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Cortex Torque Arm and Watts: An Honest, Thorough, Track Based Review

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29
Exp. Type
HPDE
Exp. Level
Under 3 Years
Maryland
I have to be honest here, the Boss 302 platform and especially the LS and R models were some of the best handling cars ever built. They are still knocking off Pirsches and BMWs at national events even today, and they had to be legislated out of existence to make way for the GT4 spec cars. So, why would you want to significantly change one of those cars? You have all the tools you need already on it.
Fabman just likes to build things, which is his excuse.
I wanted to go with the cortex watts link setup to help with corner exit and a lot of people say you won’t notice much of a difference without the torque arm. So I was going to do the watts link with the torque arm but did not want to have to lose the quad exhaust and get another H pipe. My car already has adjustable track bar and control arms and steedas Boss 302 springs. I tried a few different sets of wheel and tire setups thinking it was a tire size/model issue and some helped a little but not enough yet. The rear just needs a little extra help to keep it planted on corner exit and it seems like the watts link and torque arm setup really helped with everyone’s ability to throttle on sooner during corner exit.
 
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I wanted to go with the cortex watts link setup to help with corner exit and a lot of people say you won’t notice much of a difference without the torque arm. So I was going to do the watts link with the torque arm but did not want to have to lose the quad exhaust and get another H pipe. My car already has adjustable track bar and control arms and steedas Boss 302 springs. I tried a few different sets of wheel and tire setups thinking it was a tire size/model issue and some helped a little but not enough yet. The rear just needs a little extra help to keep it planted on corner exit and it seems like the watts link and torque arm setup really helped with everyone’s ability to throttle on sooner during corner exit.


These guys can tell you my opinion of Watts links, I wouldn't put one on my lawnmower.
If I were you, instead of redesigning the entire suspension of an already great handling car, I would just upgrade to one of the Ford Performance kits, or the R parts. The hard work has already been done for you.
I would start by going back to the stock Boss ( or Gt500) upper trailing arm, since you prolly already have it.
 
43
39
Exp. Type
W2W Racing
Reno, NV
I have a quick question to throw in here for you guys running the cortex torque arm… will that torque arm work with the Boss 302 quad exhaust? It looks like the side pipes may run into where the front of the torque arm mount is bolted on to the body.
My car has it with stock quad exhaust
 
151
136
True for independent suspensions, but (I believe) a solid axle does not produce jacking forces, at least in the same magnitude as an independent suspension.


"the lower the RC" is technically "the further the RC from the CG" - which means more of the lateral load transfer is going through the spring/shocks/ARB, and subject to the timing of the shock valving to reach steady-state roll angle, as opposed to going instantly through the suspension links. If RC=CG, then all lateral load transfer happens through the suspension links, it happens instantly, and there is no "roll" in the unsprung mass (but there IS load/weight transfer).

If the car is balanced to start with, yes. Playing with the RC-CG distances front-to-rear changes the timing of load transfer / roll on each axle, and can be used to tune transient handling (or allow the shocks to have a bigger/smaller affect on transient handling). See Figure 14 in the second link I posted.

Going back to this roll center / weight transfer discussion, my understanding is that front and rear roll centers have nothing to do with the TOTAL weight transfer in a corner. That depends only on the weight of the car, the height of the center of gravity, how fast you are going, and the width of the vehicle's track. But the relative roll centers of front versus rear can (together with lots of other suspension adjustments) affect HOW MUCH of the total weight transfer is carried by the front versus the rear.

You see a lot of comments along the lines of "lower roll center increases grip," but my understanding is what that really means is, "more grip relative to the other end of the car." If it was otherwise, you could just design the suspension geometry to drop the front and rear roll centers below the ground and the car would automatically go faster but of course that is not the case.
 
