Jump to content
SAU Community

silvia boy has skyline brake questions

Arkhaeon
 Share

Recommended Posts

Arkhaeon Collaborator

Arkhaeon

Posted
Posted

gday all,

ive got an S13 silvia Q's (ie. non-turbo: crap) and have recently converted to 5-stud w/ s14a silvia brakes at the front (stage1 is brakes, stage2 is turbs conversion, stage3 more suspension work).

The biggest problem on tap now is the brake master cylinder. Non-turbo S13s (and CA18DETs) have what i believe to be a 13/16" master, and SR turbos have 15/16" units. Being a non-turbs, I have a pathetically small master cylinder, and with these nice 4pot calipers (s13s all have single piston jobbies) my pedal goes all the way to the floor without a sweat. :ghost:

I eventually want to upgrade to r32 gt-r gear all round (non v-spec/brembo - sumitomos i believe?) but for the moment the s14 brakes will do fine. I like a very firm pedal (engages quickly) so im thinking a 1" master cyl would be the go... opinions?

hmm perhaps I should make a point here...

Id like information on all the brake master cylinder sizes from the skyline range - eg r32 gts-4/gts-t/gt-r/vspec/vspecII, r33 gts-25t/gt-r etc etc

Im told that ABS and non-ABS models have vastly different master cyls and thus arent interchangeable, and given that my car is NON-ABS, are there any units that would suit my needs?

Im sorry to babble this load of crap...

Thanks everyone,

-Ark

Arkhaeon Collaborator

Arkhaeon

Posted
  • Author
Posted

ive already got s14 brakes - perhaps you meant the master cylinder?

S13 ca18de(t)/sr20de = 250x18mm discs, single piston calipers (what I used to have)

S13 sr20det = 280x22mm discs, single piston calipers

S14 = 280x30mm discs, 4pot calipers (what I currently have - but with a small master cyl)

invigorated Rookie

invigorated

Posted
Posted

Correct me if I am wrong but I was always of the opinion that S14Ks had the same brakes as R33GTST in which case they would be 296mm fronts.

Essentially the same brakes as R32GTR Non V Spec.

As for the pedal travelling to the floor I dont see that this would be caused by master cylinder diameter necessarily. I would have thought that cyl diameter might perhaps cause a good pedal but not great stopping force.

Arkhaeon Collaborator

Arkhaeon

Posted
  • Author
Posted

nah the s14 brakes are basically the same as Z32 300ZXs (except all the s- series have iron calipers, whereas the z32 and the r- series have alloy units)

http://tuning.silviansw.com/brakes.html

The reason the pedal is so soft and braking performance is bad is because my small master cylinder simply cant push enough brake fluid into the comparitively huge 4pot calipers. I need to push the pedal all the way down to move the four pistons in the same amount as the stock single piston caliper would be with only half that movement. A bigger master cylinder would push more fluid for a given amount of pedal movement.

The pedal would feel slightly firmer because you have to move more fluid for each unit of distance moved - move more mass(fluid) and youll need more force(pedal firmness)

Do you happen to know the master cylinder bores?

thanks :cheers:

-Ark

rsx84 Veteran

rsx84

Posted
Posted

and i gather just bolting on the corrasponding s-14 master cylinder is not an option for you then??

i've just upgraded to a r32 rb20det and part of the future brake upgrade was to fit the r32 master cylinder when the engine went in and use that for the time being with old brakes, works brilliantly... :D

  • 3 months later...
Arkhaeon Collaborator

Arkhaeon

Posted
  • Author
Posted

*digs up old thread*

I was actually trying to find out the bore sizes of the skyline brake master cylinders in the hope of finding one with a larger bore than 15/16" (which all silvias have).

I have since discovered that even the big brembo equipped Nissans still use only a 15/16" master cyl, so in the end I just got an S13 SR20DET unit (still 15/16").

I was at the time of starting this thread, hoping that someone would tell me that (for example) R32 GTRs used a 1" bore (or something like that) - which would mean I could then source a brake master cylinder that would make for an even stiffer pedal...

