Retrofit T8 Brakes - 345/320mm to 366/340mm

[glennda5id]

I want to upgrade the brakes in my T6 XC90 from the stock 345/320mm to 366/340mm rotors with the larger brackets.

I want all of the safety systems to be aware and behave correctly so my thinking is that the software config should be updated. I see the section in Oribt for the brake sizes.

Has anyone messed with this? 

Power6, I saw on the forums that you had upgraded your brakes. Did you update your car config?   366/ 340mm 366/34s0mm

[glennda5id]

To add some more to this. For the front brakes there are some options that reference 19"

03 - Brake Discs 18" FN+ (Currently selected)
04 - Brake Discs 19" FN+
82 - Front Brake discs 19" Front Brake cylinder 18"
83 - Front Brake discs 19", Front Brake cylinder 19"

Wonder what the differences are? Were there markets that got the 19" brakes on the non hybrid vehicles and then they came with a different caliper?

Maybe the FN+ is the caliper reference?

Can anyone with T8 chime in on their settings?

---

I did some digging and FN+ is indeed the caliper type. These cars use an ATE FN+ caliper. There is also a regular FN caliper.

https://pagid.com/pagid-pro/caliper-app/ate-fn+/
https://www.bremboparts.com/media/assemb...N_TYPE.pdf

So for the front, it seems like 04 would be the correct setting.

The rear is more straightforward and seems like the correct setting would be:
03 - Rear Brake 18" 340x20 GG

Although there is also:
05 - Rear brake 18" Reinforced 340x20 GG

[Power6]

Oh you have come to my specialty ;-) Before I did software...I made Volvo brakes... www.upbrakes.com

The 366/340 (F/R mm) brakes are just a rotor upgrade for the heaviest model, the largest PHEV: XC90 T8, as far as I know they are only used on that model but there may be others. 

Physically, you can swap these brakes, super easy! If you have the 345/320 brakes, the calipers and pads are the same as the 366/340. All you need are the caliper brackets and rotors to do the swap. I've done both front and rear upgrade to "T8" brakes on my S60. If you have the smaller series 322/302 size rotors, the calipers and pads differ so an upgrade there would require new calipers and pads.

I have my own brake kit in the front now, which is a fixed caliper, using the OEM 366mm T8 rotor. I continue to use the OEM 340mm brackets and rotors I swapped on the rear.

   

For the electronics OrBit part of it, the brake settings are there to change the fitted brakes. I think someone tried and they got DTCs that would not go away changing the brake size settings. I haven't tried on my car, I should probably test that ;-) I think the size setting may re-calibrate the ABS (and the many other brake based systems) slightly, for the larger rotors, which will produce an increased braking leverage vs the 345/320 brakes.

FYI - Some people are not familiar with the example: '18" brakes' type terms that OEM mfrs use. That spec refers to the "smallest wheel that will fit over the brakes" it's just a sort of industry shorthand to refer to brake sizing that is used all over. The 366mm brakes for example being classified as 19" brakes, they will not fit inside an 18" wheel. I have 19" wheels on my S60, so that was no worry for me doing such a swap.

[glennda5id]

I am surprised you have swapped without trying to change the config given your interest in the config side of things these days. My next step is to try the config change before upgrading the hardware.

[afranke]

I believe wheel size changes may also be related to the indirect TPMS some of the supported cars have.  "they detect a low tire by comparing relative wheel speeds via the Anti-lock Brake System (ABS) wheel speed sensors. When a tire loses air, its diameter decreases slightly."  So its possible this is a value it uses in that calculation, so it can know how far away from the center of rotation the sensor is to calculate speeds.

[glennda5id]

Wheel size is a separate config and not related to brake hardware.
Volvo specifies brake hardware size by minimum wheel size required to clear the brake hardware.

