Boost control solenoid - how to go back to wastegate only?

[andywood]

I have a boost controller and also the electronic actuator/solenoid on my sp-turbo that is plumbed into the turbo.
Am trying to get clear in my head what needs to be disconnected or re-plumbed to run the car on wastegate pressure only (for lower performance for peace of mind over winter etc...)

Is this a simple case of just electrically disconnecting the control actuator/solenoid so that it is permanently open or do i need to re-plumb the piping from charge side to wastegate on the turbo itself?

car is mapped to the higher boost levels, so my assumption here is that the lower boost from running with wastegate only will be no problem??

Cheers in advance

Andy

[Anonymous]

boost controller should allow you to drop it to 6psi ie wastegate pressure however i think your on a unichip and that runs on the maf sensor. if so it might through the mapping out running at lower pressure.

[andywood]

boost controller defo runs off MAP sensor not the MAF.

Andy

[Anonymous]

should be ok then as it will adjust.

[andywood]

what will adjust?? If boost control solenoid is disconnected then boost controller is still seeing MAP pressure/signal, but i think it only uses MAP to determine when to open/close solenoid. So therefore either disconnecting the solenoid or the controller should have the same effect.....
If running at wastegate pressure then airflow/MAF signal will in theory be lower maximum and fuelling will just shift to another region of the same MAP to suit those lower airflows (assuming that fuelling is from MAF).

My concern is if just disconnecting the boost solenoid means it defaults to wastegate automatically or if this risks anything else (like wastegate permanantly shut!!)

Andy

[markiii]

Just turn it down adjustability is the point of having one

[SteveJ]

If you really want to play it safe, disconnect the waste-gate actuator arm and tie it in the open position with a piece of wire.

The whole point of having the MAP sensor is so the piggy-back can adjust to various intake manifold pressures - if it doesnt see any boost then it will simply use that section of it's fuel & timing map. Simples.

[stargazer30]

When I had my SP turbo I used to disconnect the boost controller to run at 200bhp.  I had a switch on the power feed to it.  I'd asked Richard at redline about it and he recon'd it was okay the car would simply run at low boost with it disconnected.

[andywood]

Just turn it down adjustability is the point of having one

Dastek boost controller and has no manual adjustment it seems

Andy

[markiii]

is it part of the unichip?

[andywood]

Disconnected (unplugged) the Dastek boost controller today and went for a spin.
Surprisingly didn't really feel that much different   s:shock: :shock: s:shock:    Reconnected and then went out again and the butt-dyno was still struggling to detect much difference. Just feels as quick as ever   s:D s:D  

Seems strange as guessing that with the boost controller it is up somewhere like 10psi and should only be at 6.5psi with non-boost controlled wastegate pressure.

Was expecting a dramatic difference but struggling to feel it. Without a boost guage or diagnostics running it is difficult to know what does change.
Plan to head over to Redline soon anyway as it has been a year since the car was mapped so will get it all checked out in more detail then.

Andy.

[andywood]

is it part of the unichip?

There is the Unichip Q which then has another small unit stuck to it with the MAP sensor line attached.
Separately there is a Dastek piggy-back ECU which i understand to be the boost controller.

Andy

[markiii]

maybe its broken and you were only running wastegate pressure to start with?

[andywood]

Just tried a v simple approach and disconnected the boost control solenoid - this would mean that it won't get electronically closed and wastegate will then see boost pressure and work as if boost control not there.
Showed a clear difference in performance (i.e. less!) and less audible turbo flutter on lift off too so would suggest that producing less boost.

Strange that this did it and other disconnection didn't   s:? :? s:?  

Andy.

[shnazzle]

Just tried a v simple approach and disconnected the boost control solenoid - this would mean that it won't get electronically closed and wastegate will then see boost pressure and work as if boost control not there.
Showed a clear difference in performance (i.e. less!) and less audible turbo flutter on lift off too so would suggest that producing less boost.

Strange that this did it and other disconnection didn't   s:? :? s:?  

Andy.

Total blast from the past here (5 year post revival) but when we got the SP240 this year it had the boost solenoid disconnected. When connected, it's an entirely different beast.
I wouldn't even believe disconnecting it takes you to 200hp. From my butt-dyno, disconnected feels like 177-180 and connected it goes into red mist mental mode at what is clearly 235-240hp.

My question is; if you disconnect the boost solenoid power, what does it do with fueling? Does it still fuel correctly by using that area of the map where boost is low? Or would it be tempted to over-fuel?

Reason I ask is because when we got the turbo, it basically hadn't had the boost control solenoid connected for a long time. The post-cat O2 sensor was knacked, and so was the catalytic converter (heavily blocked up).

It is a nice idea actually to be able to disconnect the solenoid for winter etc. So if this can be done safely, it's maybe even worth wiring it permanently with a switch in the dash   s:D s:D    s:D s:D    s:D s:D  

[s12vea]

That's a good question.
On my sp turbo I had a switch with just turned boost controller off. It ran fine, I wondered the same I'm guessing the piggy back ecu adapts when needed.