Watts link manufacturers? Pro and cons?
09-26-2012, 03:50 PM
#21
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Some believe the bolt through the pumpkin is the more correct role center design. The Techco Watts link is designed for a 1" drop from stock proper roll center. It works great and there is much more rear stability in and out of corners and rough corners.
Just felt I'd bring this thread back to life, as some have mentioned they don't believe the watts link makes a difference. My experience is other than the initial springs, shocks, and sway bar change out, the watts link was the most profound difference in cornering and stability for my car with hard driving.
Whiteline has an adjustable roll center unit that is centered through the pumpkin. Erik
Just felt I'd bring this thread back to life, as some have mentioned they don't believe the watts link makes a difference. My experience is other than the initial springs, shocks, and sway bar change out, the watts link was the most profound difference in cornering and stability for my car with hard driving.
Whiteline has an adjustable roll center unit that is centered through the pumpkin. Erik
Last edited by eolson; 09-26-2012 at 04:04 PM.
09-26-2012, 04:02 PM
#22
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I still don't sell Watts links. I have made one myself I'll post a picture below. Of the ones for sale since the last time this thread was active I like the Cortex and the Whiteline. I still think the Fays and Steeda are really poor designs.
09-26-2012, 09:47 PM
#23
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09-27-2012, 11:45 AM
#25
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Geometrically there isn't much argument that either Watts link arrangement is an improvement over the PHB.
Between the two WL variants, it's somewhat less clear and probably depends at least on link geometry and ride stiffness. There is a slight difference in the rate at which axle steer varies with ride height, and there will be differences in transient behavior depending on whether the rear RC is permitted to migrate in accordance with ride height. Just over the range of possible LCA 3D geometry, I doubt that either WL arrangement is universally better than the other.
FWIW, any bending deformation in the standoffs between the diff cover and the outer plate (and there will be a tiny bit) will shift more of the load to the diff cover end of the main pivot bolt, which will introduce a little bit of bending in the bolt and in the cover itself. Better than single shear -absolutely. But not quite as "pure" of a double shear situation as you might think.
These two bolts should absolutely be on your list of things to periodically check, because if they loosen you're right back to single shear with a pin and a diff cover that were intended to be (almost) in double shear.
Norm
Between the two WL variants, it's somewhat less clear and probably depends at least on link geometry and ride stiffness. There is a slight difference in the rate at which axle steer varies with ride height, and there will be differences in transient behavior depending on whether the rear RC is permitted to migrate in accordance with ride height. Just over the range of possible LCA 3D geometry, I doubt that either WL arrangement is universally better than the other.
FWIW, any bending deformation in the standoffs between the diff cover and the outer plate (and there will be a tiny bit) will shift more of the load to the diff cover end of the main pivot bolt, which will introduce a little bit of bending in the bolt and in the cover itself. Better than single shear -absolutely. But not quite as "pure" of a double shear situation as you might think.
These two bolts should absolutely be on your list of things to periodically check, because if they loosen you're right back to single shear with a pin and a diff cover that were intended to be (almost) in double shear.
Norm
Last edited by Norm Peterson; 09-27-2012 at 11:50 AM.
09-27-2012, 12:20 PM
#26
Bolt load on the diff cover has always been one of the biggest concerns on the Watts Links with the diff cover design. That's why when we designed the Whiteline Watts Link we made sure the load was spread evenly over 6 bolts to avoid any sort of bending, or worse, bolt snappage (which I have had the pleasure of happening to me on past Watts links).
09-27-2012, 06:14 PM
#27
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I think I might be the only person who carries Fays2, Whiteline (recently), and Steeda. I think they all work fine as Watts links. There are differences, and I'm sorry to say there is nothing wrong with the frame design.
