TJ Double Triangulated 4-link FRONT question.

[lukethedork]

Hey guys. Basically I have done a quick mock up for my front 4 link. This will be based off of the Poly Performance 3-link kit and hopefully turned into a 4 link.
First, how do my numbers look?



The next question is my real question.
I cannot get full droop on the (USA) Passenger side due to the upper link clashing with my exhaust manifold.
What I can do is get about 7" of vertical axle travel and a little more than that while articulating.
With some quick measurements and guesstimates I came out at using around 12" of shock travel on the Passenger side and the full 16" of shock travel on the Driver side.

My question is if I limit strap the center for 7" and limit strap the Passenger side for 12" (at the shock) will this give me any particularly wierd handling characteristics since the Driver side will be using all 16" of shock?

Luke.

[hurleygo3]

There is a reason most go with a 3 link in the front of their jeep. Why limit travel just to have a 4 link. 3 link it and get all the travel you can without having to limit it.

[bbaxter51]

First you need to build the front link setup with the suspension at full compression or "full stuff". Then from there, if you can make everything fit, you'll be fine. Now you might need to move some things around, or if you can't make it fit without really cutting things up you're not comfortable with, then you do a 3 link like hurley said.

If I can squeeze a 4 link in the front of my CJ5 stock frame width, a 350 and tons, then believe me, it can be done on a TJ, but there are easier ways to do it. IE, a 3 link.

[lukethedork]

bbaxter51. Full compression will be the same whether I go 3-link or 4-link. It is only the droop that will be limited if I go 4-link.

Luke.

[tncrawler99]

Im not trying to tell you anything different but i went with a 4-link when i built my front end on my 99 jeep tj and it sucked i just finished mine in may and i turned around and revamped mine and went with a 3-link with balistic joint's and 1.5 dom uppers and lowers and i love it, If you want some pics i can shoot you some in a e-mail and check it out. The 4-link was really hard to stuff under there its alot of work.

[bbaxter51]

Originally Posted by lukethedork

bbaxter51. Full compression will be the same whether I go 3-link or 4-link. It is only the droop that will be limited if I go 4-link.

Luke.

In your earlier post you said that in a 4 link the upper link would contact the exhaust on the passenger side. So with a 3 link you'd just move the 1 upper to the drivers side leaving only the lower link on the passenger side.

I guess I'm confused on how your links will contact the exhaust on full droop rather than compression. Got any pics of your mock up?

[lukethedork]

I don't have any good pictures currently. But will post some tomorrow.
If you know your way around a stock TJ with 4.0 then you should understand what I mean.


In this picture, the Upper arm will be where the red dot is. Mounted around 1.5-2" Inside the frame rail. Now you have the X, Y, Z of where the upper frame mount is. You should see it is mounted above the exhaust. The axle side upper bridge will tuck up just beside the radiator fan shroud. This gives me a rearwards slope on the upper arms at full compression. Allowing for my 7" or so of droop before the upper arms level out and then begin to slope down towards the front of the vehicle and shortly after contact the exhaust.

Luke.
PS. To mount the upper control arm below the exhaust, would mean mounting it about 1" above the bottom of the chassis rail. This leaves me with almost no seperation at the frame side between the upper and lower mounts.

*EDIT* I want to add some more information.
The reason for having the upper control arm mount so low is that if I raise it then it will interfere with some objects that are sticking out of the side of the engine. To get past these objects I would have to shorten the arm from around 36" of longitudal length down to around 24" or less. I think this is too short for 16" shocks.
The mount currently sits above the exhaust but below these objects on the side of the engine. I believe one of them is the Oil Pressure sensor.

[titleguy]

I assume you are going to full hydro steering. You do know that if you are running a box and a triangulated four link you will have bump steer, right?

Not trying to be an ass or Capt. Obvious, but I thought I'd mention it.

[hurleygo3]

Originally Posted by titleguy

I assume you are going to full hydro steering. You do know that if you are running a box and a triangulated four link you will have bump steer, right?

Not trying to be an ass or Capt. Obvious, but I thought I'd mention it.

I ran a front 4 link on my DD for 3 years. It was one of the best driving jeeps I have ever owned. If he sets it correct there is no reason he should have to run full hydro because of bump steer.

[lukethedork]

Originally Posted by titleguy

I assume you are going to full hydro steering. You do know that if you are running a box and a triangulated four link you will have bump steer, right?

Not trying to be an ass or Capt. Obvious, but I thought I'd mention it.

Thank you for your concern. I am fully aware of the movements of the draglink.

Luke.

[bbaxter51]

Luke, I can see what you're talking about now. If you're concerned about the exhaust and upper link clearance, just do a 3 link. you'll be plenty happy with it. If you're sold on a 4 link, that exhaust will need to be moved. How much does it hit? I'll wait for some close up pics when you get them.

[willie87]

I jsut finished a 3 link on the front of my yj and ran the upper on the passenger side, if the tj is the same i had to loosen the head pipe at the header and rotate the pipe up just shy of touching the tranny pan to get the clearence i needed. At first it looked bad but ended up clearing fine

[blue p.o.s.]

why don't you just run the exhaust on the drivers side of the pan, like on a yj?

here's mine, (yes, i realize its flex pipe, i got sick of replacing expensive exhausts).


