Big BREMBOs ?

[sjb]

Originally Posted by lawsy

I'll get a price for you

Cheers

[Neil M]

For sale down on the farm:
http://www.pistonheads.com/classifie...xperiment=true
If you like Brembos, or that way inclined?

[sjb]

Originally Posted by 73CSL

why the move from 4pots to 6 pots ?

My reasons,

90% for the extra bling
10% for the extra performance

Seriously, the extra area of the larger discs, also the 6 pot pads are 50% (ish without working it out again) bigger than the 4 pot pads all add up to in theory on paper etc etc a more powerful set up. There's no reason why this shouldn't compare to an AP 6&4 pot set up, the AP front 6 pots have 27/32/38mm pistons compared to my 28/32/38mm for example. Also I just love tinkering with things like this and it would bug me to know this is possible but I hadn't bothered to try it out. My present 4 pot set up will be easy to move on over on the cutters for good money, I paid peanuts for them before the easy refurb.
I'll be getting all OE is best in a few months

[The Gorilla]

Hi,

Not sure I follow this ?

The 6 Pot Brembos as posted etc
are approx 1 kg heavier a piece than
the AP's due to being a Monoblock
caliper and with lugs.
[Shaving the lugs saves a little]

BMW E9X M3 Front discs are approx 1.2
KG,s each heavier than the std CSL front
disc

On the Priomates Calculator thats a gain
of approx 2.2 kg/s plus of unsprung weight
per side, which in real terms is a 1-5 ratio for
roll centre and weight transfer.

Thus the slide rule calculates that the marginal
improvement on braking over say 4 pot Brembos
on the std CSL discs [which are very good]
has added 10ks of weight each side [20kgs]
overall.

I know which I would prefer.

Therefore struggling with the ethos of the gain, although
the yanks have this misconception that if
its bigger then it sure must be better attitude
to most things, of which motorsport is included.
Porn may be the exception to the rule.

Regards,

The Gorilla.

[sjb]

Originally Posted by Neil M

For sale down on the farm:
http://www.pistonheads.com/classifie...xperiment=true
If you like Brembos, or that way inclined?

Seen those a few weeks ago, 4 pots though and although a straight bolt on not exactly great value for money and then you'd have to get the rear discs to match and check whether the piston size would effect bias if sticking with OG rear calipers (although if it's a bespoke CSL front set up you'd hope that would be ok) etc etc
Oh, and they aren't bling enough for me

[sjb]

Originally Posted by The Gorilla

Hi,

Not sure I follow this ?

The 6 Pot Brembos as posted etc
are approx 1 kg heavier a piece than
the AP's due to being a Monoblock
caliper and with lugs.
[Shaving the lugs saves a little]

BMW E9X M3 Front discs are approx 1.2
KG,s each heavier than the std CSL front
disc

On the Priomates Calculator thats a gain
of approx 2.2 kg/s plus of unsprung weight
per side, which in real terms is a 1-5 ratio for
roll centre and weight transfer.

Thus the slide rule calculates that the marginal
improvement on braking over say 4 pot Brembos
on the std CSL discs [which are very good]
has added 10ks of weight each side [20kgs]
overall.

I know which I would prefer.

Therefore struggling with the ethos of the gain, although
the yanks have this misconception that if
its bigger then it sure must be better attitude
to most things, of which motorsport is included.
Porn may be the exception to the rule.

Regards,

The Gorilla.

An AP 6 pot caliper weighs 3000grms (internet search) and my GT3 cup 6 pots weigh 3496grms dead. I don't know which brembo 6 pot you are thinking of but these aren't 1000grms heavier.

I'm very interested to weigh the E9X M3 front discs later tonight/tomorrow to check the weight of those but 1.2kg a piece heavier than CSL ones?????Interesting.

For the record my CSL iron front caliper weighs 5800grms !

20kgs extra weight is simply not the case (in my case).

I'm more interested in the performance difference between std CSL > 6&4 pot brembo set ups. The marginal difference between 4 pot fronts and 6 pots fronts isn't too much of a concern. The 6 pots look much better

And not that it really matters but I'm saving myself a shedload on buying an AP front kit new, £2.5k+??? and having something a bit different.

[sjb]

Originally Posted by The Gorilla

Hi,

Not sure I follow this ?