I, personally, am not a huge fan of mounting to the diff cover for various reasons, but most notably you need a way heavier cover to mount to, and that means the diff will run hotter. There are also legality issues of diff cover mounted ones for ESP in SCCA Solo, unless you just want to wish it was all ok. Might be, but there are questions, and until those are ruled on better safe than sorry. If you don't like the frame design, that's ok. There are some that suck to be sure, but not all do and you should not paint them all with the same brush. And lastly... if you are doing a watts link to give you the most precise location you can get, well rod-ends have less deflection than any bushing.
The Fays2 unit is a proven design that has worked well for myself an others, and doesn't cost $900-1000. If you want to spend that, ok but I'm very much a person who wants value for my dollars. I will pay for performance, and quality, so don't think that means since the Fays2 is $650 that is the reason. The reason is it works. So do others. There is a lot of room for interpretation here.
I, personally, am not a huge fan of mounting to the diff cover for various reasons, but most notably you need a way heavier cover to mount to, and that means the diff will run hotter. There are also legality issues of diff cover mounted ones for ESP in SCCA Solo, unless you just want to wish it was all ok. Might be, but there are questions, and until those are ruled on better safe than sorry. If you don't like the frame design, that's ok. There are some that suck to be sure, but not all do and you should not paint them all with the same brush. And lastly... if you are doing a watts link to give you the most precise location you can get, well rod-ends have less deflection than any bushing.
The Fays2 unit is a proven design that has worked well for myself an others, and doesn't cost $900-1000. If you want to spend that, ok but I'm very much a person who wants value for my dollars. I will pay for performance, and quality, so don't think that means since the Fays2 is $650 that is the reason. The reason is it works. So do others. There is a lot of room for interpretation here.
09-28-2012, 04:20 AM
#28
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Agreed, I didn't want to imply that I chose the Techo(through the Diff.) Watts Link 4 years ago because I thought it was the best for all out and frequent racing, I believed then and now that the Griggs and Fays2 were better suited to that.
I chose the Techco because it had superior parts and bolt strength to the Saleen unit that I was replacing out of fear of bolt snapping, and didn't want the NVH that some were reporting with the Frame units that were designed for racing priority. The Saleen and Techco units are very quiet from my direct experience.
I certainly don't doubt that the Fays2 and Griggs units are stronger and a better bet for racing compared to the Saleen and Techco types because of the single bolt as Sam and Norm have mentioned.
Both designs work great for improving the car's handling from my experience and from what has been reported. Red Devil is just being polite in not mentioning the numerous bolt breakages from S****n's Generation 1 and 2 units that prompted me to switch to a direct fit replacement with the Techco, which I got for $495.00 from Techco because they were going out of business, and wanted to clear as much stock as possible. It is still going strong.
Whitelines new design might solve the single bolt problem it seems, having to have only one super human double sheer bolt. Now there are 6. I don't think the Diff cover is overly heavy or thick on this one. Maybe I'll switch to that one if it's quiet when my Techco bolt snaps........Erik .........( s n a p )
I chose the Techco because it had superior parts and bolt strength to the Saleen unit that I was replacing out of fear of bolt snapping, and didn't want the NVH that some were reporting with the Frame units that were designed for racing priority. The Saleen and Techco units are very quiet from my direct experience.
I certainly don't doubt that the Fays2 and Griggs units are stronger and a better bet for racing compared to the Saleen and Techco types because of the single bolt as Sam and Norm have mentioned.
Both designs work great for improving the car's handling from my experience and from what has been reported. Red Devil is just being polite in not mentioning the numerous bolt breakages from S****n's Generation 1 and 2 units that prompted me to switch to a direct fit replacement with the Techco, which I got for $495.00 from Techco because they were going out of business, and wanted to clear as much stock as possible. It is still going strong.
Whitelines new design might solve the single bolt problem it seems, having to have only one super human double sheer bolt. Now there are 6. I don't think the Diff cover is overly heavy or thick on this one. Maybe I'll switch to that one if it's quiet when my Techco bolt snaps........Erik .........( s n a p )
Last edited by eolson; 09-28-2012 at 04:24 AM.
09-28-2012, 04:43 AM
#29
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On a separat note about the watts link, maybe Sam or Norm could weigh in on this?
