Turner Motorsport Underdrive/Power Pulley Kit for BMW M3 S65/S65B40 V8 (E90/E92/E93 4.0L) – Lightweight Billet Aluminium Crank & Accessory Pulleys, Serpentine Belt Performance Upgrade

Underdrive Pulley Upgrade for BMW M3 V8 S65 E90 E92 E93

Unlock effortless, usable performance from your V8 with this lightweight accessory drive pulley set. By reducing parasitic drag on the belt-driven systems, this underdrive solution frees up power that would otherwise be lost to the water pump, power steering and alternator. Expect meaningful gains where it counts on the road and track.

Independently tested on standard cars, this upgrade has shown increases of up to 10 to 14 bhp and 7 to 9 lb ft. The result is sharper throttle response, stronger mid-range punch, quicker revs and a more eager BMW M3 that pulls harder across the rev range.

Why choose this pulley set

• Dyno proven improvements on stock S65 engines
• Reduces accessory drive speed by approximately 10 to 20 percent to minimise losses
• Hard-anodised black finish for excellent wear and heat resistance
• Precision machined 6061 aluminium for durability and reduced rotating mass
• OEM-like appearance with increased strength compared with plastic components
• No compromise to steering assistance, charging or cooling when installed as intended
• Ideal for fast road and track day use, no remap required

What you will notice

• Improved acceleration and faster engine response
• Smoother power delivery and a livelier feel throughout the rev range
• Enhanced driving engagement without adding noise or harshness

Construction and quality

Manufactured from high quality 6061 aluminium and finished in a tough hard-anodised black coating, these pulleys are built for long-term reliability under heat and chemical exposure. They retain a factory-style look while delivering a tangible performance edge.

Compatibility

• BMW E90 M3 V8 S65 4.0 litre
• BMW E92 M3 V8 S65 4.0 litre
• BMW E93 M3 V8 S65 4.0 litre

Real-world results from MJ Modifications

We have fitted this underdrive pulley kit to numerous customer cars and feedback has been excellent. Owners report crisper pick-up, stronger in-gear acceleration and a more responsive feel without downsides to daily usability.

Fitting service

Professional installation recommended. Book fitting with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

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