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Discussion Starter #1
I have redesigned the system and I have found it to be excellent. I am very happy with the result and now recommend it to others. I’ve posted an explanation and pictures on my website. Dual Stage Boost Control

Transition between controllers is very smooth and quick. The issues brought up before about ECU adaptation can be laid to rest, power outputs are very consistent.


 

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An ingenious but not too complicated arrangement I would say. Full credit to you ERP .
Can you give a more detailoed breakdownn of the performance with and without the 2SBC?
 

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This is really useful. Thanks a lot for sharing all of your hard work with us.

Right, I'm off to make one myself...

Alanb
 

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Discussion Starter #4
I believe that the ECU receives feedback from the Boost Solenoid as it regulates boost. Because of this when a MBC is used in instead of the Boost Solenoid the ECU sees no feedback and retards timing at high rpms. With this setup, the MBC after the Boost Solenoid, the ECU still receives feedback and allows for maximum power at full boost.

So why not just use a MBC after the Boost Solenoid and forget about a dual stage device? I have found that over time the ECU realizes that it is not in complete control and backs off the power at high rpms. With this setup I have found myself letting the ECU control boost about 90% of the time. In the cases when I want more power I switch over to the MBC and get an extra kick in the pants.
I use MBC control primarily during circumstances when I want quick spool up and low-end torque. And with this setup I can keep the MBC in control to redline and still have max power without the typical timing retard that usually occurs with MBC control.

I give an example of a wide open throttle accelerations on my website.
ECU control has max boost at 17 psi. The button is pushed to close the solenoid and the MBC takes over. Boost quickly rises to 20 psi and there is a noticeable power increase.

Eric
 

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Very clever setup, Eric! As per the others, thanks for sharing and letting us benefit from your hard work and tinkering around. I'm definitely going to see about hooking one up for myself in the near future.

Are you going to be at the next PA Saabcentral meet on the 22nd? Since I started a Saab club here at UNC in the past couple weeks, there's one other guy here who's interested and I think we might drive up there. If we both end up there, I'd be very interested in taking a look at your car and seeing how it runs with the dual-stage boost control. Let me know.
 

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Discussion Starter #6
pyronerd - yes I will be at the meet this Saturday. And my offer still stands if you want to stay at my Fraternity, but this time I am about 40 minutes away from the meeting site.

See you Saturday,
Eric
 
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