What Brake Master Cylinder Should I Sue In My Ke25 20valve?

[KE25 RACER]

I'm in the process of doing a 20v conversion into my corolla, what brake master cylinder and clutch master is recomended due to th lack of room?

Edited May 30, 2006 by KE25 RACER

[Jono]

hi mate,

I have a small port 4age in a ke20. I have just bought a 3/4" trailer brake master cylinder which is still pretty close to the manifold. not sure if this will help

[KE25 RACER]

any chance of posting a pic for me mate? where did u get the master cyl from?

[Teddy]

Mate, you need to go and talk to an engineer about this one. Its not as simple as putting up a master cylinder & break booster assembly and expecting it to work. Think of it as the diagram below..

 

A is a stock ke20 setup, with only a bit of break pedal being applied. (note break shoes slightly moved)

B is a stock ke20 setup, with almost all of break pedal being pressed down. (note break shoes almost all out)

C is an example (with break booster) with too small a master cylinder, resulting in wheel cylinders being pushed too far, or possibly having to push break pedal down only very slightly and having extreamly touchy breaks

D is an example (with break booster) with too large a master cylinder, resulting in alot of pedal being pushed down, and very little effect on the breaks, possibly pedal to floor wont result in full 100 breaks.

 

Make sure you get the correct one. Id assume you would need to get a master cylinder and break booster assembly has has a duel split line, along with the same "fluid" area as a stock ke20 one. even then, adjusting things like the break pedal push rod will be specs from that vehicle you got it off combind with the mesurments of the ke20 pedal to firewall assembly...

 

uGh !

[Teddy]

oh btw, this is going of newly learnt tafe stuff, and what ive been taught.. it may or may not be correct !

[Felix]

i think it is for a race car Teddy.

 

you have your C and D mixed up. with a smaller bore m/cyl you need a lot more pedal travel than with a larger bore m/cyl.

 

KE25 RACER look into the early Nabco style m/cyl's that came on early mitsubishi's, mazdas, and datsuns. dual circuit, non-boosted. think you can get them in 11/16" and 3/4". pretty much a straight bolt up to the firewall in a ke1x and ke2x. i'll see if i can dig up a pic.

Edited May 31, 2006 by Felix

[Teddy]

Ahh ok, thanks for that - ahaha, I'm getting better :P

 

Note that for others - swap C and D around !

[Felix]

attached is a pic of a ke20 with the type of m/cyl i was talking about. you can always add remote fluid reservoirs for more room.

 

alternatively you could always do something like i saw on the ke20 hillclimber that Redwarf is/was wrecking. it had a crossover linkage setup which put the m/cyl on the passenger side.

Edited May 31, 2006 by Felix

[Corolla_Kid]

Yeah look for a mitsubishi galant with a twin circuit master cylinder. They bolt straight up to the 20 series no worries at all. Not sure how you would go with clearance though.

 

Actually on 2nd thoughts it might be a chrysler galant. But have a look at a few and it becomes obvious which one I'm talking about as it doesnt have a booster.

Edited May 31, 2006 by Corolla_Kid

[Jono]

the setup i've bought has been used with success on a ke20 for ages. while the stroke of the piston is reduced (smaller brake master cylinder) the bore has been increased.

My mate is still using the same setup on his GZE with small port inlet manifold with T28 turbo. He is a qualified mechanic.

Edited May 31, 2006 by JC807