cortex watts link

[Whiskey11]

1.) My problem with the fays + steeda units is the use of the axle clamps. Some folks have reported that the axle clamps shifted on the axle..and both shifted as much as 1/4" or more. Giant U clamps are not the ideal clamping method....and at least 2-3 should be used on each end. U clamps don't have any surface area vs a clamping block. They really should be welded to the axles.

The griggs /cortex /WL version articulates on the diff cover /spider /football..no axle clamps required.

2.) My other problem with the fays /steeda version is the huge truss that spans the width of the car...... whose only purpose is to support the articulation point. The cortex /griggs /WL doesn't require it.

Jimbo

1.) The Fays2 unit's axle clamps are not U bolts and nor are they really U clamps either. Basically they are a circle cut in half such that a large portion (basically all) of the axle tube is in contact with the clamps. If one has shifted it was due to improper installation of the Watts link and NOT because of the design. I'm sure Sam Strano can post his lateral G numbers for his Mustang with the Fays2 and mine were peaking in the 1.25-1.3 range on a 3750lb car with driver in competition weight and I'm on narrow street tires. Zero displacement of the Fays2 watts link clamps but I followed the instructions for setting up the watts geometry (equal but opposite angles and no length differences).

Ideally you are correct though, welding would be a lot stronger but it is also permanent which most street car folks would rather not do in case they decide to change out parts.

2.) Why is this a problem exactly? It is simply the best way to support the center point. The total package is still the same total weight as any diff mounted unit is (around 28lbs) but instead of being primarily unsprung weight (diff mounted) it is mostly unsprung weight. There are other advantages in mounting the pivot on the chassis as well and the biggest one is adjustment range. Not that I hate Cortex Racing but how much rear roll center height adjustment do you actually have? I'm 99% sure my Fays2 has more and costs less. I also find it ironic that you talk about the PHB brace as being flimsy (even though as Norm pointed out it is only ever going to be effective in tension) yet the Fays2 brace is replacing that piece with a far superior brace to even that of any aftermarket PHB brace.

You know what my huge problem with a diff mounted watts link is? The fact that 3800 lbs of car and driver, moving laterally around 1.3g's is being transmitted through 10, 3/8" diameter bolts on the differential cover which sits atop a bead of RTV before it hits anything solid under it. The other thing is the increase in unsprung weight. Sure the Fays2 increases unsprung weight by a few pounds (less than 5 if I remember the math I did a long ass time ago) but not nearly the 25lbs of unsprung weight that is most diff mounted units. But I hear you scream "It's a LIVE AXLE! It wont matter!", then why worry about 18lb 18" wheels vs 24lb ones? Why worry about heavy ass iron brakes or the weight of a Torsen T2R vs the T-Lok? Why worry about the weight of your dampers, your control arms? Because unsprung weight, any addition, has to pass the "does it perform better regardless of the weight penalty" factor and when you have OPTIONS that accomplish the same goal (zero lateral displacement of the rear axle) that are less, why opt for more?

Do you think I would have chosen the torque arm over an adjustable 3 link setup (by that I mean lower control arm relocation brackets and new UCA mount) if I was allowed to under the rules? Hell no, but I had to get my forward bite back somehow within the framework of the rules and the torque arm fit that need.

 

[NoTicket]

In all of my searching I have only been able to find a single forum post where somebody claimed that the axle clamp slipped on the Fays2. Link

The user does not respond to any questions after making the claim. I haven't found any other example of this happening.

Are there other examples out there?

 

[ArizonaGT]

I beat the hell out of the car on the track a couple weeks ago with the Fays and nothing shifted. I had witness-marked all the bolts, and properly installed everything per the instructions. See the latest 2-3 videos in the link in my signature if you're curious about the application.

 

[NoTicket]

I beat the hell out of the car on the track a couple weeks ago with the Fays and nothing shifted. I had witness-marked all the bolts, and properly installed everything per the instructions. See the latest 2-3 videos in the link in my signature if you're curious about the application.

Was that a Syclone out there???

