Torque arms

[ericjon262]

I have a 1991 Camaro RS, and the torque arm is mounted on the side of the differential. I was wondering how the handling of the car would be effected if I went to a torque arm similar to this BMR piece for a first gen Camaro.

http://www.bmrfabrication.com/1F/TA003.jpg

Thanks for any input-

Eric

[ArtosDracon]

The torque arm on the third gen camaros is designed to set pinion and handle torque, because it's a round shaft mounted with a simple rubber clamshell, it can twist pretty easily. BMR has several different designs of torque arms to replace the stock one. Personally, I would recommend the torque arms that ditch the clamshell all together for a heim as it will allow the most freedom of movement without allowing axle wrap.

[ericjon262]

I see what you're saying, but I was more questioning how handling would be effected by going to a torque arm that runs below the drive shaft as opposed to running alongside it.

[ArtosDracon]

Well, offset to the passenger side actually helps mitigate torque better, if both bars were designed equally. The first gen torque arm you're showing is obviously beefier than just about any third gen torque arm. A lot of the decision would come down to the rest of the rear design.

Are you looking at this for a replacement of the stock torque arm? Have you figured on the extra 3" or so required below the driveshaft for one of these into your ride height? Are you planning on any other mods to the rear suspension?

IMHO torque arms are really more for ensuring a hard launch for drag racing than for hitting the twisties extra hard.

[Norm Peterson]

A true torque arm running below the drive shaft should have little effect on handling. That's because it doesn't affect either the rear roll center height or the axle roll steer. Transitionally with cornering plus either acceleration or braking, I'd expect some effect due to the anti-squat/anti-lift being different.

<snipped after seeing a picture from a different viewpoint>

I see it as being much more similar to a single ladder bar (or a longer version of the arrangement used in the GNX), and probably more oriented toward drag racing.


Norm

[ericjon262]

so to make the BMR piece a true torque arm would I have to make a front mount more like the one on a third gen F-body?

[Norm Peterson]

<snipped after seeing a picture from a different viewpoint>


Norm

[novaderrik]

a lot of torque arms have a front pivot point that slides in and out of the torque arm to prevent binding.

[LSx_88_Ciera]

so to make the BMR piece a true torque arm would I have to make a front mount more like the one on a third gen F-body?

It is already a true torque arm IIRC it has a Delrin bushed slider at the front.

[ArtosDracon]

I just looked up the page and LSx is right, it uses a telescoping delrin bushing at the front so it doesn't interfere with the lower control arms and bind.



All in all it's not a bad design at all, though personally I would rather just go with a true three link.

In terms of that torque arm versus the standard third gen F-body control arm, I don't think there is any major advantage to be had.

[Norm Peterson]

I stand corrected.

This picture shows what's going on a whole lot better

http://www.bmrfabrication.com/f1/f1ta.html


Norm

[ericjon262]

In terms of that torque arm versus the standard third gen F-body control arm, I don't think there is any major advantage to be had.

I think It would probably allow me to run a true dual exhaust efficiently, without a million bends, also, it would allow me to up grade my 7.5" ten bolt POS to an 8.5" ten bolt without having to resort to ladder bars, welding on the cast housing, or spending $3000 on a 12 bolt, while upgrading suspension components at the same time.

[BMR Tech]

It is already a true torque arm IIRC it has a Delrin bushed slider at the front.

Thanks for clarifying that in my absence. We took great care to eliminate bind in this system. With the Delrin-bushed front slider, Delrin bushed Watts link, and spherical bearing equipped Watts link bars and control arms, the system articulates very well with very little resistance.

[ericjon262]

do you guys think this would work on a third gen? I understand it would require a one off crossmember, and a new panhard/watts link setup, anything I'm missing?

[BMR Tech]

do you guys think this would work on a third gen? I understand it would require a one off crossmember, and a new panhard/watts link setup, anything I'm missing?

