Possible rules changes for 2005 -- Submit by Jan. 15, 2005.

Started By: Steve Weinstein on 2004-12-29 03:04:11

After the major re-write of the Slalom Rules in March 2004, things seemed to work fairly smoothly this year. The Slalom Committee did not receive any significant complaints, nor were there any significant number of questions raised regarding interpretation of the new rules.

Now is the time to consider possible changes to the rules for the 2005 season. So far, the only proposal that has been floated is one to exclude polyurethane bushings from the list of modifications that would place a car in Street Prepared class. It has been pointed out that especially on some of the older cars, it is almost impossible to find OEM bushings, and that polybushings are the only ones available from suppliers. Additionally, polybushings alone are not viewed as giving any significant advantage in the slalom over stock bushings.

So, at this point, the only rules change that the Committee is considering is to exclude the use of polyurethane bushings, not accompanied by other modifications that effect performance, from the list of modifications causing placement in Street Prepared class.

If any member or any club has any additional items that they wish the Slalom Committee to consider for the 2005 season, please submit them to me for review by the Committee not later than January 15, 2005.

Thanks to everyone for their continued support of the slalom program!

Steve Weinstein
JCNA Slalom Committee Chairman

Comments

The effect of poly bushings is going to depend on the durometer of the bushing material. Most of the widely available bushings aren't hard enough to make a huge difference in handling. However, there is no way to tell by visual inspection what the hardness of the material might be. Will a durometer gauge be standard issue to slalom inspectors?

There's also a question of where the poly is used: the most dramatic effect will be in the swaybar droplink bushings, followed by the swaybar frame bushings. There is less effect if poly bushings are used on the control arms. Use of harder bushings in the rear end trailing arm is harmful to handling, and should not be discouraged ;-).

What about different materials? Delrin has been used with good effect. Will inspectors recognize it on sight? What about pillow blocks? Shaft rings? Rod-end drop links?

OTH, poly is not necessarily easy to spot by eye: Polybush makes black poly bushings which look almost identical to rubber.

Finally, I'd like to know one model where rubber bushings are NLA, and MUST be substituted with poly. Those are the models that should be exempt.

Steve - my .02 worth puts the use of alternative materials in suspension joints in Street Prepared. Anyone can cheat if that's their wish so there's no need to bust the scrutineers chops if some bozo has to show up in a stock class with suspension mods. Tires, however, are another issue!
Bob Grossman

XK120 FHC
XK140 DHC
Mk2 competition
S1E - coupe
C-replica

Steve is to be commended for his efforts as National Slalom Chairman. We need to be forward thinking as the Slalom program progresses and many of the cars get older. The Street Prepared Class is intended to keep the range of performance capabilities level within any stock class by moving lightly modified or heavily modified cars into the appropriate "Street Prepared". Allowing poly bushings in "stock" works well because most of our time driving these cars is on the highway with modern traffic and at modern speeds. My drive to the slalom is 200 mi. round-trip on Interstate 93. Although rubber bushings are available for my two 50's vintage Jaguars, poly is safer at speed, better handling, and longer lasting. Likewise, a modern radial tire on stock rims within a stock wheelwell should be allowed as these tires are safer all-around than bias-ply or the specialty, limited manufacture tires on the market. Using the "stock rims/wheelwell" criteria keeps the "hot rods" out of any stock class and can be easily checked by the Tech Committee. The Slalom Committe could also develop a list of acceptable tire sizes for our cars for use by both the Techs and owners in their purchase decisions. We should encourage drivability improvements to these cars, not penalize them, while keeping the stock classes "level" and fun.

Adrian Curtis, JANE
XK120 DHC
MVIIM
AH Sprite Series III

Steve,

WRT Adrian's suggestion that
"The Slalom Committe could also develop a list of acceptable tire sizes for our cars for use by both the Techs and owners in their purchase decisions"
I have started this exercise based on the Concours list. I will forward it when it is complete, hopefully in the next week or so.

Regards

Keith
JTC

Edited on 2004-12-31 10:48:52

Edited on 2004-12-31 10:47:25

First, thank you, Adrian, for your comments about my work as Slalom Chair. If it doesn't show, it is a "labor of love" for me, and I very much want to see the program continue to grow, locally and nationally, along with our HPDE program.

I put the "polybush" proposal forward without expressing an opinion on the issue, to see what types of responses we might get. I think Mike Frank's comments are most apt. There is no question that polybushings improve handling, to a greater or lesser degree, depending on where and what is used. Adrian even notes that this was the reason he opted for polybushings. My personal inclination is to leave it as a modification, but I'm willing to consider alternative views. I certainly don't want to start us down a "slippery slope" to diluting the stock classes with lots of "exceptions" for modifications.

As for tires, as raised by Adrian, radial tires are already allowed in all classes. However, the rule requires that tire size be "appropriate" to the class. That means that radial tires must be reasonably close in size to the original tires, and must be mounted on stock rims for that class. We have previously discussed a "tire guide", and if someone wants to undertake the task of compiling a list of sizes for each class, similar to the concours tire guide, we'd be glad to review it and adopt it if appropriate. Any volunteers?

