Torque Arm vs. 3-link IMHO

Discussion in 'Suspension and Chassis' started by Tri-bar, May 7, 2018.

  1. Tri-bar

    Tri-bar TMO Race

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    First off I want to say this is only my opinion with the testing I have done with my car.. This is not a be all end all statement. Results may very and often do.

    I have tested a lot of parts for the S197 chassis over the years. Shocks, springs, upper and lower control arms, Pan hard bars etc. I can tell you what parts I like and dislike. I have now tested back to back the 3-link to the Torque arm. With every thing being equal, spring rate, anti-roll bars and shock settings. I'm a little OCD about car parts I guess. I wanted from day one to build my car to a race car spec and over time I finely got to do that. Last part of the puzzle was the Multimatic upper rear control arm.

    After a few years I just got one. Brand new, paid too much for a arm that was easily cheaper from another manufacture. I like the Hotchkis arm, I still have one sitting in the parts bin almost new, but it wasn't the arm used on a race car. Silly me I know. I bought the damn thing never the less. The set up I have on the car as I write this is as follows.

    Suspension,

    Front:
    Cortex RJI #CFS-40-1000-JRI-SA Single Adjustable Struts.
    Eibach Coil Over Springs, 0800-250-0500, 500lb/in.
    Maximum Motorsports/Cortex Camber/Caster Plates.
    Ford Racing #M-3052-R1 Caster Adjuster Bracket.
    Ford Racing #M-5638-B Bushing Kit.
    Ford Racing #M-3200-EPAS Boss 302R Electric Steering Rack.
    Ford Racing #M-3130-R4 Boss 302S Bumpsteer Kit.
    Watson Racing/Howe Extended Screw In Ball Joint.
    Watson Racing Adjustable Sway bar End Link Left Side.
    Moog #K80899 Non-Adjustable Sway Bar End Link Right Side.
    BMR #SMK013 1-3/8 Billet Sway Bar Mount w/ Delrin Bushings
    Strano Performance Parts #8336 1-3/8 3-Way Adjustable Anti-Roll Bar (Middle Hole).

    Rear:
    Cortex JRI #SHK-40-1000-JRI-SA Single Adjustable Shocks.
    Eibach Coil Over Springs, 1000-250-0200 200lb/in.
    Cortex #CWL-40-2000 Watts Link.
    Multimatic Boss302R1 Upper Rear Control Arm.
    Ford Racing #M-5649-R1 Lower Rear Control Arm.
    Watson Racing 1/2 Anti-Roll Bar.

    What I have on the car is a World Challenge setup more or less. I have the Ford Racing #M-5649-S Lower Rear Control Arm and the Ford Racing Anti-Squat brackets also to be use on the track if needed. Funny though, not really needed. Now with that out of the way. First thing I did was drive the setup with the torque arm. I ran the car as hard as I could looking for the weakness in the setup. I found them.

    There is one corner I use out of many, a flat 180* 25mph long entry with a short exit onto the Highway. This one turn will show any weakness in your set up. 80 mph into the brake zone 25-35 corner speed with as much power as you can give it on the exit.

    Before I do the compare, I want to head off any comments about the rear springs. I change rear spring rates all the time and run the same corners. I use 150lbs to 400 lbs in the rear with 500lbs fronts staying the same. The same goes for the rear anti-roll bars, I am always testing.

    Before I ran the last drive with the torque arm. I swapped rear spring rates from 300lbs to 200lbs. To get more bite off corner. This was the only change I made before the drive.

    This is what I noticed. I always had a slight push on corner entry. Spring rates be damned it was always there. Full camber at 3*+ it would still be there. No matter what I did at turn in other than drive in slow it would push. It did the same with this run as well. Mid corner would be okay. I would get bite back so the mid corner push wasn't a thing. Now the fun part, corner exit at the apex on the 180* corner as I rolled hard into the power will and did produce a very nice and controlled slide to the exit. Merging onto the highway at a good clip. Faster than a yellow flag lap at Button Willow lets say.

    30 minuets later I rolled into my garage to do the arm swap. I had already mounted the upper arm to the bracket and torque it down so it was ready to go. Did the swap. I just pulled the TA out, left the frame bracket and stuff to speed things up and if needed to put the TA back in if it all went bad. Set ride height to match what it was before and went out for the second test drive.

    The 3-Link setup was smoother over the uneven pavement was the first thing I noticed. Dips, risers and joints were all smoother with more control. Noise was about the same, you hear every bump in my car and a chatter from the rear anti-roll bar. Side note, wish Watson Racing made polly bushings instead of the derin. Turn the radio up and the windows down and it all goes away. Now corner time.

    Same corners as before in the same order as before. Back to the 180* bend. Matched mph into the corner as before. Under braking I noticed just a little more nose dive, this time under turn in however there was no push, it just turned and held it though mid corner . This is where things really changed. Just before the apex I started to add power hard, With the TA it would have started to power slide at this point. The 3-link just held on and wanted more power. No slide, just forward movement with no drama.

    Corner exit speed was 10 mph higher than before. I went back around to the corner again to see if it was just a fluke. It wasn't it did the same thing. Every corner I ran had the same results, no push into the bend even at higher entry speed the push was gone. The back followed real nice under power off exit. It was a real joy to drive.

    With the 3-link the chassis moves around just a tad more. Just not as much as you would think. No real noticeable squat either even without the anti-squat brackets. The torque arm on the other hand didn't just limit the squat it also lessened the dive and to some degree the roll if you are under power. It felt flatter all the time. I like the 3-link and it is going to stay on my car. The Torque arm will be up for sale as soon as I get all the other parts off the car. But not in a rush right now to remove them.

    Do you need the $$Multimatic$$ upper rear control arm ? OH HELL NO!! There are things I like about it. It's ease to install, just like the factory arm, It's rebuild able. It's length is fixed, no guess work as to how long/short it should be. Makes no extra noise until the bearing wears out. Most of all it just looks right. The truth is any good upper arm should work fine. I would have gotten the same results if I had reinstalled the Hotchkis arm I have.

    Do I dislike the torque arm. No. The Cortex torque arm is a very well built and thought out unit.
    I would tell anyone who wants to try it, to well try it. I can say though on my car. It's not the be all end all part and I can say that on my car, I tested it back to back and it lost. Take it for what this is worth and spend your money on good shocks and strut, springs, that's where the best bang for the buck is.
     
    Last edited: May 7, 2018
  2. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Good read. Thanks for sharing!
     
  3. VoodooBoss

    VoodooBoss Rick Moderator

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    There are those that like the TA but it was never on my radar. It might work better on high HP cars. Like you when I installed my Cortex JRi setup it made a world of difference. Rode as nice or nicer than stock yet was hooked up on track.
     
  4. racer47

    racer47 All I got left is fast

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    Seems like a decent test. I'd like to see higher speeds but thats hard to pull off on the street.

    I've never been a torque arm fan. I lived through the development of Trans Am (GT1, GTO) cars from production based to full tube frame. There were a couple torque arm chassis along the way but eventually all the chassis designers settled in on 3 or more commonly, 4 link rear suspensions. If the torque arm was actually better than that is what would have become the norm.

    Plus in the oval track world, all the non-nascar sanctioned asphalt late models run 3 link rears as well (nascar is stuck on truck arms). I see no reason to go against proven race car tech. In my opinion, torque arms for Mustangs exist simply because enough guys buy them to justify making them. Just because a different part is available, doesn't automatically make it better.
     

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