Need RPM triggered output

[joenationwide]

Hi everyone,

I have a C5 Corvette road race car with an LS6 and an OEM PCM, and I'm looking for something in HP Tuners to give me an output voltage at a certain RPM trigger.

My goal is to turn on an Accusump electronic valve above a certain RPM (say 3000rpm) so it doesn't dump at idle.
And if I could find a second circuit to send a signal at a programmed RPM (say 6500rpm), I'd like to use it as a shift light.

I'm new to HP Tuners and new to this race car, so I was wondering if anyone has any advice as to repurposing a factory switch in HP Tuners to turn on something at a programmable RPM.
I found under "System" there is an AC switch, but it looks like it will turn something OFF at a max RPM and turn it ON at a min RPM. I'm looking to turn something ON at a min RPM.
I know you can buy window switches for NOS, and you can buy shift lights, but I'd rather control something using HP Tuners with a factory system that I don't use (like AC compressor).

Thanks in advance!

Scott

[blindsquirrel]

If you could go in and fiddle a few virtual knobs and make things like that happen, aftermarket ECUs wouldn't, for the most part, need to exist.

[joenationwide]

Sure, I hear you. But I think there's got to be a way to do something simple like this using the factory PCM and HP Tuners. Like I mentioned the AC switch. And I would have thought other people would be attempting certain "hacks" like these as well.

[Shnraines]

Why can't you use spdt relays on the outputs that work in reverse of your desire. You can reverse the control with the relays.

[blindsquirrel]

Does the Gen 3 compressor cutout actually follow the throttle/RPM settings as you'd logically expect it to based on the tooltip descriptions? Because the Gen 4s certainly do not.

[TheMechanic]

I would try the shift light setting. Engine tab>General>Shift light. Or CTRL+N 250

[joenationwide]

Why can't you use spdt relays on the outputs that work in reverse of your desire. You can reverse the control with the relays.

Sounds like a good idea. I'll have to look into that.
So if I just adjust the RPM values so that it comes on at the low RPM (3000 rpm) and turns off above redline (7000 rpm)... would this work, or does it require the RPM to hit 7000 to first deactivate it, and wait until it comes down to 3000rpm to reactivate?

Does the Gen 3 compressor cutout actually follow the throttle/RPM settings as you'd logically expect it to based on the tooltip descriptions? Because the Gen 4s certainly do not.

Yes, it looks that way.

ac fans 1.jpg

I would try the shift light setting. Engine tab>General>Shift light. Or CTRL+N 250

Doesn't look like my PCM supports that.

general.jpg

[kingtal0n]

Anywhere in my car that a function does not exist because the OEM ecu cannot or does not capable,

I use the basic microcontroller as Arduino,

For example there is no transmission temp output (GAUGE) from the OEM ecu or transmission fan temp activation,

So I take Arduino NANO ($20?) and a $.05 temp sensor 1/8" NPT from ebay and utilize voltage divider to interpret resistance (1 wire temp sensor into ADC voltage input)
Then measure with multiple thermometers, generate a semi-log curve for resistance:ADC:Temperature, finalize the curve using excel curve fitment (lets see if I have a picture of that... hmm)

Pics! (Open in new tab should give a large picture)





SO now I get Transtemp readout on Display LCD in the car, and I can switch on the transmission fan using Arduino -> Darlington pair (transistors 2N2222) -> Fan Relay -> Fan Activate

Furthermore you can get crazy with it. You can use motion detector for example to determine whether fan is actually spinning or not. You can measure temperature in front of and behind the trans cooler if you wanted using air temp sensors (Very cheap). Same for radiator and underhood temperatures. You could spray water (water drip system is ideal to prevent heat soaking in traffic) Using water detection through transistors to turn the system on and off. Use external PWM drivers to make it simplicity.

And so forth.


SO for your proposed project, simply read how others are doing it. bring in tach signal then use transistors (I recommend darlington pair a 2N2222 for most automotive relays, has been reliable for me) to switch things on and off if the relay is fast enough for the job. Some things you might need a Solid State Relay or some other fancy things, but the idea is the same, using microcontroller to make up for missing features.

https://forum.arduino.cc/t/reading-a...gnal/128761/14

[blindsquirrel]

Yes, it looks that way.

ac fans 1.jpg

That's what I'm saying - the behavior does not always follow what you would think based on the descriptions for those items. If you have tested it, and when you put a certain number in the box the compressor really does turn off at that RPM reliably, then great. A lot of them don't work that way and whether it works in a logical way or not can depend on hardware/platform/OS, even though the enable/disable settings and their descriptions are exactly the same in all the tune files. It seems you're assuming that if the settings are there in your file then you're good to go.

[kingtal0n]

That's what I'm saying - the behavior does not always follow what you would think based on the descriptions for those items. If you have tested it, and when you put a certain number in the box the compressor really does turn off at that RPM reliably, then great. A lot of them don't work that way and whether it works in a logical way or not can depend on hardware/platform/OS, even though the enable/disable settings and their descriptions are exactly the same in all the tune files. It seems you're assuming that if the settings are there in your file then you're good to go.

Hehe. "The textbox says it will shift at 6100rpm, why does it actually shift at 6700?!"