 

[Pentalab]

1.) The Fays2 unit's axle clamps are not U bolts and nor are they really U clamps either. Basically they are a circle cut in half such that a large portion (basically all) of the axle tube is in contact with the clamps. If one has shifted it was due to improper installation of the Watts link and NOT because of the design. I'm sure Sam Strano can post his lateral G numbers for his Mustang with the Fays2 and mine were peaking in the 1.25-1.3 range on a 3750lb car with driver in competition weight and I'm on narrow street tires. Zero displacement of the Fays2 watts link clamps but I followed the instructions for setting up the watts geometry (equal but opposite angles and no length differences).

Ideally you are correct though, welding would be a lot stronger but it is also permanent which most street car folks would rather not do in case they decide to change out parts.

2.) Why is this a problem exactly? It is simply the best way to support the center point. The total package is still the same total weight as any diff mounted unit is (around 28lbs) but instead of being primarily unsprung weight (diff mounted) it is mostly unsprung weight. There are other advantages in mounting the pivot on the chassis as well and the biggest one is adjustment range. Not that I hate Cortex Racing but how much rear roll center height adjustment do you actually have? I'm 99% sure my Fays2 has more and costs less. I also find it ironic that you talk about the PHB brace as being flimsy (even though as Norm pointed out it is only ever going to be effective in tension) yet the Fays2 brace is replacing that piece with a far superior brace to even that of any aftermarket PHB brace.

You know what my huge problem with a diff mounted watts link is? The fact that 3800 lbs of car and driver, moving laterally around 1.3g's is being transmitted through 10, 3/8" diameter bolts on the differential cover which sits atop a bead of RTV before it hits anything solid under it. The other thing is the increase in unsprung weight. Sure the Fays2 increases unsprung weight by a few pounds (less than 5 if I remember the math I did a long ass time ago) but not nearly the 25lbs of unsprung weight that is most diff mounted units. But I hear you scream "It's a LIVE AXLE! It wont matter!", then why worry about 18lb 18" wheels vs 24lb ones? Why worry about heavy ass iron brakes or the weight of a Torsen T2R vs the T-Lok? Why worry about the weight of your dampers, your control arms? Because unsprung weight, any addition, has to pass the "does it perform better regardless of the weight penalty" factor and when you have OPTIONS that accomplish the same goal (zero lateral displacement of the rear axle) that are less, why opt for more?

Do you think I would have chosen the torque arm over an adjustable 3 link setup (by that I mean lower control arm relocation brackets and new UCA mount) if I was allowed to under the rules? Hell no, but I had to get my forward bite back somehow within the framework of the rules and the torque arm fit that need.

Points well taken. The WL watts kit includes a heavy duty chromolly brace... ( to replace the oem flimsy PHB upper support brace). Brace is sprung weight.

How do you know the entire 3800 lbs is on the 10 x 3/8" differential bolt covers ?? I would think perhaps 40-50% of that at most. I use a lubelocker diff gasket....but that's a moot point. It would take one helluva lot of stress to shear the 10 x 3/8" bolts. I think they are G8, but I may be wrong.

Inner ends of the WL watts tubes are connected to the football/spider/diff cover. Outer ends are connected to the frame. I would not say the weight of the pair of watts arms are all unsprung weight. Perhaps 1/2 of the weight of each arm. Moot point really, since they don't weigh much to begin with. ( the super thick AL diff cover, spider + football are all unsprung weight).

You are correct though re: roll center adjustment. The WL only has 2 sets of holes to pick from. My car is lowered 1"....so I have to use the lower set of holes on the diff cover. Then both watts arms end up parallel to the ground. Upper set of holes is used on stock ride height cars.

Re: the broken weld on the WL watts link. That's unacceptable.....it's a catastrophic failure. Can you imagine the weld breaking at 50-100 mph....on a public hwy ?

Jimbo

 

[Norm Peterson]

How do you know the entire 3800 lbs is on the 10 x 3/8" differential bolt covers ?? I would think perhaps 40-50% of that at most. I use a lubelocker diff gasket....but that's a moot point. It would take one helluva lot of stress to shear the 10 x 3/8" bolts. I think they are G8, but I may be wrong.

Bolt shear would not be the critical consideration. Think total clamp load and resistance to cover movement from friction and gasket or gasket cement adhesion.

