Phase 4, done :)

[Don Plumley]

Originally posted by Bill Verburg
IMO JIC Cross is the only way to go,

* great selection of springs
* monoballs and camber plates are included
* adjuster is more positive than PCCB
* ride height and corner weight are independantly adjustable

The rear drop links are a bit of an issue w/ TRG sways

+1

[Brother]

What does JIC stand for?

[Bill Verburg]

It's a good bet that the J stands for Japan or Japanese other than that I dunno.
They make great adjustable suspension components and Ti exhaust components.

[klaucke]

Looks great Bill! Definately meaner than when I briefly say it.

[kgorman]

Bill, looks great! Any impressions on track? Did you switch up to the firmer spring rate?

[Tom W]

I just got back from 3 days of tweaking my suspension for better performance. We ended the weekend with 600/850 springs and I'll take the car back in this week to get some firmer springs added. I think 800/1000 or something like that will be the next step.

[Bill Verburg]

Originally posted by kgorman
Bill, looks great! Any impressions on track? Did you switch up to the firmer spring rate?

My track time has been severely curtailed by a domestic disaster. But yes, the spring rate was more than doubled from ROW M030. I am using the 7/10 probably should have gone straight to 8/12, but I wanted to try this set up first.

Issues are
bump steer- I definitley need EVO uprights and tie rods.
driveway transitions - the nose is very low
getting the car on a lift - the whole car is very low, especially the front.

Front ride height is currently some what lower than low RS spec by ~18mm


I may try raising the car by ~10mm.

[Tom W]

Bill: FWIW, my last 2 months have been spent working on suspension issues. I had 2 problems to solve: bad bump-steer and bad rear tire wear (cording the inside edge after 8 sessions instead of 20+). For ride height comparison, my car's nose is about 1 3/4" off the ground (front jack point is 3.0" off the ground).

The bump steer was eliminated by going to EVO uprights and associated bits with all monoballs up front. Not cheap, but having the car move over 2 feet when applying the brakes was not fun and not safe if trying to pass in a turn.

The cording was due to too much toe/camber change as the suspension traveled. We went to monoballs and spring plates a couple months ago to increase the amount of camber adjustment that was possible and to try and get the back more planted - that worked but did not solve the cording/poor wear. We did solve it last weekend by upping the spring rates to the 600/850 I posted above and changing the camber (the easy way by raising the perches 2 turns). I will be having 700/1000 put in next week and having the car lowered back down (while maintaining the camber) before going to Sears Point on Oct 6-8 to see if it helps more.

I was amazed at how much change in handling you can get by simply raising or lowering the spring perches 2 turns and the change you get by increasing the spring rates. Some of what we tried was positively diabolical in handling, but we did work out settings that accomplished the initial goals. More tweaking is planned to get even better grip.

We also got very even tire temps across all 4 tires that indicates we are getting close. At the start, the temps were 30 °F different (more hot inside) in the rear but even up front. I had the importance of doing tire temps re-inforced and the cost of the fancy Longacre pyrometer has been saved in the longer tire life I will now get. (I even got my wife to learn to do the temps and get them for me as I came into the hot pit!)

In order to simplify sourcing, the shop has switched from JIC springs (2 1/2" ?) to to different springs (2 1/4" IIRC) and machined the hats to accomodate the change.

[Bill Verburg]

It appears that the 964 uses the same height measuring reference points(at least at the front) and the 964RS spec is roughly the same as for the 993RS. Did you ever measure the front height using the factory method

2 turns up = much worse handling?

[Tom W]

No, I never measured at the factory points, but I should drag my lazy butt out and do it so I know where I am (for future reference).

In the final adjustment of the weekend we went 2 turns up (which provided less camber and would transfer more weight forward). When we did that the rear sway was also tightened to the middle (which I was really worried about as it has always provided too much oversteer when set to the middle in the past - especially 2 days earlier when it left the handling diabolical and "helped" me spin at 90 mph in a turn). However, as Rich predicted, it worked out well and the tire temps were evened out more and the rear stayed planted.

The car will go in Friday to measure the existing camber (that is working well), change the springs, and go 2 turns back down to get the ride height and corner weights back into line. Then I go to infineon and test. If needed, we swap springs again as seems best.

I should mention that in this "we", I provide some input but I can't feel all the nuances that the guy directing the work (Rich Walton from Jerry Woods) does when he drives the car. Having the help of someone who knows what they are doing and is a damn good driver is invaluable and well worth the cost. To me, the moral of the story is don't spend a small fortune on "go fast" components and not learn to use them properly. Get the appropriate help to do it right

[Bill Verburg]

I agree that these cars need to be set up by someone that knows them, mine was done by a very prominant east coast shop. Problem is sometimes they are even more hardcore than we are.

[mjshira]

Bill

Your 3.6 car and Jack's got me into this, now I see this so I went and got a newer 911, I HATE YOU! LOL :-)

nice work man, like a lot.

[RideShoot&Drink]

Bill, what are you impressions of JIC on street? Is it too harsh? Obviously, it seems like more track oriented setup. What do you think? Thanks in advance.

[Bill Verburg]

Originally posted by RideShoot&Drink
Bill, what are you impressions of JIC on street? Is it too harsh? Obviously, it seems like more track oriented setup. What do you think? Thanks in advance.

It is very track oriented, spring rates are almost 4x RoW M030. That said I don't have any issues on the street except the front end is so low that transitions and lifting can be challanging.

The ride is stiff but very well controlled, ride motion is short and abrupt.

[Bill Verburg]

[RideShoot&Drink]

Would I be better off with Bilstein HD/ H&R setup for the street and some AX? I still have original shocks and springs. Too soft, too much roll and looks awful for my taste . Therefore, I need to decide on which replacement components to use. What do you think?

[Bill Verburg]

I think that it would depend very much on your preference, tolerance and usage.

Bilstein HD(fully threaded body) and sport springs is certainly a huge improvement over stock in terms of performance yet don't have the extremes compromises of something like mine, don't forget adjustable sways.

I think that for most RS ride height is a very good compromise and the Bilstein HD a very good shock.

[RideShoot&Drink]

Bill, are any of the suspension components interchangable between 964 and 993, let's say springs or sways?

[Bill Verburg]

not afaik

[Avery]

Hi Bill: What wheels are on your car and what are the specs? They really look cool.