Effect of upgrades on stability control

[Gunnytron]

I watched a Speed Academy vid the other day where they had to reprogram something in the ECU of a BMW after they put larger brakes on.

I am trying to resist modifying my v6 Jag but on my list of mods (that I am not going to do), is larger brakes and an LSD and it got me thinking, would that have an effect on the stability control or the way the stock diff slip is managed (stock is torque vector)?

[digitalsolo]

Short answer is yes, it absolutely can.

Changing brake pad materials, tire compound, etc. can as well.   The smarter the system (closed loop, PID feedback, etc.) the less it will impact it because it can make decisions and "learn" based on the feedback it gets from the actions it takes.   I don't know how smart/good the setup on the Jag is, to really say what level of impact would be (if any).

[Gunnytron]

It would be interesting to get a couple of f-types and compare the settings of one that came with an lsd and one that didn't.

[shainiac]

I did a quick search on eBay and the F-type uses a Bosch ABS pump. It looks very similar to the Bosch M5 Motorsports pump, but the manifold block is slightly thicker. The electronics-end looks the same if not identical. I don't know how custom each OEM's ABS calibration is, but it might be possible to get it flashed to a motorsports-oriented tune. I'd also bet the calibration is pretty decent out of the box.

Do you have issues with it currently?

[Gunnytron]

Not having issues. I just want to know that if I was to upgrade the brakes and fit an LSD, whether it will mess with the Stability control.

I managed (unintentionally) to get it to kick in recently. It straightened the car out pretty violently to the point where I tapped my head on the side of the roof.

[Exidous]

There is a reason so many of us have been installing Bosch BMW ABS units. I have the 2004 M3 version. 818.3(813.3 is programmable but good luck finding on, CSL) and it tolerates so much and performs excellently. They are a bit rare these days so folks are swapping in the mk60e5 from 4cyl BMWs of the e9x era. They normally require a magnetic ring on the front to pick up direction but a guy makes a box to lie to the unit allowing normal hall or VR setups.

The mk60(what I have), mk60e1 and mk60e5 all use pressure sensors. E1 and E5 are internal and don't tolerate a bias valve. The mk60 can be tricked because the sensors are external. Valve can be between the sensor and module.

They all have EBD and honestly don't need a valve unless there is a huge difference in front and rear balance.

[shainiac]

Can you not run a bias valve between the master cylinder and module/pump?

[Exidous]

You can but if the pressure varies too far outside how it's programmed it'll fault out thinking one of the master sides is bad.