nonM Z4 braking upgrades

[3002 tii]

Originally Posted by dre99gsx

UPDATE:

First time at the track with the 135i rear calipers/Z4M rear rotors, and 335i front calipers/Z4M front rotors - PFC08 all around.

Brakes were very soft and squishy after installation, possibly due to the pads not being square or needing to be worn in. Felt like the brake pedal had tons of air.

After the first few laps, I had a solid pedal and braking was predictable yet progressive. No brake fade throughout two HPDE days, and could induce ABS if I really wanted to from high speed. When induced, steering wheel would get 'light', thus still front-biased to some degree.

Brake bias: Didn't notice anything strange. I'm running 295/255 R888R and on a 80deg day, was able to brake from 150 to about 70 without much fuss.

Pedal/knockback: I didn't feel anything strange while braking->trailbraking-> tight turn with regards to brake pedal loosing pressure or vibrations. Note last HPDE I had felt the pedal drop a bit on a turn, and indeed was a bad front wheel bearing.

I think this upgrade to your nonM-Z4 is definitely worth a look vs a full fledged BBK. Out of every session I've run (not advanced group mind you), I was able to out-brake mostly everyone with some headroom. Noticed I said: "MOSTLY everyone".

Here is where I am perplexed.

I know my car has lots of power, and it is masking my driving ability. I have a lot to improve as a driver, but more so, I have a lot of work to do on harnessing the extra power from this vehicle (and the open diff, and the fact that I have either 10%, 20%, or 100% throttle...).

There were occasions where on a long straight, I would pull pretty hard on a seemingly stock E46 M3. Let's just say a few bus lengths. I would then hit my brakes as hard as I could to the edge of ABS at marker 5. Then, 5, 4, 3, 2 and about 1 where I start to trailbrake, I look in my rear view and the M3 has made up all of the distance.

I thought I had very strong brakes. I thought I was applying them as hard as possible. Is it possible to brake even harder with these cars? Am I missing something else? Surely can't be a BBK that is allowing increased stopping power? Suggestions welcome

Function of pad compound, 08’s don’t have the strongest initial bite but they last forever. I’m still on my set from last year and have ton of life left. If you were to run say 01’s you’d notice drop in braking distance.

That said, braking 5 marker sorta early (acknowledge you’re carrying way more speed than most cars) but you might want to try practicing different threshold braking points... OR maybe you can actually carry more speed into T1. What’s your entry speed?

Thanks for the update btw. I just snagged a set of 335i calipers and CSL rotors and plan to install mid-season after I burn through my current pads. However I’ll be upgrading fronts only for now.

[dre99gsx]

Awesome, can't wait to hear how you like the upgrade.

I usually coast after 150, hit the brakes at marker 5, get down to 70mph before the turn but am on the throttle before the apex. Like I mentioned, pedal feels solid, no fade.

I wasn't aware 01s would provide more braking force, only because compounds are still new to me. Looks like 01s are no longer around?

[3002 tii]

Originally Posted by dre99gsx

Awesome, can't wait to hear how you like the upgrade.

I usually coast after 150, hit the brakes at marker 5, get down to 70mph before the turn but am on the throttle before the apex. Like I mentioned, pedal feels solid, no fade.

I wasn't aware 01s would provide more braking force, only because compounds are still new to me. Looks like 01s are no longer around?

Sorry forgot 01’s got replaced by 11’s

You should be able to go little faster than 70 especially with the mild aero. Come out to Lightning in May and we can compare notes!

[trident12120]

Sorry for the hijack. I currently have a Z4 coupe 3.0si and a set from front Brembo GT brakes 6 pot spare from another car. I would need a bracket and possibly new rotors. Searched everywhere for just the brackets. Can anyone point me to the right direction? and would be complication with this mod? Cheers

[dc_wright]

Originally Posted by dre99gsx

UPDATE:

First time at the track with the 135i rear calipers/Z4M rear rotors, and 335i front calipers/Z4M front rotors - PFC08 all around.

Brakes were very soft and squishy after installation, possibly due to the pads not being square or needing to be worn in. Felt like the brake pedal had tons of air.

After the first few laps, I had a solid pedal and braking was predictable yet progressive. No brake fade throughout two HPDE days, and could induce ABS if I really wanted to from high speed. When induced, steering wheel would get 'light', thus still front-biased to some degree.

Brake bias: Didn't notice anything strange. I'm running 295/255 R888R and on a 80deg day, was able to brake from 150 to about 70 without much fuss.

