Description

Part Number / Product Name
P00033 Powered ECU Spec 2 (High-Octane Spec)
Vehicle Compatibility
Jimny Sierra JB74 (Models 1–4); compatible with both MT and AT. *Not compatible with Model 5.

Product Description
This product involves reflashing the stock JB74 ECU. By optimizing various control maps, it unlocks the vehicle’s true potential.
Programs vary based on fuel octane ratings; this is the “Spec 2” version designed for high-octane fuel.
It represents an upgrade over the regular-gasoline “Spec 1,” adding more power and smoothness.
It is a tuning option that is easy to implement yet delivers highly effective results.
While the JB74 Jimny Sierra handles city driving competently, drivers often feel a lack of power on highways, bypasses, and uphill slopes.
It lacks the brisk, agile responsiveness one might expect from its displacement, offering a more relaxed driving feel instead.

Although the peak horsepower and torque figures do not show a massive numerical increase, this high-octane Spec 2 transforms the JB74’s K15B engine into a unit that feels noticeably more powerful and smoother—a difference you can truly feel.
It builds upon the snappy, aggressive character of the regular-spec Spec 1 (which already vastly outperforms the stock setup) by adding even more power.
The overall sense of headroom—and specifically the rich low-end torque that mimics the feel of an engine with increased displacement—combines with sharp, light revving to create a driving experience defined by refined, high-quality smoothness.
Naturally, the tuning retains the focus on improved drivability in everyday situations.
There is absolutely none of the temperamental nature often associated with tuned engines; the vehicle responds faithfully to throttle inputs, delivering satisfying acceleration whether you are driving on city streets, highways, or off-road. Whether you are an aggressive driver who frequently pushes the throttle or someone who simply wants a more relaxed driving experience, this upgrade transforms both daily city commuting and long-distance drives into something more comfortable and enjoyable.
Experience the sense of ease and composure that comes from having ample power, even when driving in a higher gear.
*For owners of the “JC” grade model, the cruise control setting will also be updated to a 120 km/h limit to accommodate the increased highway speed limits.

【Modified Control Maps】
Fuel
Ignition timing
Throttle
Air-fuel ratio
Cam timing
Requested torque
Torque limit
Cruise control limit (JC grade only)

We recommend upgrading to the specified aftermarket spark plugs (HKS racing plugs).
This product involves reprogramming your vehicle’s original ECU (Engine Control Unit).
We will receive your original ECU, reprogram it with our tuning data at Showa Garage, and then ship it back to you.
Please send the unit to us via freight collect (shipping costs paid by the recipient).
Please pack the ECU securely, taking care to protect it from impact and water damage.
Once received, we will perform the tuning and ship it back within 5 to 7 business days.
*Please note that during busy periods, such as event days, processing may take longer (up to approximately two week).

“Sub-computers” (piggyback controllers) like the MINICON cannot be used with this product, as they interfere with air-fuel ratio settings; please remove them.
Throttle controllers (such as the Response Booster) can be used in conjunction with this product. However, since throttle opening characteristics and related parameters are already optimized by this product, using a separate throttle controller is generally unnecessary.
For automatic transmission (AT) vehicles, using a throttle controller allows you to fine-tune shift points to better match this product’s power and torque bands. If you choose to use one, we recommend the Response Booster due to its wide range of adjustable settings. Please note that depending on the throttle controller settings, the adjustment may be excessive.