Charge control valve / actuator question
Thread Starter
Joined: Mar 2003
Posts: 2,319
Likes: 32
From: South Jersey
Charge control valve / actuator question
I was having some boost issues over the past few weeks (solved), and decided to tap a pressure and vacuum gauge into the charge control actuator (the one on the y-pipe that controls the butterfly valve).
Here's what the tests showed -
1). Pre 4.5k, the actuator sees vacuum
2). Post 4.5k on acceleration the actuator sees boost
3). When I then let the rpms fall / decelerate, the actuator doesn't transition back to vacuum until the rpms fall below 3k.
Does 3 make sense? I would assume that it would go back to vacuum at 4.5k. It's perfectly consistent, so it appears that the ecu is consciously doing it.
It's interesting because if accelerate starting under 3k, I get fast boost and a great transition. If I decelerate to 3k+ rpms (but less that 4.5k) the car builds boost slower until the transition. So I can feel the effect of having the valve remaining open after a deceleration.
Is the system behaving as designed?
Here's what the tests showed -
1). Pre 4.5k, the actuator sees vacuum
2). Post 4.5k on acceleration the actuator sees boost
3). When I then let the rpms fall / decelerate, the actuator doesn't transition back to vacuum until the rpms fall below 3k.
Does 3 make sense? I would assume that it would go back to vacuum at 4.5k. It's perfectly consistent, so it appears that the ecu is consciously doing it.
It's interesting because if accelerate starting under 3k, I get fast boost and a great transition. If I decelerate to 3k+ rpms (but less that 4.5k) the car builds boost slower until the transition. So I can feel the effect of having the valve remaining open after a deceleration.
Is the system behaving as designed?
That is odd. Do you have a PowerFC? The PFC has a setting that sets the on and off points for the turbo transition, if the "off" point is set too low (3000 RPM) you would see this.
This setting is only available with the Datalogit.
The PFC has the settings by default fairly close, like 4500 on/4250 off or something like that.
Do you know if your turbo control is also showing the same behavior?
Dale
This setting is only available with the Datalogit.
The PFC has the settings by default fairly close, like 4500 on/4250 off or something like that.
Do you know if your turbo control is also showing the same behavior?
Dale
Thread Starter
Joined: Mar 2003
Posts: 2,319
Likes: 32
From: South Jersey
That's good to know... Hopefully that's all it is. Car is getting tuned in the next few weeks, I'll have the tuned check that. I haven't checked the turbo control solenoid.
See my Sequential Turbos Desmystified thread. https://www.rx7club.com/3rd-generati...tified-841821/
The switching is 4000rpm on acceleration and 3000rpm on deceleration with the stock PFC map. On the stock ECU, the switching is gear based, with 1st gear switching at 5,500 acceleration and 5,250 deceleration. Then it's lower rpm at higher gears. I believe it's around 4000rpm.
One of the tricks with the PFC is to set the "turbo transition low" setting from 3000 to 3500 rpm, so that it falls back into primary-only operation more easily.
The switching is 4000rpm on acceleration and 3000rpm on deceleration with the stock PFC map. On the stock ECU, the switching is gear based, with 1st gear switching at 5,500 acceleration and 5,250 deceleration. Then it's lower rpm at higher gears. I believe it's around 4000rpm.
One of the tricks with the PFC is to set the "turbo transition low" setting from 3000 to 3500 rpm, so that it falls back into primary-only operation more easily.