Sunday, 19 October 2014

Brake bite

I have found the J15 as originally constructed has underwhelmed me in terms of the brake bite. In other words I am not getting the control leading up and into a hairpin in a Sprint track. I have had the need to emergency brake the  car and it did lock up the wheels fast enough but far too much pedal pressure for my liking.

The original brake design by Sylva Autokits specified HiSpec (on the front), my  brake setup is similar but uses 2 x 4 Pot Willwood midlights (on vented discs) on the front and 2 x VW Passat rears (Rally Design OEM handbrake callipers). The setup is common enough as I have something similar on my Westfield and I have no problems. I recently changed the front discs for X drilled and grooved discs similar to my Westfield. This had little improvement effect.

The master cylinders are the Sylva Autokits recommended 0.75" on the rear and 0.625" on the front with a balance bar configuration.

I decided to swap the 0.625" on to the rear callipers and fit a new 0.5" on the front. This by my calculation should increase the effectiveness by the change in the piston areas. This equates to 17% for the rear and 20% for the front.

I tried to get a Willwood part for the master cylinder but all I could get is a Rally Design copy at a reduced price. Apparently Willwood don't make them.

Only time will tell if I am on the right track. This is the third major change recently to the Sylva and I am beginning to feel I am at last getting somewhere.

The fourth and final change is to add ARB's - another winter project I think. I doubt I will get to try all this out properly before the spring. Early indications on a test day at Kames are promising. The effectiveness has improved but I still get a less than totally firm pedal. I think this may be due in some part to the pads needing time to bed in.

RD master cylinder

No comments:

Post a Comment