840i Brembo caliper test fitted

[Ian Godney]

The bells I have quoted on are to be used with AP discs or similar , if you have AP 325mm x 28mm discs with bells that I can make , the 850 brembo caliper will fit straight on , Bells are usually around the £200 a pair mark , but have given Jake a deal of £150 a pair for 5 or more pairs. As the AP discs are quite expensive I can also supply our own make of discs the same size.the retail price on AP discs are £197 each

If you are going to use the E46 M3 discs , then you will need the spacer shown up a few thread to put the discs in the right place for the calipers , but this will bring your wheels out by the thickness of the spacer , so if your tight for room in the arch (fender) for the tyres they won't work for you

[John]

>As the AP discs are quite expensive I can also supply our
>own make of discs the same size.the retail price on
>AP discs are £197 each

yes they are expensive. the price you quote is for the
5000 series AP disc (about 287 euro retail).
It gets even more expensive with their better discs,
385-400 euro for each disc.

I hear coleman in USA makes discs for $100 each
in 330x28 mm size. I doubt its the same quality,
but at those prices you can afford to throw them
away...

that being said, I have already 180 nordschleife
laps on my AP 3047 series discs. 3744 track km
(2326 track miles). and they are still in good shape.
Not bad at all IMO. When looking at prices also
factor in how long the part lasts...

John

[Jake]

Ian's brought up a good point. Going with a custom bell and disc assembly will not affect your wheel offset, assuming the bell is the same thickness as the stock disc. You will still need some extra clearance behind your wheel spokes for the caliper, but if you already have the room your golden. Going down the E46 M3 route for discs means you will already have a 14mm spacer in the mix, and your wheel choice would need to account for it.

HTH,
Jake Larsen

[Dietrich]

OK guys - I got a quote from my favorite discount dealer:

-E31 Brembo caliper: 34-11-1-161-177/178 - $378.89 ea
-E46 M3 MS rotor: 34-11-2-282-801/802 - $186.48 ea
-Cool Willy (TMS) pads: $189 Note: There are probably other pads available, but these are quality race pads that can (at least) be driven to the track.
Total thus far: $1,323

-spacer for E46 rotor: $ ??? Who can make these for us? Note: seems to me that you might need another spacer for wheel spoke clearance. Given the thickness of the caliper, I doubt this setup would work with my 8x18 style 5's (ET 20).
-SS brake lines: are these necessary, or will our 'stock' lines work with the E31 caliper?

This is getting kinda spendy but the results could be *awesome* brakes. HTH.

-Dietrich

[wookie1976]

Anyone think these Wilwood rotors would work?

Diameter - Width - Bolt Circle - Hole Type - Far Side I.D. - Lug I.D.- Weight LBS - RH/ LH Part Number
13.00" (330,2) - 1.10" (27,9) - 12 x 7.00" (177,8) - .251" - 8.57" (217,7) - 6.38" (162,0) - 14.4 - RH 160-5810

The measurements are 330mm x 28mm (approx), but would the both pattern be the same? If so, then there are other rotor alternatives for much cheaper.

[Ian Godney]

Yes the bolt pattern is the same as AP , they also have an 177:8mm PCD 12 bolt holes , but the AP discs have a :25" hole size , you could always drill out AP bells to suit but then you couldn't go back to AP discs ,

Dietrich , the spacer fits in between the disc and spacer if you use the E46 discs , if you dont have room in your spokes , you would also need a spacer bewteen the disc and wheel , which I doubt the wheels would fit in the arch

[Jake]

Originally posted by Dietrich
spacer for E46 rotor: $ ??? Who can make these for us? Note: seems to me that you might need another spacer for wheel spoke clearance. Given the thickness of the caliper, I doubt this setup would work with my 8x18 style 5's (ET 20).

Keep in mind putting a spacer behind the disc or in front of it does the same thing as far as caliper/spoke clearance. That 14mm spacer behind the disc will give you 14mm of extra clearance between the caliper and the back of the wheel spokes.

Originally posted by Dietrich
-SS brake lines: are these necessary, or will our 'stock' lines work with the E31 caliper?

