The spacer to move the swaybar down a bit is what is being made and was to be shipped out separately. I can check on the status of that, or if you are in a hurry (not sure when I can make the call), a call directly to Fays2 ought to get you the update. Just let him know you are one of my customers.....

Ideally installation is to be with the suspension loaded. However if you have to lift the car, that's fine, but everything needs to be checked and retightened with the car @ ride height.

What's the recommended maintenance for the bellcrank (aka "propellor") bearing? It doesn't appear to be sealed. Shoot in some WD-40 every now and then, or some aerosol lithium grease, or ???

I was under the impression that Sam had always said it was a fruitless venture to change the rear roll center and had even commented on several occasions that the PHR lowering from UE was a waste of time given the insignificant amount that the rear shifted from side to side even in a stock configuration... especially in a soft suspension.

Has something changed?

Is this product a result of consumer demand?

Are there any real world experiences as far as performance improvements go?



I've read the books, I know the theory, but theory and real life doesn't always match up.

I suspect Sam is busily preparing for Nats, or already on the road by now.

This is an attempt at an unbiased overview. I'm not trying to put words into Sam's (or Jason's) mouth, but if you want his full opinion on the matter (in his own words), it's already out there to search for.

Sam has said that it is a fruitless venture to lower the roll center, and as recently as a few weeks ago (a page or so back in this thread) his opinion hadn't changed. The Watts link does allow lowering the roll center easily, but that's not the reason Sam is promoting it. In fact, he asked Fay to ensure that there was enough range of adjustment to avoid lowering the roll center.

Sam's objection (ie the drawback of lowering the roll center) is primarily that lowering the roll center requires stiffening the rear springs and/or swaybar. This reduces "mechanical grip" (the static ability of the car to maintain the weight distribution between tires on pavement that isn't perfectly flat). The stiffer suspension (all else being equal) also causes the axle to skip around more when crossing bumps, potentially reducing even straight-line traction.

Jason contends that he can address the bump handling with different shock valving.

The advantage of lowering the roll center is that it keeps the handling balance more consistent through the turn, and reduces jacking (which is a bigger issues with swing arm suspensions, but still applies somewhat to live axles). Weight transfers much faster through the PHR (or Watts) than through the shocks and springs. Lowering the rear roll center lowers the PHR/Watts contribution to the total weight transfer, which reduces it's ability to dynamically change the handling.

The advantage of the Watts link setup is also that it helps keep the handling more consistent (though not in the same way), even at the original "approximate" roll center height, because it keeps the roll center from moving around as much relative the chassis center of gravity.

The Watts link does reduce lateral movement of the chassis. Besides any effect on handling, lateral movement increases tire rubbing issues.

Lowering the rear roll center, whether by lowering the PHR or lowering the Watts pivot, will increase lateral movement and rubbing, though the Watts link is starting with an advantage in that regard.

So, Sam's argument against lowering PHR (or Watts pivot) has never had anything to do with "the insignificant amount that the rear shifted from side to side" because lowering the PHR does not reduce lateral movement at all. He has argued that lowering the PHR (specifically on the fbody) will increase lateral movement even more than is inherent to lowering the roll center anyway due to increased flexing of the long brackets.

Outside the context of PHR lowering, Sam has also argued for the importance of using a very strong, rigid PHR with rod ends to minimize lateral movement. So, I don't think he has ever meant to downplay the significance of controlling lateral movement.

Sam has argued that the transitional handling balance changes due to the relatively high roll center in the stock-like configuration do not cause a significant driving problem. In other words, he is arguing that he can adequately address transitional stability with his setups.

As I said, this is just intended to be a summary (OK, a verbose "summary") of the different issues and points of view, not an argument for any particular point of view. I don't think anyone disagrees on the physics/geometry involved with the various topics. I think all the disagreement lies in how much importance to assign to each topic.

Now, the fact remains that if you lower the roll center significantly, you will need to buy a new set of (at least) a new rear bar and springs. Sam sells any springs you may want, and up to at least a 25mm solid rear bar (ST). While he certainly doesn't recommend them, he does sell most of the parts you need if you want to try it.

The Watts link will make it fairly painless to experiment a little. Springs and bars are relatively cheap, and if you change your mind before they get too rusty and scraped up, they are fairly easy to resell. If you lower the roll center enough to need custom shocks, that does complicate the situation a bit, though.

The Watts also allows movement of the roll center by as little as half an inch. That opens the possibility of small tweaks for tuning, even if you aren't going to completely overhaul your suspension package for a large change..

For example, lowering the roll center with no other changes will increase the understeer tendency of the car. Aging tires or a slick surface tend to increase the oversteer tendency of the car. So, lowering the Watts pivot by 1/2" or so as your tires get old or when heading to a notoriously slick site could be a very convenient option. Heck, it should only take a few minutes to move the pivot using ramps (with no further adjustment needed if it was set up properly to begin with), so even a quick adjustment for weather change is feasible.