I had mentioned in a couple Mustang and Camaro forums during the build up and release of the ZL1 vs. Boss 302 LS,2013 GT500 period, that I believed if the Boss LS had a Watts Link when it ran back to back against the ZL1, that it would have had less twitchy and squirrley behavior as described by Randy Pobst, which caused him to not be as aggressive in the curb corners with the boss, and added up to be slower times in those corners than with the ZL1. With better brakes as well of course. What do you guys think?
Also I had mentioned that the 2013 GT500 with an X brace and a Watts Link would fair better in the corners against the ZL1 also, because the X brace dis-allows as much torque twist in the frame in hard corners tending to lessen the grip of the rear inner tire and rear in general, and the watts link eliminating the lateral frame sliding in hard bumpy /uneven cornering. Also having wider tires would of helped out with brake duct cooling.
A lot of Mustang guys said i was full of crap and those items( watts and x brace) wouldn't make a difference anyway, and the PHB system was not at all a negative factor for the GT500 at all.
What do you guys think? I think those two items and wider tires would make a difference with the 2013 GT500. Thanks a lot, Erik
I had mentioned in a couple Mustang and Camaro forums during the build up and release of the ZL1 vs. Boss 302 LS,2013 GT500 period, that I believed if the Boss LS had a Watts Link when it ran back to back against the ZL1, that it would have had less twitchy and squirrley behavior as described by Randy Pobst, which caused him to not be as aggressive in the curb corners with the boss, and added up to be slower times in those corners than with the ZL1. With better brakes as well of course. What do you guys think?
Also I had mentioned that the 2013 GT500 with an X brace and a Watts Link would fair better in the corners against the ZL1 also, because the X brace dis-allows as much torque twist in the frame in hard corners tending to lessen the grip of the rear inner tire and rear in general, and the watts link eliminating the lateral frame sliding in hard bumpy /uneven cornering. Also having wider tires would of helped out with brake duct cooling.
A lot of Mustang guys said i was full of crap and those items( watts and x brace) wouldn't make a difference anyway, and the PHB system was not at all a negative factor for the GT500 at all.
What do you guys think? I think those two items and wider tires would make a difference with the 2013 GT500. Thanks a lot, Erik
09-28-2012, 09:45 AM
#30
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A PHB is pretty good until you start crowding the car's limits, where its asymmetry gets in the way. A partial solution of sorts is to lose the OE rubber bushings for something firmer.
It's a little harder to claim that the X and a WL would represent the total solution, even though they represent steps in the right direction. I can't see harshness over curbs is being particularly helped by a WL, as driving over an FIA curb will still kick the rear of the car outward (albeit symmetrically, left vs right).
With the X in place the car's own structural response to the "one-wheel" bump is likely improved, and would tend to change the crossweight (more load on the outside front-inside rear pair as the rear tire is climbing over the bump) in an understeerish direction which is at least trying to make things more predictable.
What I really think would help the harshness issue all around is some relatively minor revision to the LCA geometry (think 3D here) that would allow the axle to move back slightly as it goes up into 'bump' - and do so without messing up the roll steer which seems to be pretty good right where it is. Easier said than done, unfortunately, and it still won't fix the matter of shock damping.
Norm
It's a little harder to claim that the X and a WL would represent the total solution, even though they represent steps in the right direction. I can't see harshness over curbs is being particularly helped by a WL, as driving over an FIA curb will still kick the rear of the car outward (albeit symmetrically, left vs right).
With the X in place the car's own structural response to the "one-wheel" bump is likely improved, and would tend to change the crossweight (more load on the outside front-inside rear pair as the rear tire is climbing over the bump) in an understeerish direction which is at least trying to make things more predictable.
What I really think would help the harshness issue all around is some relatively minor revision to the LCA geometry (think 3D here) that would allow the axle to move back slightly as it goes up into 'bump' - and do so without messing up the roll steer which seems to be pretty good right where it is. Easier said than done, unfortunately, and it still won't fix the matter of shock damping.
Norm