"In this entry, I document the installation and my notes along the way. It isn't complex - but you need to know what you're doing. "
- Matt

This is not a DIY for most.

There are a couple reasons I make this claim.

The exhaust, driveshaft and transmission need to be removed off. As a result, the lightweight flywheel is an upgrade usually performed with other maintenance and upgrades to the transmission, driveshaft, etc.  

Getting the DCT transmission off this car is not an easy task; it weighs +/- 150 lbs. It's +/- 40 lbs heavier than the manual transmission. You absolutely need a proper transmission jack. 

For professionals, expected labor is 6 to 8 hours. 

The DCT has extra coolant lines and peculiar fittings that require hands-on knowledge, otherwise you're in for a long, rough, and risky experience. All the hoses seen below were awaiting refitting. We had to replace all one time use O rings as well. 

Mission critical steps. 

Starter Alignment

Both the OEM and lightweight flywheel have a bolt holt with a different shape others: this is your crankshaft alignment guide. The crankshaft also have a visible bolt hole with a dowel sleeve. The two needs to be matched - If the bolt hole is not aligned, the DME won't allow the S65 to fire up. 

On the original flywheel, the alignment bolt hole is designed with a tear drop shop as seen below. 

On the lightweight flywheel, the alignment hole is machined slightly large to fit with the dowel sleeve. It's more obvious from the engine side of the flywheel. I suggest you mark the hole with a pen directly on the flywheel for a visual reminder. 

Bolts. 

The original OEM bolts are T60 torx encased in the original dual mass flywheel. They cannot be removed nor re-used. They can be seen below on the engine side of the flywheel.

BMW requires their extended T60 tool to access the bolts for proper torquing sequences. This tool is not required for the lightweight flywheel.

The updated version of the S65 DCT lightweight flywheel is now packaged with new flywheel to crankshaft bolts with the correct ratings.

Torque specs. 

BMW TIS (11 22 500) requires the bolts be dipped in engine oil before being torqued to 105NM (77.5 ft lbs). The wet torque reduces friction and improves the consistency of the clamping force.

Flywheel lock tool.

BMW's TIS also requires the use of the flywheel locking tools (11 9 263 and 11 9 260) to ensure proper seating of the flywheel. For proper alignment of the flywheel's starter teeth with the locking tool, it must be bolted into the engine block's bolt hole shown below.  

Per the TIS, there is no order to the torque sequence. We suggest using common sense and going criss-cross. 

No tune needed. 

Bolt it up, start her up, and be on your way. I do personally run an increased idle RPM to 900 to improve drivability in cold start conditions. You can learn more here.

No break-in period.

The flywheel itself doesn't have a break-in period per say. You can rev it to the moon. The sound will have a break-in period: it will evolve over time as you start using the car. 

Up next: we bolt everything back, and we go for drive.

What is worth it?

We'll have a chat, and record some clips.