Wilwood Brake Upgrade
#1
Wilwood Brake Upgrade
I am using Wilwood calipers on my Mk 2 front wheels. I also have a modern replacement vacuum booster replacing the OEM set up (LR18230).
The present calipers are Wilwood #120-6808 equipped with EBC Yellow Stuff pads DP4038R. These calipers are ones supplied in kits for this car from various vendors - the pads are my choice.
The brakes certainly work adequately but I would like to have more powerful braking. I have measured the brake pressure with and without vacuum and see maxima of 1600 psi & 600psi respectively. These are fine and within the expected range so the hydraulic system is definitely working correctly.
The installed Wilwood calipers have a net piston area of 3 sqins compared to the original Dunlop calipers of 3.55 sqins so nominally I only have 85% of the original front braking effort. Increasing the piston area is a way to get more powerful braking however this would require more fluid displacement and hence pedal travel. I have not yet worked out how much volume flow the master cylinder can supply.
Wilwood make other calipers as direct fit replacements with areas of 4.12 sqins and 4.8 sqins. My sense is that it is safe to go to a 4.12 sqins caliper since this would only increase the total brake fluid flow by about 10% over the original design (note that this is a single circuit system with the rear brakes as original). The increased braking effort would be 16% over the original design. Probably worthwhile and also not sufficient to upset the overall brake balance.
The 4.8 sqins caliper might require more flow than the master cylinder can provide, but I will not go there unless there is experience with this area sized caliper.
Before I make the choice it would be useful to know what the piston areas are on other retrofit calipers from vendors such as BCC and Coopercraft.
Anyone?
The present calipers are Wilwood #120-6808 equipped with EBC Yellow Stuff pads DP4038R. These calipers are ones supplied in kits for this car from various vendors - the pads are my choice.
The brakes certainly work adequately but I would like to have more powerful braking. I have measured the brake pressure with and without vacuum and see maxima of 1600 psi & 600psi respectively. These are fine and within the expected range so the hydraulic system is definitely working correctly.
The installed Wilwood calipers have a net piston area of 3 sqins compared to the original Dunlop calipers of 3.55 sqins so nominally I only have 85% of the original front braking effort. Increasing the piston area is a way to get more powerful braking however this would require more fluid displacement and hence pedal travel. I have not yet worked out how much volume flow the master cylinder can supply.
Wilwood make other calipers as direct fit replacements with areas of 4.12 sqins and 4.8 sqins. My sense is that it is safe to go to a 4.12 sqins caliper since this would only increase the total brake fluid flow by about 10% over the original design (note that this is a single circuit system with the rear brakes as original). The increased braking effort would be 16% over the original design. Probably worthwhile and also not sufficient to upset the overall brake balance.
The 4.8 sqins caliper might require more flow than the master cylinder can provide, but I will not go there unless there is experience with this area sized caliper.
Before I make the choice it would be useful to know what the piston areas are on other retrofit calipers from vendors such as BCC and Coopercraft.
Anyone?
#2
Primaz has fitted Wilwood to his S-Type (seat of your pants) V8 conversion, I'm sure he will give you the low down on the Wilwood calipers he has used, send him a message, or he will probably comment here anyhow, he is more than happy to help/advise.
Or look at his thread on his conversion, you may find he has posted the info you need.
Or look at his thread on his conversion, you may find he has posted the info you need.
#3
What I did was change the rear inboard brakes of my 3.8s to the later model E-type and that with the front Wilwoods seem adequate for my 400+ HP V8. One other option I got from Jag Outlet in San Louis Obispo in CA that I have not opted to try was Terry provided me a front brake bracket that enables you to mount two (2) of the Wilwood brakes in the front. Rolls Royce and Bentley and some race cars have used dual brakes on the front wheels. Thus far my brakes are decent so I have not taken that next step.
#6
#7
The new booster is fitted in the same place as the original. However the position of the vacuum fitting caused interference with the fan shroud. I therefore slackened the clamp ring around the vacuum chamber and rotated the forward half by about 120 degrees. When mounted in the car, the fitting is now down below the fan shroud.
I also reoriented the air valve cover by 72 deg so that I could still use the short hose
The new Wilwood brakes have been fitted and are noticeably more powerful than the originals. The balance is good and I can, at high foot pressure, just lock the front wheels on a dry road.
So the change was beneficial and the pedal stroke is not excessive and well within the capacity of the master cylinder.
I also reoriented the air valve cover by 72 deg so that I could still use the short hose
The new Wilwood brakes have been fitted and are noticeably more powerful than the originals. The balance is good and I can, at high foot pressure, just lock the front wheels on a dry road.
So the change was beneficial and the pedal stroke is not excessive and well within the capacity of the master cylinder.