Variable output based on RPM

[Anthony Parle]

I need to control variable ram intakes based on rpm.  Can I use a GP PWM output and can I change it based on RPM

ECU is G+ Thunder

[Brad Burnett]

Are you using both dbws on the thunder?   If not you could use the spare dbw controls for the actuator and put a position sensor on the shaft.

[Adamw]

I need to control variable ram intakes based on rpm.  Can I use a GP PWM output and can I change it based on RPM

ECU is G+ Thunder

Yes you can do PWM controlled by a 2D or 3D table.  Are you sure you need PWM though?  Most servo or motor type actuators would need push/pull.

[Anthony Parle]

Hi Guys,

I am open to the best way to do it, I am using one PWM on the idle (if I understand correctly) its a Subaru motor, so the other is spare so feed back would be good,

Is there any other options?

[Adamw]

You have 8 Aux outputs that can do GP PWM.  What type of device drives this variable intake - Solenoid, DC motor, stepper motor???

[Anthony Parle]

I have two concepts in mind,

One is just a 1 shoot Solenoid but would need to occur at the same time in relation to the piston and intake,  Just not sure how I could do that unless I use the injector timing and run them batch unless you guys can tell me how I can do it.

The second I would  guess would be a DC motor but I need some way to feed back as Brad mentioned.

[Brad Burnett]

Are you trying to use the tumble generating valves in the intake manifold runners for something fancy?

I do tons of subarus and most of the time we just delete the TGVs.

But the ecus do have provisions for TGV control.

[Anthony Parle]

Hi Brad,

No, my engine is a EG33 no valve I also have machined the centre out of the manifold and fitted twin snorkles.  Now I am working on a set of individual throttle bodies and as part of that I will either adjust there length as revs change or use a new idea on each cylinder.

 

Do you know if on the Thunder I could install it on a 4 cylinder and have two different injector timing maps etc.  I could use the first 4 for the actual injectors and the last 4 to control the valves on each head?

Thanks for your help.

[Adamw]

Do you know if on the Thunder I could install it on a 4 cylinder and have two different injector timing maps etc.  I could use the first 4 for the actual injectors and the last 4 to control the valves on each head?

We dont have a separate timing map for the secondary injectors at the moment.

 

Now I am working on a set of individual throttle bodies and as part of that I will either adjust there length as revs change or use a new idea on each cylinder.

How about use an RC servo, like this type of thing: https://www.pololu.com/product/1057.  You would need to give it a separate power supply since most can only take 5V but a PWM aux out will control its position.  I've never used one but in theory it should work.  If you use a 100Hz PWM, then 10%DC will give you full anticlockwise, 15% will be centered, 20% will give you full clockwise. 

 

[Anthony Parle]

That sounds like a plan Adam, I will give it a try,

I used one on my engine dyno to drive the throttle.