(this bent upper is a recycled lower off an old build)


the only clearance issues i've had is the drivers upper on the driveshaft. it's REALLY tight.

[nriver]

If you are planning on running the Poly brackets I think you will end up placing your frame mounts a bit farther back than your red dot. JMHO

This is where mine ended up. I tried to go farther forward, but the bend in the frame made me move them back.



I also played with the calculator and had all sorts of ideas based on it. At the end of the day, the mounts found their own position on the frame.

If you still go the 4-5 link way, this may help.
On your exhaust you can tighten up the passenger side exhaust and give yourself more room. In front of the oil pan, cut it and sectin out a couple inch section. Then you will have more room on the passenger side. May not be enough though. Something to look at. Thinking AEV has some instructions on their web site.

Good Luck

[customcreationsllc]

Luke Double check your numbers antisquat is based off your roll center and 28" seams very low. Someone correct me if I'm wrong the RC for the calc should be the RC of the sprung weight.

The only issue I see with limiting the travel would be with jumps crawling you will never have an issue maybe not get full flex but you will get over it.

The only time I see it being an issue is jumping the axle will droop more on one side than the other so landing one side will start compressing sooner so you will have that offset for the whole travel until it stabilizes at ride height again.
Then again most axles are heavier on one side than the other so full droop one side hangs lower than the other.

I would say run it.
Or reroute your exhaust.
~Justin

Originally Posted by lukethedork

Hey guys. Basically I have done a quick mock up for my front 4 link. This will be based off of the Poly Performance 3-link kit and hopefully turned into a 4 link.
First, how do my numbers look?



The next question is my real question.
I cannot get full droop on the (USA) Passenger side due to the upper link clashing with my exhaust manifold.
What I can do is get about 7" of vertical axle travel and a little more than that while articulating.
With some quick measurements and guesstimates I came out at using around 12" of shock travel on the Passenger side and the full 16" of shock travel on the Driver side.

My question is if I limit strap the center for 7" and limit strap the Passenger side for 12" (at the shock) will this give me any particularly wierd handling characteristics since the Driver side will be using all 16" of shock?

Luke.

[lukethedork]

Originally Posted by blue p.o.s.

why don't you just run the exhaust on the drivers side of the pan, like on a yj?

I feel I lose too much ground clearance if my exhaust is under my oil pan.

Originally Posted by nriver

If you are planning on running the Poly brackets I think you will end up placing your frame mounts a bit farther back than your red dot. JMHO
This is where mine ended up. I tried to go farther forward, but the bend in the frame made me move them back.

I have already played with the mounts and they will fit further forward, approx where my red dot was. I understand your issue with the frame though. But it is not a concern of mine.

I also played with the calculator and had all sorts of ideas based on it. At the end of the day, the mounts found their own position on the frame.

The mounts will not find a position of their own on my Jeep. Their only position will be where I place them.

If you still go the 4-5 link way, this may help.
On your exhaust you can tighten up the passenger side exhaust and give yourself more room. In front of the oil pan, cut it and sectin out a couple inch section. Then you will have more room on the passenger side. May not be enough though. Something to look at. Thinking AEV has some instructions on their web site.

Good Luck

Thank you, I have taken a look at this.

Originally Posted by customcreationsllc

Luke Double check your numbers antisquat is based off your roll center and 28" seams very low. Someone correct me if I'm wrong the RC for the calc should be the RC of the sprung weight.

I do not believe you are correct.

The only issue I see with limiting the travel would be with jumps crawling you will never have an issue maybe not get full flex but you will get over it.

The only time I see it being an issue is jumping the axle will droop more on one side than the other so landing one side will start compressing sooner so you will have that offset for the whole travel until it stabilizes at ride height again.
Then again most axles are heavier on one side than the other so full droop one side hangs lower than the other.

I do not see how having the axle heavier on one side would make it droop more on full extension, unless you are talking about the elasticity in your limiting straps.

I have played around under my Jeep and seem to have found something that will allow more articulation and still holds decent pinion angle / anti dive. The arms have to be shorter, uppers 30" and lowers 28". This also gives me greater angle of triangulation.

Currently I am waiting on a few little tabs and pieces before I finally weld it in.
I shall post up again when I have it completed.

Any more input would still be helpful.
Thanks,
Luke.

[blue p.o.s.]

I feel I lose too much ground clearance if my exhaust is under my oil pan.

i've never hit the exhaust on anything, it doesn't hang down like it looks like in the pics, it's higher and more protected than it appears. as you can see in the pics, my oil pan has taken more hits than the exhaust in 3 years of wheeling it like this. from the side, you can't even see it.

here's 1, i'll try to find a better one.


here's a more recent,


i'll take a better pic from the side tommorrow if i get a chance.

[lukethedork]

A quick update.

I cut my exhaust... Cut it right after it goes from 2 into 1 and also just before what i think is the O2 sensor?.
I also got the lowers tacked on both axle and frame side mounts.

