bmwe21.net forums

i spent a lot of time reading stuff about brake bias boxes. having gotten used to the brakes in my mk2 polo (unassisted) there shouldnt be a problem with such a light car. My advise is to wait till ive got it fitted and then let me iron out the bugs lol.

The pedal ratio is a 6:1 - clutch 0.75, rear 0.75 front 0.625 - standard 323i rear calipers and wilwood powerlight front calipers.

I'm pretty sure the US wilwood site has online calculators for master cylinder and caliper/ drum piston sizes, i think for drums your shooting for around 500psi and discs up to 900-1000psi.
will try and find it later.
the HotRod sites have a lot of good info on all the brake setups.

Will upload more pics later after i get back from the Fairground with the little one.

Yeah mate thats right - i think i even know the article your referring to! ive got a graph and you can play with piston / disk / tyre and input ratios etc - it does all the maths. I heard that in total you want to make as close to 10000lbs in total between your brakes.

I have 2x 1.38" pistons in the wilwoods on a 10" disk i got on my car. The rx7 calipers i want to use in the future are 2x 1.41 pistons and will be a ~12" disk

this is what the graph says ill have with my current setup - its units are in "old money"

Braking %
Front 0.82
Rear 0.18

Distance Between Master Cylinder Rods= 2
Distance Front M.C. Rod to Brake Pedal= 0.75

Front Rear
Tire Dia 15 15
Rotor Dia 10 10
Master Cyl Dia 0.625 0.7

Brake pedal input force 110 lbs
Brake pedal ratio (usually 3) 6
Brake pedal force on balance bar 660 lbs
Front Master Cylinder Force= 412.5 lbs
Rear Master Cylinder Force= 247.5 lbs
Front Pressure= 1344.54 psi
Rear Pressure= 643.12 psi
Front Caliper Force= 8044.19 lbs
Rear Caliper Force= 1786.95 lbs
Front Tire Force= 4622.73 lbs
Rear Tire Force= 1032.86 lbs

photobucket is down, but found this:
http://acceleratingperformance.blogspot ... ained.html
its a good read on basics of brake calculations.

good little article is that. I downloaded a brake force calculator but you do really need to understand how this all works. Mark has got pristine to modify the e21 so that the e30 brake stuff fits in, for some reason that sounds more complicated then the brake bias box does lol.

just wondeering if you do cars as a living mate? you are knowledgable....

Thanks very much,
I work on high bypass jet engines for General Electric, cars are just a hobby/obsession.
Here was yesterdays efforts, still waiting for my grindidng discs to start cleaning things up.






the main reason i am replacing the front panel, there has been crash damage in the past and it is a bit deformed

and rush is behind the panel joint and i dont want to paint over it.

this has come in handy

I think you made the right choice by replacing the front panel. The last thing you want is for rust to get a grip again after all your hard graft thus far.

Are you staying with the original colour? What other plans have you got for when the body is finished?

got to say you have skills the work so far is beyond impressive

Thanks very much guys, without having seen a professional, repair restoration its hard to tell if what I have done is good or not.
Origional colour was chamonix, before it was badly painted red, so back to chamonix. i think i will re-paint the wheel centers the same.
after body plans are, keep my 5 speed and 4.11 lsd
m42block m44 valves stroked bored balanced with M3 pistons and suitable bmw rods.
motorcycle carbs/ pitot tube with chargecooled eaton supercharger
side exit exhaust home made
either gaz or home made tein coilovers with edfc
1 piece carbon propshaft "if possible" rx8
bmw 4 pots front 323i discs
rear disc conversion
camber castor adjustable rear subframe.
uprated front ARB and install rear ARB
i may be changing the fuel tank to suit exhaust
remove rear quarter fuel filler and move somewhere else more streamlined
i may do some carbon panels, boot/bonnnets after its completed to have a go at that.
pedal bias box or master cylinder with remote bias valve.

I still have all black door cards and panels so interior will either be black or cream/brown
simple minimalist trimmed interior.
e24 recaros or similar from 80s car,
custom carpet (i might buy a sewing machine depending on cost)
new cream headlining, suede effect like the 7 series .
remove center console
nardi steering wheel
simple stereo with only an amp and hidden imput with input from smart phone.
no rear seats but weld in fittings for isofix seat both sides.
pop out rear windows
delete wing mirrors install new one on drivers side.
dont know if i will go chrome or shadowline yet.

i want to try and complete this year or by spring next year. but we will see.

found some good pics of a lightened modified front end


and this is nice, i like the front fenders but the rears should be tapered the same i think, nice to see destripped doors in the colour i like.



not keen on the rear tho, matt black rear valance and sits like a 4x4

My old 320/6 had stripped doors also. Even the badges had to go.

pandemonium001 wrote:found some good pics of a lightened modified front end


and this is nice, i like the front fenders but the rears should be tapered the same i think, nice to see destripped doors in the colour i like.



not keen on the rear tho, matt black rear valance and sits like a 4x4

Those rims are very cool. I want to like the arches. I want to but....

I know what you mean, it only looks good from one angle, but from the rear its a bit odd.

Todays progress




with the aid of this

just clamped in place

need a bit of tinkering, 24" c clamps on order and primed with high zinc weld primer.

Got an hour or so today:
front panel is now welded on


did a load of grinding but that gets a bit dull so moved on to the back end



i had some X3 discs so thought i would try them in the wheels


325mm diameter. E38 brembo's
vs rover 75 rear discs 280mm