The 6 Pot Brembos as posted etc
are approx 1 kg heavier a piece than
the AP's due to being a Monoblock
caliper and with lugs.
[Shaving the lugs saves a little]

BMW E9X M3 Front discs are approx 1.2
KG,s each heavier than the std CSL front
disc

On the Priomates Calculator thats a gain
of approx 2.2 kg/s plus of unsprung weight
per side, which in real terms is a 1-5 ratio for
roll centre and weight transfer.

Thus the slide rule calculates that the marginal
improvement on braking over say 4 pot Brembos
on the std CSL discs [which are very good]
has added 10ks of weight each side [20kgs]
overall.

I know which I would prefer.

Therefore struggling with the ethos of the gain, although
the yanks have this misconception that if
its bigger then it sure must be better attitude
to most things, of which motorsport is included.
Porn may be the exception to the rule.

Regards,

The Gorilla.

Ok the E9X M3 discs are heavier on the front compared to the OE CSL disc, slightly less so on the rear. For a non full time racecar I COULD live with this because the other improvements outweigh the weight, here's what I know already....

Both caliper and disc are unsprung weight.
(every 1 unsprung lb. is equal to aprox 3 sprung lbs of weight savings)

The disc is also a rotational weight savings which is the most beneficial.
(every 1 rotational lb. is equal to aprox 6-7 lbs. of actual weight savings)

The Benefits

Increasing heat capacity at the same time, NO more fade.

For the caliper I save weight by eliminating a big heavy sliding caliper and gaining an aluminum opposed piston caliper. Precise response, improved pedal feel, more control, and overall confidence.

HOWEVER I am sticking with the calipers but will be looking into a change of disc as rotating weight is far more important...
Fronts..
345MM CSL 8.95KG OE
360MM E9XM3 10.2KG OE
355MM BREMBO 2-PC 7.3KG
356MM Performance friction 9.2kg
Others to be investigated....

All interesting stuff

[The Gorilla]

Hi,

What fluid Transfer do the Brembos
have in relation to say the std Calipers
or say the AP's which were both designed
with the E46 Pedal ratio /fluid transfer ?.

The E46 M3 master cylinder has a restrictor
in the rear system so when AP designed
the Fronts they retained the front to rear
ratio split v pedal ratio v fluid transfer
which is approx 70/30..

Alcon never got this right hence why you
have a different pedal feel etc.

As regards the weight of the calipers
check them weight differnce wet not
dry I think its more than your saying.

Rotational mass is irrelevent on the twisties
where cross plane weight transfer occurs
its down to unsprung weigh etc, so less
is better, and its in the twisties where
you sort the wheat from the chaff.

But hey just trying to understand.

Std CSL disc with a 4 Pot brembo would
stop justy as well, not sure wht you feel
the need to lug [no pun] those E9X M3
discs around ?.

As a tailnote on my E30 M3 with the CSL
engine reducing unsprung weigh was
important so much so that I ran 24
vane not 48 vane 28mm discs at 353mm diam
and saved over a kilo aside just on the
discs.

It all adds up.

Regards,

The Gorilla.

[sjb]

I'm getting what you're saying, the performance friction discs are the discs of choice now as they appear to be near as dammit the same weight as the CSL OE ones.
My calipers are bone dry as I have already blown them through with an air line, the AP's (CL5555) were weighed dry right out of the box, hotwheels was the site I think. A guy bought together lots of new calipers, new brembo 4&6 pots, AP 6 pots, tarox etc to weigh for an alfa comparison test.
I have no real knowledge of the influence of the fluid transfer issue but the brembo (4 & 6 pot (cayenne)) conversion is very common on the E46, my present set up certainly has a lovely pedal (monkey @ ML got them bled up nice and firm) and a known good bias as does this new conversion, as long as I don't end up with a solid wooden pedal I can live with (and get used to) any pedal feel that I end up with. There's plenty of positive reviews out there in internet land worldwide.

I will end up with PF discs that weigh as good as the same as OE CSL even though they are bigger.

Brembo 6 pot calipers are 500grms heavier than AP's , but 2200grms lighter than OE CSL on the front per caliper.

As for the rear, Brembo GT3 4 pot 2397grms, AP 4 pot 2200grms, OE CSL 3426grms per caliper.

Piston sizes between AP & Brembo 6 & 4 pots appear VERY close.

I can see where you are coming from regarding considering the weights to the extreme but my car is not a full on race car, what I will end up with will be more than adequate for my needs and a fair bit better than OE, which is my only concern. Even with the added cost of PF discs over OE I'm still doing fine cost wise over AP and having something a little different.



Oh and they look better