Turbo system

[DTM_Yaris]

Originally Posted by acrbill

Put the MAF sensor on the inlet side of the turbo. Let the piggyback do all the work. Theh stock ecu shouldn't even realize that the car is no longer stock.

The maf sensor is able to output over 8 volts. Thats not the problem. The problem is the voltage the ecu sees!
If it sees over 2.8 volts at "x" rpm and throttle position it will go crazy. Trust me I have done it.
But I am working around this, meaning the stock ecu will never know that it is force fed.

[acrbill]

Originally Posted by DTM_Yaris

The maf sensor is able to output over 8 volts. Thats not the problem. The problem is the voltage the ecu sees!
If it sees over 2.8 volts at "x" rpm and throttle position it will go crazy. Trust me I have done it.
But I am working around this, meaning the stock ecu will never know that it is force fed.

If the MAF sensor is on the inlet side of the turbo Its not going to have compressed air going through it so the reading of the air going into the turbo will be accurate when your not in boost. Maybe once your in boost the turbo is sucking in more air there might be an issue, but all you would need would be a voltage clamp. Thats strange that it reads 8 volts. I would have assumed that it was 5v like a MAP sensor.

[DTM_Yaris]

Originally Posted by acrbill

If the MAF sensor is on the inlet side of the turbo Its not going to have compressed air going through it so the reading of the air going into the turbo will be accurate when your not in boost. Maybe once your in boost the turbo is sucking in more air there might be an issue, but all you would need would be a voltage clamp. Thats strange that it reads 8 volts. I would have assumed that it was 5v like a MAP sensor.

Whether the MAF is on the inducer or discharge side of the equation makes little difference for drivability. Closed loop operation was and is fine. My posts have been strictly about boost and open loop mode. The voltage clamp will not help when you are in boost either. The computer takes into account Airtemp, throttle position (or anticipated position for DBW), coolant temp, rpm and crank position.
It is not like the old days when we could just play the analog game. It has checks and balances in the algorithms.
It is very difficult to overcome.

[spkrman]

Originally Posted by DTM_Yaris

The maf sensor is able to output over 8 volts. Thats not the problem. The problem is the voltage the ecu sees!
If it sees over 2.8 volts at "x" rpm and throttle position it will go crazy. Trust me I have done it.
But I am working around this, meaning the stock ecu will never know that it is force fed.

details? :)

[03Z33]

I'm happy to see you working on this. I'll be in the market for something like this shortly.
Regarding the MAF signal, what I usually see people do is one of the following:

1. Reprogram ECU to accept higher volage input (usually not possible on newer cars)

2. Oversize MAF housing to reduce air velocity (requires retune of ECU or piggyback to recalibrate for the new lower signal inputs)

3. Install resistor in-line between MAF and ECU on signal wire to recalibrate the maximum voltage to the ECU (this also requires recalibrating the ECU software for the different signal, or a piggyback to adjust).

4. Clamp MAF signal to max voltage ECU likes. This will usually benefit from a retune also.

5. Install any one of many piggy-back options which will adaptively do the above for you by constantly monitoring and adapting the different signals the ECU is depending on. This sometimes doesn't work well due to the adaptive nature of the stock ECU, which sometimes "undoes" the corrections the piggy-back is trying to implement.

6. Or you can always dump the MAF all together and convert to MAP, by either reprograming the ECU to accept MAP signals/voltages instead of MAF signal or by dumping the stock ECU all together and running a stand alone ECU.

[Nutzoids]

I am not 100% sure… but so far the only difference I have found between a Turbo kit for the xA/xB and the Yaris has been… the Intercooler on the Yaris needs to be a little bit thinner… 3” in thickness, as opposed to the Scion 4”… I think the tubing has all the same bends too… But that is the last thing I need to research, and admittedly it is much harder… Short of buying both kits and checking it out for shits and giggles… And I am way to poor for that… Plus I don’t think our Venders want us knowing that either way!

Did anyone else compare the 2 on that link????

[DTM_Yaris]

Originally Posted by Nutzoids

I am not 100% sure… but so far the only difference I have found between a Turbo kit for the xA/xB and the Yaris has been… the Intercooler on the Yaris needs to be a little bit thinner… 3” in thickness, as opposed to the Scion 4”… I think the tubing has all the same bends too… But that is the last thing I need to research, and admittedly it is much harder… Short of buying both kits and checking it out for shits and giggles… And I am way to poor for that… Plus I don’t think our Venders want us knowing that either way!

Did anyone else compare the 2 on that link????

They are different in many ways. The intercooler piping will not bolt up whatsoever, the downpipes will not bolt up tot he Yaris cat, midpipe, ETC.
The only good thing about these kits is the fact that they have a nice turbo manifold that is reliable.

[DTM_Yaris]

Originally Posted by 03Z33

I'm happy to see you working on this. I'll be in the market for something like this shortly.
Regarding the MAF signal, what I usually see people do is one of the following:

1. Reprogram ECU to accept higher volage input (usually not possible on newer cars)

2. Oversize MAF housing to reduce air velocity (requires retune of ECU or piggyback to recalibrate for the new lower signal inputs)

3. Install resistor in-line between MAF and ECU on signal wire to recalibrate the maximum voltage to the ECU (this also requires recalibrating the ECU software for the different signal, or a piggyback to adjust).

4. Clamp MAF signal to max voltage ECU likes. This will usually benefit from a retune also.

5. Install any one of many piggy-back options which will adaptively do the above for you by constantly monitoring and adapting the different signals the ECU is depending on. This sometimes doesn't work well due to the adaptive nature of the stock ECU, which sometimes "undoes" the corrections the piggy-back is trying to implement.

6. Or you can always dump the MAF all together and convert to MAP, by either reprograming the ECU to accept MAP signals/voltages instead of MAF signal or by dumping the stock ECU all together and running a stand alone ECU.

1.Unfortunately reflashing or reprogramming interface is unavailable at this time.

2.Unfortunately reflashing or reprogramming interface is unavailable at this time.

3.Unfortunately reflashing or reprogramming interface is unavailable at this time.

4.The problem with this, like I mention above, is that the ecu will look at preprogrammed values. They will not be in line with the amount of airflow it would see N/A with a certain throttle voltage and air temp. It will think the MAF is bad. Now not while the car is just daily driving, Just when under boost when it counts!

5.The problem with many piggybacks is also the fact that there aren't that many outputs. they usually will allow 256 point adjustments for (1) 0-5 volt analog input. Some will do 02 feedback manipulation, BUT they only work well on older ECU's. Not the CANBUS system we see in the Toyotas and many OEM applications.

6.Unfortunately reflashing or reprogramming interface is unavailable at this time.