850 RetroTurbo big brake adapter with Alfa Romeo 159 calipers

paper_planeKyle @paper_plane Melbourne
edited June 11 in Modern

Hi rollers,

I'm just trying to find out if anyone has used those adapters and if there's anything I need to aware of, here's the link http://www.retroturbo.com/?product=big-brake-kit-for-850

The brake discs recommended on the website comes from XC90, and I noticed the thickness of that disc is 30mm where disc on the Alfa is 28mm, so I'm not sure if there'll any issue.

Lastly, I have standard 17" pegasus wheels, will the bigger brakes fit underneath them?



  • SpacSpac @Spac Canberra-ish.

    I would be surprised if the 30mm rotor doesn’t fit in the caliper.

    Worst case would be to have the rotor machined down - 29mm would do it.

  • Thanks mate, totally forgot about the discs can be machines down 😅

  • AshDVSAsh @AshDVS - Geelong, VIC
    edited June 18

    I'm not convinced you'll get these behind any of the Volvo factory 17" wheels.

    I think that if you can find 159 calipers at a reasonable price, its a pretty decent caliper and even nicer being that it is radial mount. Seemingly, they're $400 - $700 a pair as a bit of a rule of thumb.

    The holy grail of 'cool' here is going to be one of the oem/genuine Volvo AP Racing brake package, available as an option when the cars where new, which is long since NLA.

    Renault Megane RS radial mount Brembo calipers are a good potential option here too and seem to, typically, be cheaper.

    The Porsche 'big red' caliper upgrade, using 330mm S60R front rotors can be made to fit under 17" wheels, though some wheels may require small spacers to clear. Being Porsche calipers though, they do (at least in Australia) demand a premium price. This would probably be my pick of the bunch in terms of multi-piston calipers in the non-aftermarket space - who wouldnt agree that a porsche logo peeking out from behind a wheel spoke looks really cool.

    Depending on your application, of course, we do a 320mm front brake upgrade package for the P80 platform that uses calipers from LS-LV Focus XR5 and Volvo S40/V50 T5 AWD models - it uses just about everything as off-the-shelf parts and is entirely 'bolt on'.

    While its a vast improvement over either of the standard 280mm or 302mm factory brake packages, it still isnt a multi-piston caliper. With a good set of pads, it's more than capable to serve you well for track days and even light motorsport events.

    Via another of our partners, we'll have a true multi-piston brake upgrade available soon, in a few different configurations. We'll fit that up to our V70 soon(ish) and do some wheel test fitting as well to see what factory wheels we might be able to get on the car.


  • Thanks Ash, I actually came across your brake upgrade package when I was doing my research and it is a very attractive option indeed, especially considering if I go down the path of using Alfa calipers, I am risking to be forced upsizing the wheels to 18 inch which would bring the total cost to almost 5k.

    So for the adapters you are selling, can I use calipers from Gen 2 V40? My research suggests they use the same 320mm rotors as S40 T5 AWD, this would definitely give me a lot more choices when it comes to sourcing the parts.


  • AshDVSAsh @AshDVS - Geelong, VIC

    No worries at all. Happy to help and offer insight, regardless of what you might end up with.

    The Gen2 V40 uses the same rotor as P1 S40/V50T5 AWD models but the caliper is different - I actually dont know if the mounting is the same as P1 cars. My thought is that it'd feature M14 fasteners rather than M12 which may present challenges.

    You make a good point about the added expense of a complete wheel change too. As an example, for our V70 project, we are moving to 18" wheels to accommodate brakes. I opted for a custom ordered set of Koya SF05 wheels with specific offsets (different front to rear). I got what I feel is a good deal on wheels and tyres but, even then, by the time we wrapped them in decent rubber, its nearing $3k for wheels and tyres before even considering brake costs. It escalates quickly.

    With any brake upgrade, using an alternative oem caliper, we need to consider local supply/demand and pricing. This also changes over time too.

    A further example is that we offer an upgrade for the 240 which allows you to fit a Mazda RX7 series IV caliper to the car. We've offered this for 15+ years. When we first started offering it, the calipers were in plentiful supply and were pretty cheap. These days, they're actually tougher to come by, a LOT more expensive, they're older and therefore more likely to need a rebuild/service kit before use too.

    This makes them less financially attractive and makes some alternatives really appealing. One of the members on here did a BA (I think) Falcon large sliding caliper swap which looks really good - while you're stepping away from a multi-piston caliper, there is a vastly bigger pad surface area, much bigger rotor and the added simplicity of a single front brake line (as per the Mazda swap) which is a godsend.

  • AshDVSAsh @AshDVS - Geelong, VIC

    I meant to add, if you want to get your head around what you need to do the 320mm conversion, we have a really detailed fitting guide. Shoot us an email and we can send you a copy.

  • You will receive an email from me shortly mate, thanks for all the pro tips, really appreciate them!

  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.

    If you like , I have calipers and brackets sitting here for many years!

    Not taking away from Ash though.


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