Quick reference wiring for SAFC
for 1993-98 Toyota Supra turbo (2JZ-GTE)



* NOTE - THIS DIAGRAM IS FOR US SPEC SUPRA MODELS ONLY!!!
The JDM 2JZGTE ecu does not use a MAF sensor, therefore you must intercept the MAP sensor signal. Please note - tuning guidelines for the JDM ECU will be different.


Remember to setup the SAFC settings properly.

Some people always forget to adjust the default settings. You must manually select the proper sensor type for the Supra and you must set it to 6 cylinder. The safc is designed to work on multiple cars so you must set up the basics right from the start. If you can't even do this, you have no business trying to set this up yourself, so go hire a professional tuner before you blow up a motor.

The supra uses the PR setting for (PRESSURE).
So do not set it to FLAP, HOTWIRE, or KARMAN.

Please refer to the A'PEXi instruction manual for all other basic instructions.




A note about tuning your A'PEXI SAFC & HKS VPC setup.

This is a pretty common "piggyback" fuel tuning setup on the 1993-98 Supra turbo so here are some basic guidelines that seem to yield good results when running a setup like this.

Typically, you want to leave all the HKS VPC settings at 12 o clock (arrow pointing straight up). You can try turning the idle back a click but it seems the supra factory ECU responds best to settings that are left at ZERO.

As for the APEXI SAFC adjustments, there is only one setting that you should adjust on LOW THROTTLE which is at 1000 rpm. Basically, the idea here is to adjust the safc on low at 1000rpm to take out fuel until you have a good AIR/FUEL ratio in the neighborhood of 14.7 at idle. All other low throttle settings at should remain at ZERO. Due to closed/open loop parameters, the factory ECU usually makes the minor adjustments with this foundation to maintain normal drivability. So you really don't need to mess with the other safc low settings because it typicallly throws things out of wack. Next, you can adjust HIGH THROTTLE fuel trims by making the adjustments roughly in the 4000 RPM+ range. Setting up your safc rpm parameters in increments of 4000/5000/6000/7000 rpms help keep a consistent tune that results in a pretty smooth and flat A/F ratio. We have found that making too many adjustments here seems to confuse the ECU and causing it to do all sorts of weird things which usually results in a choppy A/F ratio under wide open throttle. Remember, this posted info is only a simple "suggestion" to help you setup a piggyback system on the supra. Hopefully, this helps give you a rough idea of what you should do to get started.

By following these recommendations, you can usually get a HKS VPC + APEXI SAFC piggyback setup to trim fuel up to 1000cc injectors without any major hiccups in driveability. However, we recommend a full stand alone ECU setup when setting up a supra with anything larger than 720cc fuel injectors for best results. Nothing beats a properly tuned up supra from a professional tuner. Remember, these piggy backs do not adjust ignition timing at all. A proper tune up requires tweaks in both fuel and ignition curves. Remember, if you have never tuned a car before, it is not worth the risk of blowing up your motor to "experiment" and learn as you go. If you need your car professionally tuned, just let us know and we can assist you.

 

note:
All technical info is posted to offer you some "GENERAL" insight. So take it with a grain of salt. The information posted here is very BASIC. We will not be held liable for any of the information provided. We do our best to provide accurate, complete, and timely information. However, we cannot guarantee the quality, content, accuracy, or completeness of the information. You should always confirm information from another source to gain sufficient technical insight.