Transverse Suspension - Advice please

[pistolpete]

My build is slow moving, partly due to me wanting to keep it a roller. But I have been piecing things together, I am using a '40 banjo rear open drive from a flathead/T5 combo. I want to do a triangulated rear similar to the stock set up with wishbones or some sort of ladder bars, but don't want typical tube ladder bars. If I go with making a ladder bar I will make some sort of tapered tube. I did a quick mock up of what I am thinking with '40 front wishbones, but this option will require another set of front wishbones, a cost I'd rather not endure. The wishbones would then mount to a uni-ball joint (like 4x4 link ends) mounted on a new cross member with the ball as close to directly under trans yoke as possible. Hopefully the sketch helps explain better then my words.

Do you think a 3/4" bolt through the UniBall would be sufficient in this application? http://www.4wd.com/Fabrication-Tool...spx?t_c=86&t_s=528&t_pt=101460&t_pn=R/ERE3795

More or less looking for some feedback don't have anyone to bounce ideas off of, and the wife looks at me crooked when I ask her opinion.

 

[sawzall]

I am lost as to why you need the front wishbones in there if you have the rear bones already. Sorry I must not understand your question.

 

[MercuryMac]

It looks like the white arms will act as the torque tube did and the transverse spring will act as the panhard bar. You should be O.K.

 

[Bamamav]

With both sets, yes. With just the inner set, no.

 

[pistolpete]

MecMac, that's what I figured, need to replace the torque tube in some fashion.

My main concern is the uni-ball if a 3/4" bolt would be enough to hold the links to the uni-ball. I know typically with a split rear wishbone and tie rod ends they are smaller then 3/4" but wasnt sure if connecting them at one point changes anything or if I'm just over thinking things as usual. Also the stock rear wishbones would be shortened and bent in to connect to the side of the front wishbone.

 

[MercuryMac]

If your suspension system was a parallel leaf one, you would probably have two half inch bolts holding your rear-end to the car[spring pins through the eyes].
One grade eight, three quarter inch bolt, in your system, would be equal to those two little spring pin bolts.

 

[BlueNorther]

the word is redundancy, you have two sets of arms doing one job!!

inner set is waste of time , if outer torque arms are attached to rear axle properly, you have no need of inner set.

a wide based 360* mount for outer arms will be sufficient for torque control.

 

[Torchie]

the word is redundancy, you have two sets of arms doing one job!!

inner set is waste of time , if outer torque arms are attached to rear axle properly, you have no need of inner set.

a wide based 360* mount for outer arms will be sufficient for torque control.

Agree with BlueNorther.
Open drive line conversions using a banjo rear end with stock wishbones are fairly common. Most people just shorten the rear wishbones and make a mounting bracket from the frame to allow room for the drive shaft to clear. On a totally stock set up the torque tube had the mount for the rear wishbones to attach to.
Plus if you are using the 40 rear spring you don't need a panhard bar as the spring is under tension the moment you attach the shackles. 46-48 banjo rear ends and spring setups need the panhard bar.
And don't forget to put a vent in that banjo housing.
Torchie

 

[pistolpete]

I have to disagree with you two to be honest. The stock wishbones are not enough to control the torque of the rear end (even if it is commonly done), that is what the torque tube did, the wishbones only controlled the twisting front to back of each side in a stock set up. I've been reading about this for a while, and came accross this video:

http://www.youtube.com/watch?v=okBrx2RTUAQ

I do not think that the stock rear wishbones will take that twisting force the way a front I-beam will, as they are the weak link in the set up as the rear end will not twist. Hence why I have been thinking about the pictures above. Maybe I am just ovethinking things as usual, but anything that will have my kids in the back seat and or be on the same roads as my kids I'd prefer it be safe, and not just commonly done.

