• S300

s300/s300j Overview

The s300 version 3 is a plug in module to the OBD1 factory Honda Engine Computer (not included) which vastly expands the capabilities of the factory ECU. Forced induction, datalogging, real time programming, Bluetooth and engine protection are but a few of the comprehensive s300 features.

Designed, manufactured and assembled in the USA.

There are rectangular frame ECU (US) and square frame ECU (Japan) versions of the s300.

The S300 usesĀ SManager software for tuning and datalogging.

Sales Region Unrestricted
Model List Civic 1992-2001
Integra 1992-2000
Prelude 1992-2000
Part Number P06, P28, P30, P72, P74, P75

New features for Version 3:

  • Ethanol content sensor support
  • Bluetooth technology for laptop programming/datalogging and mobile datalogging
  • 2-4 times faster datalogging
  • CAN output
  • Serial output for dashboards like the AiM MXL and Racepak IQ3 - (needs 230-vmefi-hond)

Main features:

  • 8 analog inputs.(datalogging only)
  • 1 digital input. (datalogging only)
  • Additional security to help identify and prevent theft
  • Datalogging memory doubled in size for up to 2 hours recording.
  • Non battery memory backup for greater reliability and longer life.
  • On board calibration storage.
  • USB and Radio technology connection for speed and compatibility
  • SManager Windows based software for parameter & table editing, calibration uploading and datalogging.
  • Real-time updating of ECU parameters & tables.
  • Built in calibrations for common engine combinations
  • Built in datalogging to a laptop
  • On board datalogging memory (8 MB memory, 20-240 minutes datalogging) with trigger conditions.
  • Adjustment for different sized injectors, with overall fuel trim.
  • Configurable for any MAP sensor (to 5 Bar and above)
  • TPS based table lookup for ITBs
  • Engine protection from over boost.
  • Expanded fuel and ignition tables to 60 + lbs boost and 11,000 + rpm
  • Three multi purpose outputs for nitrous control or similar
  • Supports lambda tracing from a wideband o2 (PLX wideband recommended)
  • PWM output for boost control with fixed or gear based boost.
  • Dual tables for high/low octane calibrations etc.
  • Two analog inputs for wideband, EGTs etc.
  • High and low speed 24 x 20 ignition and fuel tables for correct VTEC tuning
  • Injector size fuel trim
  • Fuel trim for starting, throttle tip in and individual cylinder trim
  • Rev limiter with fuel cut or fuel and ignition cut
  • Launch control with anti-lag
  • Full throttle shift
  • Adjustable VTEC window with load and throttle control
  • Secondary intake runner control
  • Adjustable idle speed
  • Adjustable boost cut with hot and cold settings
  • Shift light
  • Closed loop control
  • Air temperature compensation
  • Water temperature compensation
  • Fuel and ignition correction based on gear
  • A/C shutoff conditions
  • Closed loop
  • Three general purpose outputs for nitrous control, quad boost control or similar

Real-time Update

The s300 can be updated in real-time with the engine running without affecting the operation of the vehicle.  This means that calibrations and changes can be uploaded to the ECU very quickly (2 seconds for a new calibration, a fraction of a second for anything else), without interrupting the operation of the engine.  Changes made in the SManager software are uploaded to the ECU instantly and you can see the effect immediately.  The s300 does not use an EEPROM or equivalent, so you never need to open the ECU to change chips nor 'burn' ROMs. No EPROM programmer is necessary - you just need a laptop with USB port or Radio technology capability.


The s300 has datalogging to the SManager software built in via the USB or Radio technology. Using a laptop or mobile device the various ECU sensors can be data-logged, viewed, graphed and saved for later analysis. 

Additionally the s300 has on board flash memory which allows a datalog to be made without a laptop, for later access and download.  Multiple recordings can be made and stored in the s300 for a total of around 120 minutes of total datalogging time. An external switch can be used to start and stop recordings, or engine conditions can trigger recording. For instance in a drag race, the s300 can be set to start recording once the rpm is bought up to near launch rpm and automatically stop once past the traps and the rpm drops below a certain level.


  • $495.00

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