Dyno diagnostics and dawes valve, is it necessary?

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

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.

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

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

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.)

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... :biggrin: ) 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.

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..

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

Quote:

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Originally Posted by 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.)

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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

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

too true about the dawes sweet spot.

Seems that they maybe unfamiliar with ZD30s, dawes valves and VNT turbos?? :wink::wink:

Time will tell really, they are happy to "fine tune" so we get a good result, so I can't complain. One thing I have found since, is that it seems to be quite slow in 1st and 2nd (lower rev range). I know that it has never been a ball tearer off the line, but I would have thought that with mods made and a tune that this would have changed and I would have had some sort of performance increase in this area????

Quote:

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Originally Posted by WA-Waz

Seems that they maybe unfamiliar with ZD30s, dawes valves and VNT turbos?? :wink::wink:

Time will tell really, they are happy to "fine tune" so we get a good result, so I can't complain. One thing I have found since, is that it seems to be quite slow in 1st and 2nd (lower rev range). I know that it has never been a ball tearer off the line, but I would have thought that with mods made and a tune that this would have changed and I would have had some sort of performance increase in this area????

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Couple of things ,,,what size tyres are you running and at what pressure??
When was the last time you had the MAF sensor cleaned, ??
I think mine goes great off the lights......do you have the needle valve fitted.???

Quote:

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Originally Posted by 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

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I had a little chuckle to myself reading the mechanics opinion. I would think they are just not familiar with the dawes function and variable vane turbos. Reminds me of a comment a local mechanic said about blocking the egr. He said you will only damage your motor blocking it. A big lol from me on that one.
Fitting the dawes is only half the job. All it does as mentioned, is limit boost. So not a lot of performance gain will be had by just that. The needle valve is where the performance gains are made mostly. This adjusts the spool up rste of the turbo in a nut shell.
I know for a fact when i had the ZD30, after i fitted the dawes and needle valve, i decided to remove them and go for a spin and notice what the boost and egts were doing. I reckon i got about 5ks before i turned around and refitted the valves. The motor ran no way near as good without the two valves.

Sent from my SM-P600 using Tapatalk

I have 33" Mickey T MTZs (285s) on it running at 36psi. I would expect a reduction in overall power output because of running these(?) Its funny you mention cleaning the MAF as I did this when I installed the new intercooler, and after doing so and having the results I did, thought I had broken it... no I don't have a needle valve, it wasn't offered when the dawes was fitted.

When adding intercooler and catch can I thought it would be a good idea to swap the MAF housing for one from HP Diesel. Looked bling and I thought it's only a bit of tube, oh how wrong I was. It seems that this was causing me a great deal of trouble. It was causing the huge spikes in boost apparently. Not sure why, maybe caused the MAF to misread or something like that? The injection mob took out this housing and put back the original and the car went back to having a much smoother boost that maxed out at 18psi without the dawes. The car is back to driving as it was drivability wise and the performance seemed to be how it was plus some after having the exhaust and chip done. It's now sitting on 80kw at the rear wheels, which probably isn't a lot but is still a huge increase from where it was.

As for dawes and needle valve, I didn't realise that the needle valve was such an important part in the whole scheme. I didn't really want to know either to be honest... as I thought it was best left to the pro's.............

For my own interest I think I will look into it further though, just can't help myself... and I'm sick of wasting money :icon_bonk:

When I ran 305 MTZ's the mighty patrol was slow off the line even with 40 psi.
I don't run them now. You'll need to fit a needle valve to control your spool up rate.
Not a huge cost, give Mudski a PM and talk to him about it.
When it warms up i'll be fitting a bigger intake,,,lol

Just a tad bigger :-)
Went for a drive in the country over the weekend, so gave the old girl a good run. started off okay, but I found that it kept going into limp mode. I'd be sitting on 100 and if i applied a bit more of the loud pedal it wouldn't respond at all, until I took my foot off and put it back on again. I found it did this at 80, 90, 100 & 110km. My first thoughts are get the chip removed my second thought is get my hands on that needle valve mentioned earlier and put the dawes back on.