I'd be more concerned with gasket durability depending on how much cover bolt to cover hole clearances exist - given that the 8.8" diff cover does not appear to be dowel-pinned for positive location. Inspecting the cover for evidence of shifting around the bolt heads, and for fluid seepage would probably be a couple of good things to work into pre and post event inspections for diff-mounted Watts link propeller designs, particularly if your rear tires are no strangers to FIA curbs, or if a couple of wheels (or four) unexpectedly find an unpaved surface to run on.


Norm

 

[Roadracer350]

Jesus Christ we are still bitching about this... It's VERY simple... A watts link will produce a better handling car over a PHB setup. Period. Now the question is what to buy... Well look at what is out their, see what one you like then look at your wallet an figure out what to buy. Simple. If you can afford a diff mount and you like it then buy one. If you like the Fays 2 style chassis mount then buy it. It's all about preference and what YOU like not what everyone else likes. Look at me for instance, I liked the Whiteline unit but everyone else bitches about it. I bought it, installed it and drove it 1300 miles within 2 days of install. Handled great, no noise and WORKS. Some people like cortex. Some like Fays. Buy what you like an what will work for YOU. it's that simple. All the diff mounts install about the same as do the chassis mounts.

 

[Norm Peterson]

Well look at what is out their, see what one you like then look at your wallet an figure out what to buy. Simple. If you can afford a diff mount and you like it then buy one. If you like the Fays 2 style chassis mount then buy it. It's all about preference and what YOU like not what everyone else likes.

It is not as simple a decision for everybody as it appears to be for you, and the reasons for preference are wider than just appearance or even simplicity of installation.

There are too many threads on other topics where people have made multiple guesses at what they thought they were going to like before finally settling on something they actually did. But since choices in suspension modification involve a somewhat more critical vehicle function than exhaust sound it's better to think more and snap-decide less here.

I will probably end up with a Watts link at some point as well. But when or if that happens, all the ducks will be lined up in a row before a dime gets spent.


Norm

 

[dontlifttoshift]

Jesus Christ we are still bitching about this... It's VERY simple... A watts link will produce a better handling car over a PHB setup. Period.

Why? Show me data, not theory.

In regards to the Fays axle clamps. I ran a similar clamp arrangement as an axle side panhard mount and in 10,000 miles and loads of autocross never did it move one bit on my roadster. That said, it is welded on now.

 

[Pentalab]

Bolt shear would not be the critical consideration. Think total clamp load and resistance to cover movement from friction and gasket or gasket cement adhesion.

I'd be more concerned with gasket durability depending on how much cover bolt to cover hole clearances exist - given that the 8.8" diff cover does not appear to be dowel-pinned for positive location. Inspecting the cover for evidence of shifting around the bolt heads, and for fluid seepage would probably be a couple of good things to work into pre and post event inspections for diff-mounted Watts link propeller designs, particularly if your rear tires are no strangers to FIA curbs, or if a couple of wheels (or four) unexpectedly find an unpaved surface to run on.


Norm

The WL aluminum differential cover flange..that bears on the gasket is a hair less than 5/8" thick. 4 x 30mm long bolts and 1 x 25mm long bolt hold the spider to the diff cover. ( this portion of the differential cover is like 2" thick.).

The 4 x 30mm long bolts get 60 ft lbs of TQ. The single 25mm long bolt gets 40 ft lbs of TQ.

I don't remember how much TQ is on the 10 x 3/8" bolts that hold the .61" thick WL differential cover flange to the diff. Mine hasn't budged..but its a street car.

I did some very rough math calcs... but I suspect the load on the watts assy..assuming a 1.3 G side load...might be in the order of 2321 lbs.
( 3800 x .47) x 1.3

Jimbo

 

[sheizasosay]

Techco Watts diff cover screws that secure it to the pumpkin are torqued to 33ft/lb. It also doesn't use a diff gasket. Just black RTV silicone.

 

[Pentalab]

Why? Show me data, not theory.

In regards to the Fays axle clamps. I ran a similar clamp arrangement as an axle side panhard mount and in 10,000 miles and loads of autocross never did it move one bit on my roadster. That said, it is welded on now.

Place your car on a 'finger lift' with all 4 wheels dangling down..and take note of the position of the axle relative to the wheel well. Then lower the car down to the ground..so its entire weight is on the ground. Then note the position of the axle.

