Good idea John, I was thinking about trying to get the DL1 in your car as well. Maybe the answer is only two weeks away. Hopefully this cold snap goes away.

Jason--

John Crouse is bringing his car to a DC event this weekend, and I'm going to run it a bit. Frankly, I can't wait. The reviews I've gotten from John and others who have gotten it on have been damned good. Ranging form more predictable, to a feel more like an IRS car. I'm looking forward to it, and come Monday I'll probably have a lot to say if you want to give me a ring.

And I see John volunteered his car to you on the 19th too, so seeing hopefully be believing. I only wish my car was currently in working order so I could back to back them this weekend. But Mr. Burdette will be there and I know his car is basically my car, and what it's like. So as long as he lets me in it, I'll get the back to back data I need.

Your data is pretty damned cool, and shows *EXACTLY* why I was/am so high on a Watts for the car and why I've wanted to do one for while. The way the PHB's mount on our cars and on the Mustangs means that when you turn right the RC goes up and the PHB actually pushes the body up, unloading the inside rear tire more than when you turn left and the RC drops and the body is pulled down. And FWIW, F-stock cars do this too, it's only worse on ESP cars given the more tire and grip, but I've see the same thing on friction circles both in my Camaro in FS and the Mustang now.

Maybe you can mount your MaxQ (or whatever data logger you have) in both cars.

And post the information in that thread on thirdgen.org so someone can tell you how the Watts Link isn't working.

Pat

I'm sure the DL1 will find its way into my car this weekend. Can't wait to try out the Watts Link, too. Both John and I have fresh Hoosiers so this should be a very good test.

Don't forget that the driver makes the left side of the car heavier also.. That's an LH turn advantage in-it-self.

I have the DIY Coleman / JonA Aluminum PHB. I'm not impressed with its stiffness (or lack there of) if I grab a hold of it in the center and pull down. I understand that that is different loading that what it sees in the car, but I think it is related in terms of resonance and buckling, which would be applicable in a RH turn. I eventually want to make a new PHB out of a 1.5 or 2” thin wall steel.

Sam, if you can mount your Max Q in John's car this weekend that would be awesome. I'm really gald there's some interest here to put some data behind all of the comments. If someone's got something to post, let's see it!

Now all we need to do is figure out how to get an adjustable/shorter UCA for '09 and the 4th gen's might get taken to a new level. I suppose that's another thread though.

<edit for typing>

True, but the blue are on the graph I posted is HUGE. Comparing this effect to some data that I have from Marcus Merideth's ESP Mustang (PHB and higher roll stiffness) was interesting. The effect was still there in his car, but there was a much smaller empty area on the G-G. I'm thinking this is due to the stiffer setup not having as much of a change in distance between the CG and RC.

Howdy,



What type of diff do each of you have? I'd have expected any live axle car to put down power better on an exit of a left hander vs. a right hander.

Interested to hear what Sam/Brian/others find with back to back comparisons!

Mark

I have a T2R.

I have the Auburn Pro Racer Diff after my T2R blew up at Nationals.

I have a noisy T2R. Yes. It makes noise sometimes... like automatic gun fire aimed at the drivers butt. It has not done it in a while though. /shrug

I don't know if I'll have time to use the MaxQData.... Being an Autocrossers Inc. event, the core group of us pretty much busy our butts from 7 AM on. I have to do the course, find time to walk it, get ready to drive, etc.

I have to tell you not to expect the data. If you want you'll get it on the 19th as you can put your DL1 in John's car (since he's planning on coming up). I am, and have been more interested in how the car drives than what some little lines say. That annoys some, but I think I've proven overall what I do on setup works pretty well--and on a lot of different cars, not just F-bodies.

We all have our ways. I'm simply looking at a back to back to back test between John's car which is identical to mine but for the Watts, Brian's car (also 98% like mine and will be there), and to compare how fast vs. the Shelby since it's another known. I don't know if there will be a time difference... I'm looking for how the car reacts and feels. Even if it's not faster, easier to drive fast is still something I'm interested in.

Fair enough.

Don't forget that while his car is much stiffer, the RC is also a lot lower too because the PHB is mounted so low and the car is also lighter.... it also has the 5 link (ok, really a 4-link and PHB) where he can adjust his instant center where we really can't.

So while it's a Solid axle RWD car, it's a bit different. Though every time I've driven mine back to back they are pretty much the same speed. Proof you have two ways to skin a cat--ours is just more cost effective.

FYI, I think Kevin will ban your @$$ for using analogies about cat dismemberment.

