Setting up a drive pressure sensor using V2 interface?

[DuramaxPowered]

Has anyone here setup a drive pressure sensor using EFILive? I've been looking around and found a 0-130psi sensor that has an output of 0-5v. I read in the scan tool manual on how to set it up, but it seems a little confusing to create a calculated PIDS. I would like to get this setup and start playing around with this since I feel it will be better to be able to log this data instead of just looking at the maximum from a gauge.

 

[McRat]

I was recording it using the 0-5v port, and doing the calculations using EXCEL. You can also just hook it into your EGR position sensor if you want, and look at it that way.

 

[DuramaxPowered]

well egr isn't hooked up. I wondering if using a/d1 will work and create a custom gauge in the scan tool to display 5 volts and make it equal 130 psi... I guess i have to get the sensor in and hooked up and start playing. On a different note, do you know how high the DPF differential pressure sensor goes up to, i've been thinking of using that to read difference in exhaust and boost to get the reading that way.

 

[McRat]

I doubt it would go high enough, but I will take a look.

The EGR plug has a 0-5v signal when you supply it with 12v and ground. Anything you plug into it will read on a Tech2 under EGR Position Sensor Voltage, or you can read EGR position PID in EFILive. This only works if you are not using your EGR plug.

 

[Fingers]

Making the PID is simple. I had my Spa boost gauge hooked up as a drive pressure sensor. From my calc_pid.txt file:

#External chan 2 used as backpessure guage from SPA sensor
*CLC-00-015
psi 0.0 100 .1 "({EXT.AD2}-1)*50"
.
.
.
.
CALC.Drive F601 CLC-00-015 psi Performance "Turbo Drive Pressure"

You will need to determine the offset and gain for the sensor. It may be 130PSI at full scale, but what voltage is full scale? Most 0-5 Volt sensors only go to about 4.75Volts for full scale and start at 0.5 or so.

In the case of my SPA sensor, Zero PSI was at ~1 Volts and then ~50 PSI/Volt from there. So the formula is PSI = (Voltage - Offset)*Gain or PSI = (Voltage-1)*50 for my SPA as you can see from the PID file.

I have killed 2 sensors already for drive pressure. They have to deal with significant pulsing and there is a lot of acidic condensation in the line that damages the sensor diaphragm. Keep the sensor high with the line running down hill back to the manifold and, if you have access to the sensor's diaphragm, smear a thin coat of RTV over the membrane.

VVTs will see pressures up to and including 100 PSI while normal spinners will be way less. Usually 1.0-1.5 times the boost they are producing. At least from what I have looked at.

....but what do I know.

 

[Brayden]

I have some pigtails made up for Autometer pressure transducers as well as the transducers themselves. They read 0-100.

Same as fingers on the PID hacks.

 

[DuramaxPowered]

Fingers, what type of lifespan would you say that these sensors have in this environment?......I would not need it all the time and the way I am now thinking about setting it up would be a mechanical gauge that could get unhooked at a fitting under the hood and pressure transducer screwed in for tuning/logging changes...... Maybe I'm going a little overboard here, but I'm wanting to fully evaluate the stock turbo before building my compound turbo setup utilizing the stock turbo.

 

[McRat]

The SPA tranducers aren't very good. I blew 2 of them using them as normal boost sensors.

 

[DuramaxPowered]

http://www.aeroforcetech.com/oil_fuel_sensor.html This oil pressure sensor is the one I'm looking at, do you think that it would wwork?

 

[sweetdiesel]

0.5 to 4.5 on Autometer gauges work great! you can build a custom gauge on the dash and use a Calc Pid as allready stated

Also you can use the EGR if its not hooked up and use EFI to log it that way or tie right into the wires for voltage and ground

 

[Fingers]

That oil sensor should work, but I don't know how long it will last since you can't protect the diaphragm. You really need to pay attention to the required supply voltage for the sensor. Some require 5 Volts and others 12 Volts or more. Even if they only produce a 0-5 volt output. It will be called excitation voltage some times. Both voltages are readily available under the hood, but you have to look at the specs.

The other thing you will want to look at is the slew rate of the sensor. Unlike other applications, you want a larger slew rate to help dampen out the pulsing that will be going on. Depending on the setup, the pulses can be as large as 10 PSI or more. Your mechanical gauge will give you a feel for the amplitude of the pulsing. If the needle is jumping ~10 PSI, then the pulses are actually about 15 PSI for instance. Depending on when EFI samples the sensor, it might catch the pulse, or maybe not. Makes for some head scratching if you don't know what is going on.

 

[sweetdiesel]

That oil sensor should work, but I don't know how long it will last since you can't protect the diaphragm. You really need to pay attention to the required supply voltage for the sensor. Some require 5 Volts and others 12 Volts or more. Even if they only produce a 0-5 volt output. It will be called excitation voltage some times. Both voltages are readily available under the hood, but you have to look at the specs.

The other thing you will want to look at is the slew rate of the sensor. Unlike other applications, you want a larger slew rate to help dampen out the pulsing that will be going on. Depending on the setup, the pulses can be as large as 10 PSI or more. Your mechanical gauge will give you a feel for the amplitude of the pulsing. If the needle is jumping ~10 PSI, then the pulses are actually about 15 PSI for instance. Depending on when EFI samples the sensor, it might catch the pulse, or maybe not. Makes for some head scratching if you don't know what is going on.

Is there a way to dampen these spikes with the PID formula?
Or can the sample rate be changed?

 

[Fingers]

Not within EFI that I know of. If you need to dampen them, either increase the volume of the sensing tube or put a Capacitor across the sensor.