Dyno diagnostics and dawes valve, is it necessary?

[WA-Waz]

Hi Just a quick one,
I have my car (2002 3ltr Di) at a fuel injection place getting checked over after I had an exhaust, chip and upgraded intercooler fitted. He called and said that the dawes valve is unnecessary and in fact reduces power, possibly significantly? I mentioned that it was to stop boost spiking and that this is a possible issue with these vehicles, which he responded by saying yes it is to stop overboost, but that they don't believe in using them. So should it be removed permanently?

Any advice/comments??

cheers

[4bye4]

Interesting sort of comment. This debate can and frequently does go on forever. I and I think most others believe that the 3ltrs do grenade and that the NADS, of which the Dawes valve is part, does help in extending engine life. Most would also agree that a 2002 motor would be one of the engines in danger of grenading. Without trying to stear the thread into yet another argument on the issues of the three ltr motor, I cannot agree with the guy and certainly would not remove the Dawes valve if it is already fitted, especially if i had done the exhaust and chipped a 2002 engine.
Thats my opinion for what its worth.

[threedogs]

Blocking the egr will also help.
The dawes just takes the thinking away from the ECU I think
Removing and cleaning the intake will also help, you may be surprised
how gunked up they can get. But have a search as there is oodles written on it.
Google Chaz Yellowfoot for more info

[Sir Roofy]

It is interesting as we know it helps with boost when I bought this G U 2002 3l the first thing I did was the Dawes and needle valve
when I cleaned the intake you could just maybe get your little finger in the gunk
I got an extra 4yrs out of that motor before it pulled the pin and with this motor I never hesitated and put it back on beleaving that it
it works once you find that sweet spot just leave it

good luck with your choice

[WA-Waz]

That was my thoughts too about the 2002 being included. I'm after reliability before performance.

The dawes was added and set by my mechanic many moons ago. My only problem with the valve is that when I was installing my intercooler I did wonder if I may have accidentally altered its setting. And without a boost gauge, I wouldn't be able to tell if I had.
(I found the locking nut was loose, so brought that back up to the main section of the unit and then when I went to shift the piping to fit the intercooler I noticed that I was holding the main body and this rotated in my hand. This second time the locking nut was in the same spot so I rotated it back to where I thought it was originally and left it at that.)

[WA-Waz]

threedogs,
I was going to remove and clean the "throttle body" but didn't want to go too far beyond my mechanical abilities or open a can of worms. (which it seems I have... ) I have read a bit on Chaz's build, it is very comprehensive and this is what I was basing a lot of my thinking on. I will have another look at his site and do a bit more research.

[WA-Waz]

roofy, That's a fair call, so it could be a matter of just adjusting the dawes then. I've had a real trouble free run with the GU and I want to keep it that way. What's the ol' saying, "if it ain't broke don't fix it" I think this is appropriate..

[WA-Waz]

Just had a call back from injector mob and the dawes is staying. He found that with it removed the boost went through the roof so he has left it in. This I assume is why it's there in the first place. He was unsure if it meant the turbo was on it's way out or not as it was a very abnormal thing to happen, thanks for the opinions/thoughts guys

[Sir Roofy]

That was my thoughts too about the 2002 being included. I'm after reliability before performance.

The dawes was added and set by my mechanic many moons ago. My only problem with the valve is that when I was installing my intercooler I did wonder if I may have accidentally altered its setting. And without a boost gauge, I wouldn't be able to tell if I had.
(I found the locking nut was loose, so brought that back up to the main section of the unit and then when I went to shift the piping to fit the intercooler I noticed that I was holding the main body and this rotated in my hand. This second time the locking nut was in the same spot so I rotated it back to where I thought it was originally and left it at that.)

Very sensitive the Dawes you can be with in a ciggy paper -on the sweet spot or a friggin mile away
depends on the day I reckon

[muz muz]

maybe the Injector mob aren't familiar with vnt turbos?