Triangulated 4 link question

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siuauto

siuauto

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I am putting a triangulated 4 link in my 71 duster and I understand all the geometry for a 4 link but I am wondering if there is an advantage of having the top bars angle from the center of the axle to the frame rail over having the bars come from the axle to the center of the vehicle via a cross member. I would love to hear your thoughts!
 
IIRC streight 4 links need a panhard rod or a watts linkage to keep the rear centers under the car.

A triangulated 4 link uses the angled uppers to center the rear.

Benefits... Fewer parts.
Drawbacks... IMHO, the rear will be a little more able to move side to side
 
Dana67Dart said:
IIRC streight 4 links need a panhard rod or a watts linkage to keep the rear centers under the car.

A triangulated 4 link uses the angled uppers to center the rear.

Benefits... Fewer parts.
Drawbacks... IMHO, the rear will be a little more able to move side to side
Click to expand...

Thanks for your reply and I understand the difference and benefits of a parallel vs triangulated. My question is in a triangulated 4 link is there an advantage of running the top bars from the center of the axle to the frame over running the upper bars from a wider spot of the axle to the center of the vehicle.
 
Got it, sorry I misunderstood.

As for a single point on axle housing or body I don't see there would be much of any difference.

What is your intended use for your car.


Back in the 80's I read a lot on the subject designing a 4 link for my 56 F100, I went with Panhard Rod, I had the room.

There are a bunch of chassis tuning and building books on the subject.

By the way, there was a fast and loud episode where they built and ran a car up pikes peek and the video of the rear moving laterally was frightening. I do not recall the type of suspension other than it was a 4 link variant.
 
Dana67Dart said:
Got it, sorry I misunderstood.

As for a single point on axle housing or body I don't see there would be much of any difference.

What is your intended use for your car.


Back in the 80's I read a lot on the subject designing a 4 link for my 56 F100, I went with Panhard Rod, I had the room.

There are a bunch of chassis tuning and building books on the subject.

By the way, there was a fast and loud episode where they built and ran a car up pikes peek and the video of the rear moving laterally was frightening. I do not recall the type of suspension other than it was a 4 link variant.
Click to expand...

It's basically a street car that may go to the drag strip once in a while. I know parallel would be ideal but its a street car and I don't want to loose the back seat. As you know these A bodies are so tight under the there I am struggling where to position the top bars. The lower bars are going where the leaf spring perches are in line with the frame since it is mini tubed. I don't see how I can put the top bars to the frame since that is where the brake lines, fuel lines, E-Brake cables etc... are. The real reason I am doing this is to fix a problem from when the mini tub was done and leaf spring relo was done. The rear end is not sitting square to the frame. I have confirmed the "frame"/ body is square so I am not sure if the issue is in the perches or the axle mounting points. If I am going to tear it all out and fix it correctly I can't see doing all the work just for leaf springs.
 
To your question;I have no answer and
I know you didn't ask but
IMO, why go to all that trouble for; "Basically a street car", which implies, you don't need much more than go-cart suspension,lol. On the street,
IMO, it's really hard to beat a well-executed leaf-spring back there.
On the street, your rear suspension takes a back seat to tires and traction, limiting how crazy you can get. For me, the tires are the first to give up.
As to "dragracing once in awhile", on multilinks; is that a good idea?
IMO, if it was, everybody would be doing it
I don't know what to say about your reluctance to move brakelines etc.

I got a lot of opinions here, and that's because I have never had a multi-link rear in a performance street car, to compare my leafs to. Nor do I want one,lol.
IMO, for "basically a street car with occasional trips to the track",
I think you are unnecessarily complicating things.
IMO, I would not compromise my street car for occasional trackdays. I sorta tried it, and finally came to my senses, built my street car for street duty, and on trackdays, concentrated on trap speed only, letting ET be what it was.
Along the same lines;
IMO, for a streeter, I highly recommend to not let the Mopar292/292/108 cam be your first cam.

Whatever your trapspeed ends up at; it points directly to your horsepower. On-line calculators are pretty good at predicting best ET for that trapspeed. Actually getting to within 1 second of that is gonna cost money, and the last half-second is gonna cost even more money, and over IDK,say 100mph ,there won't likely be any multi-links involved.
IMO, multi-links are for rock-crawlers,monster-trucks,and old men with sore backs.

Yeah, yeah; I know you didn't ask; but for the final installed cost, I could have a supercharger,dial up the boost, and spit those links right into the next county,lol.
 
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siuauto said:
I am putting a triangulated 4 link in my 71 duster and I understand all the geometry for a 4 link but I am wondering if there is an advantage of having the top bars angle from the center of the axle to the frame rail over having the bars come from the axle to the center of the vehicle via a cross member. I would love to hear your thoughts!
Click to expand...
The position of the bars will potentially affect how you run your exhaust, but I don’t think there would be much difference in how the suspension will work.
 