I like cats... Let me rephrase: You can do things differenly and end up with a competitive result. Mine just costs less (and you know, wins).

F-bodies have quite good cross weights with driver most of the time anyway. I see this as a non-issue.

I agree on the PHB. It's why I WILL NOT use aluminum on the PHB. It's much too far of a run, and the aluminum is just not as strong as steel is. Even then a steel PHB has some of that flex too, which is just another thing that makes the Watts Link so cool. The arms, while aluminum are much, much shorter and therefore harder to bend.

Cross weight is different than L or R side weight. No matter what you do with your spring seats you can't change the front/rear or right/left weights. You are only making the cross weights as close as possible.

Mark brings up a good point about the driveshaft torque as well.

Howdy,

What's the scoop on weight of this setup vs. a panhard? Anyone got numbers yet?

Somewhat related... What do you folks think about legality in SP of removing the panhard bracket from the axle? 15.H.1 might justify it, but might not, too.

Maybe I should care more, about watts vs. panhard, but what I really like about this setup is that its an easy bolt in way to get good rear roll center adjustment...

Of course, I can modify my panhard mount for "free"... :-/

Mark

Howdy,

More SP legality questions...

What rule allows you to remove the bolt in panhard mount brace that goes from the factory frame rail on the left to the panhard mount bracket on the right?

Mark

added weight
Watts frame: 11 3/4 lb
link assemblies, total for pair: 3 5/8 lb
axle clamp assemblies, including rod end and mounting bolts, total for pair: 10 3/4
bellcrank assembly, including rod end and mounting bolts: 2 1/2 lb

removed weight
"upper PHR" brace: 4 1/4 lb
LG/G2 aluminum PHR w/ aluminum rod ends, including bushings and driver side bolt: 2 3/4 lb

I used a medical balance beam scale with 1/4 lb graduations. My PHR probably is/was lighter than typical. The aluminum rod end bodies are definitely lighter, and I suspect the swedged tube uses thinner walls than the typical smaller diameter, straight tubes.

I did not weigh the mounting bolts that are reused.

BTW, both the stock driver side PHR brace bolts and the replacements supplied by Fays2 are too large to fit. Or at least, they were too large for my car - YMMV. I used M10x25 grade 12.9 "zinc plated" socket-head cap screws (machine screws) from McMaster. They show up as plated as you drill down through the part selection, but when you get to the final part and pull up the spec, they actually have a zinc-flake coating of some sort, which should reduce embrittlement concerns. I ordered both 25m and 35mm. While they were the same brand, the 25s were made in italy and the 35s were made in Tiawan. The threaded plate that the bolts go into probably won't withstand sufficient torque (the factory spec is only 35 lb-ft) to properly load grade 12.9 bolts, so the split washer is important for maintaining some tension. I used the black oxide finish, "high collar" (made for use with small head machine screws) M10 split washers from McMaster, directly under the bolt head . I also used some extra-thick, hardened 3/8" Lawson washers I had on hand, under the split washers, so the slotted holes in the Watts frame won't break the spilt washers.

A 3/8" drive, long 8mm hex drive bit (also from McMaster) will come in handy if you use a torque wrench

There's a seam in the chassis just inboard of those driver-side bolts. If you look closely or use your fingertips, there's a short tab that protrudes a little above the seam. I ground down that tab a little to avoid interference, but left the rest of the seam alone.

The swaybar shims provided by Fay are only 3/4" wide. That's about right for the stock rubber bushings, but for typical poly bushings, it's a little skimpy IMHO. I made my own from the 1.5" wide stock carried by Metal Supermarkets. They cut the pieces to length, so all I had to do was drill them.

15.8.H.1

Or is there something overly vague about "Addition or replacement of suspension stabilizers (linkage
connecting the axle housing or De Dion to the chassis, which
controls lateral suspension location) is permitted."?

Drove the car, as did Brian, Pat and maybe a few others back to back with 2 other "strano" standard cars. Ran pretty much the same times, but John's car needs a little more dialing in. Brian's and Karl Bender's cars are working great, and I matched my time in those cars with John's. Considering this is but the second time out for the car, and was on tires not quite as new (but not bad) as Brian's and Karl's I'm encouraged.

The setup needs a little dialing in. I had John move the RC up to the top hole as the car was just a little too tight, and that helped the car out. But considering we started with EXACTLY the setup we have on Karl Bender's car with a PHB more speed is there to be found. Both Brian and I had had driving position issues in John's car (he has a street Recaro) and we both found the position to be awkward. That does effect the speed, as I later drove another car I setup, again almost identical to the others but with a stock seat and couldn't run the time I could in the other cars, and it turned as well. I just couldn't drive it as well.

