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Author Topic:   z-link reversed
washeduptoo
Dirt Maniac

Total posts: 155
posted September 07, 2004 09:17 AM  
I believe I've read somewhere on this forum where someone reversed the z-link. Was this done with the chassis having 4-link brackets or did you use the z-link brackets and have the top forward bar angling down and the rear bottom bar going up? Thanks, for the information if someone has any knowledge on this. Thinking about this for next year.

dirtywrench13
Dirt Freak

Total posts: 324
posted September 07, 2004 11:14 AM  
MY DIRTWORKS HAS STANDARD STYLE Z-LINK, BUT I'VE SEEN ON THE CRAFT MODS THAT THEY USE THE UPPER 4-LINK, ANGLED UP, AND THE LOWER LINK GOES TO THE REAR OF THE CAR.
IT'S JUST THE OPPOSITE OF WHAT I TOOK OFF THE LEFT SIDE OF MY CAR. MY LOWER ANGLED UP AND FOREWARD, AND THE REAR WAS THE UPPER, AND WAS FLAT.HOPE THIS HELPS!

washeduptoo
Dirt Maniac

Total posts: 155
posted September 07, 2004 11:25 AM  
My brother has seen this set-up on the kraft cars earlier in the year at a USMTS race and I was wondering how it was set-up and what advantage this would allow vs. the regular z-links. That means we will have to have some brackets made. Thanks

zeroracing
Dirt Forum Champ
Total posts: 1875
posted September 07, 2004 11:38 AM  
a regular z link wil gain thrust as the car rolls over, and free it up, more bite on rr. the other way like you talk about would tighten up the car on the gas, loose bite.

STICK01
Dirt Maniac

Total posts: 164
posted September 07, 2004 01:26 PM  
ask some of the Rocket Late Model guys...that run this setup in the black...no need to worry about side bite as it pushes the RR forward a ton and makes it extremely tight on the dryslick...but appears to only work if you are LR clamped in front and know how to set up the rest of the car to use what you stumbled into.

STICK

washeduptoo
Dirt Maniac

Total posts: 155
posted September 07, 2004 03:16 PM  
What do you mean when you say, know how to set the rest of the car up to meet this z-link set-up? Is this going to drastically(sp) alter the set-up as far as springs and wts. at the wheels? My brother also saw a car in Ark. with this set up. The spring is behind on the rr with a swing arm and clamped in front on the lr. What length swing arm would you use going to the back. Thanks again for the help and the knowledge.

STICK01
Dirt Maniac

Total posts: 164
posted September 08, 2004 07:40 AM  
It has a tendency to make the car do things that you normally would not see, or have to change your car to get it to work correctly. Like RF springs, RR spring (big time), LR "wedge", and shock valvings...etc.

It is not an out of a box type setup, it takes alot of work to get it right and can be a handfull to drive.

[This message has been edited by STICK01 (edited September 08, 2004).]

washeduptoo
Dirt Maniac

Total posts: 155
posted September 08, 2004 08:51 AM  
Thanks, I thought that was what you were refering to. Maybe we can contact the car in Ark. and get a base set-up from him, if they decide to go that way. Thanks again.

#13 mod
Dirt Full Roller

Total posts: 72
posted September 08, 2004 06:12 PM  
If this setup take alot of time to develop and can be a hand full to drive, is it worth the extra work and time not being fast? I guess will it really payoff in the end if you get it working right?

