MWR AEM EMS4 ECU Kit – Race Car with 2ZZ and 3-row Harness


SKU: MWR-870235 Category: Tag: Brand:


MWR’s AEM EMS4 kit is the most powerful tuning tool available for your 1ZZ or 2ZZ powered race car.

This kit is intended for a race car with minimal body wiring and a 3-row engine wire harness from a 2ZZ Celica (cable throttle) or Europe/Japan Corolla Runx/Sportivo (does not work with US market 4-row harness). The MWR harness plugs directly into the 2 connectors from the engine wire harness and has flying leads for chassis side connections such as fuel pump, fans, relays, etc. Instructions are included and custom wiring is requires. Stock ECU is not retained so there is no CAN bus, no AC control, no OBD2. Intended for aftermarket gauges or dash display.

Main Features:

  • Full tuning control of fuel, ignition timing, idle speed, VVT, VVL.
  • Additional outputs configurable to control boost level, radiator fan, fuel pump, nitrous, shift light, water/meth injection, etc.
  • Adjustable rev limiter and launch limiter.
  • High resolution datalogging capability with or without laptop connected.
  • Closed loop fuel control using stock O2 sensor or aftermarket wideband O2 sensor (sold separately and strongly recommended.)
  • Fully configurable knock sensing and control.
  • Very flexible- easily tune for larger injectors, bigger cams, stroker, high compression, ITBs, supercharger, turbo, nitrous… you name it!
  • MAF meter may be removed (optional- you just need to add an air temp sensor) so no more limitations caused by maxing out the MAF at high boost levels. You can also make your air inlet and intercooler pipes any size you prefer.
  • MWR base tune provided- we’ll provide the best start-up map for your application at no charge. This is a good base map only so an experienced tuner is needed to get the system 100% dialed in for your car.
  • Stock ECU completely removed, NOT emissions legal, NO OBD2.

Included in the kit:

  • Custom configured AEM EMS4 engine computer
  • MWR custom wiring harness
  • OEM quality 3-bar MAP sensor (made in Germany)
  • 3 meter USB programming cord
  • Base map (emailed to you – startup tune only, requires tuning)

Software download – we recommend:
AEMtuner Version 2.98 for Windows 7 and older
AEMtuner Version 3.20 for windows 8, Windows 10

Note: you must add a password to your tune for any EMS4 unit to operate properly. You can do this in the AEM Tuner software in the ECU menu. It does not matter what you set as the password (we use 123). Without a password the ECU may not shut down properly at times because of a bug in its firmware; this prevents the car from restarting for a short period of time after being shut off. Adding a password eliminates this issue entirely.

Results from our standard EMS4 kits tested on a variety of vehicles:

Tested on a stock 2003 Matrix XRS with only a cold air intake. Notice the huge increase in torque through the midrange thanks to optimized VVT and the advantage of engaging the VVL at 5700 rather than the stock ECU’s lazy 6200rpm. We also tested vs the later 2005-06 ECU with the 6800rpm VVL engagement. The results speak for themselves.

Tested on a stock 2000 Celica GTS automatic you can really see the optimized VVT/VVL settings doing their job. With the auto trans you can increase your rev limiter and shift the transmission manually for best acceleration. This tune is slightly more aggressive and you can really see the advantage of being able to optimize your fuel and ignition maps.
Tested on a stock 2000 MR2 Spyder with 1ZZ engine. Even without other engine modifications there is room to optimize fuel and spark and you can get a really healthy torque increase through the midrange thanks to optimized VVT. Add air intake, header, upgraded cams etc and the gains are even greater. Rev limiter can be increased a bit to broaden the power curve and help avoid unnecessary upshifts in autocross and road course applications.
MWR AEM EMS4 vs Power FC
MWR’s EMS4 is a far more powerful tuning tool. It has additional configurable outputs, does not rely on factory MAF, works with 1ZZ or 2ZZ, and is available for far more different car models. Planning a 2ZZ swap in the future? You’ll just need to add VVL connectors, no other wiring changes, adapters or different ECUs needed. It also includes the tuning cable and software at no additional cost. That said, the EMS4 is not a beginner’s tuning tool. The software has incredible depth and if you start tinkering with it your car may not run right. If you get the tune wrong you might damage your engine. That is the reality of a powerful tuning tool like the EMS4. Want more information so you can decide if the MWR EMS4 is for you? Please see the AEM support forums HERE and search YOUTUBE for a huge amount of information on AEM EMS systems and software.

Fits with Toyota T3 (3-row) ECUs.


Additional information

Weight 4 lbs
Dimensions 10 × 6 × 6 in


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