Electric brakes

Hey guys, it’s been a while... looking for some options on brakes. What are your thoughts on this Lexus brake setup?

i had looked at that a while back, and after discovering i would be stuck with lexus master cylinder as my only bore size choice i decided it wasnt for me. instead i ended up with a dual master cylinder setup and the car stops as well as any boosted system ive driven.

Thanks for clarifying, I just stumbled across it...

What is the master cylinder size bore on this? I like the idea of this setup. I like that combining this with a manual rack, I could completely eliminate the power steering pump. And I would be able to change spark plugs possibly!

looking at rock auto i come up with .750 and .875, however the one shown at .875 looks different. either way, those are a small bore size for a power system, i really question how effective the "booster" is, on our cars people argue between .750 and .812 bore for the front on a manual system. this would require carefully sizing the rear calipers to such a small bore size, looking at the calculator using my car as a base, i figure calipers around 28mm bore (4 piston) would match to a .75 bore master cylinder, or at least put it in a useable range.

this braking system is kinda interesting, it seems kinda weak for a large lexus suv, however being a hybrid a lot of braking force can come from the motors. if anyone remembers the gm ev1 from the 90s, it didnt have any mechanical brakes at all, all its braking came from the motors. another thing to consider, its possible that this unit isnt 12v, in a hybrid small electrical devices can be anywhere from 5v to 48 volt dc.

sharkey wrote:looking at rock auto i come up with .750 and .875, however the one shown at .875 looks different. either way, those are a small bore size for a power system, i really question how effective the "booster" is, on our cars people argue between .750 and .812 bore for the front on a manual system. this would require carefully sizing the rear calipers to such a small bore size, looking at the calculator using my car as a base, i figure calipers around 28mm bore (4 piston) would match to a .75 bore master cylinder, or at least put it in a useable range.

this braking system is kinda interesting, it seems kinda weak for a large lexus suv, however being a hybrid a lot of braking force can come from the motors. if anyone remembers the gm ev1 from the 90s, it didnt have any mechanical brakes at all, all its braking came from the motors. another thing to consider, its possible that this unit isnt 12v, in a hybrid small electrical devices can be anywhere from 5v to 48 volt dc.

Hybrids are severely limited by the rate at which the battery can uptake the electricity that could be generated if all the energy dissipated under braking could be stored. Only a small percentage of the energy dissipated during a braking event goes back to the battery (unless you are braking very slowly). Because of this, they still do heavily rely on mechanical brakes, since anything above 10-15% braking is done with the mechanical brakes.

The EV1 also has hydraulic disc brakes, they were just electrically boosted. Of the few EV1s left in existence, I've seen two of them. One is sitting in a lot at work.

well that was my theory as to the seemingly odd master cylinder size out the window lol.

more food for thought, the master cylinder above is also used on the prius.

Hmm... Prius parts in a V8 swapped Porsche. Haha.