All in all the back of car is definitely different, and it's not far off. The change of one hole up in RC height helped it a lot in and of itself. The balance got better and the the rear was better stuck. We need to play with tire pressures and shock settings a bit more, but it'll be pretty easy to dial in based on what I felt and the speed the car exhibited vs. a known, fast setup.

FWIW, it might be time to move this to the Suspension section....

Hunt, poke. Double post.

Howdy,



For sure that allows you to remove the panhard bar and replace it with a watts link. But I don't know that its a slam dunk that the upper panhard brace on the car is part of the panhard, vs. part of the car's chassis.

It'd make me nervous enough to want a clarification anyway.

The answer to that would probably also dictate if it was legal to cut the old panhard mount off the axle.

Mark

OML.

The rule includes the bracing. It is obvious that that bar serves no other purpose then to support the panhard bar.

Yeah unfortunately I didn't get a chance to run the car with the RC raised so I don't think I have a good feel for the advantage of the watts vs. phr. With the lowered RC the car just pushed and was generally unresponsive. It was a no-brainer to slalom but it would give it all back in sweepers. Oddly, the rear would stick well but then let go violently if you really tried to make it move around. I was able to run within about .5 of my fast time in my car in two runs in John's. I don't know what Sam ran ultimately in John's car.

Bravo on the course design, Sam. It had a little bit of everything and was a lot of fun.

So far, events have conspired against any competition Watts testing for me.

However, based on my testing with the PHR lowered a little (not roadkill-scraping), you might want to try a Hotchkiss rear bar (or the ST bar, but I think it's going to be a lot heavier) before giving up on the lowered roll center That should allow you to run the roll center about 1" lower, plus/minus 1/2", with no other changes.

First of, if anyone wants to try a 25mm hollow bar, we have those from both Hotchkis and Addco....

But I don't think anyone wants to spend money before they need to, and the car is damned close as is w/a 22mm bar. Witness the fact both Brian and I ran similar times in John's car to Brian's and in my case including another car too. That can't happen if we're way off, and I did drive John's after raising the RC height and it was better.

And fwiw my rational for the Watts isn't to get a lower RC. I'm very happy with the balance where it is. It's to get rid of the jacking and lateral movement of the PHB. I don't want to change the suspension setup all around, and don't feel we'll need to unless someone does opt to slam the RC down.

I tried a 22mm solid bar.

(we had a test and tune)

I moved the pinon down 3 holes to get back to my liking. So, it was lowered 1.5 inches.

With the car like this I was lifting inside front wheels on corner exit.

Err, that's desirable?

Howdy,



So does that mean that I can completely cut off all the panhard brackets on the car, and completely fabricate my own from scratch?

If I thought it was obvious, I wouldn't be asking. This is the same class where some people consider welding to not be an allowed method of update / backdate and also where the amount of metal in a bushing must remain the same as stock.

Mark

Oops, I thought the 25mm solid bar you carried was the ST, not the Addco.

At any rate, my reason for suggesting the Hotchkiss bar was not that it is needed to fix the Watts at all - it certainly isn't "broken". As you said, the pivot can be tweaked to restore the balance with everything else unchanged. In fact, tweaking the roll center height with the Watts is even quicker than swapping bars.

In contrast to my earlier tome, this is not an attempt at unbiased overview. It is my biased opinion based on previous testing. As I said though, I have not yet tested it in anger on the Watts. In my opinion, lowering the roll center a little (not slamming it all the way down) and rebalancing it with the larger swaybar makes the car easier to drive compared to the higher roll center with a smaller bar (springs and shocks the same, and resulting balance roughly the same in either case). At least, that was the case with the PHR. I aSSume it will work that way with the Watts as well. Time will tell.

I agree that you have never promoted the Watts setup as a way to change the roll center. I, on the other hand, purchased it partly because it allows changing the roll center quickly, and in relatively small increments. Nobody needs to do that; it's just an option available to anyone who wishes to capitalize on it.

That seems a little low for that bar. Do you mean three holes down from the top, or three holes down from the center of your former PHR (ie from a string connecting the bolt holes)?

Depends who you ask... I don't think so, but shortbus tends to march to his own beat.

I don't know and don't care. It's not relevant to this conversation as you aren't cutting *ANY* of the brackets off the car, and the Watts link directly bolts the the mounting location the upper PHB brace does so it is replacing, not removing.

I've got both hollow and solid 25mm's if that's what folks want or need.