I agree strongly that what the tuning software claims will happen, and what will actually happen, is often two completely different things and based on more variables than it would lead us to believe or we are initially aware of at least.

Which is fine. I am not complaining. Only agreeing strongly that empirical (experimental) testing is always required and assumptions are not valid when setting up diagrams for wiring and sensors and so forth.

Today you measure the output and its got 12v or ground and tomorrow because the coolant temp is above some obscure number listed elsewhere in the tune file you don't get the same output anymore kind of stuff can happen. "When the engine is between 20KPA and 80KPA and only when coolant is over 112*F...." it is full of stipulations and contingencies, presumably ( I assume ) for reliability reasons and general 'clamping' of behaviors under set parameters. But if you are doing some sort of scaling to fool the ECU you also need to watch out for ratios between pre-set constants AND configurable variables, even if they 'made sense' in the original scale and you just ignored them....

[agentruley]

If you are looking to trigger/output a voltage at/above a specific RPM value, try making your own circuit using a cheap ebay shift light. First set to whatever RPM you want. Then you tie into the relay/transistor that turns on the shift light at desired RPM and in parallel to that circuit you have it trigger another transistor/relay. Boom, problem solved. Shift light sees RPM, turns actual light on which would activate whatever relay/transistor you have tied to it. If this doesn't make sense I have a practical application where I made a variable path exhuast system, or known as VPES (not vtec) and below a certain RPM, a cutout stays closed. Above the cutout opens, and not slowly either. I used a windshield wiper motor to control the opening and closing so its instantaneous. Works amazing, and its like having vtec but for an LS in terms of sound haha.
If you need help with the circuitry I can provide information

[joenationwide]

Wow, thanks for all the responses everyone!

Anywhere in my car that a function does not exist because the OEM ecu cannot or does not capable,

I use the basic microcontroller as Arduino,

For example there is no transmission temp output (GAUGE) from the OEM ecu or transmission fan temp activation,

So I take Arduino NANO ($20?) and a $.05 temp sensor 1/8" NPT from ebay and utilize voltage divider to interpret resistance (1 wire temp sensor into ADC voltage input)
Then measure with multiple thermometers, generate a semi-log curve for resistance:ADC:Temperature, finalize the curve using excel curve fitment (lets see if I have a picture of that... hmm)

Pics! (Open in new tab should give a large picture)





SO now I get Transtemp readout on Display LCD in the car, and I can switch on the transmission fan using Arduino -> Darlington pair (transistors 2N2222) -> Fan Relay -> Fan Activate

Furthermore you can get crazy with it. You can use motion detector for example to determine whether fan is actually spinning or not. You can measure temperature in front of and behind the trans cooler if you wanted using air temp sensors (Very cheap). Same for radiator and underhood temperatures. You could spray water (water drip system is ideal to prevent heat soaking in traffic) Using water detection through transistors to turn the system on and off. Use external PWM drivers to make it simplicity.

And so forth.


SO for your proposed project, simply read how others are doing it. bring in tach signal then use transistors (I recommend darlington pair a 2N2222 for most automotive relays, has been reliable for me) to switch things on and off if the relay is fast enough for the job. Some things you might need a Solid State Relay or some other fancy things, but the idea is the same, using microcontroller to make up for missing features.

https://forum.arduino.cc/t/reading-a...gnal/128761/14

You just got me thinking in new directions. And your 5.3L turbo S14 thread is crazy! Holy crap so much to unpack but damn that is impressive.

That's what I'm saying - the behavior does not always follow what you would think based on the descriptions for those items. If you have tested it, and when you put a certain number in the box the compressor really does turn off at that RPM reliably, then great. A lot of them don't work that way and whether it works in a logical way or not can depend on hardware/platform/OS, even though the enable/disable settings and their descriptions are exactly the same in all the tune files. It seems you're assuming that if the settings are there in your file then you're good to go.

Wow, that's a great point. Maybe it's best to leave special functions to external controllers rather than the PCM.

If you are looking to trigger/output a voltage at/above a specific RPM value, try making your own circuit using a cheap ebay shift light. First set to whatever RPM you want. Then you tie into the relay/transistor that turns on the shift light at desired RPM and in parallel to that circuit you have it trigger another transistor/relay. Boom, problem solved. Shift light sees RPM, turns actual light on which would activate whatever relay/transistor you have tied to it. If this doesn't make sense I have a practical application where I made a variable path exhuast system, or known as VPES (not vtec) and below a certain RPM, a cutout stays closed. Above the cutout opens, and not slowly either. I used a windshield wiper motor to control the opening and closing so its instantaneous. Works amazing, and its like having vtec but for an LS in terms of sound haha.
If you need help with the circuitry I can provide information

I love this idea. So I just bought an Intellitronix 3012 which takes the tach signal and outputs a voltage at whatever RPM you select, since this is kind of an easy button.
I can set it to 3000rpm to turn on an Accusump electronic pressure (EPC) valve. This way it will only dump above 3000RPM and if oil pressure drops below 55psi.

https://www.intellitronix.com/produc...th-dipswitches

I'd hate to have to buy another one to do a shift light. Maybe I'll research some Arduino's and see if I can create a multi stage shift light like all the other racers have with their fancy AIM dashes.