ECU Tune Stage 2

[TomsSVX]

They are all over ebay

Tom

[$ gest24 $]

Looked at Ebay, there are tons of FPRs... which one is the better/best one?

[TomsSVX]

well that is more personal taste at this point, it is simple a pressure regulator that can restrict flow going back to the fuel tank on the return line. With this pinch it will increase fuel pressure on the incomming line to make up for it. So in reality, any regulator will work but which gauge is the most accurate is now a concern

Tom

[$ gest24 $]

What threw me off was the labeling of the FPRs for diff. kinds of cars.

[Jade Dragon]

An idea im drawing up for inclreasing airflow. is to take the intake and split it into to individual intakes. Run one to each side of the car. It would require remote mounting the battery and doing a little triming, but it would douple the possible airflow.

[shotgunslade]

As I understand it, the ECU controls the idle fuel delivery in open loop mode, in that it doesn't receive O2 sensor information to adjust the fuel injector pulse width. The ECU normally receives inputs for rpm, throttle position, air flow through the MAF, some temperatures, O2, and a few other things. Does it receive inputs on fuel pressure? If not, can it really adjust to higher fuel pressure when it is in open loop operation mode, as it is when the engine is idling?

[TomsSVX]

No it cannot sense fuel pressure. But when the AFR gets too rich the engine will compensate for it

Tom

[mbtoloczko]

Up to 20-25% throttle position (never took the time to determine the exact value), the ECU controls the motor in closed-loop using O2 sensor data to do its best to maintain a 14.7:1 afr. At idle, its difficult for the ECU to control the afr precisely though because at idle the volume of exhaust gas passing the O2 sensors is small, and it takes a while for the O2 sensor to sample enough gas for its output value to change. And if the fuel pressure is too high, the ECU might not be able to compensate the injector enough to bring the afr into range.

In open-loop, the O2 sensor data are not used, and more fuel pressure means richer afr. The increase in fuel goes roughly as the square root of the fuel pressure.

[$ gest24 $]

I've been getting ready to start ordering parts for my SVX. I want to get the stage 2 but really can't swing $700 for the full set up. So could I get the chip and not buy the Z32 MAF and just source one on Ebay at a later date.

[TomsSVX]

yes, but in this case. You need to wait until you gte the MAF to install it. I figured you knew that but just being safe

Tom