 

[Dirtyrat]

I guess I'm not sure what exactly you are worried about, even some more modern suspensions use 3 and 4 link triangulated rear setups, some with panhard bars.. the torque of the housing itself I do no see being an issue you are going to "control" with the control arms. You have a pivot point at the center of the rear axle on any rwd vehicle, you will be loading the suspension on one side on a launch seeing as how the springs will be on the rear axle whether it be leaf springs, or coils.

 

[MercuryMac]

Pistolpete, Thank you for the utube video. It opened my eyes a bit.
What might be scaring you is the flexing of the torque arms on a split bones system; whereas yours will be triangular and won't have that twisting stress. Your white bones might be a little overkill, but they won't hurt anything, and they will give you piece of mind.
You have engineered room for the front end of your driveshaft, right?
Keep on tinkering.

 

[Torchie]

I have to disagree with you two to be honest. The stock wishbones are not enough to control the torque of the rear end (even if it is commonly done), that is what the torque tube did, the wishbones only controlled the twisting front to back of each side in a stock set up. I've been reading about this for a while, and came accross this video:

http://www.youtube.com/watch?v=okBrx2RTUAQ

Don't worry about it as I don't take offense at much.
But let me state my case....
I agree to a point with Mr popsicle sticks. But what he is doing is not only spliting the wish bones but bending them out ward to parallel the outer frame rails. Like he is splitting a front wish bone. This has been proven to be a bad idea long before U-tube.....
What many have done and what I was suggesting is that you leave the angle on the bones and shorten them up (Just enough to clear the driveshaft if necessary or not at all.) and put in a crossmember to mount the ends to. This may be common but perhaps the reason it is common is that it works.....
The rear end that you are working with didn't have a wishbone ball attachment point. I believe that it has a bracket on the torque tube well behind the trans that the wish bone ends bolts to.
So basicly what I was suggesting was a setup much like what you drew, just with out the extra set of bones down the middle.
I applaud your wanting to be safe both as a fellow driver and as a father (Or perhaps a passenger ) and would never suggest that you do otherwise.
Oh and by the way if you look hard enough on u-tube you will find a video of JFK living in Argentina.[ddd[S
Keep posting pics as your build looks like it will be interesting.
Torchie.

 

[pistolpete]

Thanks guys, I didn't mean to come back in a defensive manor was just stating what I have read and was trying to make sure I am understanding everything properly. I did misunderstand you Torchie, as I had understood you to say attach the wishbones to the frame not a new cross member. One of the joys of computer age where tone of voice and an uncomplete understanding can cause some issues. And yes as great and all knowing as the internet/youtube is, most still needs to be taken with a grain of salt.

My main concern with my original post was more so with the use of the uni-ball joint and what size to go with, but I think the 3/4" will be enough, I just didnt word it that way.

I do have to admit I am still concerned about the stock wishbones and will probably come up with some sort of ladderbar/anti wrap bar to take the torque and ease my mind, might be had for me to find another set of bones for a reasonable price, as the ones in the picture are spoken for, for use on my front end.

I will post up more of a build thread as I get a little further along. If I had started one already it would have three posts, with 15 pictures in the span of over a year. I'm not the fastest car builder to say the least.

 

[Dirtyrat]

Looks like I perhaps misunderstood which direction of torque you were referring to as well, I thought it was along an axis with the driveshaft rather than along an axis with the axle itself...

 

[Torchie]

It's all good pistolpete..... I could have been clearer

...but try to keep my post from getting wordier than they are...
There is a world of info out there. That's the big difference now Vs when I was a youngblood building a car. We didn't have the internet or forums likes this.
As I said the guy in your video wasn't wrong but was kind of comparing apples to oranges.
If not done properly even front split wishbones will crack.
I dig the fact that you are using a banjo rear end. They are a unique animal unto themselves.
And I also dig the fact that you are looking for a different way to do things. That what makes this site so good. Lots of out of the ordinary things on here.
And there are some really good suspension people on here as well so hopefully someone will come up with some ideas for you.
Keep at it.
Torchie.