QUOTE(fiid @ Jan 3 2004, 12:25 AM)
Does one just put this in the circuit to the rear, and replace the stock 50lb block thingo with a T? How does the top one work???
How hard is it to retrofit antilock? Just another crazy idea - wondered if anyone had thought of it.
the top one only works if you use a dual master cylinder system like race cars - one for the fronts, one for the backs. the knob turns the flexible cable which turns a jackscrew in the pedal cluster that changes the location of a pivot giving more or less mechanical advantage to the front or back master cylinder. it's the best system but it is not trivial to fabricate or install.
the hydraulic pressure-relief/pressure regulator types (pictures 2 and 3) work like the much-maligned 914 proportioner, but they are easily adjustable while the OEM one isn't (and is really heavy and hard to bleed besides.) but yes - goes in the line to the back before the tee.
for antilock, the hard part would be finding a way to add power brakes in a car with floor-mounted pedals and finding room for the vacuum servo - and finding a vacuum source to power it with. the BIG reason 911's went to suspended pedals was to make room for the power brake booster, although improved clutch operation (with an over-center spring) was a factor too.
anyway - after you make the power brake thing work, it's 'only' a matter of fitting wheel sensors to the 4 hubs and finding an ABS controller from a car of comparable weight with similar weight transfer characteristics and similar wheel rates. lots of cars use the Teves 060 ABS controller...
once upon a time, some company made a device called 'Safety-Braker' that worked like the air column in your house plumbing, and temporarily relieved the pressure spike associated with a locked wheel. i'm guessing liability, product quality issues (the quality was very high, meaning low margins...) and the widespread availability of 'real' antilock systems fiinally did them under, but i used the parts on my 914.6 and later my GTi SOLO-II car and thought it was A Good Thing. however, it seems to have gone the way of the friction spring damper; too bad...