washeduptoo
Dirt Maniac

Total posts: 155
posted September 08, 2004 07:37 PM  
You are probably right on the time and effort, but don't you keep trying things to get better and hopefully you will soon or later match the chassis set-up with the drivers ability and comfort? It's a challenge and I believe that is what racing is about. Thanks

zeroracing
Dirt Forum Champ
Total posts: 1875
posted September 09, 2004 06:13 AM  
How would it push the rr forward, if the rr rearward bar is almost level and the upper bar has alot of angle up to front, then when the car rolls over onto it the car will make the upper bar loose angle, push the top of rearend backward, and if the lower bar is level or almost level then it will loose angle till it goes to upphill to front angle which will make it pull the rearend backward. so really wouldnt the car have more rearsteer?
if sounds like your taking alot of the rr drive out of the car, which will make it a ton tighter, with alot of rr spring in the car seems like your trying to free it up off the corner, becuase the bars have it too tight.
i am not trying to tell people not to do this, but it seems like to me alot of work to get the car to handle right, and less traction than a regular z link set up. you may be wasting time, maybe not, but i think more time could be spent on the lr four link with better results.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted September 09, 2004 07:23 AM  
why is everyone worried about traction jeez
get the car going thru the corner right and the traction will come to you

Kromulous
Dirt Forum Champ
Total posts: 796
posted September 09, 2004 08:15 AM  
If it was set-up right it would push the rear-end fwd, i think thats the key. Lower bar running aft, at an upward angle, and the upper bar running fwd at downward angle would indeed drive the rearend fwd.

Only on chassis roll thou, so this type set up with low roll centers and the right shocks (3 wheeler car basicly) could very well work. As it starts to come up off the corner and the LF tire started to come up the rear end would begin to "square up" in the car and should make the car drive off hard and straight. Static Axle lead would be another key to utilizing this set-up i would think as well.

Although i can see major issue's getting the car set-up to go in well. As well major issue's with a "out of the corner" push or understeer, once the rear end squares up you better have enough stagger to keep you turning or aimed straight down the shoot or your gonna be pushing to the wall coming out.

Great idea, never seen it run before thou. I've been thinking about it the last couple days. Think we may try it next spring in practice on a spare rig.

STICK01
Dirt Maniac

Total posts: 164
posted September 09, 2004 08:22 AM  
Zero...the rear bar is where all the angle is at...from the birdcage up to the frame at about the same angle as if it were the top front bar...then the top upper bar is level...and not necessarily at a positive or negative angle to the birdcage. make better sense? It "scotches" up the Right side in the corner making the car tight and really drive through the black when there is limited traction...but then again I have only seen this work on a Rocket LM where they had dual shocks and springs on both LR & RR, and a pull rod...so I do not know if you could get this to work on a mod that is not capable (rules) of having the same type of setup (dual shocks/springs)

STICK

washeduptoo
Dirt Maniac

Total posts: 155
posted September 09, 2004 09:32 AM  
Probably one of the reasons their are thinking of trying this is because a guy with the same chassis is running this set-up and is doing well. If it was me, I probably would run something without that 4-link, but then again, trying to figure out things is what it is all about. I wished we could try this by years end, so I could let yall know the problems or solutions this causes. Right now the car has a ripped out drive shaft loop and bracket and other bent problems from pull bull breaking the loop out. Do yall ever have this problem? Thanks

zeroracing
Dirt Forum Champ
Total posts: 1875
posted September 09, 2004 10:48 AM  
if the front bar is angled down to frame and the rear bar is angled up to back, the car will have a neg thrust angle and not have any drive, hince the super tight cars, driving off the lr only.

dirtywrench13
Dirt Freak

Total posts: 324
posted September 09, 2004 11:44 AM  
I MUST HAVE MISSED SOMETHING, BUT THE Z LINK A SAW LOOKED AND ACTED JUST LIKE A 4 BAR SET UP.
ALL THEY HAD TO DO IS FLIP THE LOWER BAR AND IT WAS A 4 LINK.

MikeN
Dirt Full Roller

Total posts: 27
posted September 09, 2004 12:05 PM  
Correct me if I'm wrong hear, but I would think that the Z that dirty just described would be the only way it would work. Uphill
with the top bar to the front, and probably level or slightly downhill to the rear with the bottom, with the spring in front. Also, I would assume that the bottom for this would want to be long.
Also, what are we trying to do? Get the forward bite of a 4 link right side, and limit roll steer?

