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Author Topic:   3-link help
jay116
Dirt Freak

Total posts: 428
posted December 15, 2004 07:48 PM  
no........a lot of mods are going to a solid top link even when the rules allow for a spring bar, or rubber biscuit. I think if you put a solid link on the top it will be as least as good if not better than with the spring bar. It really depends on the feel of the driver but there is nothing wrong with a solid upper link.

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"son this aint a car its a racin' machine."

boas51
Dirt Maniac

Total posts: 190
posted December 16, 2004 09:30 AM  
my personal opinion of the benefits of the torque absorbing upper link vary from average. i do not feel that the spring or rubber cushioned upper link helps cushion the torque to the tire contact patch as much as it allows a huge amount of dynamic wedge adjustment when locating the springs opposed to each other, one in front one behind.
i personally run a solid upper link, most of the time.

mod70
unregistered Total posts: 190
posted December 16, 2004 05:37 PM           send a private message to boas51   Edit/Delete Message   Reply w/QuoteBBBBBB
The whole reason for the spring loaded top link is to absorb some of the power being put to the rear wheels. In high HP to weight cars it is very easy to 'shock' your tires when you jump back into the throttle, so the spring allows the rear to rotate a bit more and have some give to it.
A solid top link will put the power instantly to the rears, and will hook up faster, when conditions are right, than a spring arm. The time when it would hurt you is on a dry/slick track when the extra forgiveness of the spring will help.
I have switched to a solid top link in my 3-link and have noticed a big difference when the track is tacky. When it starts to dry out you have to be eaiser with the right foot to maintain traction. good luck.

jay116
Dirt Freak

Total posts: 428
posted December 23, 2004 09:33 PM  
As for the top link use a solid bar and get the rubber bushing type rod end on each end this will allow some give upon throttle application liks a rubber bushed bar or a spring bar.
As far as a J-bar, I would try to get it to fit into the chassis or you could fab a mount to the center of the rear housing and use a straight bar from the left side of the chassis to the rear. You can get a steel front mount and use the threaded portion and weld it on a bracket to the center of the rearend in the same location as if it was in the front of the housing.

UFnARacing
Dirt Maniac

Total posts: 179
posted December 29, 2004 10:49 AM  
OK, now you got my curiosity up. Imagine that you could just as easily use a J-bar in front or a long bar in back, what would be better? I know the J-bar is supposed to be quicker to react, but with all solid links, what does that matter?

Just wondering which bar you guys would rather run and what the difference would be?

Don't want to jump in on your post Jay, but my rules are very similar on my pro stock.

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Ego Racing
Dirt Forum Champ
Total posts: 724
posted December 30, 2004 11:08 AM  
Quicker reaction is sooner bite off of the corner. A track bar places the weight onto the tire the bar is mounted closest to. A long bar will load the right rear tire more when the body/weight rolls onto the bar, a J/bar plants the weight in the center of the housing and a short bar plant the left rear more. This is with ANY rear linkages. solid links cause it to happen sooner as there is no wasted movement being absorbed in the rubber biscut or mounts.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted December 31, 2004 12:20 AM  
quote:
Originally posted by Ego Racing:
A track bar places the weight onto the tire the bar is mounted closest to.

This is dependant on the angle of the bar. On a relatively flat bar the jacking forces are negligable. On an underpowered class of car you typically want to keep any jacking forces, lateral movement, and roll steer to a minimum.

If you look at the spring rates that are run on the top links of some mods and the torque vs available traction you'll see why a solid bar won't hurt you especially on a slick track. All the spring create is wasted energy. The worse part is that they do less as the track gets slicker because there has to be traction for the spring to compress. As far as the typical lr in front rr behind spring setup to gain diagonal on the gas, you can still accomplish that with a solid bar. The geometry of the top link controls the pinion angle as the suspension rises/squats, so you can still have a change in diagonal without a spring loaded toplink.

Short version:

Run a solid top link and longest possible panhard bar.


WPP
Dirt Freak

Total posts: 451
posted December 31, 2004 08:15 AM  
Good point wfo i never have ran a 3 link but i have seen guys run a soild upper bar with them but the bar did not have much angle and these cars were hooking up on the slick foot control i guess i was thinking about trying with the clamped swingarm and should the soild bar be short or long.

