Torque Arm questions.

[Lamoogle]

I'm kicking around the idea if doing a torque arm set up on my project and have been searching that and other forums and still have a few questions.

First- What can be used to mount the front of the torque arm to the frame? Most replacement arm like BMR arms for a 4th gen f-body use a link setup with bushings like this setup http://www.bmrsuspension.com/?page=products&productid=320 and I can't find anything that shows what a setup like Speedtech and others are using.

Second- From what I've read the decoupled setup would be the way to go, but I can't find much info on what to use to setup one up.

Third- Has anyone here built a decoupled torque arm setup?

[exwestracer]

I think most of the manufacturers have settled on a sliding, rotating joint at the front. I've built a few of them (not decoupled) using front mounts as simple as a 4130 steel rod going through a 1" heim joint mounted to the crossmember; to a "dogbone" double spherical bearing.

While the decoupled setup does treat acceleration and barking forces separately, I think if I were getting that far into it, I'd just put a set of caliper floaters on the housing and take full advantage of the braking leverage. Just my $.02...

[Lamoogle]

Would you be willing to show some pictures of the setup you have done?

I've searched the "dogbone" double spherical bearing, but have only come up with them in kits that come with a torque arm and I will be building my own. Are the custom made or is there a place to get them?

Don't look down on me to much for this, but I've been looking at a lot of dirt track cars to see how the have the some what decoupled setups and they look like it may take up to much room as well as over built for what I would like out of the car.
I was going to do a triangulated 4-link setup, but I've read enough stuff that the TQ arm setup sounds like a better setup and I have had a 4th gen f-body and it worked well in handling as well as take off, so I'm sure thats the direction I want to go.

[SLO_Z28]

I was talking to one of the leading manufacturers of decoupled torque arms for non roundy round use, and they don't use them in their autocross car. The time it takes for the arm to load is much too long for an autocross situation. They love the setup on the road course though.

[dontlifttoshift]

James, what company was that? A friend of mine runs a 4th gen in ESP and upgraded to a decoupled setup from Unbalanced Engineering and is very happy with it. Oddly enough it still brake hops more than he would like but it has never hooked up out of the corner like it does now.

[SLO_Z28]

Unbalanced... lol.

[Antti66ht]

Unbalanced... lol.

Honest name, not claiming to be balanced ;) lol

[exwestracer]

Would you be willing to show some pictures of the setup you have done?

I've searched the "dogbone" double spherical bearing, but have only come up with them in kits that come with a torque arm and I will be building my own. Are the custom made or is there a place to get them?

Don't look down on me to much for this, but I've been looking at a lot of dirt track cars to see how the have the some what decoupled setups and they look like it may take up to much room as well as over built for what I would like out of the car.
I was going to do a triangulated 4-link setup, but I've read enough stuff that the TQ arm setup sounds like a better setup and I have had a 4th gen f-body and it worked well in handling as well as take off, so I'm sure thats the direction I want to go.

There is a picture of the one I use in post #10 of the "rainy day" thread on torque arms (in this forum). I tried to link it here, but that isn't working for some reason. Note: they are metric and use 14mm bolts.

Sorry, no pics of the latest one I did (on my 51 Plymouth). I had them in my old "PT garage" but lost them when the site migrated. They're nothing special...I just build them to suit the car and use. I've been racing supermodifieds with torque arms since 1999, so I happen to have a little experience with them, is all.

[Lamoogle]

Thank you for the info, but I think I'm going to use the BMR front setup when I build a T/A. It looks like it will be easy to setup and use. Now the next thing will be to figure how long it will need to be! My 62 Impala is 119" wheel to wheel and will have a BBC in it.

Also I've got a buddy with a 50 Plymouth 2door, it was a running car when we first met, but has not been on the road for 6-7yrs now. Poor car...

[SLO_Z28]

Me and a friend were talking about it, and a IMCA style torque absorber might be ideal in the torque arm. This would help with the shock load of the braking forces.
https://static1.pt-content.com/images/pt/2012/09/16891-1.jpg
I cant help but think that the 3rd gen camaro did a good job from the factory. Whatever you fab make sure you can adjust the lower control arms and torque arm angles so you can set your instant center.

