“Back pressure” Manuel Boost Controller

[Trolkar]

Hi guys!

After having some problems maintaining the boost level at high speed, I have installed a Manuel Boost Controller.

Before, the boost pressure when accelerating from 0-140 km/t was around 1.0 bar between 0-90 km/t and at 90-140 around 0,8 bar.
But when traveling at 110 km/t and then accelerating “hard” but still in 5 gear the boost pressure was only 0,3 - 0,4.

After installing the MBC, the boost gauge shows peaks around 1,8 bar when accelerating in 3 gear, and easily hitting 1,3-1,5 bar when accelerating in 5 gear at 110 km/t.
Of cause, I let go of the throttle instantly at those readings.

However, in my opinion this is not possibly with my current setup with standard turbo.

I therefor search through the web, and found this video on YouTube.

https://www.youtube.com/watch?v=w0lxBJ4k8mk

At 2:50 – 3:45 in the video, it states that the boost showing on the gauge is much higher, than the actually boost level.

I do not want to ruin my car, and would like a steady 1.0 bar at max. – But how do I get that?
If I turn the nob, so the gauge is showing 1.0 bar, it reached 100 km/t at around 8 second. Telling me, that it is not “enough pressure”.
I have checked the gauge with my compressor, and the readings is fine.
My installation is the same as on the video.
Help or comments is appreciated.

Alternatively, is the best way to simply by a Tactrix 3 ports plug and play? – Or other?

http://www.tactrix.com/index.php?option=com_virtuemart&page=shop.product_details&product_id=20&Itemid=53&vmcchk=1&Itemid=53

[Davezj]

My guess is you have connected it wrong and the wastegate actuators are not seeing any boost pressure, so giving you absolutely max pressure the turbos can give. Just like if you disconnect then completely.
I have bought one of these MBC before and they are real crap if it is one of the £12 versions.
Many people have said they have fitted this type of mbc correctly but most have not.

My version of this mbc did not work at all it was so badly made with swarf and globs of paint on the inside of the mbc it was blocked. It have max boost all the time.

I threw it away and bought a mbc that worked.

As for the 3 port boost solenoid this will not do anything for you with respect to boost control unless you can reprogram your ecu. If you have standard boost pressure set in you ecu changing the boost solenoid will not change the boost pressure.

[Trolkar]

What did you bought?

[Subaru ETA]

Turbosmart do a very good one.
You are wasting your time trying to get a steady 1 bar as you just won't, especially using a MBC

[Davezj]

What did you bought?

I ended up buying an EBC so I can change the pressure as and when I want to from within the car. It took a little bit of playing with to setup but it works great.
I can't remember the name off the top of my head but it was only £100.
Turbo smart is quite a good mbc as stated above and I did have one, but I let someone borrow it and never got it back, and I can't remember who I loaned it to.
But the turbosmart one I had cost about £60. elnevio nev's bought a very good mbc for less and found it to be very reliable he can tell which type he bought. I am sure he will read this post and respond.

But this topic has been covered many many times before and a bit of searching will come up with the bad and good mbc (daws device).

[elnevio]

I got one from 3 Bar Racing in the States. Home of the original Dawes Device. :)

The Dawes Device website is the place to get one now, at http://dawes-devices.com/collections/turbocharged-automobiles/products/dawes-devices-mk-ii-hybrid-boost-controller

I had excellent results with mine, no spiking, just lovely smooth boost! :)

[Z-Kev]

I have a dawes device with the ceramic ball bearing, cant fault it, holds boost well , very small boost spike of .1 bar for less than a second on WOT gearchanges.

[Trolkar]

Problem solved for now/woot2

It turned out, that the ”cheap crap” had the labels done wrong. – Therefore, the “T” piece with a one-way valve did not allow air to pass to the waste gate, causing the boost level to peak a 1.5 bar.

I have turned the “T” piece around, and it now boost 1,1-1,2. For an extremely short time, it may hit 1.3.

And it holds the pressure between 0,9-1,1 up to 130 km/t. (Haven’t been able to test on highway yet)

Therefore, for now, I am happy. – But the thought of a “cheap thing” in my engine bay is killing me.
Should I buy a Dawes MBC or the Tactrix Solenoid? – OR just accept the fact that it is working for now?

[Nick Mann]

It's a bit of a personal choice. Personally I have a 3 port solenoid controlled by the ecu.