Just wondered if anyone has fitted 6 pot Cayenne/Q7 calipers or anything similar?

Ive had Porsche 996 fronts fitted to mine for some time now but now want to go bigger!

this guy has HERE good read, all 11 pages of it! he has fitted cayenne 6 pots, so HUGEEE!

Yeah just read through that ta!

Thats the brakes im looking at!

why go bigger ???

you will need to change master cylider that will work with the larger brakes and you will prob find there crap as there to big

you still running only 200+ bhp so pointless imo

those calipers would have less braking power than standard vrs brakes - basically dangerous

ps

I have compbrake 6pots, which are going to be changed to Brembo GT's ( unless I get a better OE MC that doesn't cost huge $$ to fit )

snow muncher have you found one that will fit in the same place yet without to much work????

not yet ...

I have been in contact with Compbrake themselves over the issue.

Had quite a long discussion, they want to get more info on my brake setup so they can investigate further.

My current plan is to fit the Brembo GT's I have with some 312mm discs I've got from a previous setup, this should tell me if I've got fundamental brake-force problem, or if the Compbrake's are just too large

If I end up keeping the Brembo's on, I'll replace the 312 disc with a Badger5 bell/rotar

To some extent this thing about the master cylinder is a myth!

If you work out the standard size of slave cylinder on a VRS i.e. 54mm, even though it only pulls on one side in effect it actually acts on both! But using that diameter of 54mm which is designed to mated to the existing master cylinder with no issues obviously!

Using pi

3.14 is basically Pi. And the area of a circle is (Pi) R^2. And diameter is (Pi) D

So the area of a circle is (Pi) 10^2. Which is 314 (3.s.f)

The circumference of the diameter is (Pi) 20. Which is 62.8 (3.s.f)

You can work out the surface area and once you’ve done this something like 2900, can’t remember now! But if you divide that by two to represent two pistons on ONE side of a four piston caliper the ideal size of piston works out to be, using the standard 54mm piston as a starting point! 38mm, so the 38/40mm pistons on the front calipers from a 986 are ideal and don’t impair the braking at all, you don’t gain any breaking force as such but none is lost.

It’s only when you start to get bigger pistons than the aforementioned that is when you could come into problems

So................

Without looking obviously the 6 pot pistons will be a lot smaller than the 4 pots, for obvious reasons, i.e. space and if you added them up you’d find that, if I was a betting man they would be around or not much bigger in surface area to the standard 54mm caliper or the Porsche 4 pot with is basically the same!

As a rule travel is also equal to force, you need travel to create this force!

The idea of having 4 or 6 pot brakes isn’t necessarily about force, it’s about modulation and feel and even braking force.

A Porsche 986 front caliper give no more force that the standard 54mm VRS caliper!!!

It just does it in a different way with better feel and brake modulation.

For example a standard VRS running Ferodo DS2500 or DS300's will have more braking force than a modified car running 4 pots with standard pads!!!

Jeez Danny thats impressive

Jeez Danny thats impressive

Not really lol just simple maths!

Ill find out how big the pistons are on the Cayenne calipers and work that out!

Porsche Cayenne 6 pots come in 3 different piston sizes and are as follows depending on whether you had 17/18 or 19" wheels on the Cayenne they cam off of.

Piston sizes total area

30/34/38 = 2750mm2

34/36/38 = 3060mm2

32/36/38 = 2956mm2

Standard single piston 288/312mm caliper = 2290mm2

I thought it was 2900 something like I said earlier for the standard 54mm piston lol but this is right!

Ideally, infact you should! use the 30/34/38 versions as the others will give you far too much pedal travel and this is when you will find out that the master cylinder cant cope and you may find that your foot will be all the way to the floor before you’ve got a full brake application!!

If you use the ones off of the 17 inch wheels i.e. the ones with the smallest piston diameter you will gain a 20% increase in effective piston area.

It does work out to be a lot more but you only take into account the one aside as they are opposed to each other and cancel each other out!

But if you wanted to work it out on stroke volume it would be something like 50%!

So as you can see the standard VAG 23.8mm master cylinder isn’t as bad as what some would make out to be and is fully capable of taking an increase, although not too much of one in piston surface.

These are equations that would be wise to follow if you are thinking of upgrading your brakes, not just buy calipers from EBay willy nilly as you could infact make you brakes a lot worse that they are standard and it not just a case of getting a bracket, disc and a caliper and throwing then together on your drive!

Having said that most 4 pots from say Scooby’s, Mitshis and obviously LCR,s "Should" be fine as the master cylinder size doesn’t really vary that’s much from car to car, but its always worth checking and doing your math’s!!!

Hope this dispels some myths and putts a few things straight?

those calipers would have less braking power than standard vrs brakes - basically dangerous

ps

I have compbrake 6pots, which are going to be changed to Brembo GT's ( unless I get a better OE MC that doesn't cost huge $$ to fit )

Please read above!

but in the real world when all these different brakes have been tested on cars in the real world it has been proven that some of the larger brakes are rubarb due to the master cylinder not up to the job

i can see your maths make sense

same as all things that we bolt onto cars the maths say it should do X but 9 times out of 10 it will do Y

anyways you seem to have you sight set on big big brakes then crack on and report back your findings. be good to see if they will work

Please read above!

I assumed from seeing these calipers (porka 6pots) close-up (but not able to see actual piston as fitted), that they had huge huge pistons ~ that's what they look like from the outside

The other issue with these calipers will be the weight. They look quite heavy.

