Valvetronic has an interesting side-effect in that there's no "vacuum" in the intake manifold nor is there a traditional throttle plate that would cause a "vacuum". In fact, the intake manifold is always at some positive pressure due to the turbo. For performance and responsiveness, this is a Very Good Thing. But that got me thinking about the brakes. After a bit of peering through some small openings in the plastic ocean under the hood, I was able to identify what sure looks like a common vacuum-operated brake booster. If that's right, how do they do that? Or, possibly it operates on positive pressure, but that wouldn't seem so reliable since it wouldn't have much working pressure at idle.

The only remaining possibility that comes to mind is that they've added a separate vacuum pump just for the brakes. Could be engine-driven or electric.

Anyone know how this actually works?

 

My 95 Audi S6 (inline 5 cylinder turbo) uses a pressure accumulator system (referred to as the 'bomb' since it looks like one from the cartoons) that is driven off the hydraulic system pump. Pressing on the brake pedal then actuates a switch that lets pressure out of the accumulator and into the lines to provide the stopping power.

This all looks like a normal setup if you were just looking at it from the top down. It has a normal looking ABS booster and what not. Mini may be using something similar. I'm sure someone with access to ETKA or similar can confirm.

 

Nope. There is no need for a hydraulic system because steering boost is electric. Which, BTW, seems to work very well.

 

Hello? The op is asking about power brakes not power steering. Bet it's electrically driven though.

 

Whatever system is used it could use beefing up. I still think the brakes are a bit soft.

 

there is a vacuum pump on the engine

 

Thanks for clearing this up.

 

I have no complaints with the brakes except to say that it will be nice once some options as far as aftermarket pads start to open up for the F56.

 

Absolutely agree - inferior to my last car (Golf GTI) which was a step down from my 2012 MX5. Hmmm only weak spot on the car!