It would definitely "work" but I guess the question would be where do you draw the line when it comes to expense and complication vs. performance gain. I think the gain in performance would be marginal when compared to using our tubular components already designed specifically for the Third gen.

Lets break this down a little: You definitely have to get rid of that stock 7.5" rear, they aren't even good for boat anchors. 8.5" rears are fairly cheap and can be built almost as strong as a 12 bolt for about $1k. I don't know how different the widths are but I think the brakes are interchangeable. If the width is different, you may be looking at new wheels or shortening the rear. You would have to custom fabricate the torque arm cross brace as well as the shock crossmember. Also the control arms would need to be a custom length (You could probably use our 3rd gen F-Body control arms). If this is all stuff you can do yourself, the expense wouldn't be too bad, you would just have a lot of labor in it and in the end something truly unique.

Positives:

• Less expensive rear
• Better rear locating device (although marginal in this application because the OE panhard rod is fairly long and does a pretty good job already)
• Potentially (although not proven) better centralized torque arm pivot.
• Better coil-over shock and spring combo

Negatives:

• Hours of fabrication labor
• reduced ground clearance
• Unknown performance advantage
• Unknown rear end complications

If it were me I would probably look for a used 12 bolt or 9" on LS1 tech and then install one of our tubular adjustable torque arms and trans crossmembers that are made specifically for the 3rd gen. This trans crossmember removes the torque arm load from the transmission and relocates it to the crossmember. It also provides multiple mounting heights for adjusting the instant center height. We have been building this setup for over 10 years now and have thousands of them on everything from street and autocross cars to 1000 horsepower drag cars.

[ITLBTU]

I still want to copy this design since they won't sell me the components I need to make it work on my '69 Camaro... I think this will be the ultimate rear suspension. When I build it... maybe I'll see if others would like the same and our shop could make a run of some...

[ericjon262]

Lets break this down a little: You definitely have to get rid of that stock 7.5" rear, they aren't even good for boat anchors. 8.5" rears are fairly cheap and can be built almost as strong as a 12 bolt for about $1k. I don't know how different the widths are but I think the brakes are interchangeable. If the width is different, you may be looking at new wheels or shortening the rear. You would have to custom fabricate the torque arm cross brace as well as the shock crossmember. Also the control arms would need to be a custom length (You could probably use our 3rd gen F-Body control arms). If this is all stuff you can do yourself, the expense wouldn't be too bad, you would just have a lot of labor in it and in the end something truly unique.



Positives:

• Less expensive rear
• Better rear locating device (although marginal in this application because the OE panhard rod is fairly long and does a pretty good job already)
• Potentially (although not proven) better centralized torque arm pivot.
• Better coil-over shock and spring combo

Negatives:

• Hours of fabrication labor
• reduced ground clearance
• Unknown performance advantage
• Unknown rear end complications

I'll be running different wheels whether I do this or not,

I don't feel like it would be a big deal for me to fab up a crossmember for the front TA mount,

I was thinking I would use thirdgen spec lower control arms, and possibly shock mounts.

How much would this lower the ground clearance on a first gen? I know the first gen cars ride higher then the third gens, but I'm sure you factored in that most cars getting this kind of setup would be lowered.

I'm planning on using just the T/A, I wouldn't buy the whole first gen kit, when the only part I could use is the T/A.

[ericjon262]

I still want to copy this design since they won't sell me the components I need to make it work on my '69 Camaro... I think this will be the ultimate rear suspension. When I build it... maybe I'll see if others would like the same and our shop could make a run of some...

I've seen these, and they've peeked my interest, but to me, it looks like it would feel like something is broken in the suspension.

[BBPanel]

Anything for a 66 Nova? If so can you provide a link? Thanks. -Bob

[ericjon262]

Anything for a 66 Nova? If so can you provide a link? Thanks. -Bob

here's a link to the product ITLBTU referred too.http://www.unbalancedengineering.com/Camaro/

To me, it looks like it would whip around too much, more of a race piece than a street piece.