Using a BBK from a 'normal' M3

[Porter]

Hi guys - I'm after some brake know-how, please.

I used to have a normal E46 M3. The best thing I did to that car was to put a StopTech BBK on the front. It's a 4-piston caliper and 355mm disc set up.

I've been emailing StopTech in the 'states, who have said that I should fit a different StopTech kit to retain the correct front/rear balance. They say that, as the rear caliper pistons on the CSL are larger (46 vs 42mm?), I need calipers with larger pistons on the front. This all makes eminent sense so far.

My quandry comes when I look at other manufacturers' kits (including AP, as far as I can make out). They seem to offer only one front BBK, for both the M3 and the CSL. So I am left wondering how much difference there is between the 2 StopTech kits and whether I really need to buy different front brakes.

I am happy with the other options (pads/fluid/brake less etc), but I tried all those on the M3 and I am sure that I will eventually go for a BBK on the CSL.

Thanks for taking the time to read all this rubbish. Grateful for any ideas - the wife will have a hissy seizure if I tell her I want new brakes.

[s.mac]

I transferred my M3 BBK to the CSL with no issues, the M3 is heavier so if it works on that, it will work on the CSL (this was my take on it)
I only changed later to the AP as I saw one for sale, I couldn't tell the difference. Although it is easier to get the AP replacement parts.

[Porter]

I transferred my M3 BBK to the CSL with no issues, the M3 is heavier so if it works on that, it will work on the CSL (this was my take on it)
I only changed later to the AP as I saw one for sale, I couldn't tell the difference. Although it is easier to get the AP replacement parts.

That makes sense. Was that just a front kit you transferred, or all 4 corners?

[s.mac]

all 4 corners, all 4 pots

[glendog74]

all 4 corners, all 4 pots

Was that your fake Brembo kit Steve? :hahaha:

[CraigMillwardCroft]

Can you not tell the wife you don't moan when she gets new hoover bags :thumbs:

[Porter]

Can you not tell the wife you don't moan when she gets new hoover bags :thumbs:

If I told her that, you'd hear the slap from miles away.

Broached the topic of some new brakes last night. Apparently money is tight, so if I get some new brakes, she will have to get a new pair of boots. I'm still struggling with the logic, but then who ever married a girl for her logic?

I'm still undecided, though. One option is to get some front APs, then sell the StopTechs to buy the rears. That would be a lovely set-up, but it costs the earth. Oh, what to do...

[The Gorilla]

Hi,

Typical American Sales Talk.

Fit your std StopTech E46 M3 BBK to your
CSL.

It should work fine, if you find that there
is two much rear bias, then fit an
in-line Bias Valve to the rears which will
allow you to give more bias to the fronts.

Good for Wet Track Days as well.

Regrards,

The Gorilla.

[s.mac]

boots, now we are talking :smt045

[Porter]

boots, now we are talking :smt045

You are assuming a lot. I can vouch that, unfortunately, they will not be this variety:



(This is also not a picture of my wife)

[Porter]

Back on topic, although searching for those boots was a lot of fun...

Hi,

Typical American Sales Talk.

Fit your std StopTech E46 M3 BBK to your
CSL.

It should work fine, if you find that there
is two much rear bias, then fit an
in-line Bias Valve to the rears which will
allow you to give more bias to the fronts.

Good for Wet Track Days as well.

Regrards,

The Gorilla.

The voice of reason. I just don't want to discover that there is too much rear bias by disappearing through a hedge backwards. That said, I am guessing that the differences will be minor...?

[The Gorilla]

Hi,

I doubt you will notice it.

A std E46 M3 is circa 70%
front 30% rear.

The Stop Tech std M3 Kit will be
somewhere close to 70/30.

Regards,

The Gorilla.

[Porter]

Hi,

I doubt you will notice it.

A std E46 M3 is circa 70%
front 30% rear.

The Stop Tech std M3 Kit will be
somewhere close to 70/30.

Regards,

The Gorilla.

Thanks for that - top advice. Of note, I only have Stoptech fronts (designed, I gather, to retain balance with OEM M3 rears). I guess that shifts the balance slightly, but not too much.

[The Gorilla]

Hi,

Fronts only will work fine.

Would be good to match up
the rear pads though, if you
can.

Regards,

The Gorilla

[s.mac]

You are assuming a lot. I can vouch that, unfortunately, they will not be this variety:



(This is also not a picture of my wife)

:hahaha::hahaha: