Re: E32 Brakes

[Brett Shortland <shorty@xxxxxxxxxxx>]

"Chris Brandt" <Chris.Brandt@domain.elided> wrote

>.....The question I have is how do the e32 front brakes compare 
>with the e28 M5 front brakes. The components look cheaper to replace and 
>would be easier to get. Not to mention I would have two cars with all the 
>same components...If the e32 front stuff is better than the e28 M5 stuff I 
>might trickle the M5 stuff down to the coupe and do the upgrade on the M5. 

In all of the discussions on these brake mods, one thing that has been
overlooked is the design of the M5/M6 (E24,E28,E34) front discs.  The single
biggest problem is the venting of the discs.  Nearly all vented brake discs
are supported on the outer edge, allowing air to flow in a straight line
directly through the backing plate and through the vents in the disc.  M5
and M6 discs for reasons only known to BMW are supported on the inner edge,
which means that the cooling air has to pass through large holes in the
'hat' of the disc and turn back on itself in order to flow through the
vents.  The original 'cure' for poor cooling was to make up stainless steel
covers that fitted over the 'hat' of the disc, forcing the air through the
convoluted path to keep the disc cool.  In most cases, even this is not good
enough.

What I have done in the past with M635CSi's is turn down 840i discs to the
required diameter (300mm) and that has been a great improvement.  As far as
we can ascertain, the entire 840/850i brake assembly should fit the M6 strut
housing giving us 324mm diameter discs. :-)  Getting hold of some 850i
brakes in Oz to try it is another issue...

If you really want flash brakes, give some thought to the brakes fitted to 
6/94 onward M5's with 4spot calipers and 345mm diameter discs!!!  Mmmmmmmmm

Brett Shortland
'82 535i
Brett Shortland
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Terry Le May Automotives
Morley, Western Australia
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