I have been building my own Manual boost controller (MBC) over the last few weeks, It's almost ready...

After seeing what is available on Ebay, most MBC's are cheap brass valves put together using plumbing fittings!

Whilst they usually perform OK, It's not the sort of thing that looks very nice under the bonnet!

I could also see some improvments to the standard design.

For those that may not know,...

A good MBC features a ball and spring.
When there is enough boost pressure to lift the ball off it's seat, pressure can then reach the wastegate actuator, and the wastegate opens. Because the wastegate opens, this then lowers the boost pressure, so the ball goes back down onto the seat, and the process starts again.
This process is happening very fast and a MBC keeps the boost pressure very steady and at the level you adjust it to open at.

The advantage of MBC's over older bleed style boost controllers, because no pressure can reach and open the wastegate actuator until the ball lifts off it's seat, the boost pressure builds as fast as it can.

Normally this means your car with a MBC will boost up faster than the standard setup which is often a bit tame.

Boost pressure at lower RPM gives more torque.

Even if you set the MBC to the standard factory boost pressure, torque is higher.

Anyway, the MBC I have made consists of anodised alloy, It will be available in a few colours such as blue,red,silver, maybe more.

Inside, as well as the normal ball and spring (my spring is stainless steel), I have also fitted a diaphragm under the ball for perfect sealing of boost (and vacuum if people need to connect the MBC to inlet manifold, normally though MBC's are best connected direct to the nipple on the compressor housing, then other side of valve goes to the actuator).

Also the MBC has a low or high adjustment range, with the low spring setting (will be dispatched in low mode), valve can be set to open between approx 5psi and adjusted up to 15-17psi.
This will suit the vast majority.
By fitting a supplied "nut" under the spring to increase tension, the controller then works at 10psi minimum setting, max is well over 20psi! (of course most cars wont allow boost to ever go this high, as the ECU will trigger the safety fuel cut/boost limiter, unless a Fuel cut defender is fitted)

Finally, to keep the MBC adjuster screw from moving once it's adjusted to your desired boost, and to also stop the valve from getting scratched or knocked about underbonnet, A silicone "protection boot" sleeve is provided to slide over the valve, (also available in different colours to match the valve (or mix colours)

Problem is, I don't actually have a turbo car up and running (yet), so the only testing I have done is using a hand operated Vaccuum/pressure pump and electric air compressor.
It seems to work very well when compared to another MBC I have (thats known to work OK)

Proof though is in the real world testing,

So I'm after someone to free trial it on their car and report back to me.

I'm just waiting on the silcone protection boots to turn up, and then it's ready.

If anygood, the plan is to sell them on Ebay. They will work on any turbocharged engine (petrol or diesel) that use a wastegate actuator to regulate boost (95% of turbo vehicles)

Will put photos up and keep you posted, when ready!

Still thinking of a good product name,
maybe "PocketRocket Boost Control", lol

Thanks for reading,

Nathan Munns

ADDED photos:
http://imageshack.us/g/217/dsc09989h.jpg/