I have recently picked up a FAB (Front Adjustable Brake) system for my SX3.
The FAB comprises a fixed pulley for the mid belt and a one way pulley for the front belt. The one way pulley is sandwiched between a pair of slipper plates which provides an off power braking effect to the front wheels. The tension, and therefore the brake strength, can be adjusted via a nut in exactly the same way as the more familiar gearbox mounted slipper clutch.
I had been using a front one way diff, which I felt was quick through the twisties, but hankered after a little more stability coming off of the higher speed sections. The FAB, on paper, seemed to be the ideal solution offering the perfect adjustable compromise between a conventional diff and a one way.
It is a bit of a job to fit as the front bulkheads need to be split to get the new shaft in. It can be done without dismantling too much but is one of those jobs that is better done at home rather than at the track.
Once fitted I couldn't wait for the next meeting to give it a go.
I would suggest starting with it set fairly loose so that it behaves like a one way then tightening little by little until you become comfortable. This will take just a few laps and a 5.5mm driver. Don't over tighten and bind up the spring.
I was instantly comfortable with the FAB.
It turned out to be everything I wanted it to be, making the car agile in the twisties whilst remaining stable off power. The car was much less edgy than when fitted with a one way making it so much easier to drive. Although no quicker over a single lap this results in a much more consistent, and therefore, quicker run.
So far I have only used it on carpet but expect it to be equally effective on astro and can't see myself going back.
I really like this part and would recommend it, at £46.99 however it is not a cheap experiment.
I am not sure I would have splashed out on new one but was lucky to get hold of a pre-loved example at a good price.
I am glad I did.
What a fabulous FAB!