When up on the finger lift... the axle will shift a mile towards the pass side. It will shift a whole bunch towards the driver's side when back on the ground. Now load the suspension..and it will shift again...towards the drivers side. IMO..when that aprx 2300 lb side load kicks in laterally..and in a microsecond when you hit a bump on a corner, with a PHB, the load will simply transfer to the other end of the PHB.... (axle end) and presto..the back end kicks out on you. (pass end of PHB goes to the chassis)

I don't have any hard data to show to you....suffice to say that any idiot can tell the difference within 6 blocks of his home. (WL watts link vs PHB). It's not a subtle difference either....it's blatantly obvious. Any version of a watts link will eat the oem PHB for lunch..hands down.

Jimbo

 

[dontlifttoshift]

I am well aware of how a PHB works, and a watts for that matter. Are you? There is a huge difference between a mile and .050". The real advantage to the watts, assuming identical RCH, is that it loads the outside tires the same in left and right turns......but you already knew that.

This idiot wants data and track times on an A/B test. Until then, it is all theory.

 

[ArizonaGT]

Was that a Syclone out there???

ASA "Speed Truck" set up for road course. Sub-2500 lbs tube frame and about 350hp, with some nice wide slicks. That one only has a two-speed tranny but some out here have 4-speed Jericos; very quick in the right hands.

 

[Roadracer350]

It is not as simple a decision for everybody as it appears to be for you, and the reasons for preference are wider than just appearance or even simplicity of installation.

There are too many threads on other topics where people have made multiple guesses at what they thought they were going to like before finally settling on something they actually did. But since choices in suspension modification involve a somewhat more critical vehicle function than exhaust sound it's better to think more and snap-decide less here.

I will probably end up with a Watts link at some point as well. But when or if that happens, all the ducks will be lined up in a row before a dime gets spent.


Norm

I agree with you 100% that their is more into picking a watts than looks but most of the guys that drive these cars never track them or if they do it's at a drag strip. They just want it for looks and to say look what I have. Their was a LOT behind me picking the Whiteline unit. The deciding factor for me was ease of install, adjustable and quiet. I read a lot of Terry's posts an even exchanged emails over the course of 8 months with the Whiteline guys. With that being said maybe I need to retract what I said and clarify that MOST of the guys just need to pick what they like because they won't be able to tell the diffrence and won't care about the install because they will pay a shop to do it for them. For the rest of us do the research and see what will work best for you and your clubs rules.

 

[SoundGuyDave]

Place your car on a 'finger lift' with all 4 wheels dangling down..and take note of the position of the axle relative to the wheel well. Then lower the car down to the ground..so its entire weight is on the ground. Then note the position of the axle.

When up on the finger lift... the axle will shift a mile towards the pass side. It will shift a whole bunch towards the driver's side when back on the ground. Now load the suspension..and it will shift again...towards the drivers side.

You are absolutely correct, assuming you have, and use, a country-mile of suspension motion. I plotted the lateral motion through a 4" suspension cycle (2" of jounce, 2" of rebound), and the total net lateral motion was 0.100" (0.050" each way from "centered"). Unless getting the rear axle completely off the ground is your normal mode of driving, your example is irrelevant. +/- 2" of travel is a lot more "normal" and reasonable to look at. If you want to spend 4x the price of a rod-end PHB and add 20-30lbs (sprung/unsprung, who cares) to an already portly chassis, all to eliminate a problem that doesn't exist, be my guest. The bottom line here is that tire carcass distortion is several multiples of the axle shift allowed by a rod-ended PHB. Enough that the "signal" is buried in the "noise."

IMO..when that aprx 2300 lb side load kicks in laterally..and in a microsecond when you hit a bump on a corner, with a PHB, the load will simply transfer to the other end of the PHB.... (axle end) and presto..the back end kicks out on you. (pass end of PHB goes to the chassis)

WTF??? And a Watts will "magically" dissipate your theoretical side-load? If you're hard into a corner, all loaded up on the outside rear tire, and it hits a bump, it will unload, you will lose grip, and the back end will kick out on you. Regardless of the type of lateral-locating device you use on your axle, and regardless of directon of turn. A PHB (and Watts assembly for that matter) is simply in compression in one direction and tension in another.