Thanks to everyone for the input, and keep the comments and proposals coming. The above comments are not an official acceptance or rejection of any proposals by the Slalom Committee. Rather, they are my own comments. After all proposals and comments have been received, they will be reviewed by the full Committee to determine if any formal proposals will be submitted to the AGM for consideration.

Happy New Year to everyone, and may your New Year be filled with lots of "speedy" events!!!

Regards,

Steve Weinstein
JCNA Slalom Committee Chairman

p.s. I hope that as many of you as possible will plan on attending the Challenge Championship in Atlanta in September. We are, of course, going to be holding a slalom event there, so bring your Jaguars and LET'S RACE!!

Steve, I drove 800 miles over to my last slalom with rubber components in my XK140's front suspension. Yep, had radial tires as well. Had an absolute ball running in the stock class at 6500 feet elevation. Turned a 50.38 second lap (though not in my official 5 runs). Then, I drove the 800 miles back. I would have been really put out if there had been stock competition using modified suspension parts. That 3200 lb Mk2 of mine has turned 43 second laps on the standard slalom course at 5500 feet elevation, so I do know the benefit of suspension mods. My point is that if you want to put 'big boy' parts on your car, go run with the big boys. Personally, I really enjoy taking a car that I don't have to prepare out to the slalom and just have some real fun.

XK120 FHC
XK140 DHC
Mk2 competition
S1E - coupe
C-replica

This brings up an interesting point which might need some consideration. Many people with R&P steering models, like those with XJs, have replaced the rubber rack bushings with neoprene or poly, not for any performance reason, but because the oil from our leaky XK engines turns the rubber to mush in short order. One of my XJs has poly rack bushes and while the steering feels more direct and there's a bit more road vibration transmitted to the steering wheel, I don't think there's any performance enhancement.

Suspension bushings are another matter, but they are out of the direct line of oil droppings. Most XJ owners eschew poly suspension components because they make the ride harsher, but a large number use them in the three rack mounts. If there is not an exemption for non-rubber rack bushings, you are going to loose a lot of competitors in the stock class.

Another factor to consider is that neoprene bushings are black and poly bushings can be made in black, making them indistinguishable from rubber ones. Is there going to be any easy way to enforce this rule? Do most XJ owners even have a clue what rack bushes they have?

I'll leave the suspension bush question to you guys, but I think there almost has to be an exemption for rack bushes.

Mark Stephenson
Jaguar Club of Central Arizona

Bob,
What size are your XK140 tires? Manufacture? How are they at highway speed?

Adrian

This is my last posting, but I can't ignore Mark Stephenson's comments because he mirrors my feelings exactly. Many of us want to slalom in stock class but are going to put "drivability" improvements to our cars first. If the minor changes we make push us out of "stock", participation may drop. The slalom committee needs to find a way to allow updates to our cars: poly bushings, a modern tire, whatever, in stock class. Then the Tech Inspectors will be able to concentrate on "safety of the car" for slaloming while the owners makes the determination as to whether the car is "stock" or not. We can always cheat, and that's hard to beat. Most of us would rather participate in the appropriate class with a level playing field. To be specific, my 120HP XK120 was placed in SPL this Fall because I put on a set of 205 Kuhmos. I competed against, among others, a modified Series III with a minimum of 272HP and wider tires. I'm sorry that the Kuhmos weren't allowed in stock, but I'm not putting on a lesser tire. Thanks.

Adrian

Adrian - the 140 is using Coker's reproduction of the 185R16 Firestone Cavallino. Road performance is OK considering the source. Sure would be nice to see the Pirelli Cinturato back in production. Having gotten my 120 off of racing tires is certainly easier on the old butt when doing highway work. Yea, not as responsive, but I've got other cars properly equipped for fast touring.
Regars, Bob G.

XK120 FHC
XK140 DHC
Mk2 competition
S1E - coupe
C-replica

Steve,

Having conducted Tech Inspection for several events since the new rules were adopted, I have only one suggestion:

The two items dealing with checking for under-inflated tires and advising the entrants to increase tire pressure should be removed from the Tech Insepction check list document and only made part of the advice section of the general rules and regulations. It is highly unlikely that any tech inspector will ever take a gauge to the tires of the competitors' cars during the inspection process, and once a car appears for inspection it is too late for the owner to do anything about increasing tire pressure.

Other than that, congratulations for a job well cone this year. I'm really looking forward to the upcoming season!

Warren Hansen
70 E-Type FHC "Silver Bolide
96 X300

Rod Winegarner
Has a final decision been reached regarding poly bushings? My opinion is that this item alone, without any other mods would have very minimal benefit. Our current rule which requires only one modification to place a car into the street prepared class results in a pretty wide range of competition within a particular street prepared class. The gap in what is acceptable within the street prepared class is significantly wider than what we would get if cars with only one modification, such as poly bushings, were left in the stock class.