Z32 bmc

[craig8585]

What difference does fitting a Z32 BMC actually make? At the moment my brakes are really sharp (K-Sport 8 pot fronts and standard rears) and the brake pedal hardly moves when I apply the brakes. I am fitting the K-Sport rear setup very soon too though, hence this question.

Would the Z32 BMC mean my pedal would travel further or less? This is one thing I've never really looked into as the standard BMC seems fine to me. Even though the K-Sport callipers are 8 pot, the pots are quite small so the amount of fluid displaced isn't too much.

Thanks in advance!

 

[DeanS15]

i need this answer too - wtf craig have you got a crystal ball or something??? i was thinking this today lol
i've also been wondering about k-sport handbrakes - apparently as they have a mechanical lock (similar to a line lock) on the handle they will pass mot but i'm waiting to confirm this. this could make the whole thing easier as z32 backplates etc wouldn't be needed.....

 

[craig8585]

Haha! Great minds mate! :wack: that, or neither of us have got a clue!!

Would you trust the hydraulic handbrake though? I've read that they aren't any good as acting as a parking brake but this was a while ago. And you have to butcher your console to get them in, which would be fine on a drift car but I couldn't do it! :ghey:

 

[AllanOrr]

guys a hydraulic handbrake will not pass a mot in the UK I am also wondering what set up to go for on the brakes inc if its worth getting the Z32 BMC but you will need to keep the stock handbrake to drive on the road but you can just mount the K-sport one at the side

 

[TurboAL]

I would suggest its a good idea to fit a z32 bmc if you fitting big brake kit to the rear otherwise your rear brakes will be doing too much braking and will lock the rear up under hard braking(the rear doesn't require much braking force although the standard single pots are poo!). brake balance is very critical to the handling of a car.

And dean from an mot point of view you require a mechanical handbrake that does not rely on the hydraulic system.

 

[craig8585]

Ah, so it affects the bias? At the moment my car stands on its nose under seriously hard braking and you can feel the back going light. The rear setup should counter this somewhat but I'll have to find somewhere very wide and very quiet to find out exactly how it handles with the setup.

 

[TurboAL]

yer it changes the bias. if you have big brakes on the front and under braking the nose dives making the back end go light, putting big brakes on the rear will only cause the back to skid more. getting correctly matched braking components front and rear is critical. That the problem with some of these big brake kits. big brakes are good but if there not balance then it will effect ur braking performance. Correctly ballanced brakes mean having the right sizing and number of the pots. The purpose of bigger brakes is not necessary to increase the force which the brakes apply but they allow for bigger rotor which allows greater heat dissappation mean that the chance of brake fade is reduced meaning the brakes can be applied for a more sustained period of time without them fading.

 

[craig8585]

Yeah, heat dissipation is the key to good brakes. To give an example of this - on my last track day, after a few hot laps and a couple of cool down laps, I came into the pits and was checking the car over. I touched the front wheels and they were cool. Then touched the rears and they were quite warm as the heat had transferred from the disks to the wheels. This shows how well the bigger K-Sport brakes dissipated the heat. Very impressive with no fade at all.

One of the other big reasons for fitting this rears setup is because it looks odd having massive brakes on the front and piddly rears! I barely ever use them to their full potential TBH but it’s just nice to know they are there when you need them. Is there any way of controlling or getting your brake bias set up properly?

 

[AllanOrr]

So that kind of shows the whole "more is better" saying isnt always true :wack:

 

[craig8585]

Ummm, yeah it is and you know it!!


Nah, seriously though, the rears would certainly benifit from an upgrade. As I said, they got redders on my trackday as the disks couldn't loose the heat quick enough. Fronts didnt even come close to fadeing.

 

[TurboAL]

Allan Orr: In terms of the stock brakes "more is better" because the stock brakes are garbage. But yes you get more to the point where you get to much. If you brakes are that good that in the dry at high speed u can activate the abs having more breaking isn't gunna do you any better.

Also having too big a brakes that they don't heat up to a working temperature aint any good either.

It makes me laugh when you see hot hatches with huge brakes. You only need big brake if you have a large mass to stop and you have enough traction on the road (normally down to tire contact patch with the road) to allow you to stop.

Craig - yer your right the rears look gay being tiny when u have big brakes up front. The single pot sliding rears calipers are garbage. so up grading to 2 pots is a good idea. Going any bigger and i think there'd be over kill.

The only way to really adjust your brake bias is to get a pedal box with balance beam. These have independant brake cylinders for front and rear but are not normally servo assisted. you can get brake bias valve which are restrictors which go in a single line. Usually used on hot hatches to limit the braking force going to the rear as hot hatches are particually light on the rear. I guess the same could be adopted on the front if the braking on the front needed reducing in respect to the back maybe?

 

[AllanOrr]

Al - Yea I ment more, the more pistons in your calipers dont always mean a better braking system

My plan was running the 2 handbrake systems and the Wilwood brake kits but depending how much I can find a Z32 BMC kicking about on SXOC I miught just pick one up

 

[craig8585]

I admit the rears are overkill. But saying this, the pistont are really small and the size of the pad is not much bigger than the standard rear ones. I should have it fitted by christmas so will keep the thread updated or will make a new one when its done.

Back onto the topic of the Z32 BMC.. - does it change the pedal feel or travel at all?

 

[TurboAL]

I don't know whether pedal feel will change but i assume it wouldn't much as the brake assist servo stays the same but then the piston size might be different and this may have some effect?

 

[LuPix_S15]

Craig you can try first and then I'll follow suit lol

 

[TomK]

Craig, i've got an Z32 BMC kicking about if you want it, send me a PM and we could talk money.

 

[sliding-r]

I changed to a z32 BMC at the same time as the r33 rear twin pots and i think my brakes are much imporoved now..

BMC stoppers really work aswell by stopping the flex in the firewall, my brakes are so responsive now.

 

[craig8585]

Cool. I'll try the new setup with my current BMC and see what it's like. If it's too sharp then I'll change to the Z32. Those BMC stoppers don't do anything though IMO. If the firewall flexes enough to effect the braking then there's defiantly something wrong!

 

[sliding-r]

I'm sorry but that simply isn't true, don't comment till u try it..

Why do they increase the thickness of the firewall around the bmc on rally cars.. Simply for the same reason.. Try it you will see

 

[craig8585]

I did have one on my EK9 and noticed no difference at all, even on trackdays, so sold it. Did you fit yours at the same time as another part?

http://www.rx7club.com/showthread.php?t=543383