Finished the way over the top brakes :-)

So after three weeks away making V10 noise I've finally had a second to collate all the bits together for the way over the top front brakes that are going on my C4.

To recap these are Cayenne 6 Pots converted from lug mount to radial mount with specific brackets to allow them to mount to the C4 front upright. Discs are boggo Cayenne Turbo 350mm items with a smattering of drillings.

Caliper - these have been recoated silver to match with the original C4 silver caliper thing.


Lower view showing the bracket:


And the bracket:


You can see the bracket is machined to make a mechanical fit with the front upright for strength and rigidity. Also the caliper is machined to make a flat mounting face with the bracket again for rigidity. No silly spacers or opportunities for flex here!

Disc with a pound coin for scale.


These are generic grey iron Cayenne discs. I might drill them to take the 996 style retaining screws but as the current standard discs and the set before them have been running with no retaining screws it's not really neccesary.

Pads are default road car spec Pagids but obviously in a size suitable for stopping 2.2 tonnes of Cayenne from 160mph so on a 1260KG 996 they will be more than enough with the added benefit of good cold performance and very little brake dust.

I will try to get them on the car this coming weekend if opportunity presents itself. Then it's just a case of slinging the current 4 pots on the rear with 330mm discs at which point I WILL need to fit a 27mm master cylinder

Considerably better brakes than a GT3 for similar money to a pikey K-Sport brake kit

Great work but the Cayenne 6 pots are the poor relation to GT3 6 pots! Id love to put some on the back of mine (do you have a CAD drawimg of the brackets)

Fantastic! Mind if I copy and paste it into 'What I bought my 996 this week.....' thread once it's all done? This is a fantastic mod that I think deserves to be known as widely as possible :thumb:

JohnnyDangerous said:

Great work but the Cayenne 6 pots are the poor relation to GT3 6 pots! Id love to put some on the back of mine (do you have a CAD drawimg of the brackets)

Click to expand...

Poor relation on the basis that they are a generation newer, stiffer and carry a larger pad area?

The bracket is the easy bit, machining the caliper is the hard bit. Is the rear of yours identical fitment to a 996 C2/C4 front including the profile of the rear upright?

New996buyer said:

Fantastic! Mind if I copy and paste it into 'What I bought my 996 this week.....' thread once it's all done? This is a fantastic mod that I think deserves to be known as widely as possible :thumb:

Click to expand...

Help yourself

poppopbangbang said:

JohnnyDangerous said:

Great work but the Cayenne 6 pots are the poor relation to GT3 6 pots! Id love to put some on the back of mine (do you have a CAD drawimg of the brackets)

Click to expand...

Poor relation on the basis that they are a generation newer, stiffer and carry a larger pad area?

The bracket is the easy bit, machining the caliper is the hard bit. Is the rear of yours identical fitment to a 996 C2/C4 front including the profile of the rear upright?

Click to expand...

From memory the rears from a turbo are stock fitment front C2/4 and turbo front rears bolt directly on.

Stiffer? never seen a side mount caliper stiffer than a radial mount! If they were a better caliper dont you think they would be on the flagship GT3. i can buy those cheaper new than the GT3 6 speed calipers I bought but when we went for lunch with one of the guys from Porsche Motorsport and mentioned fitting those he said Nah you dont want those, hence I ended up with GT3 6 pots with the ceramic brake buttons in the pistons to stop overheating the pistons and seals.

JohnnyDangerous said:

poppopbangbang said:

JohnnyDangerous said:

Great work but the Cayenne 6 pots are the poor relation to GT3 6 pots! Id love to put some on the back of mine (do you have a CAD drawimg of the brackets)

Click to expand...

Poor relation on the basis that they are a generation newer, stiffer and carry a larger pad area?

The bracket is the easy bit, machining the caliper is the hard bit. Is the rear of yours identical fitment to a 996 C2/C4 front including the profile of the rear upright?

Click to expand...

From memory the rears from a turbo are stock fitment front C2/4 and turbo front rears bolt directly on.

Stiffer? never seen a side mount caliper stiffer than a radial mount! If they were a better caliper dont you think they would be on the flagship GT3. i can buy those cheaper new than the GT3 6 speed calipers I bought but when we went for lunch with one of the guys from Porsche Motorsport and mentioned fitting those he said Nah you dont want those, hence I ended up with GT3 6 pots with the ceramic brake buttons in the pistons to stop overheating the pistons and seals.

