We are currently running 550cc injectors in our xB with no idle issue what so ever. We have converted the MAF on our production kits for suck to blow through to eliminate the idle issue with the car loading out. The MAF location is just as important as pipe diameter. The relation of the sensor to the vacuum or boost source is critical in identify are creating proper voltage v. RPM and boost load.

I am not sure where the issue comes in with the car not maintaining consistent AFR. We have heard this in the tC arena also and it is not correct. We have been able to hold 11.5AFR for 5k plus mile with no issue or a retune.

I can tell you if the car see leaner than 12.1 at power levels over 150whp the car will detonate. We have logged detonation at these AFR. 11.5-11.3 is where we run the car with no issue and still maintaining 28-31mpg if somewhat normal driving is maintained.

The Greddy Pressure Sensor is a very valuable piece when building a reliable daily driver map. It eliminates the surging due to map loading when the car makes the vacuum to boost transition. This is especially helpful when building a good fuel mileage map as you can lean the car out off boost with out fear of the car making boost in high gears at low TPS%.

The xB is a solid platform with minimal issues thus far. The ECU is complicated but no different than other Toyota platforms and a lot simpler than the tC.

If there are any other questions please feel free to contact us.

-Kenny

 

Injector size, fuel line size (diameter), pump capacity, fuel pressure, etc all will need to be taken into consideration. Here is some helpful info http://www.raceprecision.com/forums/...ic.php?p=35#35

There is nothing to be afraid of. You have plenty of people (Me, Pro, zpi, and many others) trying different things out before your car will see boost.

I have a pipe housing the AFM between my intercooler and throttle body. I did this on my MR2 also before switching out to a map sensor. It worked pretty well. Im not sure if this is what you meant. 550s are BIG for the hp that you guys are making. Im assuming that you are using the stock pump? Im running the 310s and I still need to trim my fuel to maintain idle or it would stall out.

 

I am going to try to add some information to this thread, that I have learned from racing my eclipse GSX. I hope it can be translated into our scions.

First, we also upgraded the MAF sensor on our cars. We used GM's 3" and 3.5" sensors. It allowed us to get more air flowing and it was also used to vent our blow off valve in the air, when located after the turbo. It also provided better (accurate) signals to our ECU, but we had to use a converter (MAF translators from full throttle speed). The signals between the 2 systems were different.
Their were also people that modified the restrictor in the stock MAF sensor. They drilled a bigger hole. But I don't know what they did specifically, because I got the MAF translator and deleted the stock MAF for a 3" GM one.

Second, the 4 wires of the O2 sensor are 2 for heating the sensor and 2 for measuring of the O2. Some of us got CEL when we installed a straight pipe (no cat). What we did was, cut the 2 wires that measured the O2 of the rear (2nd) O2 sensor and installed a resistor to stimulate ideal O2 output. This deleted the CEL's.
This might be helpfull for us too. But I think our biggest enemy is our ECU (PCM or computer).

BTW, the second O2 sensor is there to measure if the gasses are completely burned up or cleaned after the cat. It's there for emissions only. The first one measures the engine output and sent information to the computer for adjustments. This is true for the eclipse, I am not 100% sure for our scions.