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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

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Pbondar

(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by Pbondar » Mon Jul 19, 2021 5:19 pm

Gearbox wrote: Mon Jul 19, 2021 5:11 pm hi Just reading through this thread... and interested to do this... Did you get the '35i rear callipers from the US just so you could refurb them and not lose the use of your car, or was there another reason. I have just compared the 35i and the 20i realoem parts list and they seem to be the same?

Cheers...
I screwed up..in the UK and Europe 35i AND 35is have the same over size rear caliper..

In the US the 35i has the same size caliper as the 18/20/23/28/30 only the 35is has the oversize rear caliper..

I was in the process of buying two 35is rear calipers ..ordered the parts then the seller said he couldn't find one side..absent minded went to another US supplier with a35i not 35is (forgot the US only issue)..

jenniferlouise
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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by jenniferlouise » Tue Jul 20, 2021 4:03 pm

Hi Gearbox, the technical know-how belongs to others on here, however my understanding - which I think is captured in the thread - is all Z4 have the same rear discs and callipers from 20i to 35i with the 35is being the only exception. I’m sure I’ll get corrected if I’m wrong. :(

The callipers on the rear of my car were reconditioned by Bigg Red in Worcestershire here: http://biggred.co.uk/ and I have been fortunate to secure BMW replacement discs and pads to compliment. :thumbsup: Bigg Red appear to stock and sell refurbished brakes so may be worth a phone call. Otherwise it’s a case of sourcing a pair and having them reconditioned.

I believe the US issue you refer to was our friend trying to source the larger callipers from wherever possible to accompany a max size rear disc. Again I apologise if I’ve got that wrong!

I have to say they look a great match with the #…734 OEM Performance yellow front callipers, and again were easily fitted without any complications.

BMW will happily supply the front kit but will tell you they cannot recommend as, technically, there is no BBK upgrade for the Z4. This probably then calls in to doubt any future warranty, if you needed to do so. However my local BMW Specialist https://bartlett-auto.com/ supplied and fitted mine with no problems and if I had any issues it would go back to them.

It’s an expensive option, one that is unlikely to pay itself back when selling, but it looks sooo much better and probably gives improved stopping… I’ll let you know when I’ve actually done enough miles to bed them in.

Hope that helps a little. A

Pbondar

(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by Pbondar » Tue Jul 20, 2021 5:00 pm

The primary issue is that 35is rear calipers (or 35i rear calipers in Europe) are like hen's teeth..cost me the best part of £300 in parts to 'build' a 35is rear caliper set using used parts then £235 for a biggred refurb..with discs you are into £700 ish for a quality rear disc set

Given that the E89 has a great DCS system you can use that to get the most out of the standard rear disc /caliper.. they are much cheaper and get a nice re-furb on it!

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by jenniferlouise » Sat Jul 24, 2021 9:27 am

Pbondar wrote: Tue Jul 20, 2021 5:00 pm The primary issue is that 35is rear calipers (or 35i rear calipers in Europe) are like hen's teeth..cost me the best part of £300 in parts to 'build' a 35is rear caliper set using used parts then £235 for a biggred refurb..with discs you are into £700 ish for a quality rear disc set

Given that the E89 has a great DCS system you can use that to get the most out of the standard rear disc /caliper.. they are much cheaper and get a nice re-furb on it!
I knew that help would quickly follow; there are far cleverer people in here than me. :thumbsup:

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by mittu » Fri Jan 12, 2024 6:38 am

Hi, Im a little late to the party here. Just bought a 35is.
Has anyone figured out the rear brake upgrade?

Front brake upgrade is straight forward enough with M sport callipers from the Fxx generation of cars.
The rear callipers are tricky though. Existing rotors are 324mm, but there aren't any plug and play oem upgrades.
Closest are the current gen 3 and 5 series (G20 & G30) M Sport callipers.
They're widely available and cheap £150-200 for both left and right.
The electronic handbrake uses the same revised module as the e89, but the calliper wont line up with the mounting holes.
A little adaptor plate is required, which nobody sells.
There is one guy on a bimmerpost thread who's made them for his own z4, and was offering to sell the adaptors to others, but the thread is from a couple yrs ago and he hasn't replied to my message.

Has anyone figured out a solution to this?

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by john-e89 » Fri Jan 12, 2024 7:02 am

mittu wrote: Fri Jan 12, 2024 6:38 am Hi, Im a little late to the party here. Just bought a 35is.
Has anyone figured out the rear brake upgrade?

Front brake upgrade is straight forward enough with M sport callipers from the Fxx generation of cars.
The rear callipers are tricky though. Existing rotors are 324mm, but there aren't any plug and play oem upgrades.
Closest are the current gen 3 and 5 series (G20 & G30) M Sport callipers.
They're widely available and cheap £150-200 for both left and right.
The electronic handbrake uses the same revised module as the e89, but the calliper wont line up with the mounting holes.
A little adaptor plate is required, which nobody sells.
There is one guy on a bimmerpost thread who's made them for his own z4, and was offering to sell the adaptors to others, but the thread is from a couple yrs ago and he hasn't replied to my message.

Has anyone figured out a solution to this?
Hi Mittu,

As far as I know, which isn’t much admittedly, I dont think a rear kit is available for the 35is as in the parts swap scenario you suggest. You don’t specify a budget so maybe have a look at PB brakes, they do a front and rear BBK kit for the E89 which includes a rear line lock for the electronic handbrake to be able to utilise 4_6_8 pot etc, calipers. You could use just the rears if you already have the front stitched up.

It’s at least an option. :driving:
M roady...OEM CSL’s, strut brace, Remus back boxes, ZHP
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by mittu » Fri Jan 12, 2024 7:09 am

Thanks for the suggestion. Unfortunately PB brakes are expensive and out of my budget.
I'd like to retain the factory look and electronic parking brake,
Including the sale of my existing callipers and discs, I should be able to upgrade all 4 corners for £500-600

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by john-e89 » Fri Jan 12, 2024 7:22 am

Yes I get the cost side of them, shame as they’re bolt on and away you go.

I’m guessing you’re going to struggle as B21 hasn’t fitted anything to his 35is, probably have to stick with standard as as I said I’ve certainly never seen a rear non standard solution either.

Anyway bast of luck in your quest….seems you definitely are seeking the grail…. :wink: :driving:
M roady...OEM CSL’s, strut brace, Remus back boxes, ZHP
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
G29

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by B21 » Fri Jan 12, 2024 12:26 pm

From a technical viewpoint there’s no compelling reason to upgrade the 35i/35is rear as the car already doesn’t come close to using all the rear brake’s capabilities..but I understand that’s no reason not to do it..

I know one pathfinder did do a F series upgrade but it wasn’t trivial and required a lot of machining…so I passed on it..

Good luck..
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard..

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(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s

Post by mittu » Sun Jan 14, 2024 12:53 am

You guys are spot on. Only reason I'd like to change up the rear set is to minimise the size the difference between the front and rear discs. Purely aesthetic. I'll give it go, but if I find it too challenging I won't bother.
Quick question about the front set for you guys; can the larger M callipers for 370mm discs be fitted as easily as the ones for the 340mm discs?

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