I thought my post was rather simple, and after re-reading my post today I see the first stnad-out opportunity for correction was that I mentioned "so im thinking a 1" master cyl would be the go... opinions?" - instantly someone could have said "Nissans' largest master cylinder bore is 15/16". Case closed. Ark is a tool." but alas no.. I get someone telling me to downgrade to s13 brakes, and others telling me to use a 15/16" master cyl which wasnt my question... a bit like someone asking "im getting 18x10" rims, what offset do I need" and people replying with "you can use stock rims".

I guess if I didnt know some of you in person, id figure you were all 14y.o dreamers who regurgitated "facts" they heard some other 14y.o say (like nissansilvia.com)

Im sorry for the rant im doing now... people give me the shits when they dont listen :D

mokompri Community Regular

mokompri

Posted
Posted

someone posted up the specs on all the skyline brakes, one of them did actually have a 1" master cylinder

im running the same setup as you are on my 180sx, i have the 15/16" master cylinder, its ok, although still is a bit spongy, i have stainless brake lines as well...

mokompri Community Regular

mokompri

Posted
Posted

here you are, specs ! .. stolen from roy's post

R32 GTST

Master Cylinder diam (mm) - 25.4

Front Caliper Piston(diam x qty) - 40.4 ×4

Front rotors (diam x thk) - 280×30

Rear Caliper Piston(diam x qty) - 38.18×2

Rear Rotors (diam x thk) - 297×18

R33 GTST

Master Cylinder diam (mm) - 23.8

Front Caliper Piston(diam x qty) - 40.4 ×4

Front rotors (diam x thk) - 296×30

Rear Caliper Piston(diam x qty) - 38.18×2

Rear Rotors (diam x thk) - 297×18

R32 GTR (Non V-Spec,)

Master Cylinder diam (mm) - 25.4

Front Caliper Piston(diam x qty) - 40.4 ×4

Front rotors (diam x thk) - 296×32

Rear Caliper Piston(diam x qty) - 38.18×2

Rear Rotors (diam x thk) - 297×18

R32 GTR V-Spec / R33 / 34 GTR with Brembos

Master Cylinder diam (mm) - 26.9

Front Caliper Piston(diam x qty) - (44+38)×2 ... leading pistons larger then trailing

Front rotors (diam x thk) - 324×30

Rear Caliper Piston(diam x qty) - 40×2

Rear Rotors (diam x thk) - 300×22

v-spec has biggest one that seems to be ~1-1/16" size

by the way how does yours feel now with the 15/16" master cylinder ?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kinkstaah
      RB25DE NEO with Haltech ECU

      By Kinkstaah · Posted

      @Haggerty this is your red flag. In MAP based ECU's the Manifold pressure X RPM calculation is how the engine knows it is actually...running/going through ANY load. You are confusing the term 'base map' with your base VE/Fuel table. When most people say 'base map' they mean the stock entire tune shipped with the ECU, hopefully aimed at a specific car/setup to use as a base for beginning to tune your specific car. Haltech has a lot of documentation (or at least they used to, I expect it to be better now). Read it voraciously.
    • GTSBoy
      RB25DE NEO with Haltech ECU

      By GTSBoy · Posted

      I saw you mention this earlier and it raised a red flag, but I couldn't believe it was real. Yes, the vacuum signal should vary. It is the one and only load signal from the engine to the ECU, and it MUST vary. It is either not connected or is badly f**ked up in some way.
    • Murray_Calavera
      RB25DE NEO with Haltech ECU

      By Murray_Calavera · Posted

      @Haggerty you still haven't answered my question.  Many things you are saying do not make sense for someone who can tune, yet I would not expect someone who cannot tune to be playing with the things in the ECU that you are.  This process would be a lot quicker to figure out if we can remove user error from the equation. 
    • MBS206
      R32 GTS (RB20DE) Injectors Replacement

      By MBS206 · Posted

      If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • Haggerty
      RB25DE NEO with Haltech ECU

      By Haggerty · Posted

      I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
×
×
  • Create New...