The piece might be slamming into the bump stops.

Cut the eyes off the ends of the bar and welded on a square tube with a slot machined in it. I had to make some brackets that bolt onto the body to use rod ended links. I'll try to remember to take some pics when I get home, it's sitting in my "car room" because I didn't like the lowered roll center.

Ah! Now that makes sense!!! With all else unchanged, lowering the rear roll center reduces rear lateral weight transfer (which will also help hook up the rear under power) but it will increase the roll. That's why a bigger rear bar is needed (and possibly spring and shock changes if the roll center is dropped a lot).

Remember, roll and weight transfer are not the same thing. You can have a lot of roll with little weight transfer and vice-versa.

Once the car lifts the inside front enough to park the outside rear on the stop, it will stop pushing, but not in a good way Until you hit that outside rear stop, there's lot's of roll (and camber loss at the front) but little weight transfer. When you hit the stop and the rate spikes, weight transfers suddenly to the outside rear even though there will be little additional roll.

That's not in any way an indictment of the Watts link.

It's also not an indictment of lowering the roll center, though the required swaybar/spring changes are at the heart of Sam's objection to it, and of course some may not like it. I also haven't tried it nearly as low as some, might not like it, and may never try it. Some is good doesn't always mean that more is better.

Brian, I'd suggest either buying the hollow Addco 25mm bar (that would be my choice), OR raise the pivot until the push comes back, and then keep raising it until the push goes away again

Wanna sell it?

Ha, no... no bump stop slamming.

I went from an extended 19mm rear swaybar (think 17 or 18mm at most) to a 22mm solid bar.

--> I miss spoke before. (Sorry, hangover issue)

I lowered the pinion on until the looseness went away and the car got [to what I call] neutral.

Not until I do the same thing to one of Sam's 22 bars.

My car doesn't have a watts or any other mechanism for changing RC on it, at least not right now it doesn't.

Once I took one run in John's car I went out on the 2nd one and literally tried to make the thing transition as fast as possible and mostly the rear just stuck which was nice. I bet the rear letting go had more to do with some bumps in a very fast slalom/lane change than with any inherent issue with the RC change. The mid-corner push had everything to do with the RC height change, though. I'd be more incline to compensate for the RC change with spring vs. bar because I'm already torching my T2R coming out of slow right-handers.

But, I'm still not sure I'm gonna mess with it yet anyway on my car.

The Hotchkis has always been available separately for the rear--it's the front one that's not. And I don't have either on my website, I just can't possibly keep up with every single thing out there, and try and concentrate on parts that work best for the masses.

I have both bars, and I *BEG* you guys to ask me about things you don't see on the website. I might not be able to help, but chances are I can.

I have it narrowed down to two things... The trouble is finding the time to work on it and then running it to shake it down, not tracking down the problem...

Here's a question specifically for those who have tested and at adjusted the Watts on race tires with no other changes:

To get the car back to "balanced", where did the pivot end up relative the center of the PHR that was removed?

The RC height moves around in roll with the PHR, as well as the distance from the roll center to the CG. That also changes a little in trail braking, by about half as much as the tail rises, but of course it changes a lot more as the turn-in is initiated. So, the balance isn't static, and to some extent we choose the swaybar (and etc) so that the car is manageable at worst case.

The RC height shouldn't move much in roll with the Watts. The roll center height will actually change a little more in trail braking, but the distance from the roll center to the CG will NOT. It also shouldn't change as the turn-in is initiated.

In other words, I wouldn't expect the Watts and PHR to behave exactly the same with equal static rear roll center height. That's kind of the point So, I wouldn't be surprised if the Watts pivot needs to be a little higher to achieve approximately the same average balance or feel. That seems to be consistent with the descriptions of dialing in John's car above, but I don't know where it started or how much it had to move.

Again, I'm specifically interested in how the RC height had to change (if any), relative to where it was before, without any other changes (ignoring things like wheel bearings, of course).

I'm only going to get one testing opportunity this year on a semi-decent surface, and there won't be any opportunity for tuning until next year. I missed several testing opportunities because of my wife's major surgery, our last great-surface event was canceled due to a garbage truck rodeo (seriously) failing to clean up the site on time, and what's left will be on a small, slick site that's too misleading for testing.