5,322
6,065
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I have to be honest here, the Boss 302 platform and especially the LS and R models were some of the best handling cars ever built. They are still knocking off Pirsches and BMWs at national events even today, and they had to be legislated out of existence to make way for the GT4 spec cars. So, why would you want to significantly change one of those cars? You have all the tools you need already on it.
Fabman just likes to build things, which is his excuse.
Actually I was not shopping for a torque arm or watts link when I got mine. As an old circle tracker I was perfectly happy with my 3 link and modified pan hard bar. (Custom built to be adjustable for roll center height ala NASCAR) It’s what I am used to and it worked fine. I was offered the T/A W/L package dirt cheap off a wrecked race car so I went with it and have no regrets. Fancy parts are great, but it’s what you do with them that matters most. We’ve all seen that guy with every high buck gizmo in the world get waxed by a guy with a very modest platform because the first guy adjusted himself out of the ball park and the second guy had a simple setup that was dialed in. Nothing wrong with a 3 link and panhard bar, clearly. And yes, I do love to build stuff….it’s who I am. For me it’s not just about having a fast car, it’s about building a fast car around my own engineering, building or buying specific pieces because I think they serve some specific purpose (not because it’s popular) and learning from my own experience and the experience of others and making sense of it. Present company included. That’s how I roll, but it’s not for everybody. Seems like two roads to success might be the exploratory road of self engineering or the purchasing of a proven package that works for those who are maybe less comfortable with the rabbit hole of discovery and more focused on track performance and the pleasure of driving. I think it’s the guys with one foot in each camp that have the hardest time. Conflicting ideas from different camps with different strategies that may work well, but not work well together. That’s why I say test….try everything in extremes….don’t make small changes, make big changes and see what they feel like. Then once you’ve had the experience of super stiff vs. soft springs, high RC vs. low RC, big bar/small bar etc. it all starts to come together like the picture on a puzzle that once seemed like a box of oddly shaped un associated scraps of paper. THAT is the fun of it for me. But that’s me. The easy button is finding a builder/platform that’s proven to work and do everything they say. Like Ford racing, cortex, vorschlag, Maximum Motorsports, Kenny Brown, Phoenix etc. Once you start mixing parts and strategies from multiple sources you have begun your own research and development program. I guess the trick is to recognize which camp you want to be in and go with it.
 
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5,270
Thank you so much good to know
I'm going to post this pic again, much to some people's chagrin, I'm sure. You may take one look at this and think it's the most oddball looking jacked up suspension you have ever seen, It's not, this car sat on the pole at VIR at the 25 hour, (or 23 or something like that) This car is correctly going through this corner in the hands of a skilled driver. This is what a good handling s197 looks like.
qGKqzwcl.jpg
 
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Actually I was not shopping for a torque arm or watts link when I got mine. As an old circle tracker I was perfectly happy with my 3 link and modified pan hard bar. (Custom built to be adjustable for roll center height ala NASCAR) It’s what I am used to and it worked fine. I was offered the T/A W/L package dirt cheap off a wrecked race car so I went with it and have no regrets. Fancy parts are great, but it’s what you do with them that matters most. We’ve all seen that guy with every high buck gizmo in the world get waxed by a guy with a very modest platform because the first guy adjusted himself out of the ball park and the second guy had a simple setup that was dialed in. Nothing wrong with a 3 link and panhard bar, clearly. And yes, I do love to build stuff….it’s who I am. For me it’s not just about having a fast car, it’s about building a fast car around my own engineering, building or buying specific pieces because I think they serve some specific purpose (not because it’s popular) and learning from my own experience and the experience of others and making sense of it. Present company included. That’s how I roll, but it’s not for everybody. Seems like two roads to success might be the exploratory road of self engineering or the purchasing of a proven package that works for those who are maybe less comfortable with the rabbit hole of discovery and more focused on track performance and the pleasure of driving. I think it’s the guys with one foot in each camp that have the hardest time. Conflicting ideas from different camps with different strategies that may work well, but not work well together. That’s why I say test….try everything in extremes….don’t make small changes, make big changes and see what they feel like. Then once you’ve had the experience of super stiff vs. soft springs, high RC vs. low RC, big bar/small bar etc. it all starts to come together like the picture on a puzzle that once seemed like a box of oddly shaped un associated scraps of paper. THAT is the fun of it for me. But that’s me. The easy button is finding a builder/platform that’s proven to work and do everything they say. Like Ford racing, cortex, vorschlag, Maximum Motorsports, Kenny Brown, Phoenix etc. Once you start mixing parts and strategies from multiple sources you have begun your own research and development program. I guess the trick is to recognize which camp you want to be in and go with it.

Yeah, but you're just different than most, but I understand you, completely, I like to do the same kind of stuff, but it takes resources and experience, and most guys don't have both. Think of it if you had to pay someone to do that to that car, and go down all the rabbit holes you went through, If you think it was $$ now, it would be off the chain expensive then.
 
5,322
6,065
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Yeah, but you're just different than most, but I understand you, completely, I like to do the same kind of stuff, but it takes resources and experience, and most guys don't have both. Think of it if you had to pay someone to do that to that car, and go down all the rabbit holes you went through, If you think it was $$ now, it would be off the chain expensive then.
Exactly. Which is why I pointed out the second path….follow someone else’s program completely, like phoenix or another reputable shop and do everything they say. The easy button. You know it’s going to work with the least amount of heartburn.
 