Anyway, new settings are going to be very similar to this

Uppers Frame X 19.50, Y 13.50, Z 26.00
Uppers Axle X -1.50, Y 7.80, Z 22.25

Lowers Frame X 36.00, Y 13.00, Z 17.00
Lowers Axle X 4.00, Y 20.00, Z 13.75

Antidive -7%
Roll Center Height 18in
Roll Axis Angle 3 degrees

Axle seperation 8"
Frame seperation 9"

And triangulation is about 12 degrees on each Lower (for 24*)
And triangulation is about 15 degrees on each Upper (for 30*)

Any opinions or suggestions are welcome.

I will post up pictures and more info on the 'EXACT' placements when I have the uppers on.
Luke.

PS. The reason the axle side mounts are so low is that i am basing it off of 31" tires right now (15" rolling radius).

[moveaside]

Now your cooking easier to move the exhaust than other things. If your also set on four link you don't have to have both triangulated but at least a 45 degree on one. Don't get caught up on lengths of links as much as angles. The pic the guy above is posting with his kid driving is not bad at all. Some may nod at "well that would hang down why do I want that?" On a side note I will say there is a difference between the trailer pic and the kid driving I would guess he straps to the bumpers when towing.

Well here's a few reasons
1. His lowers are damn near flat. This setup will lift the tires up and over really well. Now listen to this statement before you argue go look at it in action on the rocks. His relatively flat lowers will lift the tire not the hood. How many times do you see a hood lift the shocks run out of travel and since the steep angled links can't raise the hood anymore the tire goes up and over.

2. Since we are dealing with the front people think it matters less. Well no look at reason 1. Now put yourself in the position of steep angles in the "REAR" going up a steep incline. Now "FLIP" it for a second and picture yourself going down an incline and having to back up. Same thing it will put forces to lift your ass end into the air.

3. Although he could have done more here the links are a relatively flat plane with skid plate. Hanging a bracket down is way different than having one line up with a link when encountering rocks. Ideally nothing touches but I've had both and I prefer a rig that will hook up easily on climbs and obstacles over high clearance. I have gone beside "maximum clearance" guy several times. I made it and he struggled there is a difference between designing to miss a rock and having the ability to climb one. No boasting just real world application.

4. The links are hanging down as low as the driveshaft this makes it harder in "MOST SITUATIONS" for the shaft to spin on a rock or come down hard on it and possibly shear the front output, bend the shaft, or shear the pinion yoke. Has this ever happened? Go wheeling enough and you've seen or been that guy its not fun.

Now another idea for you could be to outboard the uppers outside the frame rail behind the coils and before area where the big front tire almost contacts the frame. A good example was posted in the zuk section where a guy ran land cruiser axles underneath for searching purposes. Additionally nothing wrong with bumpstops to keep links from hitting especially since uptravel is less important than droop.
A real problem occurs when you think uptravel is more important than a link coming in contact with things like the driveshaft or oilpan.
That being said in your case those numbers are way too different for one side or the other thats not a live with it item it needs to be addressed like you are now.

[mlove6]

I just had my exhaust ran... poly 3 link front poly 4 link rear.

Stock y pipe but had to cut a few inches out so that it hugs the oil pan; and then then bends back towards the frame as it goes over the crossmember to clear the trans... pain in the ass but everything clears!

[lukethedork]

Well I finally got something sorted.
Uppers approx 23"
Lowers approx 30"

I'll get some proper pictures of it bolted in and the 4-link numbers later.
For now, here is what it looks like.







Luke.

[gtxracer]

Care to shed some light on the driver drop toy axle and some specs on your rig?
That looks like a fj80 front, which I almost slung under my TJ

Edit: just noticed you're in Australia I guess that explains the passenger steering box!

[lukethedork]

EVERYTHING you said is wrong. But you can be forgiven considering you were close enough.

Originally Posted by gtxracer

Care to shed some light on the driver drop toy axle and some specs on your rig?
That looks like a fj80 front, which I almost slung under my TJ
The front axle is from a Nissan Patrol Y61 (GU)

Edit: just noticed you're in Australia I guess that explains the passenger steering box!
I'm not in Australia. Me and the Jeep are in England, But the Jeep IS an Australian TJ (I shipped it over with me)

I have Nissan Patrol GU axles back and front on my rig. The front axle had to be flipped to get the diff on the correct side.
They have about a 9.5" Ring Gear and the CVs are alot stronger than stock FJ80 CVs.
They also have 3.75" axle tubes (not sure of wall thickness).
Tie Rod is behind the axle (and hangs very low).

Specs on the rig.
WB approx. 105"
Nissan Y61 (GU) axles
Atlas 4speed
ClaytonOffRoad double triangulated 4-link REAR - Coil spring and shock
Double triangulated 4-link FRONT - Air Shocks
Going to be running about 40s

No measurements/heights yet as it is not completed.

Luke.

[gtxracer]

Any updates on this Luke?

[JolietJames]

I'd like to see the links burned in at comp and droop. I'm building a TJ for the wife's trail rig in a couple months. Probably won't be done until fall but I assumed the front suspension would be the toughtest part of the build. I won't have the exhaust probs cuz hers will be a sbc.