If you are primarily going to use it on the street, invest in a set of CalTracs. They are much friendlier on the street that ladder bars, 4 bar, or triangulated 4 link plus you can run the full exhaust system.
 
siuauto said:
Thanks for your reply and I understand the difference and benefits of a parallel vs triangulated. My question is in a triangulated 4 link is there an advantage of running the top bars from the center of the axle to the frame over running the upper bars from a wider spot of the axle to the center of the vehicle.
Click to expand...
Depending on who you talk too, the biggest concern would be the close together, or single point at the top of the axle then going out to the frame tearing out under load. Personally, i think thats a bunch of BS. Its been done on street cars, namely the highly popular 1980s GM G bodies.
 
siuauto said:
It's basically a street car that may go to the drag strip once in a while. I know parallel would be ideal but its a street car and I don't want to loose the back seat. As you know these A bodies are so tight under the there I am struggling where to position the top bars. The lower bars are going where the leaf spring perches are in line with the frame since it is mini tubed. I don't see how I can put the top bars to the frame since that is where the brake lines, fuel lines, E-Brake cables etc... are. The real reason I am doing this is to fix a problem from when the mini tub was done and leaf spring relo was done. The rear end is not sitting square to the frame. I have confirmed the "frame"/ body is square so I am not sure if the issue is in the perches or the axle mounting points. If I am going to tear it all out and fix it correctly I can't see doing all the work just for leaf springs.
Click to expand...
what car are you putting this in? I'm running a 4 link parallel in my dart and didn't lose the rear seat. Normally with 4 link parallel's, that is not a concern. Its when you go with the 3 link setups that becomes a concern.
 
I built a triangulated 4 link in my 73 Cuda, my top bars go from mid axle to the center of the rear floor pan. There isn't a lot of room on the E bodies either but I made it work. I will say this, with a triangulated 4 link you do not get a lot of movement up and down especially with short bars, that said you do get good handling as that rearend is not going anywhere. I did a lot of research on this when I was in the planning stages of the car, I decided on the triangulated 4 link for handling, if I was building a drag car I would have went parallel 4 link.

Now just to get this out there; I am not saying that leaf springs don't work, in fact I know they do, however I wanted to do the triangulated 4 link "just because". I had never built one and wanted to do it, also at the time of planning I was leaning towards a road race car (changed directions along the way to more of a street car that handles like a road racer). If you are committed to a 4 link for whatever reason, a triangulated variant is preferable for a street car that you want to handle IMO.
 
dukeboy_318 said:
what car are you putting this in? I'm running a 4 link parallel in my dart and didn't lose the rear seat. Normally with 4 link parallel's, that is not a concern. Its when you go with the 3 link setups that becomes a concern.
Click to expand...
It's a 71 duster. Could you share some pictures of your set up?
 
70chall440 said:
I built a triangulated 4 link in my 73 Cuda, my top bars go from mid axle to the center of the rear floor pan. There isn't a lot of room on the E bodies either but I made it work. I will say this, with a triangulated 4 link you do not get a lot of movement up and down especially with short bars, that said you do get good handling as that rearend is not going anywhere. I did a lot of research on this when I was in the planning stages of the car, I decided on the triangulated 4 link for handling, if I was building a drag car I would have went parallel 4 link.

Now just to get this out there; I am not saying that leaf springs don't work, in fact I know they do, however I wanted to do the triangulated 4 link "just because". I had never built one and wanted to do it, also at the time of planning I was leaning towards a road race car (changed directions along the way to more of a street car that handles like a road racer). If you are committed to a 4 link for whatever reason, a triangulated variant is preferable for a street car that you want to handle IMO.
Click to expand...
Thanks for the feedback. I am committed to the four link due to the rear end not being square and have no adjust ability to make it square. Do you have any pictures of your set up. I know the e-body is different put the more input I have, the better off I will be.
 
siuauto said:
Thanks for the feedback. I am committed to the four link due to the rear end not being square and have no adjust ability to make it square. Do you have any pictures of your set up. I know the e-body is different put the more input I have, the better off I will be.
Click to expand...
Wait no adjustability?
Squaring it up is pie compared to engineering a multi-link.
Put it on the alignment rack, and get your front end set up.
Check your thrust angle and fix it.
Then, if your rear end is over to one side, cut off the perches and slide it over. BadaBoom!
This is the best time to also set your pinion angle.
While yur doing this you can move the entire rear end back to fit taller tires.
Recheck the alignment and center the steering.
You may have to lengthen your driveshaft.
 
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AJ/FormS said:
Wait no adjustability?
Squaring it up is pie compared to engineering a multi-link.
Click to expand...
But isn't that half the fun of owning these cars? I have changed everything else about the car, why stop now. lol... And, dial up that boost and let's dance...
 
siuauto said:
due to the rear end not being square and have no adjust ability to make it square
Click to expand...
When you say square do you mean the wheel base on the left and right are not the same?

You can put a shim between the front hanger and the body.

You can weld up and redrill the spring purch centering holes

If you are talking about the rear being laterally not centered,

You could remove the perches and re center the rear.
ALL of this is way less trouble than a 4 link.


on a side note... If the upper and lower links are different lengths or not parallel the pinion angle will change as the axle moves up and down.
 
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