On its own would refitting the dawes set at about 15psi stop the car from going into limp mode or is it the spooling up too quickly that would be causing the issue?? I'm getting in contact with the chip installers today to try and clear things up.

Quote:

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Originally Posted by WA-Waz

Just a tad bigger :-)
Went for a drive in the country over the weekend, so gave the old girl a good run. started off okay, but I found that it kept going into limp mode. I'd be sitting on 100 and if i applied a bit more of the loud pedal it wouldn't respond at all, until I took my foot off and put it back on again. I found it did this at 80, 90, 100 & 110km. My first thoughts are get the chip removed my second thought is get my hands on that needle valve mentioned earlier and put the dawes back on.

On its own would refitting the dawes set at about 15psi stop the car from going into limp mode or is it the spooling up too quickly that would be causing the issue?? I'm getting in contact with the chip installers today to try and clear things up.

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When you fit needle valve and dawes, the flow through the MAF housing accelerates, and the MAF sensor thinks there is a problem, hence limp mode. I fitted an HP Diesel housing (bigger tunnel) and fixed the limp mode.

Hey Dr Gary,
I had the same MAF housing fitted and apparently it caused the boost to spike through the roof. So it was suggested to pull it out, which they did and it seemed to settle it down? Maybe that also needs to go back in but with the addition of the needle valve to control the spool up rate of the turbo. I think the missus is gonna kill me buying extra stuff :wink: definitely don't want to do half a job though. LOL

with the egr blocked and a dawes an needle fitted "YOU" will be controlling the boost.
I take it you have a boost and EGT gauge fitted, at this price buy one as they are normally $60 Plus.
At least with it you can run a line into a gauge on a temporary basis
http://www.ebay.com.au/itm/Quick-Fit...IAAOSwsB9WDzLX

What chip and what is it set on ????
Dis-connect your battery, overnight if possible but 1/2hr is OK
that will re-set your ECU memory

No I don't at the moment, and I understand that these are necessary items. I have put in an aftermarket intercooler of the HP Diesel variety which has a port for the dawes/boost gauge.

I'm running a DP Chip and Redback 3" exhaust, the chip is currently set to 4.

G'day WA-Waz
I wont ask which "Injector Mob" you went to, but

if you get the time, swing by United Fuel Injection on Gt Eastern Hwy
go up towards the back of their workshop driveway, and ask for Matt Craig

he will be able to setup your system again so it is running sweet, take your HP Diesel thingy with you, and he would probably re-fit it
he has forgotten more about 3.0L than most "mechanic's " already know

(disclaimer - I dont work there, but I have used them, and found them to be very very knowledgeable)

Yeah okay, probably should have gone there in the first instance. cheers

not to worry mate,

geezz, it took me 5 years and about 10 mechanic's to find one who could tune a Gas / Petrol car years ago..............

take it in with no petrol in it - cause I wanted it tuned in gas
get the bill - "umm, why have you charged me for $5.00 worth of Petrol......????"

"well, we had to put petrol in to do the tune up sweetie....."

"umm, what part of tune the Gas as it does not run in petrol, did you not quite understand....................?"


as I said, sometimes it takes awhile to find the right person to do the job properly 1st time...........

hahaha sorry I shouldn't laugh but I can definitely relate :-) Its finding someone with the right experience in my vehicle and with what I'm trying to achieve. Most talk the talk, but walking the walk is another thing entirely. :smiley_thumbs_up:

,,,, I find having the DP chip on 9 tends to blow some black smoke
but you can feel it runs better,,,,,,,, But I've settled on 5 for towing and overall driving.
No smoke and plenty of power on hand. very pleased it may even be on 7 but no higher
IMO 4 seems a bit low but each motor is different, Id go to 7 and see what that does for you

Hi all,
Well I had my three weeks away with no dramas as far as the car went. As Big col suggested I contacted United Fuel Injection and spoke with Matt Craig, who despite having a full schedule found room to fit my car in to be looked at.
Within a very short amount of time he had it all sorted and the car has run perfectly since. They even found a bit more power out of it for me.
I couldn't recommend them enough.
:animierte-smilies-t
p.s. dawes refitted and adjusted