[exwestracer]

Me and a friend were talking about it, and a IMCA style torque absorber might be ideal in the torque arm. This would help with the shock load of the braking forces.
https://static1.pt-content.com/images/pt/2012/09/16891-1.jpg
I cant help but think that the 3rd gen camaro did a good job from the factory. Whatever you fab make sure you can adjust the lower control arms and torque arm angles so you can set your instant center.

James (or anyone), if you're thinking about going that route, you can use one of these
64815
AS the top bar of the torque arm. Much lighter than the full size IMCA version, and proven to do exactly what you are looking for.

[SLO_Z28]

So you agree that would be a pretty trick setup then? I cant help but think a torque arm setup would be one of the ideal fab it yourself setups.

[Lamoogle]

exwestracer- got any ideas on length of the T/A? All the info I have now is wheelbase 119" and that it will have a twin turbo BBC with a 4l80e trans. The car is on a jig with the floors cut out so I have no idea of weight.

[Sales-TCI-Eng]

I have posted these pics before of ours, I actually think in the 'Rainy Day' thread mentioned before.


Extended
https://static1.pt-content.com/images/pt/2012/09/100_5035-1.jpg

Compressed & turned
https://static1.pt-content.com/images/pt/2012/09/100_5034-1.jpg

[SLO_Z28]

You use that on a torque arm setup? Cool little piece.

[Sales-TCI-Eng]

Yeah, we use it on all of the T/A kits.


https://static1.pt-content.com/images/pt/2012/09/IMG_3362_zps2631562e-1.jpg

https://static1.pt-content.com/images/pt/2012/09/IMG_3363_zps41880c01-1.jpg

-J

[exwestracer]

exwestracer- got any ideas on length of the T/A? All the info I have now is wheelbase 119" and that it will have a twin turbo BBC with a 4l80e trans. The car is on a jig with the floors cut out so I have no idea of weight.

That will be tough... You'll need a GOOD estimate of the C/G location and height to establish a 100% or neutral Anti-squat line. From there you can tailor the location somewhat to suit your application.

[Lamoogle]

That's going to be hard with out building the car first and I need to to figure out where the cross-member is going to be before building a lot of the car???


I'm going to search how to figure the C/G and get back with you on what I come up with. I hope I comeup with some good info for you guys to help me with!

[exwestracer]

That's going to be hard with out building the car first and I need to to figure out where the cross-member is going to be before building a lot of the car???


Yup...

If you know anyone else who has one complete, see if you can get it on a set of scales. You may have to adjust the weight a little for differences in engine, turbo system, etc., but at least it will give you a starting point. In most passenger cars with a pushrod engine, the C/G height ends up being very close to the height of the camshaft above the ground. If you can get a F/R location, you can figure out your neutral line and at least know where. If the rear lower links are level, they won't account for much in the force vector equation, as the torque arm is a simple lever. That's one of the neat things about this system, the lower links ONLY push (when level), and the TA ONLY lifts. If you were to install the lower links at the axle centerline height, they would have NO lift component whatsoever.

[Lamoogle]

Well no one I know has a 61-64 Impala and then add the things I'm going to do to the car and that makes it even harder to find the info. I'm going to run a BBC, twin turbo setup, C4 front end, a 31" tall tire out back and still need to figure out the ride height as I'm mostlikly not going to run air ride.

So I think anything I come up with will be a best guess. To let you know my plans with the car. They are to just have a nice handling car that can put the power down that I can drive and have fun in, but not looking to autox or race.

[exwestracer]

Well no one I know has a 61-64 Impala and then add the things I'm going to do to the car and that makes it even harder to find the info. I'm going to run a BBC, twin turbo setup, C4 front end, a 31" tall tire out back and still need to figure out the ride height as I'm mostlikly not going to run air ride.

So I think anything I come up with will be a best guess. To let you know my plans with the car. They are to just have a nice handling car that can put the power down that I can drive and have fun in, but not looking to autox or race.

Put the front mount 1/2 way between the front u-joint and your wallet - with your butt in the driver's seat (really). That's my best educated guess having NO more info, and should be pretty close to the 100% line. Height of the front pivot will depend on the design of the front mount, but as close to the the height of the driveshaft centerline as possible, the better.