Calling out to those who have changed from cats to non cats, how did the feel of the ride change?


I plan to do this if any of my cats fail and was wondering about the impact to the ride.

 

What parts make up CATS? I know there are different shocks and springs (I assume bushings too) and probably an ECU. What else?

Thanks!

 

Why not start a new thread rather than hijack this one?

 

I believe them to be related questions. You asked when cats fails-- the natural follow on is what composes cats that will fail prompting you to go to a non adaptive configuration and then which components can be mixed and matched.

If it's just shocks and springs, items that have a very long life span, my recommendation would be to keep the adaptive. If it's NLA ECUs that are prone to go south, that's another item to consider.

I'm sorry you feel this to be a hijack.

 

Its a long time ago that I have driven with the Cats turned off, most noticeable less comfort during normal road driving in an uneven road. You can check it for yourself, just disconnect the cats system, and then the shocks will be in constant firm mode.

 

Surely the standard shocks are more compliant than the CATs shocks when off, so that would not give a representative feel.

 

Maybe the cats shocks are a bit stiffer than stock shocks, as they have the ability to switch to a soft setting when required (but only on the rebound!). If you want to know you need to have a dyno, ie performance graph of the stock shock. I have posted earlier one for the cats ones (in stiff and soft mode), then you can compare on paper.

 

Let's think about this one. Do they use any different suspension components besides shocks with cats? I'm not sure if they do.

If that's true, I'd think that the ride would pretty much mirror a non cats XK8.

About the only thing different might be Springs. Easy enough to look up. They did change that in some special editions like Silverstone.

I'm sure I'd have read threads galore about changing the anti sway bar if that was different.

John

 

I believe the springs are slightly stiffer and the roll bar may be heavier, but those are minor differences. XK8 shocks will be softer, but I seriously doubt that you are going to be driving in a manor that would make that important. That is, unless you track the car.

 

I am reasonably sure that for my car, all other parts are common between the CATs and non CATS versions.

 

The sng Barratt catalog lists different part numbers for the springs, and for anti roll bars a separate R performance part, but the standard R may be the same as the XK8 anti roll bar.

 

Yes but my car is a standard XK8, so all other parts are the same according to the SNG catalogue.


However what I am interested is what it feels like if you just swap the shocks an a bog standard CATS XK8, surely someone must have done that?

 

I'm not sure how many XK8 had cats, it is standard on the xkr so that may limit your pool of xk8 changes. That said I changed mine this past winter from cats to non. I could never tell when cats was active prior to the change,m it was just how the car felt when driving. I don't notice much if any change now. It's very subjective to how you drive and where that you could feel a difference. I've done some spirited driving just to see in various ways that would have triggered the cats if installed but the car help firm. (one note: I did put different springs on, one to replace the 14 year old ones and to ensure firmness was maintained).

Since disconnecting the control module will default to firm I suppose you could wire up a overide within the connecting harness to try and run soft, you'd have to override the three inputs somehow. I believe the JTIS explains these inputs.

 

Wouldn't recommend to set the shocks to soft, I would imagine that it would be way to bouncy.

Attached is a dyno of the cats shock in soft/hard setting, and you will find that normal non-adjustable shocks are more like the stiff setting.