Clutch Masters 21-23 BMW M3/M4 3.0L S58 Factory Fit FX350 Twin Disc Clutch w/Alum. Flywheel

Owners of a six-speed G80 M3 or G82 M4 who add a tune often find the factory twin disc clutch is the weak link: it slips on a hard third-gear pull, yet a full race clutch would make the car miserable in traffic. Clutch Masters built the Factory Fit FX350 twin disc, part number 03240-HDFF-DLX, for that gap. It replaces the stock twin disc with an upgraded kit that is meant to be driven every day while holding the extra torque a tuned S58 makes.

What the Factory Fit FX350 does in an S58 M3 or M4

BMW already put a twin disc clutch behind the S58 in the manual cars. Clutch Masters' Factory Fit idea is to keep that layout but improve the parts: higher-grade friction from its FX single disc line, lighter components and a larger disc. For the G8X cars the company says it removed the factory self-adjusting cover, cut a little over 10 pounds from the whole assembly and moved from an 8.5 inch disc to a 9.5 inch disc, which adds a good amount of friction area. Clutch Masters describes its Factory Fit twin disc kits as a full replacement with a Type 3 hard anodized flywheel, a steel floater plate, a factory-style stamped steel cover and two clutch discs. Dropping the self-adjusting mechanism also means the kit does not depend on that ratcheting cover to keep engagement consistent as it wears.

We also carry the Factory Fit FX250 and the puck-style FX400 kits for these cars, so you can compare the friction packages side by side. The FX400 versions use 6-puck or 8-puck discs, which bite harder. The FX350 is not listed as a puck design, so it is the one to look at when smooth engagement matters on a tuned car that is still driven on the street most days.

Symptoms that call for a stronger clutch

• Rpm climbs without added speed in third, fourth or fifth at full throttle
• The slip started after an ECU tune, a downpipe or a fuel upgrade
• A burning smell after spirited driving or a track session
• The clutch takes up higher in the pedal than when the car was new
• Shudder pulling away from a stop

How to confirm before you buy

A simple test is full throttle in a high gear from low rpm. If the tach rises faster than road speed, the clutch is slipping. Check the hydraulic system before ordering, since a leak, a soft pedal or a pedal that will not fully return can hold the clutch partly open. Then pick the level that matches the car. A lightly modified car may be happy on the Factory Fit FX250, while a car with big power and frequent launches belongs on the FX1000 race twin disc. Our manual versus automatic repair cost guide helps with planning the labor.

Fitment

The listing is for 2021 through 2023 BMW M3 and M4 with the 3.0-liter S58 and the six-speed manual. Note that Clutch Masters' own description for this kit names the 2021 and 2022 G80 M3 and G82 M4, so if you have a 2023 car, send us the year and the last 7 of the VIN and we will confirm it before you order. Cars with the eight-speed automatic cannot use it, and in North America the Competition and xDrive models came with the automatic only. More options are in our rebuild kits department.

Install notes

• The gearbox has to come out. Inspect the rear main seal and the transmission input seal while you are in there; oil on new discs will undo the job.
• Install the aluminum flywheel from the kit with new bolts torqued to BMW's specification, and do not mix this cover and disc set with a different flywheel.
• Because the self-adjusting cover is gone, you do not need a SAC compression tool. Center the discs with a tool from our clutch alignment kit and tighten the cover bolts evenly in a crisscross pattern.
• Bleed the clutch hydraulics with fresh fluid of the type BMW specifies.
• Clutch Masters requires a 500-mile break-in of normal stop-and-go driving with no full-throttle shifts or compression braking.

Is the FX350 a twin disc?

Yes. It is a Factory Fit twin disc kit with two clutch discs, a floater plate, a cover and an aluminum flywheel, made to replace the factory twin disc in the manual S58 M3 and M4.

FX250, FX350 or FX400: which one do I need?

All three share the Factory Fit layout and differ in friction package. Puck-style discs like the FX400 bite harder and suit harder use, while full-face discs drive more smoothly. Tell us your power level and how the car is used and we will help you choose; for big power and launches, look at the FX1000 race twin disc.

Does it fit a 2023 M3 or M4?

The listing includes 2023, but Clutch Masters' description names the 2021 and 2022 cars. Send us your VIN and we will confirm a 2023 before you order.

Does it work with the automatic?

No. It only fits cars with the six-speed manual. The Competition and xDrive cars sold in North America have the automatic.

Do I still need a self-adjusting clutch tool?

No. Clutch Masters removed the factory self-adjusting cover on this kit, so a standard alignment tool is all you need to center the discs.

• Automatic vs Manual Transmission Repair Cost