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Discussion Starter #1
Anyone done this - have any thoughts, views or comments?

I'm considering this as the best route for a reliable source of cheaper mainstream brake parts for the Bi-Turbo. I have to replace the discs as it is and for a couple of hundred pounds more can install the front brakes from the 840ci.

Dave.
 

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DaveW said:
Anyone done this - have any thoughts, views or comments?

I'm considering this as the best route for a reliable source of cheaper mainstream brake parts for the Bi-Turbo. I have to replace the discs as it is and for a couple of hundred pounds more can install the front brakes from the 840ci.

Dave.
I have read comments on the Roadfly E24 board from those who have done this brake upgrade, and it is viable. Not sure about the size of the front protective plates on the wheel assemblies of the E34, but on the E24 they must be removed, as the larger rotors will not fit. I myself have upgraded my rears to the E34 M5 brakes, and am quite pleased. I did leave the stock front brakes (same as the M5 & 6) as they were. Here is a link to a very thoughtful document detailing the options for upgrading your brakes. It is a bit old, so the pricing detailed is significantly different now (for the better). Enjoy!

M Brake upgrade options
 

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Discussion Starter #3
Hello!

Thanks for your reply. The Bi-Turbo brakes are in fact ever so slightly bigger than the E31 discs so there will not be a problem with the back-plates. Overall piston area and change to the brake pedal should also be similar. Price wise this seems to be the best way to proceed - providing they fit the uprights without modification!

Dave.
 

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DaveW said:
Hello!

Thanks for your reply. The Bi-Turbo brakes are in fact ever so slightly bigger than the E31 discs so there will not be a problem with the back-plates. Overall piston area and change to the brake pedal should also be similar. Price wise this seems to be the best way to proceed - providing they fit the uprights without modification!

Dave.
I wouldn't, frankly - the standard brakes on the E31 are pretty weak in practice - hence the 330mm/4 pot Alcon front brakes that I had put on my 840.
 

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Discussion Starter #5
hythe said:
I wouldn't, frankly - the standard brakes on the E31 are pretty weak in practice - hence the 330mm/4 pot Alcon front brakes that I had put on my 840.
The 840 brakes are single pot, the 840ci brakes are 4 pot Brembo - which ones did you have?

Dave.
 

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DaveW said:
The 840 brakes are single pot, the 840ci brakes are 4 pot Brembo - which ones did you have?

Dave.
Mine's a 1999 840Ci Sport, with the later brakes. The calipers just don't seem that effective - the new Alcon brakes are far far better.
 

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Discussion Starter #7
hythe said:
Mine's a 1999 840Ci Sport, with the later brakes. The calipers just don't seem that effective - the new Alcon brakes are far far better.
Seems like I'm caught between a rock and a hard place! Wanted Stop-techs but they won't supply, have looked a big brembos etc then found the 840ci brembo option.

What are the Alcon details - can you share supplier and parts + cost info?

Thanks mate,

Dave.

PS Thanks also to M5Killer who went to an Alpina dealer in Belgium today to enquire on original disc replacement - great price mate, thanks. I'll think this one over for a day or so and hopefully have a plan by the end of the weekend - the Ring is only a couple of weeks away.....
 

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DaveW said:
Seems like I'm caught between a rock and a hard place! Wanted Stop-techs but they won't supply, have looked a big brembos etc then found the 840ci brembo option.
What's with Stoptech and Brembo not supplying? We have pretty decent contacts to European sales managers of both, so let me know by PM if I can help.
 

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kees said:
What's with Stoptech and Brembo not supplying? We have pretty decent contacts to European sales managers of both, so let me know by PM if I can help.
Sorry should have clarified, I haven't asked Brembo as during my discovery process found out the 840ci calipers are indeed Brembo manufactured items so couldn't see the point of looking further on that one.

With Stoptech they don't have a TUV approved kit for the E34 so won't supply and their delears are bound by this rule too it would seem... Love their work however, beautiful quality and if the vehicles I've been in that have Stoptech's fitted are anything to go by, the braking is outstanding no matter what the abuse.

For everyone's information, I'm told the 840ci brakes at 324mm discs and 4 pot Brembo calipers will bolt straight on - they cost around £600 as a full price which is 50% of Stoptechs or 40% of AP's best kit. Am not sure what the Brembo GT 332mm kit works out to be as I stopped looking.

The Bi-Turbo discs alone are about £360 + vat which if I fit them still leaves the problem of the Lucas Girling Alpina Only, cast iron calipers which don't like track work...

Some people search for inner peace, I just want to stop without fade or judder!

Dave.
 

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Got mine installed at Birds - not cheap, of course. You should be able to get the details by downloading a price list of their site - Birds
 

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What about the MovIt Brakes? They have the 993 BitTurbo Calipers and 964 Discs (330mm). The original Porsche discs with Pads is about 500€. Sometimes you´ll get the Calipers for the same price @ebay.......then you just need the adapters....perhaps you can get them from Movit directly or ask at MBT Engineering http://www.mbt-engineering.de/engineering/welcome.html

I had them on my old B10 BT and they were wonderfull.

Regards,
Dirk
 

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Discussion Starter #14
Car all done, passed MOT.

In the end I went for the Brembo 4 pot brakes from the 840ci. They were a straight swap and are larger than the original brakes on the 3.6 M5. At a little over £700 they were quite reasonable too.

Thanks to all the helpful comments - M5Killer, Hythe and Kees in particular. I do appreciate Hythe's comments that on his 840ci the Brembo's were lacking but it is a heavier car and I can still mess around with pads to a certain degree. Time will tell however as I will pick the car up tomorrow and haven't driven it yet.... My garage say it's fine however and they support the conversion.

I'll let you know....

Dave.
 

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Hello,

Picked the car up and drove home - brakes are not bedded in but feel fine - intitial impression is that the pedal has a slightly longer travel to first bite but we're talking cm's nothing that would cause a problem.

Drives beautifully but I got that cold sharp reality check when it came to paying the bill.... The Bi-turbo is an amazing car but the low re-sale price of Bi-Turbo's available in the classifieds today is entirely due to the massive running costs associated with keeping the car in perfect condition... Will see if a bottle of red makes me feel better....

Dave.
 
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