Kromulous
Dirt Forum Champ
Total posts: 796
posted September 09, 2004 03:07 PM  
They way i understand Thrust angle is merely the direction the rear end wants to travel (thrust) vs the centerline of the car (or to be proper the CL of the wheels in relation to each other, considering offsets, track width etc)

Explanation of thrust angle i found on the web:

Thrust angle is defined as the deviation between the bisector of the total rear toe angle of the vehicle (the thrust line) and the vehicle centerline.

This is a tad more complicated than it sounds.. the centerline of the vehicle is defined NOT by the axle midpoints, but rather by the position of each of the vehicle wheels. In an extreme example, imagine a car which is narrower in the front than in the rear. If you draw lines connecting the tires on the left side of the car (front & rear) and the tires on the right side of the car (front and rear), the lines will intersect at some point in space out infront of the car. Bisect the angle formed by the intersection of these lines, and you will have the centerline of the vehicle's wheel system. Usually this is very close to the chassis centerline (as measured by the axle midpoints), but it's not exactly the same.

Next, to determine the total rear toe angle, the toe angle for each rear wheel is determined relative to the wheel system centerline. The sum of these angles is the total rear toe angle. If you project lines parallel to the face of each rear wheel, the two lines will intersect somewhere at a point unless the wheels are exactly parallel to each other. The angle at which these lines intersect is the total rear toe angle. Bisecting this angle with a line yields the thrust line of the vehicle. This is the direction the two rear wheels of the vehicle would travel if allowed to just roll along.

Finally, the angle measured between the vehicle's wheel system centerline (as determined by the position of all four wheels) and the thrust line of the vehicle (determined by the pointing direction of the rear wheels) is measured as the thrust angle.

Is this definition of thrust angle proper or are you referring to something else entirely, i'm confused.

washeduptoo
Dirt Maniac

Total posts: 155
posted September 09, 2004 08:34 PM  
They believe the car has too much roll steer and that is what they're trying to reduce with the reversed z-link. The bottom link is a swing arm with a spring on it going to the back of the car about level . The top link is angled upward to the frame like a 4-link design.

dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 09, 2004 08:57 PM  
Not to add confusion but D&M has a rev z link that has been on there cars for years. The upper bar forward and about 2xs longer than the lower bar going back. Now with the thrust angle and bar angle it will all depend on the placement of the bar on the cage....like right off the housing and the other 6 or 7" away....now you have the whole index thing to worry about. I can tell ya this the one i had had no movement for the bars. I have been thinking about adding some mounts this winter to try somthing like the flop of the lower 4 bar and some extra holes in the cage to mount to....

Kromulous
Dirt Forum Champ
Total posts: 796
posted September 10, 2004 08:54 AM  
Dirtracer14, you have one of these cars? Does it work, does it have good fwd bite etc? Tell us more about it please, how it drives, spring rates etc.

I'm at work and get bored and like to think about race car desgins & sketch up new desings while i sit around and wait hehe.

dirtywrench13
Dirt Freak

Total posts: 324
posted September 10, 2004 12:25 PM  
WASHED
THE Z LINK I HAD WAS THE SAME AS THE "TYPICAL" DIRT WORKS STYLE,WICH YOU CAN DOWNLOAD FROM THEM AS A PDF FILE AND PRINT. I'VE BEEN THINKING ABOUT PUTTING THE SAME AS THE WALLY CARS USE TO SEE HOW THEY WORK.
THE WALLY I'M REFERRING TO WON SEVERAL FEATURES LAST YEAR, BUT HIS NEW CAR IS ON A 4 LINK THIS YEAR. I'M JUST LOOKING FOR A NEW WAY TO GET BETTER BITE.

tornadotip
Dirt Roller

Total posts: 5
posted September 10, 2004 03:49 PM  
The set up you guys are talking about is a 6link, they are D&M type of cars, I have raced one for years and still using one today. They are a little hard figure out but one you do they are fast.

