Dual Stage Boost Controller with 2 USER Selectable Levels!

[BXSS]

So, after installing my IC, vf10 and 440cc injectors I found myself driving around town... a little fast... and maybe... always in boost lol... at about 15lbs, that, uh... DRINKS gas.

So I wanted to create somthign that would let me switch between Low Boost and High Boost whenever I wanted. Someone posted about doing something with a MBC and Wastegate Boost... But honestly, wastegate was lower than what I wanted for my Low Boost setting, I wanted to be able to switch between my MBC and the Stock Boost Controller.

So here is a diagram of what I created.



The Solenoids are from a 1st Gen Legacy. You can get them from a JY, it takes on 12mm bolt to get them off, they are mounted right below the passenger side intake runner and hookup to the Charcoal Canister... I believe they are called Canister Purge Solenoids.

I had created the Diagram awhile ago, then i built it 3 days ago and have been using it around town...

ITS AMAZING!! I love it... getting about 23 mpg on Low Boost. And killing Hondas on High!

So the Low Boost Setting I'm running 8.7psi
And on the High Boost Setting it runs at 16psi

The only warning for anyone wanting to do this... If you accidently leave the switch in the middle, off position... You will have NO boost controller connected to the Wastegate.

So make sure that you dont do that and your good!

What I'm going to do is put two lights on the dash above the center vents, one Yellow/Orange for Low Boost and one Green for High Boost. That way you know if it isnt sending proper signal to the Solenoids.

The above is basically the 2 stage set-up I figured out & had SubaruNation post up a while back using the OEM boost solenoid as the the base boost level rather than the actuator.
http://bbs.legacycentral.org/viewtopic.php?t=36506

I actually said my set-up could be improved upon with more solenoids / MBC's but I was thinking 2 MBC's & 2 solenoids on a 3 position switch that would give you 2 boost levels you could SET (10 & 15 PSI, 12 & 20psi).
To get this done -
Basically just replace the stock boost solenoid in the above diagram with a MBC & plumb in a charcoal canister purge solenoid as shown.

NOW You'll have 2 user selectable boost levels to choose from.

On TD05s or TD04s with 8-9psi actuators my old set-up & the above slightly improved set-up are basically the same - which is why I never used the stock solenoid for a base boost level as I was on a TD04 when I figured the whole CHEAP/Free 2 Stage thing out...

BUT

Good thinking on the stock solenoid idea any way - good for the VF11 guys!

I'm currently on a old HKS EVC which gives me 4 stages of boost, actuator level as a base & 3 levels I can select (off, low, med, hi) so its up to you guys to try this out & improve on it!

[smh0101]

I'm wondering how the stock system would work with the turbos with the 8-9psi wastegate... Because I the stock solenoid opens and closes based on what the MAP reads. but I'm not sure... I'll test it when i get my vf41 (yes... you heard vf41).

[BXSS]

I'm wondering how the stock system would work with the turbos with the 8-9psi wastegate... Because I the stock solenoid opens and closes based on what the MAP reads. but I'm not sure... I'll test it when i get my vf41 (yes... you heard vf41).

From what I understand it tries to maintain the 8.7 psi target it can't if the actuator is a 9psi one but it still tries. I suspect the duty cycle goes crazy when it tries to keep boost in check & it may overboost a smidge until it learns what to do.
This may or may not be correct as I eliminated the boost solenoid when I did the 2 stage thing & internet info is shaky most of the time.

I'm gonna upgrade turbos soon as well to either a 16G off a EVO III AWD/drivetrain conversion we just finished on a Mirage, or the clipped/ported TD06-20G/TD05 hybird that I'm having built right now, flow will be 550-650CFM depending on the turbo - I'll need more injector!

Good luck with the VF41, I had a VF23 that I dumped in favor of a 16G not knowing it was "rollerbearing" I wish I would have tried it out to see how it compared to the 16G on the road....

[smh0101]

I wonder... Would it be possible to swap the wastegate spring in one of the larger turbos for a vf11 6lbs wastegate...

That way you could more easily maintain the stock features. It does some cool thinkgs with boost on cruise control... IE limiting boost and stuff

[BXSS]

Well you could always adapt the VF11 actuator to work on another turbo (some bracket-making + cutting / welding my be needed).

[gijonas]

Just curious,in the diagram shouldnt the MBC be shown downstream of the purge?? seems to me that in the position shown it would have the same effect on either circuit regardless of which solenoid was powered.Also I think you mean to say 3 terminal switch not 3 position.

[smh0101]

Your right on the position of the Solenoid. But I meant what I said on the Switch.

[gijonas]

The switch only has two output circuits no?? i realize there are three wires,one being the supply but what would the 3rd position do.If 3rd position does nothing i think it still would be a 2 position.Oh well not important anyways,despite my criticism i will be doing this more than likely

[BXSS]

3 Position switches have just that - 3 positions p1-off-p2 (? if some are off - p1 - p2), while 2 position switches have 2 positions/choices off - on.

[gijonas]

Note to self:

3 Position switches have just that - 3 positions p1-off-p2