Hi gyus,
Does anybody has some technical information regarding the CATS suspension on our cars? As the car is not so old i can't find some workshop manual like i had on my previous X308 on the web.
The reason i need this info is to understand how the systems works. How dampers are operating (if it is operated by voltage so i need to know what is soft and what is firm). The idea is to emulate other voltage to the dampers because as you know the cars 10-11 has too firm suspension when it must be more comfortable and too soft on the highspeeds when it must be more firm.
I was speaking to the electrical guy and he says it's not a problem. The only thing we need to know exactly how this system is working on X351.
Thanks

 

Have a search for a post by me with the word "scopemeter"

You'll need to do the same thing to work out the signal.

 

In the options list it is written: PERFORMANCE SUSPENSION
Do you know what does it means? May be this is the problem what i need to solve?

 

If you want to manipulate the CATS then you need to get a measurement of the signal to the shocks, like I did here https://www.jaguarforums.com/forum/x...uestion-76476/

Performance Suspension sounds good?

 

It seems on X358 CATS works the same as on X308. 5V - firm suspension, 0V - soft.
Perfomance for me sounds bad because it is horrible bouncy ride at the city. So i was thinking about to make it more soft just with reprogramming the PLC unit but nobody at the dealers can tell me for sure if it can be done, but in my opinion it is easy to do.
If nobody can do it so i'm thinking to send different voltage to the dampers to make it more softer. Another question is i can make it even worse because i'm sure Juguar designers spent a lot of time to make it the best but in this case they make to sporty for a luxury sedan.

 

I would suspect that the shocks default to firm if they are disconnected, but it could be the other way round, have you tried disconnecting one and seeing how it affects the ride?

 

No. I'm affraid of all those error codes etc.
But i can try. Are you suggesting it became softer? I suspect it will go to the firmest setting because CATS on all Jags working this way.

 

In 2013, the part number for the front springs changed. Supposedly they are at a different spring rate (softer). I'm thinking about switching them out on my 2011. The part numbers for the front shocks are the same. I have heard that 2013 uses a revised software program for the suspension. The dealer would have to reprogram it. It should be a simple software download for them.

 

These Bilstein shocks have a Hard and Soft damping setting and with no voltage applied to the shock, default to Hard. There is a valve operated by a solenoid in the shock.

This damping has nothing to do with spring rates, (coil or air), as manufacturers set their own based on testing and the car's weight and what the intended use pattern will be. Cars labelled "Sport" normally have harder springs, but the damping is the same on all cars, but CATS may switch between Hard and Soft differently with Sport cars.

Car dampers are getting more and more sophisticated and the ones on the latest Jaguars have additional valving to make the car more compliant on bad surfaces particularly around town such as raised/lowered man-hole covers, missing bits of tarmac etc etc. When we were all running around on "balloon" tyres the tyre walls absorbed a lot of this stuff, but now there is this mania for low-profile tyres the ride quality of cars has markedly deteriorated, so the damper manufacturers have put in some extra valving to make the shock more compliant at low speeds, (like up to around 50 mph).