You really need to keep within the oe total weight (16.5Kg-ish from memory) , over will badly affect the balance of the car

but in the real world when all these different brakes have been tested on cars in the real world it has been proven that some of the larger brakes are rubarb due to the master cylinder not up to the job

i can see your maths make sense

same as all things that we bolt onto cars the maths say it should do X but 9 times out of 10 it will do Y

anyways you seem to have you sight set on big big brakes then crack on and report back your findings. be good to see if they will work

Yeah inderstand sods law! lol

But these brakes have been fitted to other VAG cars, so ive just read. like Mk4 Golfs with no issues

I assumed from seeing these calipers (porka 6pots) close-up (but not able to see actual piston as fitted), that they had huge huge pistons ~ that's what they look like from the outside

The other issue with these calipers will be the weight. They look quite heavy.

You really need to keep within the oe total weight (16.5Kg-ish from memory) , over will badly affect the balance of the car

The calipers themselves are not that heavy, i forget the exact weight needless to say they are lighter than the OEM set up.

Plus a slight increase in unsprung weight is not great issue, you do more damage by fitting cheap copy wheels or increasing the size to say 18's or even 19's that will make the car perform worse than a slight increase in axle weight dues to brakes.

FWIW I've got 6-pot Brembo calipers off a Porsche Cayenne with 350mm discs on my Mk2 and it stops just fine

FWIW I've got 6-pot Brembo calipers off a Porsche Cayenne with 350mm discs on my Mk2 and it stops just fine

What are they like?

Whats the feel like and the pedal travel?

different master cylinder though i think on a mk2 so not a fair comparison.

In my experience 6pots dont work as well as the brembo gts/lcr brembos on the octavia

I've jus put LCR 4 pot brembos on my mk1 and they are brill! No change in pedal feel. Infact I'd say I've now got better feeling than before. I think I've blead the system better than the garage I had it done at before.

I noticed under heavy braking with std brakes they bite well then after a few seconds of harsh braking they faded. The final few seconds of the slowing down felt like melted chocolate. And to me felt danngerouse. But with the brembos there is no fade in the entire braking period from 70 - 0. And the bite gets harder n harder all the way till the car stops. Made me feel really sic and like my eyes were coming out. Even felt dizy lol.

I was gonna get the compbrake 6 pots as they needed no spacers of fafing about, just fit and go but after hearing they made the pedal feel worse that put me off.

.. Plus a slight increase in unsprung weight is not great issue...

its where the weight is that causes the issue, not the weight itself.

I've gone over weight on a previous setup, and it screwed my handling

My current setup is under oe weight, and the front end feels noticably lighter and nimbler

its where the weight is that causes the issue, not the weight itself.

I've gone over weight on a previous setup, and it screwed my handling

My current setup is under oe weight, and the front end feels noticably lighter and nimbler

How did you manage to go over the OEM weight!!!?

And to be honest unless your driving a nicely ballenced race car the increase in weight shouldnt be a problem, infact i doubt most people would even notice!

What worse as ive said before is too bigger wheels or having too much rubber on the road and the you will notice the unsprung weight difference and the tram lining lol

How did you manage to go over the OEM weight!!!?

Astin Martin DB7 GT4 caliper with a 312mm EBC disc. I had some caliper carriers made up, and think they used depleted uranium judging by the weight. Overweight each side by about 1.5Kg.

The EBC discs where also very heavy compared to some OEM VAG 312 discs a mate had sitting in his garage.

And to be honest unless your driving a nicely ballenced race car the increase in weight shouldnt be a problem, infact i doubt most people would even notice!

my car is very nicely balanced, particularly now I've had the laser-alignment done.

I have two sets of wheels for car ('heavy' winters & 'lightweight' summers) and yes you're completely right about wheel weight/tyre sizes, etc, having a big impact.

TBH it was really pretty clear - fitted big heavy brakes - excessive oversteer induced - fitted lightweight big brakes - problem solved ...

I had a quick google - so far I've found a vague figure of 13lbs / 5.9Kg - which tbh is mucher lighter than they look (honeycombe alloy ?).

That leaves 10.6Kg for a bell/rotar or disk, should be achievable.

The smaller piston size (2750mm2) calipers (touregs ones) are only a little larger than AP 6pots that Steevie Wonder rates

IbanezDan51 on uk-mkivs is currently fitting, so worth watching

Yes snow ive seen the MK4 forums and they seam to fit the samller Cayenne calipers okay, but to be fair im happy with the set up ive got so im not forcing myself to go down the 6 pot route just yet!

Ill wait and get the calipers as and when they come up on the web.

Ive got two sets of calipers that ive used on my car 996 fronts, which are the same as the 986 S fronts and 996 rears which are the ones that your not supposed to use! because the pistons are way too small, which they are on a roda pad!

But ive used both and i like the 996 rears to be fair, im running a very extreme pad either DS3000's or DS 1.11's and they arent so good from cold but when they are warm they bite like a bitch so im using the pad compound to mak up for lack of piston area! not the way to do it i know but it works well, works very well and like you say they are very very light, using the OEM disc and the calipers which both weigh less than one of the single pot VRS ones!

Not to everyones taste but if you can put up with the squeal they are fine

All i want to do now is find out the best way to mount another set of 4 pots on the raer with a seperate handbrake caliper!!!!

All i want to do now is find out the best way to mount another set of 4 pots on the raer with a seperate handbrake caliper!!!!

TRY THIS......

I just opted for the 330mm rear disc and modified OEM calliper.... I did this more for show as I hate seeing big wheels with tiny p!ss poor brakes inside them!

In addition, very little braking force actually goes to the rears....

Steve