This post has been edited by sgarnett: Sep 8 2008, 12:50 PM

Sean, that was a most excellent reply. Kudos to you.

Wow. Thanks to Sean for taking the time to go through things. And he's almost 100% right on.

Up to now dropping the RC via a PHB height was done with very coarse adjustments. You got to weld on brackets to the body and meant the first setting down was a significant change in RC height, and then from there the further changes were also a big coarse. This setup allows smaller (and easier) changes in height.

I'm not a fan of the road-kill scraping PHB height and the on the ground RC. Years ago I messed with PHB brackets that allowed adjustment (via a slider). But couldn't make it work, and scraped the idea because in the meantime I got the car more settled via shock adjustments, etc.

And just because it has adjustments for rc height doesn't mean you have to use it.

Soo..... anyone get theres? Anyone put it on?

Any problems?

Any feedback?

In the process now Brian...and I have been working on it with squarrnet.

I just spoke with Jim Fay. He said the bearing actually is sealed, and since it doesn't move much in operation, there's also very little wear. No maintenance is required.

As a few people have already discovered, the axle clamp shims that were originally shipped in the kits are too thin for the 10 bolt tubes. A few people have already received and verified new shims, and they were shipped out for everyone else (or maybe everyone that didn't specify a 9" or 12 bolt fitment) on Monday (9/8/08).

Mine's on! ---a six pack, one f-word, and one cracked knuckle = Easy. Just need big wrenches.
Now to play. Too bad My tires are sheeeeit.

THIS THREAD IS WORTHLESS WITHOUT PICS..... (IMG:http://www.frrax.com/rrforum/style_emoticons/default/ph34r.gif)

Awaits pics of bloody hands, and empty beer cans....

Drove about 50 miles today in about a five mile radius of my house. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/biggrin.gif) So far I'm really smiling. I think this is going to work well. I was on nittos (instead of hoosiers) Figured I'd better pull in before someone called the state police. First time I liked the long response time around here.
I absolutely Can't wait to get it back on a track. Nelson ledges had two day open track this weekend and BMWCCA has a week long school /octoberfest at Watkins Glen - THIS WEEK. Damn this lack of time off.



I was going to paste some nasty hand picture and say it didn't really hurt, but here's the site. Don't want to offend anyone......yet.

http://www.irishambulance.net/gallery/trauma/machineHand
Just need to put some ice on it.

If you do come to Nelson Ledges let me know I like to come down and check it out.

I have done an autocross and 6+ hours at Putnam Park. On both Hoosiers and some pretty sticky streets.

I lowered the pinion 1/2 inch.. one hole with no other changes.

The car is manageable in the wet, and dry. The one hole made a positive difference I think.

The clamps did not move. Everything looks fine at safe. Cheers.

Nice to see some new developments for these cars....
Helps to solidify my point that...............................

I really don't see the 4th gen F-body going out of favor in ESP for some time.......As it has been mentioned in other threads that the WRX or new Mustang would be the best cars.


A S/P tangent sorry.

I've been running my '99 in ESP for the last year. I didn't want to change to the Watts right before Nationals this year, but I'm planning on making the change over the winter.

Here's a G-G diagram of three drivers in my car from the East Course in Topeka. The upper LH section of the 'circle' is typical of what the DL1 has been telling me all year. That is that the car puts power down coming out of corners better out of left hand corners than while turning right.

(IMG:http://www.wormtech.com/albums/Kolk1/Watts_G_G.jpg)

To back-up the trend I'm showing here, I've seen some A-sedan data from a local 4-th gen and it shows the same thing. I've seen the same thing in ESP Mustangs with panhard bars as well.

My theory is that the Watts will fill in the blue area of the 'circle'. Expanding the performance envelope can only be an improvement and making it mirror the right side of the 'circle' is probably what people are responding to when they find it easier to drive. This trend is, I think, the evidence of the CG and RC height getting closer while rolling one direction and getting farther apart when rolling in the other direction. Since a Watts will eliminate that difference it all seems to make sense.

If anyone has 'after'data once they've installed their Watts it'd be great to have a look. I'll post mine when I get it, but it won't be until April or May.

This post has been edited by Applejack: Oct 2 2008, 02:13 AM

That there is an awesome little graphic.

I think there will be/are improvements in the lower left too. Just judging by the absence of data in the that quadrant.

I do think the car acted well. My buddy drove the car in the wet for 30 mins at Putnam and I did roughly 2 hours in the wet.

We both agreed that the car was better. (I needed the second opinion because, as most of you know already, I am pretty insensitive. Plus, I lack the cool computerized toys to tell me such things like Jason does.)

The lack of lower left points may be due to the course layout. I haven't noticed that area being sub par through this season.

Jason,

You can try my car at the Detroit Oct 19 event...can you hook up your little toy to my car?

This post has been edited by Cr0usEEE: Oct 2 2008, 02:31 PM