Boost Control Valve issue- 2.5TD MN

[cameron250f]

Hi all,
After a bit of searching I still haven't been able to find a straight answer to my problem. Anyway, doing a bit of 4wding yesterday around Kinglake in the rain, I initially put the Trito into a bog hole that was about halfway up the doors deep, I got wet ankles but got snatched out OK, I was only in there for around 2 minutes. Car drove fine for the next 2-3 hours then after going up a steep track and having to come back down cos my mate in his Navara couldn't get up, (typical ) I noticed the exhaust note was quite a bit louder than usual. Long story short- I traced it back to the turbo not spooling due to the boost control valve not letting vacuum to the waste gate actuator. Unfortunately I didn't take a pic of the valve itself but I'm sure someone on here knows what I'm talking about. With no tools on hand, (don't judge me, I was 15 minutes from home! ) the first thing i noticed was this-

Corrosion in the plug. Tried to clean as best I could but it made no diff. Plugged the valve back in and gave it a tap with a screwdriver and voila! she boosts! It must've been stuck or had some grit in it or something. MY QUESTION IS- Can I bypass this valve with a manual boost controller or something similar, or has anyone else encountered this problem and how did you fix it? All Ive done to the engine so far is the EGR restrictor and fitted a muffler eliminator pipe.

[Tony]

Best fix would be clean the contacts, make sure the o-ring is intact then use silicon grease to seal the moisture out.

Yes it is possible by-pass the electronic boost solenoid by using a Dawes valve (Full pneumatic boost control) The MAP sensor at the firewall must stay in so ECU is aware or manifold pressure for fuel control.

Stand alone dawes.jpg

[cameron250f]

I was reading the other post about the dawes valve but didn't really understand what it does/ how it works. What is the 'in cab bleed' and why is it needed?

[Cowboy Dave]

It's for on the fly adjustments.

[Tony]

The bleed is optional and it controls the boost rampup rate in relation to RPM. It makes the turbo more efficient under cruise conditions with the stand alone set-up. Also makes boost rampup less savage if running extra fuel with chip or tune.

There is a heap of info on this in the platinum area.

[viking shippy]

The bleed is optional and it controls the boost rampup rate in relation to RPM. It makes the turbo more efficient under cruise conditions with the stand alone set-up. Also makes boost rampup less savage if running extra fuel with chip or tune.

There is a heap of info on this in the platinum area.

Said the spider to the fly.........

[cameron250f]

The bleed is optional and it controls the boost rampup rate in relation to RPM. It makes the turbo more efficient under cruise conditions with the stand alone set-up. Also makes boost rampup less savage if running extra fuel with chip or tune.

There is a heap of info on this in the platinum area.

Siiiighh.... How much for the Dawes valve and bleed?

[brodical]

Would it be a worth while conversion to setup manual boost control on an mn 2.5??

[Cowboy Dave]

How do you propose to do that with an ECU controlled turbo with VGT?

[Tony]

Easy, Remove/bypass the OEM boost solenoid and use a stand alone dawes type valve with optional rampup bleed = full manual pneumatic boost control on a vacuum controlled Variable geometry turbocharger. (MN has electronic solenoid over vacuum in stock form)

Other way is, trim the map sensor voltage (Use a voltage clamp) so Boost solenoid remains open at higher boost and use a dawes valve backing up the Electronic boost solenoid. It wont code as ECU cant see the higher boost. (This method is more efficient)

To see more, go to the platinum lounge.

[cameron250f]

My turbo lag is off the charts so I'm pretty keen to try this out.

[brodical]

Yep what you said tony;-).... And hmmm platinum lounge hmmmm