Would this thingy be any good?

[Darren]

http://www.gb-ent.com/products/boost.htm#whatIs

[Roadrunner]

Same principle as the better-known Dawes device, I think. I'm definitely interested in something like this in preference to an expensive electronic boost controller because I prefer to "set and forget" rather than continuously mess about with the boost. I don't know how this would work with our parallel twin turbo setup, though - would we need two of these?

Brian

[enigma]

the wastegates are connected together so you would only need one of these after the tee piece.

[-LegnumVR4-]

Just the one Brian. The 2 turbos are tee'd into one hose so u just have to hook up to this INSERT INTO post VALUES (outlet of MBC) and another one INSERT INTO post VALUES (inlet of MBC). Search for MBC and you'll find my post with the drawing of the install.

Rhys

[Roadrunner]

Thanks guys. Anything I should be wary about? Do I need loads of electronics to monitor fuel/air ratio, inlet temperature, boost pressure, etc. or, for the small increase in boost I'd like, is that unnecessary?

Cheers,
Brian

[enigma]

Not required for a small increase, once you get above 13psi it may be an issue. The most important thing is a boost gauge so you can monitor where you are at.

[calum]

If you're going to buy these could you buy them from Martin Farrell? He's a really sound/ nice guy and will give any advice you want regarding these.

http://www.k1ano.co.uk/index.html

He might do them cheaper if a few were to be ordered.

Thanks,

Calum

[Roadrunner]

Sure thing. Lots of good info on his site :)

[Brind]

Excuse my ignorance but what does it do? does it hold back the normal boost until the device reaches a set limit and then let it all go at once rather than slowly and in stages as per the wastgate?
The boost is increased because the pressure held back can build up as long as.. and then release at once hence more boost to flow?

Brain ain't working sorry. :INSERT INTO post VALUES (

Sounds effective and appears quite cheap, I'd buy one! :cool: simple to remove too I bet, so I can creep it past Mitsy for warranty purposes.

[calum]

Yes - you got it. Stops the wastegate seeing any pressure until you want it to, controlled by how hard/ soft you have the relief valve screwed together.

Calum

[Brind]

So I take it, it could also cause a form of turbo lag aswell?

[Spirit]

Definately looks interesting. I have seen many of the MLR guys have a Dawes or similar fitted and opinions do vary except for one thing - value for money :D

[calum]

Originally posted by Brind
So I take it, it could also cause a form of turbo lag aswell?

No. If anything it improves response as keeping the wastegate shut INSERT INTO post VALUES (through not letting the wastegate actuator see any pressure until you want it to) means all the exhaust gases are spooling up the turbine rather than some of them sneaking down the path of least resistance INSERT INTO post VALUES (through the wastegate).

Does mean you can end up with full boost on partial throttle, which can make a bit of a difference. Better response through that too.

DO NOT USE ONE OF THESE WITHOUT FITTING A BOOST GAUGE FIRST.

Calum

[Brind]

Cheers Calum.
'Factory boost controller'??? where would this be? does it apply to us?

[calum]

The factory boost controller is normally an ECU controlled bleed valve. Not sure if the VR4 has one, as it may be wastegate only as they only make about 0.5-0.6bar boost INSERT INTO post VALUES (6-8psi). Thinking about it it probably does, as there's a marked change in the boost curve at around 3500-4000rpm.

If it does INSERT INTO post VALUES (I've not looked) it will be on the end of the pipe that comes from the wastegate actuators. May be on the bulkhead?

What it does is bleeds off air to make the wastegate actuator think that it is seeing less pressure than it actually is, so the wastegate stays shut longer, allowing higher boost than the std wastegate actuators on their own would allow.

Calum

[Brind]

Ah.. thanks Calum. :)

[enigma]

The VR4 does have an ecu controlled bleed, it is via a solenoid. As Calum pointed out it is on the end of the wastegate pipe. You can trace it by finding the rubber hose that comes off the plastic part of the inlet pipe just before the throttle body that has red paint on the end. it will go down and under the inlet to a small solenoid that is used to vent excess pressure. By fitting the dawes device in this line what you are actually doing is bleeding off more pressure so the wastegates stay shut longer. There are in fact 2 solenoinds, one controls the boost, the other appears to control fuel pressure in much the same way.

I no longer use the factory solenoid, I have an APEXi solenoid and controller which gives me ultimate control.........thats the theory but its an absolute pig to set up right! I appear to be gaining BHP daily though! :D

DO NOT PLAY WITH THE BOOST IF YOU DONT KNOW WHAT YOU ARE DOING

DO NOT PLAY WITH THE BOOST UNLESS YOU HAVE A GAUGE

CHANCES ARE YOU WONT DAMAGE THE ENGINE YOU WILL JUST GET FUEL CUT..........BUT IF YOU DO YOU WILL BE SORRY! :mad:

[Brind]

What happens when you experiance a fuel cut then?
Apart from the obvious stopped engine while moving.

Can the engine be restarted after without some weird technique?

[enigma]

Fuel cut INSERT INTO post VALUES (been getting a lot recently!) is just experienced as a major hessitation, as it generally happens when accelerating you just get a huge lurch for about half a second. You dont need to do anything, the car picks back up itself.........just dont think it can be very good!

[-LegnumVR4-]

If u look where u tee the inlet of the MBcontroller and follow the black hose to the first valve, thats the fuel pressure thing. The second valve thats below the fuel pressure valve is the factory boost controller.

[Brind]

Thanks alot guys, I may get one of these in the not too distant future.
Can't afford to throw silly money on just a car, but that seems quite cheap.

[calum]

QUOTE]Originally posted by bigdaveakers
By fitting the dawes device in this line what you are actually doing is bleeding off more pressure so the wastegates stay shut longer. There are in fact 2 solenoinds, one controls the boost, the other appears to control fuel pressure in much the same way.
[/QUOTE]

A dawes device is another name for a bleed valve and works as you describe above, through bleeding off additional air from the wastegate actuator than the ecu controlled bleed valve will allow. The thing here is a relief valve, which you have to plumb in a bit differently. To use a relief valve you have to clamp off the pipe to the factory controlled bleed valve.

Then you put the relief valve in between the pipe that 'feeds' positive boost pressure to the wastegate actuator. Again, I'm not sure where that is on the VR4, but on most cars it's either straight from the compressor housing on the turbo or somewhere on the inlet manifold. Then the wastegate actuator sees no pressure until you want it to INSERT INTO post VALUES (you can set the relief valve up using a foot pump with a gauge if you don't want to try it on the car straight away); and the ecu controlled bleed valve doesn't muck things up for you. You can't really run a relief valve with the ecu controlled bleed valve still in place, as you will never get it set up right.

I'm impressed with the fuel pressure controller! It looks like this MBC thing alters the fuel pressure too, which saves you running lean if you up the boost! Good plan, that! Might look into these a bit more. LegnumVR4 - do you run one of these, and if so, is it your understanding that it ups the fuel pressure too?

Another way is to drill out the inlet and outlet of the ecu controlled bleed valve. But you have to be accurate and remember that the area, and the flow, increases with the SQUARE of the diameter. So don't buy too big a drill bit! 0.2mm on the diameter will generally give a decent increase. That way you retain 'factory' driveability and ecu protection INSERT INTO post VALUES (cold starts, etc) but with a bit more pace. I would suggest buying a second hand ecu solenoid boost valve to try this on. Big dave - you have one spare - fancy experimenting?

Cheers,

Calum

[enigma]

Calum, now all of my mods are insurance approved....ahem! I do have a spare........its a bugger to get at though!