I don't have any hard data to show to you....suffice to say that any idiot can tell the difference within 6 blocks of his home. (WL watts link vs PHB). It's not a subtle difference either....it's blatantly obvious. Any version of a watts link will eat the oem PHB for lunch..hands down.

Jimbo

Well THIS idiot has driven Watts-equipped S197s and was singularly unimpressed. Was there a difference? Yes, but very slight, and only on rapid transitions. THIS idiot has also set track records in multiple classes at several tracks doing Time Trial, sprint racing, and endurance racing... With a PHB... Must have been a fluke...

And to cap it all off, I'll add this:

Originally Posted by dontlifttoshift
To add to that, I still want someone to do A/B testing with an awesome link vs a PHB using the same roll center height.

I'll volunteer my car if there's somebody near Chicago that wants to actually do some instrumented testing in either Time Trial or race-group conditions... As mentioned, the roll center has to stay the same, though. It's not hard to swap a PHB, and from looking at it, not that hard to put on a Watts link either. I'm thinking start with the Watts, run a session, then pull it and swap in the pre-adjusted PHB (and stock brace), and re-run. No other changes. No spring rate, no damper adjustments, no tire pressure adjustements, just the rear lateral-location device. Highest peak-G and/or lap time wins? If no difference at all, then does the PHB win because it's cheaper and lighter? Assuming proper licensing and seat fitment (think skinny!), I'll even let the guy with the Watts drive both, and then we can compare data and notes to remove any potential (unintentional) bias. Can't get more fair than that. Two drivers, two different parts, no other changes, all on the same day at the same track with the same car. If there's a "ride quality" improvement to be found, I would bet it would show up on the Z-axis accelerometer.

So far, no takers. 'Nuff said.

 

[Gray Ghost GT]

I think these might be good examples of when you would not want to buy a watts link:

* Daily Driver
* Drag Racing
* Oval Track
* HPDE 1-2 on a Road Course

Examples of when you would want a watts link: quick lateral transitions with some skill:

* Autocross
* HPDE 3-4 on a Road Course
* Time Trials

 

[NoTicket]

If you lived in the area it would be easy, Dave.

There is very little A/B testing ever done on any suspension upgrades that I can find. Most of it boils down to "I went autocrossing last weekend and got 1:00 laps, I put in Koni Sports and this weekend I have 0:55 laps! 5 SECONDS JUST FROM SHOCKS!"

Also, here is some actual testing done on a Fox Body where they saw a 3 second drop in both average and best lap, but of COURSE they couldn't just test the Watts Link, they also swapped out the original shocks for Koni Sport as well as replacing the tie rods and strut mount: http://www.musclemustangfastfords.com/tech/mmfp_1201_watts_link_install_street_smart_track_ready/

I saw an 8 second drop in lap times when I swapped in a Watts Link, but that was because it was my 3rd time at the same track and I was finally familiar with it to get the better times. The track was also cooler and there was a cool breeze to cool the brakes off, so my street tires were not turning to grease, and I was able to brake as hard as I wanted in every corner. Of course I could just contribute it all to the Watts Link, since it did make the car feel better.

 

[kcbrown]

Also, here is some actual testing done on a Fox Body where they saw a 3 second drop in both average and best lap, but of COURSE they couldn't just test the Watts Link, they also swapped out the original shocks for Koni Sport as well as replacing the tie rods and strut mount: http://www.musclemustangfastfords.com/tech/mmfp_1201_watts_link_install_street_smart_track_ready/

On top of that, I don't think installation of a Watts on a fox body really counts as evidence of the benefits of a WL over a PHB, seeing how it's replacing the quadra-bind rear suspension and not a PHB...

 

[SoundGuyDave]

If you lived in the area it would be easy, Dave.

There is very little A/B testing ever done on any suspension upgrades that I can find. Most of it boils down to "I went autocrossing last weekend and got 1:00 laps, I put in Koni Sports and this weekend I have 0:55 laps! 5 SECONDS JUST FROM SHOCKS!"

I hear you... +/- a different course, weather conditions, driving skill increase (assuming a "learning" driver), etc., etc., etc. For any test to be valid, you have GOT to reduce the total number of variables to one, or at least minimize the impact of ones you can't control.

