Bambam7

Man... I love it.. there are all the 600 dollar boost controllers out there, that essentially don't work any better than the homemade grainger valve (ballvalve)!

Anyways.... I'm going to be installing a cheap MBC soon... but with a twist.
I've got the leftover VDI solonoid that I'm not using any more. I have the VDI actuator plumbed right to the manifold.... so whenever it gets a bit of pressure from the turbo, it just opens up... a lot earlier than stock, but it's still better than just locking it open... gives me a bit better low end, before the turbo spools.
Anyways.. back on topic....
I'll be hooking up the MBC, but also hooking up a vacuum line bypassing it- with the solonoid in it...
This way.. with the solonoid open, the MBC is bypassed... giving stock boost, and best relability and driveablity. But a flick of a cockpit mounted switch closes the bypass, and puts the wastegate signal through the MBC, set at whatever boost I want (probably about 11 lbs)
I could even set it up with a WOT switch too...
Why havn't more people done this??

White_FC

Funny you should post this, I'm going to be doing something VERY similar to this, I'm also doing a N/A-Turbo conversion aswell!

$100T2

iTrader: (1)

When you finish the write up, I'm sure we'll all jump on the bandwagon... If I knew how to do it, I would have already... Sounds like a great idea, let us know how it turns out.

von

your full of great ideas...thnx for the VDI input...When does it open aproximatly. 0-2000 then open would be great.

Bambam7

It theoretically opens with 2.8 psi (according to the manual)
I see that by about 2200 rpms. It would be nice to be able to delay the open later.... easily enough accomplished with just a simple bleed off hole/check valve on the VDI actuator line.

Now, who knows where the optimum point would be for switchover would be, since the intake pulse dynamics would be totally different with the compressed air.
It's not really too important anyways... I'm not going to fiddle for such a smalla mount of HP.... I'm sure if the system netted more than a few HP on a turbo car, they would have used it!! The intake air is already being forced in..... It's just good to have it in the low position for a little extra kick, and spool up assistance in the low end.

Here's a simple diagram I drew in 30 sec to illustrate the dual stage boost controller....
The controller is just a simple ball valve version.. make one yourself, for about $10, or get one from places like dawesdevices.com.. 40 bucks.

scathcart

They have. They're called two-stage manual boost controllers.

I have a friend with a starion, and I just designed the exact same set-up for him.

The reason it's not the best set-up is b/c you don't have the boost pattern that a MBC provides when the solenoid is open.

von

Bambam7 ... Great idea but just incase you didnt know or want a little extra power I found out this

Sports compact magazine I think had a shootout with 10 different boost controller all new...Turns out that the ball valve had the most lag as well as the most spiking.

The blitz , profec b and AFC were all in the top spot. The AFC was the hardest to tune thou. THe blitz was the easiest but was pricy. It also has the best power curve out of the top three and less lag. The rest were not great and couple were bad...The profec seems best for the money my .2cents

Aaron Cake

iTrader: (1)

Fancy electronic boost controllers ARE actually worlds better then manual units. Easier to adjust, not as touchy, many different "stages", etc. I thought about going with a manual unit, but I don't think I want to waste my time...

How's your engine?

Snrub

iTrader: (1)

Why do you think they're a waste of time?

Could you give us an indication of how much lag and spike compared to the others?

Bambam7

Ya.. I have that issue!
The Greddy Profec A, and the HKS EVC had a horrible boost spike prior to opening... When set to 16 psi, the greddy spiked up to well over 20!

The MBC looked to perform just as quickly as the others, but began to suffer from boost spike when set to over 15 psi...... Not a problem for me.


BTW, OK, You don't get the benifits of the quicker spooling in stock mode.... well, that's why it's stock mode! Ya Ya... I know......
If you want that quicker spooling, with stock boost, just buy/make another grainger valve, and put it in the bypass where the solonoid is, and adjust it to stock levels!

Cheers!

bambam 7... u should try the profec B or the apexi avcr

the profec A uses fuzzy logic that tries to learn your boost curve... which it can't since the stock turbos always creep when u start modding them

Snrub

iTrader: (1)

Wouldn't selecting a spring better suited to high boost cure some of that problem? (ie. stiffer)

Aaron Cake

iTrader: (1)

They're very "twitchy". I'm not sure I want something "twitchy" controlling my wastegate. Also, I like the programmability of the electronic boost controller. The ability to run two different boost curves is something I would find very useful. In addition, I would have to go under the hood to adjust a manual boost controller, then make a run and see if it needs more adjustment, then make another run, adjust, run, adjust, etc. With an electronic controller, I just set "10 PSI" and as long as my wastegate is happy I get 10 PSI.

The Apex'I AVC-R also displayes a whole bunch of extra info, like exact boost pressure, injector duty cycle, etc...

But it may just be a matter of opinion, and we're comparing a $6 part to a $600 part.