Thanks for the kudos @rado
@DaveSvendit , there's lots of options that might suit depending on your application and what you're trying to achieve.
All 850s, including R models will have 280mm rotors upfront. V70 models on the P80 platform will mostly have 280mmm rotors upfront except V70R models, which have 302mm front rotors. Early 1997 V70Rs also have 280mm front brakes from factory, though I've seen two of these in person, ever.
302mm front brakes
The shift to the 302mm brakes is simple. Calipers are the same, but the caliper hanger is different. You can replace the caliper hanger, use the existing caliper and mount this up with your larger 302mm rotor. It makes a nice difference.
Brake lines are different too (different length, fittings are of course the same).
Part numbers for the hangers are: 8251319 or 8602456. We can source these and you might also be able to source them via your local dealer.
So, if you're after a moderate improvement in performance, you'll achieve that with some decent pads and rotors or if you wanted to go for an 'oem upgrade', you might consider moving to the 302mm setup on the front.
320mm brake upgrade
If you're after something better again, moving to the 320mm front brake package (rotor and caliper) from P1 S40/V50 T5 AWD and LS-LV Ford Focus XR5 is fairly straightforward, uses a larger caliper, has both a larger rotor and larger pad surface area. It also affords you more pad and rotor options/choice and, typically, pads and rotors are cheaper (more cars on the road using this brake package).
Its a significant improvement over the 280mm and 302mm brake packages.
The key part of that is the adaptor to fit the P1 caliper to the P80 knuckle, but it requires no modification to the knuckle at all and is a bolt-on scenario.
It requires minor modification to the caliper hanger (from the P1 calipers) and for the centrebore of the rotor to be machined to suit the P80 hub. You can use the brake line from the P80 V70R 302mm brake package.
We developed the kit and adaptor for this conversion. We sell lots of them.
P2 S60R/V70R brakes
Fitting the 330mm REAR P2 S60R/V70R rotors and four-piston Brembo calipers is pretty easy. There's a couple of aftermarket adaptors available (we dont offer one, there's good options out there though).
It's not quite bolt-on - it requires modification to the backing plate/dust shield and some minor re-shaping of the hard lines.
The P80 platform is fairly heavily front biased, so for a road car, there's not a heap of point doing this on a road car at all - It does look great though and compliments (visually) a front upgrade. You just wont notice a real difference unless you're doing some extreme braking.
Like @rado though, our V70 has this conversion on the rear. 🙂
Upfront though, its tougher going.
My 'opening statement' is that its a silly conversion to fit P2 S60R/V70R 330mm Brembo FRONT brakes to the front of a P80.
You're either in for a scenario where you're modifying the knuckle for clearance for an adaptor (strongly recommend against) or you end up with a very complicated adaptor (lots of machning, super expensive) and then, once mounted, the next challenge is clearance with the lower control arm at full steering lock.
So, you're either then clearancing the arms or looking at fab'ing up a set of tubular arms - Michael Bennet did this on his 850R, the arms are very nice and afford more caster and camber adjustment too.
It's a heap of work when you could simply consider another caliper option (but, I understand the desire for Volvo hardware).
Porsche 993 'Big Red' front brakes
Pretty common conversion in europe. Using the Porsche 993 Big Red calipers with 330mm P2 S60R/V70R front rotors.
It again requires an adaptor to make this one work, but considerably easier the the P2 S60R/V70R front swap.
Of course, finding the calipers reasonabily priced is the biggest challenge.
Alfa 159 front brakes
There's adaptors available for mounting Alfa 159 front brakes for the front conversion @rado has done is nice in that it uses 'inexpensive' Brembos (likely Megane RS source Brembo calipers could be used here for a similar conversion here too - he and I probably chatted about this way back when and they compliment the P2 S60R/V70R rears really well.
Others adapted brake options
We did a (one-off) VF Commodore SSV brake conversion (calipers) to an LS-LV Focus XR5 and used an LV Focus RS rotor. Adaptor was a little complicated but, at that point in time, the calipers were inexpensive. The caliper cost would likely make this cost-prohibitive today.
Aftermarket off-the-shelf options
The AP Racing AP5200 caliper with a 324mm rotor was offered at the same time that Ohlins suspension was offered for P80 models as a dealer-fit options.
Expensive when new and not-popular. These then became a more common aftermarket upgrade in the very late 90s and early 2000s but are not offered now.
We are a KSport dealer and have their 6 piston setup on our V70 as well, using a multi-piece rotor and hat.
Its definetely aimed more at a motorsport application, though the calipers we spec in this conversion feature internal dust seals (for longer service intervals) which is not particularly common on many motorsport calipers.
While I generally recommend against a drilled rotor for a road car, the rotors on the front of our car are drilled.
Our car uses a 330mm brake rotor, only as I wasnt sure that the 354mm rotor would fit under the 18" wheel we're using.
OEM Replacement brands (for pads and rotors) -
Decent rotor brands: Genuine Volvo, Brembo, ATE, Textar, Zimmerman and DBA (T2 and above)
Must Avoid: Protex, BCP weird ebay brands
Decent pads: Genuine Volvo, Brembo, ATE, Bosch, EBC* (Red is about the highest spec you'd go on a P80, others will offer poor performance from cold and have excessive rotor wear) and then Project Mu or Hawk if considering genuine performance pads.
Must Avoid: Bendix (particularly in the rear), Protex, weird ebay brands**
Generally speaking -
Good pads can make a night and day difference to braking performance. Cold pad bite is very important on a road car.
Drilled rotors are (generally) pointless on a road car and the nature of quick heat up, quick cool down due to puddles, road debris, stop-start driving and oem pad compounds will often lead them to develop hairline cracks between the holes and require early replacement.
Slotted rotors serve the purpose of sweeping gaseous buildup between the rotor and the pad surface and 'clean' the pad (like a cheese grater) BUT…. oem pad compounds typically dont generate much of this and dont really need 'sweeping' and pad temps on a road car dont get that high for this to be any great performance gain.
(Slotted rotors look cool though. 🙂 )
Decent brake lines (new oem or quality braided lines) can make a huge difference to pedal feel.
I hope that's of interest/use.
