!


Dman
Member
posted August 19, 2003 01:20 PM
O.K
I run on the same track, I run a 355 and a 620 gear. When I ran a 406 I would use a 583 gear. When I watched you run this weekend it looked like the car had a bad push, then you would hook the car and this is why you are thinking the car is loose and not hooking up. I also believe you were driving the car to deep into the corners. A little smoother style, let the car roll thru the corner and and get your gears down will help alot.



#46
Member
posted August 19, 2003 03:52 PM
racinruss, that would be Russ Wolfe I presume. I think the 406 is destined for the chevelle that sits in my garage. I had planned on getting a spec engine for next season. The gear issue is something that I have learned a ton about this season, I sure realize now that gears will change much more than the RPM. I didn't see you there on friday the 22nd. I talked to Doug Martin and the former owner of the car and both thought that all of the rear steer that comes with a 4 bar car might be the problem that has had me so confused so far this season. I moved the top bar down as low as it goes and lead the RR forward a quarter inch, the LR still creaps forward about a quarter inch thus creating a neutral rear, I ran my heat race and lead every lap except the last 1/2 a lap, finishing second. Just when you think its safe to just go ahead and give up, you do something right. Another learning experience! It has created some excitment for us heading into the championship night and the supernationals. I will try to get ahold of the article and read it as I think my driving needs some work as well. I thought I was just using the cushion to get off the corner but sometimes you guys sitting and watching see more than the guys driving. thanks to all who keep me from just throwing in the towel, although you know us racers, we all say things that we don't really mean.


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