[afranke]

Good to know, some other cars I've coded on did it the other way.  What changes in the software when this setting is changed?  Perhaps the amount of brake force applied for automatic braking?  I had do to something similar on my '13 BMW when I swapped to M3 brakes, except not as nice and easy as Orbit: https://f30.bimmerpost.com/forums/showth...p?t=929406

[glennda5id]

I don't know what these config changes do exactly. That is the purpose of this thread. To see if anyone has any understanding of these config changes and if they have applied these config changes.

[Power6]

I don't think we will get to know what is changed with the config changes, it would be deep in the BCM or VDDM unit programming. But going logically...the brake system can account for a lot of variables, owners will change tires, brake pads etc. over the life of the car and each tire or brake pad is a little bit different. It does help the system to be tuned for the "torque output" of the brakes, the BCM has pressure sensors to sense the input to each circuit, and it is programmed knowing the expected torque output (how much "stopping") for the input pressure. It can adjust on the fly as the system is monitoring wheel speed sensors and calculating the tire slip % constantly feeding back into the program. But still it helps if the system starts off knowing the expected parameters. This would be a good reason that Volvo might have one overall "ABS/ESP" programming but have i read the config and adjust the system for which brake system is fitted. There are other things like the system calculates (i.e. guesses) at the temperature of the brake discs, it would need to know which rotors to be accurate about it. (FYI the underlying need for adjustment is: changing only the rotor size, and the caliper position, and not changing anything else, that changes the torque output due to increased mechanical leverage so Volvo using the same caliper on the 366mm does change the pressue-torque relationship of the brakes)

I should have tried the settings for sure, and I will! However I did brake development before all this software stuff. My brake kit is carefully designed to maintain very close to the torque output of the OEM brakes. On the 366mm the output is almost exactly matching the output of the 345mm OEM brakes. So there isn't really a need for me to change it, it's designed to work as a direct swap. I suspect it's a subtle at best adjustment, hardly anything one would consciously notice. If it works, I will try and see.

Those flashy aftermarket brakes...there is no setting that will adjust for the awful "engineering" on those lol. No other kits match the OEM system very closely, other than StopTech and probably a Brembo GT kit. The factory V60 Polestar brakes are essentially a Brembo GT kit on the car as OEM.

[Liven]

I don't think we will get to know what is changed with the config changes, it would be deep in the BCM or VDDM unit programming. But going logically...the brake system can account for a lot of variables, owners will change tires, brake pads etc. over the life of the car and each tire or brake pad is a little bit different. It does help the system to be tuned for the "torque output" of the brakes, the BCM has pressure sensors to sense the input to each circuit, and it is programmed knowing the expected torque output (how much "stopping") for the input pressure. It can adjust on the fly as the system is monitoring wheel speed sensors and calculating the tire slip % constantly feeding back into the program. But still it helps if the system starts off knowing the expected parameters. This would be a good reason that Volvo might have one overall "ABS/ESP" programming but have i read the config and adjust the system for which brake system is fitted. There are other things like the system calculates (i.e. guesses) at the temperature of the brake discs, it would need to know which rotors to be accurate about it. (FYI the underlying need for adjustment is: changing only the rotor size, and the caliper position, and not changing anything else, that changes the torque output due to increased mechanical leverage so Volvo using the same caliper on the 366mm does change the pressue-torque relationship of the brakes)

I should have tried the settings for sure, and I will! However I did brake development before all this software stuff. My brake kit is carefully designed to maintain very close to the torque output of the OEM brakes. On the 366mm the output is almost exactly matching the output of the 345mm OEM brakes. So there isn't really a need for me to change it, it's designed to work as a direct swap. I suspect it's a subtle at best adjustment, hardly anything one would consciously notice. If it works, I will try and see.

Those flashy aftermarket brakes...there is no setting that will adjust for the awful "engineering" on those lol. No other kits match the OEM system very closely, other than StopTech and probably a Brembo GT kit. The factory V60 Polestar brakes are essentially a Brembo GT kit on the car as OEM.

I'm already get the Brembo GT kit (Polestar version) when i change setting to 6 piston option,but shows abs function fault,it can drive like normal and break feels good than before,just lost autohold function.Finding solution to solve it....