AaronStaub

iTrader: (1)

Hi all. I recently bought a GS300 with a JDM 2JZ-GTE swapped into it. The car has USDM twins and USDM injectors, an Apexi SAFC and Blitz BCC. It appears to have the TTC mod, and the car makes about 18 psi although I have yet to identify the means of boost control.

I have searched most of the BPU FAQs and cannot figure out how this car is configured.

1. Given that the engine is running the JDM ECU with USDM injectors, I would expect to see some significant corrections factors in the SAFC to shorten the pulse duration. However, the largest correction factor in the unit is -4% and under most conditions it is -2 to -1%. How is this possible? Is there enough adaptive capability in the ECU to eventually compensate for the 550 cc injectors w/o tossing a MIL? The car idles like a champ.

2. I have verified the max boost using a manual Autometer gauge. However, the peak boost recorded by the SAFC is 0.8 kg/cm2. This seems to me to indicate that the Blitz BCC is clamping the signal being received by the SAFC, and that seems wrong. If the car is making 18 psi and the SAFC and ECU never thinks it goes above 11.5 psi, how does the mixture get maintained? I see the turbo pressure sensor on top of the intake manifold. Is that the same sensor as the MAP, or is there a separate pressure signal being sent to the ECU that the SAFC should be looking at? I don't understand how a BCC does you any good unless there is a separate input the ECU is using for A/F ratio.

Any help you can offer to a long time Mustang driver would be appreciated.

AaronStaub

iTrader: (1)

After some subsequent thought, I realized I am still confused about how MAP-controlled cars are successfully running higher-than-BCC boost levels. On a MAF-controlled car where the MAP is only being used for boost-cut by the ECM, the SAFC makes a lot of sense. The BCC can clamp the voltage from the MAP sensor to prevent boost cut, and the SAFC can intercept the signal from the MAF meter and provide the proper amount of correction. This should work under any circumstance so long as the MAF is not saturated by the amount of airflow in the intake tract.

I don't understand how this can work on a MAP car. As long as the MAP signal is getting clamped to some maximum value, I don't see how you run boost levels higher than the ECM-determined fuel cut level. Its great if my SAFC sees a MAP signal of 20 psi, and then correctly calculates that I need to remove 10% of fuel to maintain the proper A/F giving a signal for 18 psi. But if the BCC, located directly downstream, clamps the voltage for a signal of 14.5 psi to avoid boost cut- how does the A/F get maintained? This seems to be a problem regardless of where the BCC is installed relative to the SAFC. It seems like even though a MAP controlled system has a BCC on it, you can't add fuel above the clamped boost level?