early v6 butterfly actuator.

[kaighn80]

hi guys, im building up a 2.5 turbo to go into a kitcar, the engine i have has an actuator that uses vacuum or pressure (not sure which) to open or close the butterflies (again not sure which but at atmospheric pressure its holding the butterflies open). so the question is, if i turbo this engine can i use the actuator or do i need to do something different?

 

[gmorrell]

The old Yamaha Taurus SHO V6 engines used butterflys in the short runners that were held open with little springs. When the engine started and built some vacuum, the vacuum servos closed the butterflys against the spring force. When the ECU commanded the butterflys to open, a signal was sent to a solenoid valve that vented the vacuum servos to atmosphere, allowing them to open.

This is the logic you want on a turbo engine, but you'll want to add a vacuum reservoir in the vacuum line to the butterfly control solenoid, and put a check valve in the vacuum line from the engine intake vacuum port to the vacuum reservoir, so the butterflys will have enough stored vacuum to stay closed under light boost.

The other thing you could do is borrow the electric butterfly actuator (IMRC actuator) from the 2.5 or 3.0L Duratec V6 engine.

 

[kaighn80]

thanks, this is a 2.5l duratec, but it doesn't have the controller, i'm also going stand alone ecu so i don't think i can use the controller

 

[gmorrell]

You could use the electric IMRC with a stand alone ECU. The 2.5/3.0L IMRC uses a single input control line that the ECU takes low to command the IMRC to turn on it's electric motor and open the butterflys. You can dedicate a single digital output from the stand alone to run the IMRC.

 

[kaighn80]

don't suppose you know what pins i need to connect, I've a few spare outputs on the ecu that i can program to take care of this, is the motor just a normal dc or a stepper motor?

 

[gmorrell]

There's an explanation here about IMRC function and an internal schematic.
https://talkford.com/community/topic/304313-imrc/

See the second post from GearJammer, the first image is a text explanation of the function, the second image is the module's internal schematic.

Basically, at the module's 6-pin connector you supply +12V (V-ignition) to pin 2, ground to pin 3, and pin 1 to the ECU's output. Pull the ECU's output low (to ground) and the IMRC module takes care of the rest.

If you want, the 'cable switch' on Pins 5 and 6 can be used with an ECU digital input to pull it low, or high (how you wire it is your choice), to tell the ECU that the module indeed did open the butterflys when commanded. The stock engine and ECU does this verify, which is why you'll get a trouble code and MIL when the IMRC is commanded to open, but the cable switch doesn't change state verifying that the module worked properly. Trust but verify, an old Russian proverb: Доверяй, но проверяй

 

[mmc757]

I would think for forced induction you could delete the IMRC and never know the difference.
Or just use it as is...Is there some problem with it? Even a turbo car builds vacuum when the throttle is shut.

 

[kaighn80]

I would think for forced induction you could delete the IMRC and never know the difference.
Or just use it as is...Is there some problem with it? Even a turbo car builds vacuum when the throttle is shut.

not sure how well it would work having to fight against boost, the easy way to solve it is let my ecu take care of it, might even make a difference to the way the boost comes in.

 

[mmc757]

I think I would honestly just delete it. That's one less problem you have to worry about in your build.
We don't have many examples of people adding FI to the 2.5 cars because we usually switch to a 3.0 as our first power-adder, but I doubt very much that the IMRC would provide any useful purpose in a turbo car.