Wrapped up some maintenance items and decided to throw in a mod 'while I'm in there'
Installed a new alternator, replaced power steering reservoir/fluid, and installed Active Autowerke's underdrive pulley.
Old vs New Alternator
New AA Pulley Kit
Pretty substantial difference vs. OEM
My power steering fluid was in dire need of replacement and I purchased the entire kit from FCP so I figured I would replace the reservoir while I was at it as the reservoir contains a filter component. I used the turkey baster method (I have an actual hand pump) and pumped out 3 fills worth with the old reservoir. I then replaced the reservoir and ran two more through it. Fluid looks good. Difficult to avoid making a mess when replacing the reservoir regardless of how much fluid you extract. Seems like there is a good amount stored in the bottom half of the reservoir that's going to end up seeping out when you remove the lines. Lots of rags..
Alternator job was surprisingly pretty straightforward. The only trick is the bottom bolt. Thanks to this forum I learned that you need to hammer the bottom bolt after backing it out a bit to loosen the sliding internal lock. After that the alternator came right off. It's a bit awkward and you're working in tight quarters (surprise BMW) but really I didn't have any problems. You have to put some weight into the tensioner to remove/reinstall the belt but easy enough. Not 100% certain the alternator solved my electrical/charging gremlins, will need to run some tests to confirm.
Post-alternator install:
Lastly, the power pulleys. I was on the fence about this mod but figured I was already 90% there with taking off the alternator belt and having everything open and accessible. This is also the last power mod outside of test pipes/forced induction. Figured it was worth the $300 to try it. I went with AA as it seemed well developed and somewhat conservative. I like that you're only replacing the crank pulley. Install was again surprisingly easy. Same thing, have to use some muscle on the tensioner and take your time re-routing the belts but everything went smoothly outside of some scrapes and cuts which I've found just come with the territory when working on this car. Badges of honor I suppose.
Started the car up and ensured everything was spinning in the right direction. Idle looked and sounded great, gave it some revs and everything was holding up. Time for a drive.
Post-pulley install:
I'm not going to sit here and say I can feel a 10hp difference. What I did notice is that the engine tends to rev more freely - whether under acceleration or on downshifts. Even more noticeable is the reduction in engine braking. I've always thought this car engine brakes heavily when coming off of throttle. I immediately notice a reduction in this with the new pulleys. The car coasts much better now and is smoother when coming off the throttle, which I like. So far I'm a fan. I don't perceive any noticeable difference in steering weight, etc. Will see how everything holds up on the next track day regarding cooling, etc.
Inside-of-plenum video for the hell of it:
Speaking of track days. My new custom caliper set has officially shipped and I went ahead and purchased f8x rotors all the way round from FCP (lifetime replacement). Tempted to post a sneak peak of the set up but I think I'm going to wait until they arrive. Very excited about this next project as it's been a year or so in the making and I think will truly set the car apart.