rrrrick
Dirt Maniac

Total posts: 192
posted September 10, 2004 05:25 PM  
East Coast Modifieds ran that set-up 20 years ago, not sure what they run now. The only difference being the lower arm of the Z was also the torsion arm going back. Some guys even ran a spring bar on the right side upper link to get the R/R to go forward on the gas.


dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 10, 2004 06:58 PM  
The car i had was a 6 link car and there was more to it then just floping the bars...it had a separate birdcage that the spring abd shock floated on. I have a site with some pics .....if you want i will try and dig em up.

washeduptoo
Dirt Maniac

Total posts: 155
posted September 10, 2004 06:58 PM  
Tornado or dirtracer14
Doesn't Ron Jones still drive the house car for D & M? Does it have the reversed z-link? Maybe the USMTS will get close enough again and I can look at the Kraft cars or maybe a D&M car because I don't know of anyone close by the runs these cars. Do you have good forward bite and side bite with your set-up? Thanks everyone for their thoughts and suggestions.
Kromulous, If I find out any information about springs and stuff,do you want me to post it?

washeduptoo
Dirt Maniac

Total posts: 155
posted September 10, 2004 07:02 PM  
Dirtracer14, I would love to have some pictures of it. Thanks, I must of been typing the same time you were.

dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 10, 2004 07:02 PM  
yes as far as i know he does still drive for em...he was at a show here in june.....i think he was running a rev z link lr and a 4 bar rr......but they were talking about a new car he was going to. I had tons of side and forward bite...it really liked the faster tracks...not the stop and go. I can tell ya this my 4 bar with the pogo stick has more forward bite than any car i have run!!!

washeduptoo
Dirt Maniac

Total posts: 155
posted September 10, 2004 07:05 PM  
Dirtracer14,
What is a pogo stick?

dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 10, 2004 07:05 PM  
I also found some i put on the web from the first year i had it. http://www.geocities.com/dirtracer_14/dnm1.html http://www.geocities.com/dirtracer_14/dnm2.html http://www.geocities.com/dirtracer_14/dnm3.html http://www.geocities.com/dirtracer_14/dnm4.html http://www.geocities.com/dirtracer_14/dnm5.html http://www.geocities.com/dirtracer_14/dnm6.html http://www.geocities.com/dirtracer_14/dnm7.html http://www.geocities.com/dirtracer_14/dnm8.html


dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 10, 2004 07:06 PM  
Check pm

washeduptoo
Dirt Maniac

Total posts: 155
posted September 10, 2004 07:15 PM  
Thanks, dirtracer14 for the pictures and the information, I know what a pogo stick is now.

washeduptoo
Dirt Maniac

Total posts: 155
posted September 10, 2004 08:49 PM  
dirtracer14 check your pm

Kromulous
Dirt Forum Champ
Total posts: 796
posted September 11, 2004 09:29 AM  
Now that is a fasinating rear suspension set up! Gotta question thou, is the birdcages floating or fixed? also are there 2 birdcages working indpendently of each other?

Thanks for the pix, thats some interesting stuff to think about now.

washeduptoo
Dirt Maniac

Total posts: 155
posted September 11, 2004 09:41 AM  
He told me that they are floated, nothing is clamped to the housing.

dirtracer14
Dirt Forum Champ
Total posts: 1261
posted September 11, 2004 06:34 PM  
Yes they are both floated nothin clamed. The z link controls the rear and bite the other just floats the spring and shock. I have way better pictures of it from when i was rebuilding it one winter....just have to find em.

dirtywrench13
Dirt Freak

Total posts: 324
posted September 13, 2004 12:13 PM  
IT'S A Z-LINK LIKE WALLY USES, BUT IT HAS SWING ARM REAR MOUNTS. THE SWING ARMS ONLY PURPOSE IS TO LOCATE THE SPRINGS.

HOW FAR OFF AM I ON THIS?

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