My new ride comes with double adjustable JRZ's w/ remote reseviors.
Not only have I never owned JRZ's before, these are my first double adjustable shocks. Hard to believe but true after 20+ years of racing.
I called JRZ for some info and I wouldn't say they were real helpfull.Previous owner also can't help me much.
So, just some basic questions from those of you in the know:

There are thirteen (13) clicks on the bump adjustment.
Is the center most detent (#7 from L/ R) a default setting, neither stiff or soft?

It doesn't appear the rebound has as many settings or detents, correct?

What would be a good statrting point?
The car is a 914-6, springs 350F/400R.
Radial slicks on 16F/18R.
25mm Front Sway bar.
2083# w/o driver

I have had no time at all on the track with this car so I can't tell you about its tendencies. My previous 914's have all been fairly neutral, but all had custom valved/ non adjustable Bisteins or Koni.

Any general advice you can give me would be appreciated.
I know I would but there ain't one.

Tom B.

 

There's a couple threads on this but general rule of thumb is try to find an open lapping day or test and tune day, start with everything full soft run a few laps then come in and gradually increase stiffness (one adjustment at a time, pretty sure start with rebound first) until you get to the point where the car feels too stiff / bouncy or starts acting not to your liking then back off one adjustment and leave it there.

I purchased a car this year with JRZ 3-way's on it and thank goodness the previous owner was a (former) pro driver and kept setup sheets for the car. My first time out I set to his baseline settings and found the only adjustment I made on the day was one click of additional rebound on the front to get the car where it felt really good to me.

My next outing in the car I did the whole start from soft and increase to x point then back off one and leave it and I was in almost exactly the same spot as his old settings, little more high speed compression becasue the curbs at my home track aren't as bad as his home track.

So in the end I would have ended up at nearly the same result but it was nice to do it both ways just to be sure.

**edit** - Make sure you have the canister pressures set before you start any of your tuning just to make sure they're right. My shocks leak down a little and need pressures set from time to time. Canister pressures are another tuning tool as well so maybe check with other 914 guys on what they are running for pressures. I run 200psi front and 225psi rear on my car.

 

I'm not real familiar with the JRZ, but for most shocks, when you are adjusting the clicks you are either changing an orfice size or a needle valve, so there is no real "baseline" setting. You're just changing the flow rates before the shock piston opens.

I can't remember if it's Ohlins or JRZ, but on one of them if you turn the adjuster too far, you unscrew the adjuster and have to get a rebuild. I'd give SRP http://www.srpengineering.com/index.php a call and talk to them. They can get you in the ballpark real quick. Plus, if they haven't been rebuilt in the last 6 months, you should do them.

 

Tom, I would start both compression and rebound one click from full soft (never a good idea to have these on full soft or full stiff settings). Then test and adjust from there. In an ideal world, you'll want as little compression as you can get away with and as much rebound as the car can take, within reason...and there are of course exceptions for tracks, etc.

And yes, as has been said, it is critical to make sure the canisters are pressurizes, as the nitrogen pressure affects the spring rates, Maybe start at 150 psi all the way around? Or perhaps 150 front, 175 back?

Also, I sent you an email on a related topic..

 

I need to try and set some new moton's as well. When testing out the adjustments do you do all four corners at the same time or start on one end of the car and then the other?

 

IMO do all 4 at th esame time to start. Then make copious notes of what each corner of the car is doing in each corner, etc. and address the the ends of the car as appropriate. Make only 1 change at a time (i.e., add rebound to the rears) and note the results.

 

thanks. I'll give that a try and see how it goes.

 

I was told not to run JRZs with the rebound (on the top of the shock) set to full soft because it can get locked up. When you play with it, you'll indeed find that it does get "sticky" when it's at that setting. So just run one click away from full soft when you're playing with the settings. Motons are probably the same way since the parts are interchangeable.

p.s. the rebound should have the same number of detents as compression.