Click to expand...

Only these are radial mount now... and proper radial mount with a bolt down fixing on each end of the caliper (like a 997 GT3 RS) rather than one at the top and one 60% of the way down the caliper like the 996 GT3 six pot. Even with the bolt down of the bracket on the modified caliper all fixings are outboard of the pistons.



In addition as the caliper is machined to be a flat mount to the bracket so the entire assembly is supported across it's width unlike the standard 996 GT3/Turbo upright which carries the caliper as a bridge across the mounting points.



GT3 on the left in the above pic. C4/Turbo upright has the same issue but the bracket increases the vertical stiffness of the caliper to help combat this.

Finally the webs between the caliper halves are thicker on the Cayenne caliper and much more similar to the 997 RS caliper webs. The 997 GT3 RS caliper is essentially a radial mount version of the Cayenne Caliper! Here is the 997 GT3 RS Caliper which as you can see is very similar to the machined and tweeked Cayenne caliper just with larger pistons. Cayenne caliper piston sizes are the same as 996 GT3 caliper.



This bracket setup will work from 350mm to 380mm just by varying the bracket thickness so will go on the back of yours in 350mm form no problem if they're the same bolt spacing as C2/C4 front!

BTW what piston sizes are your fronts? Be good to make sure the bias still works out sensible!

poppopbangbang said:

BTW what piston sizes are your fronts? Be good to make sure the bias still works out sensible!

Click to expand...

I havent changed the MC yet BUT did notice a change in pedal feel BUT im happy to report that after a couple of BIG stops and I mean BIG the brakes work just fine, however if i get 6 pots rear the MC will have to be changed.

Im quite happy to buy the brackets from you dude :lol: Im 380 front so will be 350 rear.

JohnnyDangerous said:

poppopbangbang said:

BTW what piston sizes are your fronts? Be good to make sure the bias still works out sensible!

Click to expand...

I havent changed the MC yet BUT did notice a change in pedal feel BUT im happy to report that after a couple of BIG stops and I mean BIG the brakes work just fine, however if i get 6 pots rear the MC will have to be changed.

Im quite happy to buy the brackets from you dude :lol: Im 380 front so will be 350 rear.

Click to expand...

Brackets are the easy bit, its machining the calipers that takes all the work and CNC code. Standard Cayenne caliper is lug mount and looks like this:



So to convert that to radial mount involves something like this:

That's on a smaller Brembo 6 Pot, Audi I think.

It's not a case of just bolting a Cayenne caliper to a bracket and bolting it up..... unfortunately. Caliper needs converting to radial mount and then a bracket making to suit the installation.

If you're not in a rush I could sort out another set of calipers and brackets?

poppopbangbang said:

JohnnyDangerous said:

poppopbangbang said:

BTW what piston sizes are your fronts? Be good to make sure the bias still works out sensible!

Click to expand...

I havent changed the MC yet BUT did notice a change in pedal feel BUT im happy to report that after a couple of BIG stops and I mean BIG the brakes work just fine, however if i get 6 pots rear the MC will have to be changed.

Im quite happy to buy the brackets from you dude :lol: Im 380 front so will be 350 rear.

Click to expand...

Brackets are the easy bit, its machining the calipers that takes all the work and CNC code. Standard Cayenne caliper is lug mount and looks like this:

So to convert that to radial mount involves something like this:

That's on a smaller Brembo 6 Pot, Audi I think.

It's not a case of just bolting a Cayenne caliper to a bracket and bolting it up..... unfortunately. Caliper needs converting to radial mount and then a bracket making to suit the installation.

If you're not in a rush I could sort out another set of calipers and brackets?

Click to expand...

That would be really cool dude, thanks, Im in no rush. PM with an expected cost and Ill try return the favour if ever you need one :worship: :worship: :thumbs:

PM Sent

Just to check as the non engineer in the mix. If I followed this path I'd have six pots up front equivalent to the 997 turbo RS up front, with 350mm discs? Rather than the 997 GT3 set up? And if I added a spacer I could have 350 discs on the rear with my existing 4 pots?

Would I need to use cayenne discs? Or would any 350mm disc work?

Thanks! :thumb:

wow monster calipers and nice work. should make a massive difference to the braking.

just make sure its all balanced out as too much front bias could make life entertaining. especially on a bumpy, off camber road on a downhill gradient!

If you dont mind me asking, how much has this cost in total for 4 new brakes?