| Weistec Horsepower | 445 |
| Weistec Torque | 320 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Stock Horsepower | 420 |
| Stock Torque | 295 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2013 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| 2012 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| 2011 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| 2010 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| 2009 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| 2008 | BMW | M3 | 6MT (E90/E92/E93) | 4.0L V8 (S65B40) |
| See more | ||||
Product Description
The S65B40 that powered the E90/E92/E93 M3 might be the most remarkable engine BMW has ever built. Rather than evolve the outgoing S54 inline-six, BMW gave the fourth-generation M3 a completely different weapon: a 4.0L naturally aspirated V8 with individual throttle bodies and a race-bred pedigree drawn directly from the S85 V10 in the E60 M5. The block was cast at the same foundry that produced BMW-Sauber's Formula 1 engines, and the finished unit somehow weighed less than the six-cylinder it replaced despite gaining two cylinders. Its 8,400 rpm redline still stands as the highest of any cross-plane-crank V8 ever installed in a production car, and the engine was named International Engine of the Year in its class five years running. Few engines in this class have ever earned a reputation this legitimately.
Weistec's calibration for the S65 is a software recalibration built on top of what is already a motorsport-derived factory design. It's engineered to respect the individual-throttle-body induction and the factory's knock protection, thermal management, and OEM diagnostics rather than override them. Developed with the same validation discipline as BMW's own calibration work, the tune wakes up roughly 25 additional horsepower and 25 lb-ft of torque from this engine's factory hardware, and on a unit this special, that gain lands like exactly the next chapter it deserves.
How Do You Get Your BMW E90 M3 ECU Tune Tuned?
Follow these steps — this is what your specific vehicle needs and supports.
Choose Your Tune Stage
Core Improvements
Standard with this tuneFree Add Ons
Pick Your Tuning Method

Cypher Plus
Order a Cypher Plus and tune your car yourself from your phone, entirely through the MyFlasher app. Watch how it works.

Mail It In
Remove your ECU or TCU and mail it to us for tuning. Required for some applications.

In Person
Bring your vehicle, or just your ECU/TCU, to our Anaheim, CA headquarters. Call 714-202-0005 or email sales@weistec.com to schedule.

Cypher Pro Dealer
Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.
Complete The Upgrade
An ECU tune alone won't remove all factory limits or fix how power reaches the ground. Add these to round out the upgrade with no limitations.
Read the full CPC & TCU breakdown →
What is a CPC module?
The CPC (Central Powertrain Control) is a separate control unit that manages things like the active exhaust valves, radiator fan, intercooler pumps, and speed limiter. On many newer Mercedes-Benz vehicles, it also houses torque limiters that can hold back an ECU tune from reaching its full potential.
What is a TCU tune?
A TCU (transmission control unit) tune delivers faster, firmer shifts with higher line pressure, reducing clutch slip and increasing the transmission's torque capacity. It's a worthwhile upgrade on its own, or paired with an ECU tune for a fully sorted powertrain.
Good to Know
- This is a reflash of your original module, not a stand-alone unit.
- Power gains vary by vehicle, modifications, fuel, and operating conditions (ambient temperature, altitude, etc.).
- New or upgraded spark plugs are always recommended when tuning.
- Product may not be emissions compliant. Check local laws prior to installation.
- Always use a battery charger during programming.