After I added the WL I drove around with WL Pivot in the top hole. It did not feel all that different.

I drove at Putnam Park with the WLP in the top hole with my normal race set up (i.e.: tires, etc)

I then moved the WLP down one hole (one half inch right?) The car felt pretty much the same, but I think it was better. Probably because it pushed a bit more and there was less drama at the limit.

The next day I drove it around Putnam for 2 hours in the rain on street tires. The car was fine. Better then I remember it was with the PHR.

(Keep in mind that I am a dull person and such... my senses are dull. I'll notice the big changes like the difference between a dirt road and a paved road.)

My buddy drove my car (a very excellent and sensitive driver) said the car was better and way more manageable then it use to be. He drove the car in the wet.

Sean,

I started the car one pivot point down from top which worked GREAT at OVR's last Cooper Stadium event as the lot is not as grippy as the Fedex Field lot. I believe that I tend to turn the car more with trail braking than Brian or Sam...to which I did not notice the slight push that they did. Yeah I still divebomb slow as shit corners....

I moved it to the top most point which made a big improvement at Fedex's high grip lot in steady state turns and made slaloms a little bit worse.

I will try a few things at my next event up with Jason Kolk and those Detroit region people and see how it goes.

BTW...if I get this feel thing down cars with watts links will DESTROY at autox. The fact that I could change that RC just that little bit made the car love slaloms more than anything. I see this as a huge benefit when it comes to Nationals next year if we have a "sweeper" course and a "slalom" course. 5 min adjustment with no shock or spring changes and you can throw the car around slalom cones.

Now I just gotta add more rear spacer and roll my fenders more. The car is able to "squat" out of corners putting massive power down which is causing a little to much fender to tire contact that I would like.

Another note: I like the "feel" of the auburn racer diff in my car better than the T2R. It feels like I can just use the throttle to change the attitude of the car that much more.

I was able to bring a racket and crescent wrench and make changes to the WLP while in grid. It was easy enough to do it by myself in 3 minutes. No jack required.

Besides, your only going to move it down anyway. =)

I believe it was an 1-1/8" rachet and a 1-1/4" wrench to get it all changed...and it looks like Brian (Shortbus) and I have the same feedback as well.

I'm definitely going to start with it lower than most. My car was already dialed in with the Hotchkiss bar. I had swapped in a Hellwig bar before Putnam (at the stiffest setting) with no other changes, and swapped the Hotchkiss bar back in for the Watts because it fits My spring rates, shocks, front bar, and ride height are all the basic Strano setup, but I had the PHR lowered a little. So, by knowing where the Strano cars ended up, I can make a reasonable guess about where to start mine (which will be lower, but roadkill has nothing to fear).

I didn't realize the pivot could be reached without ramps. That's cool! I'm going to have to try it ahead of time, though. My, um, ground clearance is a bit more snug than yours

I was initially worried that I'd have to drag around a jack. I was happy I did not have to.

Don't worry though if your arms are long the ground clearance does not matter.

Well, the stars are not lining up for me to test tomorrow. My one and only test this year will be on a small, slick lot in cool weather. Good thing I can drop the pivot a notch to plant the rear if needed

How did it go?

I did a test yesterday too.... I don't think the pivot needs to move all that much. It is not a drastic change when moving the WLP down (or up). It is more of a gentle change. More akin to a small adjustment with an adjustable rear bar.

Did you move your WLP down all that much?

The small, slick, cool test will be next week at Applebee's. I was hoping to test yesterday at UPS in Louisville, but it didn't work out.

For Applebee's, I may drop it to the bottom hole Actually, my best guess for the Hotchkiss bar is the 3rd hole from the top (down 1" from top hole). I registered for CP because they usually run mid-afternoon. The 4-banger guys seem to be afraid that the old-school V8s will puke oil everywhere

ugh.

I am thinking you'll see that as too low. I have a solid 22mm rear bar and I am using the 3rd hole form the top. (All else the same)

Yeah, my first choice for Applebee's Park would be the Miata on street tires. Testing there is of limited value, except that a dry day there is a reasonable proxy for rain anywhere else.

The third hole down was at least in the ballpark with the 25.4mm (1") hollow rear bar. On a day that leaves the tires clean and nicely polished, with very little pressure gain over six runs, there's no point in trying to fine-tune it. The car was very well-mannered, predictable, and working well, so I left it alone.

