Big brakes rear 996 C2?

[wot996]

Hi,
I'm looking to put bigger discs and callipers on the rear.

1. Does anyone know if the front standard 3.4 discs and calliper will fit the rear?

2. Does anyone know of a kit that would bolt straight on?

Thanks guys
John

 

[Gt3Owl]

I think the standard discs are 330mm you can upgrade to the 350mm you need a spacer kit (design 911) or I believe Alex makes them on here?!

 

[wot996]

Rear brakes

Thank you I'll check that possibility out 👍🏻

 

[Alex]

The brakes are balanced front to back. I wouldn't change one axle without doing the other to suit.

 

[wot996]

Thanks Alex, what would you recommend for the rear?

John

 

[Alex]

Thanks Alex, what would you recommend for the rear?

John

I'll be honest, I know little about brakes. Mistercorn is you man.

 

[Parsley]

I'm sure you have your reason for going larger on the rear, I'm curious?

 

[wot996]

Hi Parsley,

Purely for front rear balance.

 

[911munKy]

I would say that Porsche probably got the balance right in the first place!
Exercise caution as you don't want the rear overtaking the front breaking into a wet corner. I've read of some folks having this problem after upgrading the fronts to bigger discs/calipers and relocating the old fronts to the rear if they get the balance wrong.

I'm no expert (calling MC & PPBB) but just upgrading the rears with standard fronts could be asking for trouble. My brakes were wooden when I got the car but after a refresh they're great, the 996 pedal needs a firm push.

 

[MisterCorn]

You can change the balance just by changing the pads if needed, if you really want more at the rear then 10mm spacers and 350mm rear disks are a cheap way to do it. No changes to calipers as the rears have much smaller area than fronts. Just a new pipe from caliper to bracket.

MC

 

[wot996]

Thanks MC,

Perhaps I should go explain the full story. I have fitted Cayenne Turbo front callipers and 350mm discs to the front. My tiny brain then says that, although the car stops on a sixpence and has no vibration problems when running or stopping, that I should "keep the balance" by upgrading the rears?
Car is a 98 C2.1 with 200 cel cats and has a on the Bench ECU TWEEK by Nicholas Lawrence. It is used for fun (I live on the North Wales border) and the odd day at Oulton park.

Do yo still think 350 rear discs on the rear or do I need bigger callipers too?

Thanks again
John

 

[Griffter]

With bigger calipers front and rear surely you'd need a bigger master cylinder? I'd go with the spacer option to begin with and see how it works.

 

[Slippydiff]

The rear disc diameter on a 3.4 Mk 1 or a 3.6 Mk2 996 is the same, 299mm.
The front discs are 318mm diameter on both models also.

As I understand it, the front calipers will fit onto the rear of the car. The mounting bolt spacing (130mm) is the same, but the piston sizes are different to the OE rear caliper pistons and can create excessive rear bias.

I'm currently in the R&D stages of producing various options for 2 piece floating front and rear discs for the non-GT 996 C2 and C4 models.

Here are some images of the larger 340mm front discs I'm currently testing :











along with the larger 325mm rear discs. These were only fitted to the car yesterday afternoon, hence the surface grinding marks are still present:











With the standard 996 C2/C4 rear calipers, you'll struggle to get anything bigger than the 325mm rear discs inside them.

I'm currently also developing a larger front disc which will be intended for track use, but will just fit inside the standard 4 piston 996 C2/C4front caliper.

Using 350mm front discs and 6 pots is overkill really. I'd be surprised if your brake bias isn't somewhat sub-optimal now.
Those one piece OE 350mm Cayenne discs are heavy too (as are the calipers and pads)

Normally it's stated that "mass is your friend" when it comes to brake discs, but that has to be balanced against the negatives of excessive unsprung weight on suspension and steering.

The 340mm front 2 piece discs I'm utilising are a kilo lighter than the OE one piece 318mm discs (and that's taking into account the 800g for the alloy bell)

The larger, thicker front 2 piece discs I propose making available for tack use, will weigh the same as the stock OE 318mm one piece front disc (again taking into account the weight of the alloy bell) but will be considerably larger diameter, slightly thicker, and better ventilated, so the pads should last longer, and provide more consistent performance along with more stable disc/pad temperatures.



The images I've posted of the 340mm front and 325mm rear 2 piece discs feature cross bolted floating disc to bell mountings, they're THE best quality AP Racing fastener sets which utilise forged bolts, not off the shelf grade 8.8/10.9 or 12.9 capheads.

There will be an option to upgrade to a fully floating bobbin style arrangement for the 340mm front discs (but this option is really overkill for road use) but the larger/thicker front discs which will be intended for track use, will only be available with the fully floating bobbin mounting arrangement.

I've yet to finalise costs, as material costs are still increasing monthly.

I'll be starting a new thread on the 996 forum about the discs in the next few days, firstly to gauge what demand may be, as is usual in these matters, the higher the demand, the lower the component costs will be, but also to field any questions potential purchasers of the product may have.

As a footnote I should add ALL the components used in the discs/bells are British manufactured.

 

[maldren]

Be careful about increasing the rear braking, as Alex said, Porsche will have done a lot to get the balance right and locking the rears first is dangerous and would fail any regulatory testing.

 

[drmark]

I would echo the posts above about not upgrading the rear. I tracked a well set up 996.2 GT3 for a couple of years and it was tweaked by a number of experts in the field (eg Fearnsport, CoG etc). All said upgrade the front brakes but leave the rears standard (discs and pads). I ran PFC on the front (plus KW3 and cup diff) and never had a problem with the rears despite some lengthy sessions.

I know yours is not a GT3 but I would leave well alone if the car brakes well as it does with your current set up.