Also, here is some actual testing done on a Fox Body where they saw a 3 second drop in both average and best lap, but of COURSE they couldn't just test the Watts Link, they also swapped out the original shocks for Koni Sport as well as replacing the tie rods and strut mount: http://www.musclemustangfastfords.com/tech/mmfp_1201_watts_link_install_street_smart_track_ready/

With this one, where do I even start? Comparing a triangulated 4-link (AKA QuadraBind) geometry to a freely-articulating 3-link plus PHB isn't even apples and oranges. At least those are both fruits. If you really want an idea of how LUCKY we are to have the 3-link, you have only to look through the Camaro-Mustang-Challenge forum and rulebook.

With the QuadraBind, lateral axle location is handled by the coverging angles of the upper control arms, which do a fair job of centering the axle and keeping it there. Unfortunately, that same converging angle creates instant bind as soon as the chassis starts to go into a roll condition. If you ever want to drive a Mustang with absolutely wicked snap-oversteer tendencies, grab a FOX or SN95 platform car and replace all the rear control arm bushing with polyeurethane! No compliance yields instant rear silliness in a corner. Okay, back on topic: The CMC rule set specifically allows the FOX and SN95 chassis cars to do all sorts of silliness with the rear suspension in order to keep up (performance parity) with the F-bodies...

1) May add an adjustable PHB for lateral location. This can help, depending on setup, but it's worth noting that the National Championship car for 2013 (SN95 chassis) elected not to run one.

2) May (effectively) delete one upper control arm, a scenario called a "Poor-Mans 3-Link" or PM3L for short. With a PHB, this frees up the rear to actually articulate without binding and the resulting snap-oversteer, but then routes all the stresses through ONE torque box, tending to tear it out of the frame, and also eats upper control arm bushings at an alarming rate.

Taking a look at the "mod list history" for the FOX/SN95 (really same chassis, a Fairmont, just with different sheetmetal and a few other small-ish changes), when it came to road-course and race duty (American Iron comes to mind...) the hot ticket is indeed a Watts. But only when you delete the upper control arms entirely and add a torque-arm. THAT, by the way, opened up another can of worms in terms of brake-hop... For a while, there was even a manufacturer that was selling a bolt-on kit that bridged the upper control arm mounts on both the axle and chassis sides, converting the rear suspension into...you guessed it...a 3-link! Obviously, you'd need a PHB or WL to locate the axle as well, and they did happen to offer a PHB.

After all the rambling, though, it still comes back to "what is good for a FOX is not necessarily good for an S197." Just look at subframe connectors and strut-tower braces as examples.

I saw an 8 second drop in lap times when I swapped in a Watts Link, but that was because it was my 3rd time at the same track and I was finally familiar with it to get the better times. The track was also cooler and there was a cool breeze to cool the brakes off, so my street tires were not turning to grease, and I was able to brake as hard as I wanted in every corner. Of course I could just contribute it all to the Watts Link, since it did make the car feel better.

Now THAT sounds like a reasonable (and reasoned) report. Lap times dropped, however there were driver comfort (with the track) increases, reduced ambient temps (MOAR POWAH!!), better braking conditions, less tire degradation, etc., etc., etc.

Did the Watts help? Maybe, maybe not. If it did help, was it because the rear end lateral motion was reduced by something approaching 0.100" or was it because the roll center was relocated making the car easier to drive closer to the limit? I bet you can guess where my money is... ;-) If it was the roll center that did it, then I would personally hack off one pound of bracketry and add two pounds of new bracketry than add a bunch of links, and another 20+ lbs to get the same effect.

I honestly don't doubt Terry Fair's experiences trying to stuff gumball rubber under the stock sheetmetal. In his case, I think he was cutting the clearances so fine that the 0.100" difference actually was important.

I'm also not saying that anybody that did put a Watts on the car is an idiot, a moron, or wasting their money, I'm just trying to get to the bottom of this whole "dropped 19 seconds off my lap time AND out-accelerated a Ferrari F430 while having a cake decorated in the back seat because the ride was so awesome, and I owe it ALL to the Watts Link" thing. A Panhard (with rod ends) just doesn't allow enough lateral motion to account for any of the reported changes.

Bonus points to the first who can ID the cake-decorating reference. Hint: it's a car ad for a model no longer in production... ;-)