In fact, the car was really behaving like there was a lot more grip than there actually was. I was able to spend a fairly high percentage of time at or near full throttle without it getting squirrely, and it still turned well. It's not dialed in yet, but as-is was pretty good (good enough for a rusty driver to win CP)

Hellwig has redesigned their adjustable bar to work with the Watts link.

Stranoparts carries the Hellwig bar, BTW

Sorry I was late to the party, I was driving back to Ohio for most of the day. The aluminum PHB discussion has been relocated here:

http://www.frrax.com/rrforum/index.php?showtopic=12718

How difficult is the Watts Link to setup?

I may have to upgrade my PHB from a poly end / rod end to a double rod end PHB to run 17x 11's and 315 35's. I figured if I am going to need new parts, should I jump in with both feet and just get the Watts Link? But if it requires the use of a Flux Capacitor and a PHD in Suspension Engineering to setup the Watts Link, then I may stick with the simple PHB and it's limitations.
Thank you.

I used an electronic level for the setup, which helped a lot, or at least allowed me to pursue precision as far as it would go. The hardest part of the job for me was just cutting off the brake line clips. They have to be ground down flush, since they will be covered by the clamps. Disconnecting the shocks to get better access would have made that go quicker. There were a few other minor installation headaches, but nothing major. The setup isn't hard, just take you time.

I do think you need to have ramps available. It would be tough to get it right on jackstands.

I just cut some notches in the spacers that go inside the clamps and pounded the tab flat. Worked great.

I used an angle finder like you'd use when setting up a torque arm. Cheap, had it, and it works. Same deal as Sean. Nothing major, just a few things you'd expect with a completely different setup. Handled all myself with normal shop tools. I had to hog out one hole a touch, and cut off some washers so I could reuse two bolts as the heads of the replacements were too big.

I didn't have to hog out any holes. I just deviated a bit from the instructions. On the passenger side, I just ran the bolts through without installing the nut. Then I pulled it into line with the holes on the other side, and walked them down evenly, then went back and installed the nuts on the driver side. I had a heads up from CrouseEEE (thanks!) about the bolts beforehand, so I ordered socket head bolts with a non-plated zinc coating (instead of the usual black, which rusts, or plated, which is subject to hydrogen embrittlement in hardened grades). I think I posted the part number for the bolts earlier in this thread.

I did have to just lightly clean up the edge of a weld on the body with a Dremel (got a heads up on that too).

Note that my car was in a big accident and had to be pulled and took a big shot to the LR. Anything I had to do to line it up is in no way an indication of the Watts itself.

I think this might also be approprate for the Chassis/suspension section as well, fwiw....

I ran my first even with the Watts link on my Camaro. I was using some take off tires Brian (BigEnos) gave me dating back to '07. My Auburn Racers is pretty well used up (ask anyone at the event). Worked well, car was a little looser than I'd like in high speed transition, but that's easily put down to not great tires and a weak limited slip. None the less the Watts link was very good, and with some dialing in will get nothing but better.

I ran FTD over some other very capable cars and drivers, including some SS and ASP C5 and C6's as well as a some fully setup Shelby's in FS (expect to run them on raw time, paxed them too pretty handily. Even by '08 PAX index for FS.

I just took an educated guess on rear bar and slapped a 24mm on it. I think it's a touch too much, and will be going to an adjustable 22 for my own car shorly.

And to address the "how much lateral movement does the Watts cut out" discussion.... At least 10mm each way. How do I know? Well, I took 10mm of spacer out of each side on the rear and never rubbed the inside--and still would with a PHB and the spacers before, though not all the time. I'm not disappointed, and it'll only get better the more I understand it, work with it, and use better tires and differential that's less worn (this one dates from before Nationals '06).

Does the 'little loose' comment apply to slaloms?

What shocks were you running on the rear?

Which pivot hole did you use with that 24mm bar? Is it solid or hollow? Which pivot position(s) did you try?

If it is solid, and has stock-length arms, it should be just slightly (3~4%) softer than the Hotchkiss bar. On old tires with a weak diff, I'd expect hole 3 (1" from the top) to be pretty decent (maybe hole 4 if the tires and diff were really bad). Regardless, it might be interesting to see how low you have to drop the pivot with that bar before swapping it out.