I'm not sure about the brake lines. I can say that on my E34 project I found that the standard aftermarket Goodridge lines for the 540 (using standard brakes) had plenty of length for the E31 calipers, they even used the same fittings. I haven't tested this on the M3 yet, and it's not really something I can speculate on. Wish I had an answer for this one.

Cheers,
Jake Larsen

[Ian Godney]

Jake , the spacer is not there to give spoke clearance , the E46 discs have more offset than the E30 , so the spacer fits between the hub and the disc to effectively lessen the offset of the discs , to bring it away from the bottom ball joint , if it doesnt give you enough room in the spokes you still need a spacer on the outside of the discs

[Dietrich]

Originally posted by Jake
Keep in mind putting a spacer behind the disc or in front of it does the same thing as far as caliper/spoke clearance. That 14mm spacer behind the disc will give you 14mm of extra clearance between the caliper and the back of the wheel spokes.
...
Cheers,
Jake Larsen

Thanks Jake. And oops - of course the spacer would improve clearance b/c the spacer is moving the wheel farther out. Dah! The hub-surface of the Style 5 is basically in-plane in the spokes. And the caliper being as wide as it is... Wish we had a pic of the strut/spacer/rotor/caliper assembly taken from front/behind so we could see where the outside of the caliper is in relation to the outer face of the rotor hub. Make sense?

Wookie - about 2 years ago (and before my engine blew up) I was trying to cobble together a bbk using nothing but Wilwood bits. The rotor hat was always the sticking point and I just resolved to have get a custom hat made. Maybe Ian could do that for us??? Ian?

OTOH - if I understand floating rotor design, the float will always allow for equal side-to-side compression. So we'd be giving that up if we dropped the E46 rotor approach in favor of the cheaper [Wilwood] 2-pc rotor. Don't know what the performance cost would be....

Ian - can/would you be willing to fab the E46 spacer???

Thanks everybody!

-Dietrich

[UweM3]

before the E46 the E36 brakes have been use for this sort of conversion and some guys milled the bosses of the caliper down where it bolts to the strut. (I have done the same to my E32 calipers). This will give you another 2mm less spacer thickness.

Before



After

[wookie1976]

Originally posted by Ian Godney
Yes the bolt pattern is the same as AP , they also have an 177:8mm PCD 12 bolt holes , but the AP discs have a :25" hole size , you could always drill out AP bells to suit but then you couldn't go back to AP discs ,

Ian,

So you are saying that your bells will work on these Wilwood rotors if you slightly bore out the 12 rotor to bell bolt holes correct. That makes sense to me. I dont see a need personally to go with AP rotors given their cost. Wilwood rotors are well made, and fairly cheap. Plus they are available at lots of racer supply shops here in the US.

Racer price on these rotors is $238.00 / ea, found them online for $220.00 ea

Total price:

220.00 (2x) Wilwood Rotors
378.89 (2x) E31 Calipers
282.00 Hats @ 1 GBP = 1.88090 USD
189.00 Pads

Total: 1668.00

Not a bad price compared to others on the market.

Still thinking of my options at this point though.

[ColinM]

Don't forget that you'll likely need a larger master cylinder. The 840i up to 8/93 (pre-Brembo??) used an ATE 26.99mm master.

[wookie1976]

I assume you could use the 25mm master and still get good modulation.

[Dietrich]

Hmmmm,

So the Wilwood rotors cost more than the E46 rotors and don't float. Can someone knowledgeable comment on the pros and cons here?

Oh - and it looks like Hawk HP+ will fit the Brembo's for < $100! Good multi-purpose pad, AFAIK.

-Dietrich
I love a good mystery...

[Jake]

Originally posted by Ian Godney
Jake , the spacer is not there to give spoke clearance , the E46 discs have more offset than the E30 , so the spacer fits between the hub and the disc to effectively lessen the offset of the discs , to bring it away from the bottom ball joint , if it doesnt give you enough room in the spokes you still need a spacer on the outside of the discs

Ian,

Correct, the main reason for the spacer behind the E46 M3 disc is to place it where it needs to be for the caliper. But, this adds material between the hub and the wheel; thus, the wheel is pushed out more. The caliper position doesn't change of course, so a byproduct of this spacer behind the disc pushes the wheel out as well and you gain clearance between the caliper and the back of the spokes of the wheel.

HTH,
Jake Larsen