I've been threatening to post a discussion of the latest brake test results for a while too, so here goes:
To recap: The brake test was done at Safety Brake & Clutch in Randburg using a Bosch brake dynomometer. The machine expresses the braking effort in kg of each road wheel as a function of the increase in torque on the motors driving the car's wheels as the brakes are applied. Maximum brake effort is achieved just prior to the brakes locking up and causing the wheels to slip on the rollers. Consequently the higher the weight on the axle being tested the higher the indicated maximum brake effort. In the case of a rear engine car where more weight is on the rear axle the rear brakes will therefore indicate a higher maximum brake effort than the front brakes. The opposite will occur when testing a front engine car. This also explains why in the Notch's case, it appears to be braking more on the right hand wheels as that is where the (considerable) weight of the technician doing the test was concentrated. Brake efficiency is calculated as the percentage of the total braking effort from all 4 wheels divided by the vehicle's test weight - which is the unladen weight plus that of the driver/technician doing the test. This test procedure and calculation comforms to UK MOT standards.
2017 raw data:
LF 175 RF 190
LR 190 RR 200
2017 calculated brake efficiency:
Total brake effort in kg
----------------------------- x 100%
Vehicle test weight in kg
755 kg
--------- x 100% = 72.94%
1035 kg
2011 raw data:
LF 130 RF 155
LR 180 RR 180
2011 calculated brake efficiency:
645 kg
--------- x 100% = 63.24%
1020 kg
That is a 9.7% improvement in overall brake efficiency. Lets make that 10%!!
Also note how the new ATE calipers with 42mm pistons have increased the maximum brake force available at the front wheels compared to the EMPI calipers which had 40.6mm pistons. Using proper ATE disc pads vs the Chinese junk that came with the EMPI setup no doubt also contributes to the higher figure. That should also mean that the front/rear brake bias has been restored to where it should be. I also understand from the sales people at my local spares shop that ATE now uses a softer compound for their brake pads which makes the braking action a bit more progressive and this might move the brake bias a little further to the front, which isn't a bad thing for a rear engine car.
Overall, I am very happy with how this conversion turned out and I have learnt a lot in the process. Yes, it has been a rather costly affair - since I had to pay some 'school fees' along the way; but it was so worth spending the bucks and getting the proper ATE calipers and tandem master cylinder.