Pedal/knockback: I didn't feel anything strange while braking->trailbraking-> tight turn with regards to brake pedal loosing pressure or vibrations. Note last HPDE I had felt the pedal drop a bit on a turn, and indeed was a bad front wheel bearing.

I think this upgrade to your nonM-Z4 is definitely worth a look vs a full fledged BBK. Out of every session I've run (not advanced group mind you), I was able to out-brake mostly everyone with some headroom. Noticed I said: "MOSTLY everyone".

Here is where I am perplexed.

I know my car has lots of power, and it is masking my driving ability. I have a lot to improve as a driver, but more so, I have a lot of work to do on harnessing the extra power from this vehicle (and the open diff, and the fact that I have either 10%, 20%, or 100% throttle...).

There were occasions where on a long straight, I would pull pretty hard on a seemingly stock E46 M3. Let's just say a few bus lengths. I would then hit my brakes as hard as I could to the edge of ABS at marker 5. Then, 5, 4, 3, 2 and about 1 where I start to trailbrake, I look in my rear view and the M3 has made up all of the distance.

I thought I had very strong brakes. I thought I was applying them as hard as possible. Is it possible to brake even harder with these cars? Am I missing something else? Surely can't be a BBK that is allowing increased stopping power? Suggestions welcome

You might have better/equal brakes but if he's going to have a higher cornering speed he's going to close the gap on you pretty quickly in the corner. Kinda like me and the 'Vette in this video.

[dre99gsx]

Update: Had a track event this weekend. Ended up with a mushy pedal near the last session from heavy braking (long straights to tight turns). This is the Pocono Tri-oval to North course Twilight event.

I'm pretty sure I boiled my Motul600 freshly bled fluid (PFC08s). All 4 rotors were glowing red from what others mentioned. Not only that, but the rear 135i calipers which were Gray? are now Gold!

Dust boots are also cracked on those 135i calipers. Hopefully the piston/seize issue is only a 135i front caliper issue. Was hoping to not need to upgrade (again) rear calipers after all that work.

Front 335i clalipers with brass sliders working like a champ so far.

This is partly my fault since I'm braking so hard, I'm entering the corners at a snails pace. Need more confidence to enter corners at a faster pace.

I'm trying to not spend $4-6k on full BBK.

[3GFX]

Originally Posted by dre99gsx

Update: Had a track event this weekend. Ended up with a mushy pedal ...

...glowing red from what others mentioned. Not only that, but the rear 135i calipers which were Gray? are now Gold! ...

Holy smokes, you've got a lot of heat into those brakes. I'm similar but not nearly as bad. 3 track days and I cooked my pads. That 1st track day I boiled my fluid. The heat has taken the clear coat off my beautiful painted calipers but they're still Le Mans blue.


What are people using for brake pads? I'm using EBC red stuff again, but I feel like I could go a little more heavy next time out.

[dre99gsx]

It's partly my fault (I hope) in that I have a habit of pitting in as soon as the checkered flag goes out. I have not been doing meaningful cool down laps. I'm sure the fluid just boils in the pits. Shame on me.

Going to SRF fluid next, upgrading from 2.5" front ducts to 3", and going to try to add rear brake ducts. Will also install the rear 135i metal pad shims, hoping it provides some relief to heat transfer.

If none of the above help, then BBK it will need to be. When does the money bleeding end!

[dbarton62]

There's a guy on the BFC site that has added water cooling to his setup for road courses.

[AK72]

Originally Posted by dre99gsx

Decided to embark on another smaller project: Upgrade the Z4 3.0si brakes. Why?

a) My rotors are completely worn and too thin for comfort
b) I like the BBK look, can't afford it, thus want to improve the look from what I currently have
c) With the additional power from the 2JZ conversion, I'll need some beefier rotors to handle high speed braking during track use
d) I know cooling is essential - will work on that as well

I'm going to keep an eye on brake bias as I make these upgrades.

First, I wanted a more modern look for the front calipers. I like the way these look:




What you see up there is the 335i front stock calipers. Yup, I bought two from the junkyard. Yes, they bolt right up to the 3.0si spindle, and yes, they clear and work right on the 325mmx25mm 3.0si rotor, albeit the pad extends further outward since they are made for the 335i 348mmx30mm rotor.

So, I took a risk and purchased a 335i rotor just for kicks. Nope. Doesn't fit, it hits the steering knuckle. I just ordered the 345x28 ZHP/M3/Z4M front rotors and will see how they fit. My guess is they will fit.

I'll do some weight comparisons, and measure caliper piston diameter/pad dimensions to see how bias will be affected.

