I just put willwood 12" rotor on my dx. I use ex 15/16" mc. The willwood kit came with adjuster that have 1 line in and out that I have no idea what is it for. I think its called proportioning valve but I thought every car has one. I still have rear drums at the back. Stopping is alot better than stock but not as much as I expected it will be. My 3700 lbs supra with 13" rotor stop better. What do am I missing here?. Do I need to change my rear brakes to disc?

 

It could be a couple of things. Yes every car comes with a proportioning valve which has been engineered to work with stock brake components and brake calipers/drums. As soon as you do upgrading to a different size that calculated proportion changes. I've never dealt with the wilwood set ups before, if someone has on there maybe they can help you, or maybe contact wilwood and see what they suggest for this upgrade, but Im sure that proportioning valve will help. It could also be the brake pads, if you have a street pad in your dx and a race pad in the supra it will be like night and day difference. As long as your rear drums are working properly that shouldn't be the issue. Are you using this car on the street or on the track?