| Weistec Horsepower | 410 |
| Weistec Torque | 480 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Stock Horsepower | 369 |
| Stock Torque | 420 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2020 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| 2019 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| 2018 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| 2017 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| 2016 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| 2015 | BMW | i8 | 6AT (I12/I15) | Turbocharged 1.5L I3 (B38) |
| See more | ||||
Product Description
The i8 is BMW's plug-in hybrid sports car, and its combustion half is unlike anything else in this lineup: a transverse, mid-mounted 1.5L turbocharged inline-3, the B38, working alongside an electric motor rather than standing alone. The B38 is essentially a B48 four-cylinder with a cylinder removed, but in the i8 it was tuned to an output that was, at launch, the highest specific output of any production BMW engine, extracting roughly 231 horsepower from just 1.5 liters. Paired with the i8's electric motor, that combination gave a car built around efficiency and a carbon-fiber passenger cell real, genuine sports-car urgency, proof that BMW's smallest production engine could still deliver a big statement.
Weistec's calibration for the i8 is a software recalibration of the combustion side of this hybrid powertrain, leaving the electric motor and battery system completely untouched. It's built to work within the B38's factory boost, knock protection, thermal management, and OEM diagnostics rather than override them, calibrated to the same rigor as BMW's own engineering work. On this engine, that translates to roughly 41 additional horsepower and 60 lb-ft of torque over stock, giving an engine that already broke records for its class an entirely new level to reach for.
How Do You Get Your BMW I8 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.

