Manual Boost control on Fleabay

[MPBVr4]

Tis' a bit strange I've bench tested the R spec one and the "release" pressure can be varied down to about 4 psig with threads to go. When I unscrewed to the limit the ball just floated about and didn't hold any pressure at all.

[aboo]

The mbc I installed is the one off ebay & looks the same as the one at the start of this thread.
Could it be a faulty mbc?

[MPBVr4]

Wouldn't think so. There is nothing to go wrong. There is only a spring with ball inside. Just make sure you've connected the pressure source from the inlet to the connector opposite and in line with the adjuster screw. The right angle connection goes to the wastegates.

You can check the ball isn't stuck by unscrewing the adjuster the ball and spring will fall out if it's OK. Don't lose them!

[aboo]

so the right angle should be pointing to the bottom of the engine?

If it was on the wrong way round would'nt I not get a reading

[aboo]

Got it.
It was on the wrong way round (dafty) but still a bit high sitting at 16psi & cant reduse it any more. still getting fuel cut but not as bad.

Dont know if I'll leave it on cause I dont want to do any damage.

[tolcol]

Got it.
It was on the wrong way round (dafty) but still a bit high sitting at 16psi & cant reduse it any more. still getting fuel cut but not as bad.

Dont know if I'll leave it on cause I dont want to do any damage.

I had the same problem when i installed my MBC, there weren't enough threads on the thing!
I was hitting 15psi and fuel cut immediately with the screw on the last thread.
I just took out the spring and cut one rung off, flattened the cut piece to try to maintain the straightness and to stop it from catching in the threads, then started again with my adjustments.
10 minutes later i was running 12.5psi with spikes to about 14 or 15psi.
No fuel cut just lots of fun!
I don't know if this is an accepted fix but it worked for me.

[madmac]

I was thinking about fitting a Dawes device to my recently purchased Legnum. It already has a boost guage showing 0.7bar at full boost. What's the general consensus with increasing the boost? Will the standard map be able to cope with going up to 0.9bar? What boost would I expect fuel cut at?

Any info appreciated

[MPBVr4]

Yep 0.9 Bar is the accepted max safe boost on a VR4 without incurring the wrath
of fuel cut.

[bigoxo]

What's the general consensus on disconnecting the battery for a few mins to let the car start 'learning' again after this mod?

Also, i presume the 'red clip' is the boost source end and the wastegate actuator is at the other end.