I went to a test-n-tune yesterday with the prototype Hellwig 1" bar. I was at a slick site that never really gets the tires warm, though the sun was out all day and the grip was better than usual for that site (which isn't saying much).

I started at the softest setting, which is roughly 37% stiffer than the Hotchiss bar due to being solid and having slightly shorter arms (stiffness proportional to arm length squared). The Watts pivot was in hole 5 (1" from bottom). The car felt really good and stable with that combination. Getting power down was no problem at all, and on any other day I'd have been content to leave it like that. This could be a "set it and forget it" combo.

Solely because I was at a TnT with untested adjustments, I tried going to the medium setting on the bar, which is quite stiff. I also moved the Watts pivot to hole 6 (1/2" from bottom). The bar adjustment is coarser than the Watts adjustment. I expected that combination to be a little loose, and it was. It actually felt great in slaloms and high speed transitions. The tail felt just slightly twitchy under full throttle, but not enough that I had to lift, and it was easy to control. There was just a little wheelspin at the corner exits, but that was offset by being able to get on the power sooner without pushing out. It turned out to be faster, at least for that course. I don't know if I'll leave it that stiff or not yet, but it is a useful combination to have "in the toolbox", at least for a smooth course.

Philosophically, I have no intention of ever trying to dial it in with the bottom hole on a dry day; that's reserved for rain. As the roll center becomes better controlled (Watts+lowered), the car can tolerate a looser setup, up to a point. On the last run of the day, I had a very fast run going but went into the last turn kind of wild. I lost the tail coming out, but was able to hang on and fishtail my way through the finish for a clean run and my fastest of the day, and as far as I know, the fastest run for anything above 2300 pounds and all but three or so drivers. Not bad for my first event of the season. The point is not that it broke loose (I screwed up) but how easy it was to save.

"On paper" (Jon's roll rate spreadsheet), the setup I started with should have been looser than what I've normally run in the past, and the last setup should have been a LOT looser. In practice, it wasn't. Without the ever-changing balance of a "stockish" setup, you can get closer to the edge without falling over. That's why I only made a small roll center change to compensate for a big bar change, which was the main point of the experiment.

BTW, the 24mm bar (assuming it has stock length arms) should be just slightly softer than the middle hole on that 22mm adjustable bar (assuming it is the one you sell ).

BTW, along with redesigning their bar to fit with the Watts, Hellwig has now redesigned the mounts to clear without spacers. I test-fit the prototypes a few weeks ago. I have some pictures, but probably won't have a chance to get them up for a few days.

Sean, great update.

Wasn't really a true slalom. And it was directly related to wheelspin (as it was fine when I wasn't igniting a tire). And the fastest part of the course was over a rise which of course made wheelspin more prevelent. Car was predictable any time I tossed it. Only when the obviously toasted LSD was the issue was the car moving around what I'd consider too much.

Bear in mind this was one course, one day, on old tires, with a not perfect LSD, and at a completely new surface that I've never run before. I can make some judgements based on driving other know commodity cars on the surface and feel comfortable with knowing what the car was doing due to surface vs. setup.

FWIW, I trailered my Camaro and made some fun runs in the Mustang. It seemed to get faster based on other's times than it had been when I was running. None the less I could not run the time I had put down in the Camaro in the Shelby (which had better tires and a better differential). And since I ran the Mustang later when numerous folks when tangibly faster in the same cars vs. 2nd heat comp runs I think that's a pretty good indication we're on the right track.

thanx Sam for the write up. guess I'll be ordering one during our 3 month break as you have shown that a well driven and setuo car CAN FTD.

Finished installing the watts link on my car today. I still have more work to do on the front of the car so it's not ready to be driven yet. Hopefully by next weekend.

Ran my car again with the Watts. Same crappy tires. Coned away my fastest run, and still playing around (hey it was only my 5-8th runs with it on my car). I ran FTD, but the event wasn't exactly filled with super fast cars and drivers. But the one benchmark was a well setup (by me) National Championship winner driven Shelby. I coned my fastest that would have had me PAXing around .4 off.

Dialing in will continue as time/events allow, but for a while my car will be back-burnered because the National events are coming and I need to tune up in the car I'm running all year.