SP20 big brake kit - Update, date etc

[twilightprotege]

yeah i was thinking of widening mine, but i decided not to worry about it

[dfvadr]

with 4 piston wont you have to upgrade ur booster

[twilightprotege]

what i'll be doing is upgrading the master cylinder to a mazda 929 one and getting a proportioning valve.

fyi the 929 MC is an almost direct replacement and it's 1" bore rather than the 15/16" we have. check out this how to :

http://www.msprotege.com/forum/showthread.php?t=72107

[Cosmo Dude]

I'm guessing that the master is from a FWD V6 HE 929.

Although if you go by the part number given then you should have little trouble. Cos their aint nuffink impressive about the brakes on my HB ops:

[BigMal]

Here are a couple of pictures I found have some relavence to me and maybe to
some others. The first one is a multidrilled rotor with 4x100mm stud pattern this
is legal isn't it ?? If its legal to have multidrilled mags then rotors should be ok
right if they are bolted to the hub and held in place by the mags. The 2nd pic
is of the bracket for the PBR twin piston how simple is that I hope it is that simple
for us. By the way where the hell is hoppers crossing ???

[Rupewrecht]

ah i bet that was done by Hoppers Stoppers in (funnily enuf) Hoppers Crossing in Vic. it's halfway between Melbourne and Geelong

[twilightprotege]

with the bracket, it all depends on the width between where the calipers connect to the suspension and the holes for the caliper. so just hope there's enough room to move...

i know the sp20 is quite wide, like 160mm between centre holes or something, nissans are all over the shop (the r32 is only 90mm or something). the wider the better to reduce caliper flex. even better is radial mount calipers, but they are very expensive.

[BigMal]

Having a big difference is good makes fowling of the bolts less likely. The PBR
caliper is very close to the std astina so will be trouble if the caliper doesnt need
to be positioned much away from the standard location the bolts will be right
next to one another.
Twilight if you are set on 4pistons why not just go the RX7 and have the mazda
logo instead of nissan or mitsu.
Dan yeah its Hoppers Stoppers did they give you any recomendations for a
conversion.

[twilightprotege]

i am going rx7 - was going to buy them today (from a jap imported in adelaide), but the idiots sold them on the weekend (i emailed them early last week saying i'll take them)..grrrrr

so now i have to find others.

a good thing about the rx7 calipers is i mightnt need an extension bracket. the arms of them already come down a lot further than the pbr ones in the picture, so that might make it real easy!

[Rupewrecht]

Originally Posted by BigMal

Dan yeah its Hoppers Stoppers did they give you any recomendations for a
conversion.

nah, but was going to talk to them.

MRT recommended the S5 RX7 calipers and MX5 SP discs, but i'm concerned about offset issues with them.

at the moment, Rank are getting a damaged strut assembly for me and are goign to make up a bracket to fit S5 RX7 calipers, and work out disc offset etc once they get that, as i'd prefer to be without my car for a mimimum of time

twiglight - dont pay more than $250 for a pair of S4/5 calipers

[twilightprotege]

rute (hehehe) - i just found (and put a deposit on) a s6 caliper for $250 a pair (minus pins, but they shouldnt be expensive)

[twilightprotege]

critter - did you have to widen the front track to fit the new calipers?

looks as if i need to widen it by up to 2cm each side to fit the calipers, rotor around the suspension setup and the wheel

[SFC01]

Widen the track or use smaller offset wheels with judicious selection? I'd be thinking through the ramifications of widening track very carefully in terms of what it does to your suspension and steering geometry as well as wheel bearing/hub loading.

[twilightprotege]

it's either widen the track or buy new wheels with less offset or make up a custom suspension mounting area thingie (no idea what it's called).

so widen the track is the easy option, and by far the cheapest. i'd widen the track of the rear as well to keep the geometry the same, but i'd have to flare the guards (no biggie)

i'm sure trevor @ brake distributors could work it out anyway

[SFC01]

I was thinking more in terms of King Pin offset, camber thrust, torque steer, self steer alignment and those sorts of things, rather than the front/rear handling bias.

There is always more than meets the eye when it comes to suspension...

Just playing devil's advocate here... :twisted:

[twilightprotege]

yeah i knew you were referring to that, was just saying to keep the front rear track the same would be optimal for handling. hopefully it'll only be 1cm more, but we'll see

[SFC01]

That 1cm could make the difference between stablizing effect under conditions with one driven wheel on a low friction surface.

But then again I could just be talking out my pie hole. :roll:

I guess the point I am trying to make not so much to you in specific but out there in general is that due diligence should occur prior to making mods. [public service announcement mode off]

[twilightprotege]

hehehe....public service announcement mode off...hehehe

did you know that apparently if you buy blank rotors and drill them to fit your car, that requires engineer's approval? weird...

[BigMal]

Increasing wheeltrack doesn't affect handling that way the problem with it
is the extra stress on the king pin assembly. Its like a see saw the further
away from the king pin you get the more force you can apply on the king pin
to bend and snap it. Old School you would tub the car so you came in as
well as out to balance out the forces having a strut you cant go in like that.
There is nothing like seeing an old school monaro with 15x10" mags on the
ass running 295 or 305x50x15" tyres

[twilightprotege]

can we strengthen the king pin easily?