Swapping in the 2JZ "made no sense" to purists, and I'm sure upgrading the brakes will "make no sense" to the hardcore track enthusiasts, but the point here is not really about function, but more about aesthetics. And since I need to replace everything anyway, why not

Hello dre99gsx

Im looking at the calipers for E90 335i and for some reason they looks different compare to yours, could you please specify from what year and exactly model your calipers is, maybe part #




One of you use is actually E60 M5 or E63 M6 calipers?

[dre99gsx]

Sure! 2007 335i. In your photo above, it's the blue one to the right.

[AK72]

Originally Posted by dre99gsx

Sure! 2007 335i. In your photo above, it's the blue one to the right.

but they looks different compare to your on left side

[3002 tii]

Originally Posted by AK72

but they looks different compare to your on left side

That’s because whoever had those blue ones went out of their way to fill in the hole on the clip/cover so they could put the sticker on

[AK72]

Originally Posted by 3002 tii

That’s because whoever had those blue ones went out of their way to fill in the hole on the clip/cover so they could put the sticker on

3002 tii

if you look carefully you will notice that its different calipers,
I took as reference first post from this thread and ordered one that shows on the picture, hope its a right calipers bcs they are on the way already

[3002 tii]

Originally Posted by AK72

3002 tii

if you look carefully you will notice that its different calipers,
I took as reference first post from this thread and ordered one that shows on the picture, hope its a right calipers bcs they are on the way already

Don’t see a difference between the 2 blue ones other than the M decal. Regardless any E90 335i/xi front caliper will work as they’re all the same.

[GuidoK]

Originally Posted by 3002 tii

Don’t see a difference between the 2 blue ones other than the M decal. Regardless any E90 335i/xi front caliper will work as they’re all the same.

The 2 blue ones are different, and maybe there's also a size difference.

[3002 tii]

Originally Posted by GuidoK

The 2 blue ones are different, and maybe there's also a size difference.

Oops, seeing this on my laptop and see it now. The left one has drilled rotors which doesn’t look stock for an E90 335i so might be an E60 m5. But the right one as Dre pointed to is right, that’s how mine looked on my old E90.

[GuidoK]

I'm not talking about the rotors, but the calipers itself.
Both blue ones are different. My guess is that the left one (with the m logo) even might house a larger pad.

I speculate that the left one is an e60 m5 caliper with dual piston, or maybe even a dual piston 7 series. The other one is 335i

You can recognize those dual piston calipers at the 2 extra slots (they're not going all the way through though) either side of the center slot where the wear sensor lead goes through.

AK72 saw that very correctly.

[AK72]

Originally Posted by GuidoK

I'm not talking about the rotors, but the calipers itself.
Both blue ones are different. My guess is that the left one (with the m logo) even might house a larger pad.

I speculate that the left one is an e60 m5 caliper with dual piston, or maybe even a dual piston 7 series. The other one is 335i

You can recognize those dual piston calipers at the 2 extra slots (they're not going all the way through though) either side of the center slot where the wear sensor lead goes through.

AK72 saw that very correctly.

well its too late looks like I have set of wrong calipers in mail thanks to the first post picture misleading

[dre99gsx]

Part of the issue here is that originally, these thread had plastered with Photobucket photos (which you would be able to use to determine the correct caliper). Somehow, they are all missing.

Sorry for the confusion.

[AK72]

Originally Posted by dre99gsx

Part of the issue here is that originally, these thread had plastered with Photobucket photos (which you would be able to use to determine the correct caliper). Somehow, they are all missing.

Sorry for the confusion.

That's fine
Not a big deal just few $$$

[3002 tii]

Originally Posted by GuidoK

I'm not talking about the rotors, but the calipers itself.
Both blue ones are different. My guess is that the left one (with the m logo) even might house a larger pad.

I speculate that the left one is an e60 m5 caliper with dual piston, or maybe even a dual piston 7 series. The other one is 335i

You can recognize those dual piston calipers at the 2 extra slots (they're not going all the way through though) either side of the center slot where the wear sensor lead goes through.

AK72 saw that very correctly.

That’s what I said in my latest post. It wasn’t till I noticed different rotors I took a closer look on my computer and noticed difference in calipers. But it doesn’t matter because I don’t see why anyone would order calipers based on generic pictures. That first post was just a reference to the “look” he was trying to achieve. End of day if you ordered calipers based on part number or cross referenced whichever fits an E9x 335i (which is what this whole thread is about) it would fit correctly. I did this upgrade on 2 separate cars, and it worked fine in both cases.