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I just ran my first day with the Cortex watts link yesterday.Actually only a half day since the vent fitting in the axle tube cracked.
What are you all using as a vent fitting.The supplied Cortex fitting sticks up to high and hit the exhaust.Looking for a low profile solution.
Sorry to change the subject but going to Watkins Glen in a week and need this fixed.
Thanks, Guy
 
I am only 4 autocross events in with my Cortex Watts and TA setup (along with the cambered axle) and am pretty happy, but most of the improvement is from the camber and the adjustability of the watts.

As Fabman and Blacksheep explained, none of this stuff is magic. I hear people say they feel improvement in handling when they install an adjustable *length* panhard on a S197. Err....ok. Or people who spout about how much better a watts is because it made the car faster over the PHB when the improvement was just the change in RC. Improvement is improvement of course, but when it becomes gospel for the wrong reasons it rubs me the wrong way.

I have scratch built suspension in one tub based car and one tube frame car from the ground up. On both, I stuck with a panhard because it was simpler to build and have a wide range of adjustment. And a simple 3 link for the same reason, easy to build with plenty of adjustment in caged car. On my S197, I just don't have the time any more to get into and maintain fab projects so I have done all bolt ons. The only reason I did a watts in the first place was to get some RC adjustability and the only reason I am at the Cortex now is it has the most adjustability.

So x3 on this:

Exactly. Which is why I pointed out the second path….follow someone else’s program completely, like phoenix or another reputable shop and do everything they say. The easy button. You know it’s going to work with the least amount of heartburn.

DaveW
 
5,322
6,065
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I am only 4 autocross events in with my Cortex Watts and TA setup (along with the cambered axle) and am pretty happy, but most of the improvement is from the camber and the adjustability of the watts.

As Fabman and Blacksheep explained, none of this stuff is magic. I hear people say they feel improvement in handling when they install an adjustable *length* panhard on a S197. Err....ok. Or people who spout about how much better a watts is because it made the car faster over the PHB when the improvement was just the change in RC. Improvement is improvement of course, but when it becomes gospel for the wrong reasons it rubs me the wrong way.

I have scratch built suspension in one tub based car and one tube frame car from the ground up. On both, I stuck with a panhard because it was simpler to build and have a wide range of adjustment. And a simple 3 link for the same reason, easy to build with plenty of adjustment in caged car. On my S197, I just don't have the time any more to get into and maintain fab projects so I have done all bolt ons. The only reason I did a watts in the first place was to get some RC adjustability and the only reason I am at the Cortex now is it has the most adjustability.

So x3 on this:



DaveW
Boom.
 
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5,270
Full disclosure here, I really don't have a problem with a Watts, it's more like the
" execution" of the unit. If you were to machine the mating surface flat, upgrade the bolts, or better yet, use studs, then install dowel pins to keep the center bearing apparatus from walking all over the diff and creating leaks, it would be far more acceptable to me. Maybe Ricky at Cortex has it figured out, but some of the other units I've seen are pretty sketchy, IMO.
Funny, no comment on my pic this time.. lol
 

Mad Hatter

Gotta go Faster
4,499
3,196
Santiago, Chile
I'm going to post this pic again, much to some people's chagrin, I'm sure. You may take one look at this and think it's the most oddball looking jacked up suspension you have ever seen, It's not, this car sat on the pole at VIR at the 25 hour, (or 23 or something like that) This car is correctly going through this corner in the hands of a skilled driver. This is what a good handling s197 looks like.
View attachment 75165
Every time the Porsche crowd tells me that Mustangs have a rear grip problem because they have a chariot axle... I sent a pic of this car to them. My boss wants to be this car when it grows up.
 
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5,322
6,065
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Full disclosure here, I really don't have a problem with a Watts, it's more like the
" execution" of the unit. If you were to machine the mating surface flat, upgrade the bolts, or better yet, use studs, then install dowel pins to keep the center bearing apparatus from walking all over the diff and creating leaks, it would be far more acceptable to me. Maybe Ricky at Cortex has it figured out, but some of the other units I've seen are pretty sketchy, IMO.
Funny, no comment on my pic this time.. lol
My watts link has recesses in the cover that register the mating components....no walking or moving around at all. You must be referring to an earlier release that perhaps predated this.
 

Dave_W

Cones - not just for ice cream
569
661
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
One of the reasons I chose a body-side pivot Watts - it doesn't put loads into the diff cover attachments they weren't designed for. Also, it keeps the same RC-CG distance under squat and dive. And depending on specific design and body lowering amount, you may be able to put the RC lower than a diff-side pivot, though you have to consider ground clearance (which is where a Mumford link beats it). Downside is it typically adds more unsprung weight (the axle clamps) than a diff-side pivot design.
 

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