WPP
Dirt Freak

Total posts: 451
posted December 31, 2004 08:33 AM  
wfo if i did go to the solid bar with very little angle could your car still lift some i run alot of gear and my engine has good torque last i would start out with no preload on a traction track with my pullbar then then the track got slick i would add a 1/2 of preload with a 1000/ 1600 progressive spring and it would calm the car down less spring it would jump around a lot so does the lift in the car happen with angle or spring rate i would like to here your thoughts

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted December 31, 2004 09:24 AM  
I would not run a solid bar... It shocks the rearend and does not let the rearend rotate... A lot of people on a 3 link try to run so much pullbar spring that it hurts them, run a 400/1000 progressive spring, and if your wanting to run a long panhard bar your going to need a lot of angle and left rear... i'd run a shorty panhard or even a j bar

WPP
Dirt Freak

Total posts: 451
posted December 31, 2004 11:55 AM  
Looking to be smooth here i can see were a solid pullbar could work you have to watch the angle and be smooth on throttle and the same with a 400/1000 spring to me the softer spring will get the car up in the air and with a lot of angle and with the angle can get the car bad on entry what happens when the pullbar flattens out with spring or no spring i figure wfo can answer this i have never ran a 3-link but i do no what i saw and it was on a slick track a 3-link with a solid pullbar with little angle maybe 10 degrees and he was bad fast but we are here to learn keep this thread going i just love this forum

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted December 31, 2004 03:55 PM  
I ran about 25 degree's downhill with a 700 pound spring... Trust me, If the solid bar was faster or better we would be on it. When you can get your car to stay on the spring more that is like traction control, it uses up the force that wants to make the tires buzz and only allows what's needed to the wheels.

Racer X
Dirt Freak

Total posts: 256
posted December 31, 2004 06:38 PM  
We thought about running a solid bar for the the third link. We thought about using a steel swedge tube,would that be strong enough of do we need a something stronger?

wfoondirt
Dirt Forum Champ
Total posts: 505
posted January 01, 2005 09:22 AM  
quote:
Originally posted by Racer X:
We thought about using a steel swedge tube

I don't use swedge tubes for anything mission critical. I make all my radius rods from 4130 and use tube adapters.

WPP,
I could write a book on this, but I'll try to answer your questions without wandering too far off topic. Also no offense but sentances/punctuation would make your posts easier to comprehend.

quote:
and it would calm the car down less spring it would jump around

More than likely you needed more spring to start with. Theoretically the more available traction there is the less compiance you need, eg. more spring rate, which with a progressive spring means more preload. When the track is tacky you probably kept the spring in a stiffer range so you didn't get the extra "jumpiness", but once it dried out the spring wasn't compressing as much so you were getting more occilation.

quote:
so does the lift in the car happen with angle or spring rate

The angle/location of the top link is what determines anti-squat (lift). The spring rate has some effect due to the travel changing the angle but that is typically neglegable.

quote:
what happens when the pullbar flattens out with spring or no spring
I'm a little confused on your whole second post, but I think you are wanting to know how taking angle out of the top link effects the handling.

quote:
Looking to be smooth here

Good. Its good to see someone that actually wants to become a better driver and not expect the car to cure their downfalls.

To try and answer your second post, the less angle in the top link the less eratic the handling and the easier the chassis will be to tune. By taking angle out of the top link you will be lengthening the SVSA length which will reduce the brake hop on entry (you may not notice it on dirt as a hop but it is still a loss of traction). You will be giving up some anti-squat but most cars today have so much built in (upwards of 400-500%) that you won't notice, especially if you are easy on the gas. I never ran over 15 degrees other than for testing, typically in the 8-12 degree range. I also ran the top link closer to the rear end than most.

quote:
uses up the force that wants to make the tires buzz and only allows what's needed to the wheels

Voodoo. Its impossible to match the spring rate to the availble traction and it also has a dimisishing effect as the track gets slicker which is what most often happens during the feature on dirt tracks. On a slick track (when the spring bar is supposed to be of the most benifit) you typically won't compress the spring enough to make a bit of difference. Even if you say your travel indicator shows 2-3 inches it isn't compressing when you want it to. That max compression usually occurs during takeoff or if you hit a tacky patch (which can be heard by listening to the motor, if you listen to the car especially on a tacky track you will hear the difference in the motor as the spring bar occilates as traction changes).


[This message has been edited by wfoondirt (edited January 01, 2005).]

WPP
Dirt Freak

Total posts: 451
posted January 01, 2005 09:37 AM  
Thats what i was trying to say when the pullbar flattens out the lower links will put more drive in the tires

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted January 01, 2005 10:56 AM  
you guys keep your solid top links and long panhard bars... we'll keep on winning on our spring bars and 10 inch panhard bars...
wfo where do you race??? i see your from illinois...

wfoondirt
Dirt Forum Champ
Total posts: 505
posted January 01, 2005 06:51 PM  
quote:
Originally posted by Xtreme12x:

wfo where do you race???

I've been about everywhere, home tracks are Spoon River and Farmer City.


Racer X
Dirt Freak

Total posts: 256
posted January 01, 2005 07:38 PM  
Thanks for the website wfoondirt didn't know they had anything like that,those will work great.

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