I understand where you are coming from, and it's a sales point for those that want to lower the RC height easily. John changed his yesterday in 10 minutes or so. While that's not really any easier than moving a PHB up and down you don't have the welding required to install PHB mounts and you get more fine tunable adjustment (smaller movements).

Again, for me it was more about getting rid of the jacking effect and the arc of the PHB. The balance of the cars is exactly what I want now. Given my Camaro has been laid up for a while, it was a sweet reminder of just how happy I am with my setup stuff. I got in Karl's car and it felt EXACTLY like my car when it's not broken, and I ran a time that PAXed favorably against what I ran in the Shelby (yep, drove that too). Admittedly I was a little rusty as the ESP F-bodies and the Mustang do drive differently.

Some cars it is almost if not unavoidable.....In a BMW you will simply be throwing away grip trying to tune out an inside front lift......But in these cars there isn't enough weight transfer normally to lift an inside front completely up. Let alone all the time. Your giving away some grip there friend. If not by eliminating any load carrying ability of the inside tire, then by having the outside tire carry ALL the load....








Sam what's wrong with your car?

Apparently Sam's car doesnt like poles...and im not referring to the people from a country between Germany and Russia

More precisely, somewhere along the line it got setup to run oval track, would turn left great, wouldn't go right very well. I don't think he's figured out the problem, yet.

An interesting note from this weekend, a local guy with a nice DSP E30 was doing fun runs with us and managed to spank Sam and I by three tenths raw time. Not bad for a grocery getter.

I've definitely not given up on trying a roll center change. With the extra throttle sensitivity of my car and more engine braking vs. an LS1 car I think it might be an interesting experiment.

Just for the record, can you sell the Hotchkiss rear bar separately now, or is there another hollow 25? I don't see the Hotchkiss or Addco bars listed; only the Strano bars.

I already reinstalled my old Hotchkiss bar, since the Hellwig adjustable bar doesn't clear the Watts bellcrank.

Sam sells Addco's hollow 25mm bar. I bought one from him and made it adjustable with sliding end links.

No, I do not think it is desirable. At least not at the height I was lifting mine. It would reliably do it in only the fastest wide open flat out sweepers... which was 6000 rpms and second gear in my car.

It illustrates a point though. As you lower the pinion more weight transfers to the rear and specifically the outside rear while cornering.

Sam said he won't want to change his suspension around and I assume that means sway bars. He does know what he wants out of his car.

So, the lesson is that this Watts Link this may not be what everyone wants. Or needs. I think the valid point of reducing jacking effect is a meaningful advancement. However, 650+ dollars to just reduce something live axle cars have been dealing with for decades is a ton of money in comparison to the benefit. With the recent probable rule changes upper control arms could be a bigger advancement. I am sure there is someone that posts on this forum that will sell you a nice set.... If only I could remember that guys name..... I am sure he has a web site.... nope. I got nothin.



As for lifting the inside front tires. I think other changes will need to be made to compensate for this. (Yes, I used "compensate" on purpose.) This goes back to my previous point of this may not be want you want to do. I suspect for most having a 1/2" adjustment in roll center with NO other changes can get the car more neutral or more where the driver wants the feel of the car. (Again this is expensive for just that little thing.)

I do have a plan on the compensating control for the tire lifting. I'll report the results. In the meantime they are evil secret plans, eyes only and stuff like that. I might just be going the wrong way anyway.

(oooh, you know what. I think I just contributed something useful.)

No, you've got it backwards. Lowering the Watts pivot reduces lateral weight transfer to the outside rear while cornering. That's why a bigger rear bar is required, and why I think your rear bar is still too small for your current setting (or, your pivot height is still too low for your current bar). If you are lifting your inside front, you are getting 100% lateral weight transfer at that end.

Also, assuming you didn't change the ride (CG) height or anti-squat geometry, if you are transferring more weight to the rear, it is and can only be because you are accelerating harder. With the roll center lowered, combined with a bar that is probably still too small, you were probably able to use more throttle without losing the tail, though I suspect it was pushing a little.

From a lateral weight transfer perspective, if the inside front is lightly loaded, then so is the outside rear and vice-versa.

Ah, yes. Thank you for correcting me, Sean.

It certainly did not feel like it was pushing. At the Test and Tune on Saturday I kept lowering the pinion until the push went away.

And yes. I did have boat loads more throttle at corner exit.

In other words, you kept increasing the push until the push went away.... There's a piece missing from this puzzle.

Got pics? Did you weld on a slot, or make a slider that clamps around the tube? Is the Addco bar CM (with associated welding issues)?