Dawes and needle valve clarification please.

[Ben81C]

Hi all, been a while since i have posted lots going on in the world, but back to the important stuff, i have fitted a catch can and am currently wondering if i fit a manual boost controller (which i am about to do anyway), does this remove the need for a Dawes and needle valve, or is this still required to provide a mechanical fail safe to prevent over boosting? Its a 2003 3lt turbo diesel. Thanks patrolers.
Ben

[Rusty86]

The Dawes and Needle valve set up is the manual boost control which takes the control away from the ECU. You use these to set the max boost (dawes) and then control the turbo spool up rate (needle), so you will set these up as the fail safe to stop any overboosting problems. Blocking the EGR is also advisable to stop the recirculation of exhaust back through the engine which causes problems.

Probably the best place to look is these pages from Chaz's website. http://www.chaz.yellowfoot.org/zd30_engine_problems.htm and http://www.chaz.yellowfoot.org/Manua...Controller.htm It explains the need and reason for doing the NADS mods, and then detail on how to install and set the Dawes and needle.

Hope that helps,

Rusty

[Ben81C]

Thanks Rusty i think i misread the link you sent the first 10 times i read it. I missed the placement of the needle valve i.e in dash. Which confused the hell out of me. Pays to read carefully before posting an apparently silly question.

[megatexture]

Better off posting a silly question then doing something wrong and costing $ or doing irreversible damage to your rig!
if your anything like me its bloody late when you researching stuff and have to read things twice as your seeing double.

[Rusty86]

The Needle valve can either be installed in dash if you have 2 boost settings or which to change spool up according to conditions on the fly, or installed under the bonnet at a set setting.

Yes as megatexture says better of asking just to be sure, there's sometimes so much info that it gets mighty confusing!

Cheers

[mudski]

I saw this kit listed but it doesn't have the dawes valve. 1St. Would this kit be good to buy? 2Nd. Whers a good place to get the dawes valve? As the same one in the link provided by Rusty86.

http://www.crosscountry4x4.com.au/pr...?productid=274

[boots]

Dawes valve purchase from www.3barracing.com very good mob to deal with .

[mudski]

Er sorry mate. Check out the link I stupidly forgot to put in in my OP. Am I correct saying that in that kit that is the needle valve? As what I would prefer to do when I set my car rig up is have the boost controller in the dash just like what is in the link Rusty has posted.
So the things i need to buy is :

• Boost and EGT gauges
• Catch can
• EGR blanking plate
• Dawes and needle valve
• and about ten years to fit it...

[Rusty86]

The Cross Country kit contains Dawes, catch can and egr blanking plate, no needle. I had enquired and they had had problems with a few client's trucks with setting the spool up rate with the needle valve, so they leave it out and didn't recommend it. They set the Dawes as purely a boost limiter to like 16psi or abouts and leave it at that.

I had initially looked at getting this kit but you can do it for cheaper and better quality buying individual items from different places.

- Dawes from 3barracing as boots mentions approx. $40 shipped to Aus
- Needle from Dependable Distributors in Adelaide $85
- egr blanking plate from Ferret here on the forum $30
- Provent 200 catch can form Western Filters on Ebay for $170 plus another approx $50 for hoses and fittings etc, or whole kit for $300.

I've read that the Cross Country catch is no where near as effective as the Provent which is by all accounts the only way to go. There were reports of the CC catch not catching everything as supposed to. I'm only going on what I've read on this one as I don't have either catch cans, but hearing this about the CC one switched me off the kit and I'll be getting a Provent 200.


Yes, the list of items to get is correct. Search for people's install threads for guidance, there's heaps out there on this forum.

I'm not sure if its advisable running just the Needle valve, you can have this in dash to adjust the turbo spool up rate but the Dawes valve is the one which will control the max boost and with tweaking of the 2, you'll set the required boost at various rpm as mentioned in Chaz's document.

Don't worry, it took me a few months to get boost and egt gauges and almost a year since I've owned the car to finish the other mods (all going well this will be done in the next couple of weeks). I'd definitely get the gauges installed to begin with so you can monitor levels and actually see what's happening, then go about the others mods. Dawes, Needle and egr block should be done together as you shouldn't need to mess around with the vnt screw on the turbo which you would need to adjust if you did the egr block by itself (which may cause overboosting problems).

Hope this helps,

Cheers,
Rusty

[Ben81C]

I have spoken to a few trusted mates some of whom are mechanics including the diesel specialist i use (who said they used to fit Dawes and needle valve but not any more) and some are just car nuts, they all say the same thing, and that is that they cannot work out how the Dawes valve could stop over boosting, they all say over boost is caused almost exclusively by the waste gate failing or as was explained to me today by the bloke i ordered my boost and EGT gauges from that u can think of overboost as a shop with a front and a rear door, say you can only have 6 people in at once (say 6psi) with standard boost control, as the 7th person (or 7psi) enters the shop, at this point the door at back (ie wastegate opens) and the first person (or psi) exits the rear and only 6 remain inside. However there can be a delay from when the signal to open the rear door (wastegate) and when this actually happens (ie open wastegate) and this is where the problem begins as 7,8,9 and so on can be forcing there way through the front door as the rear door is trying to open, they cant get out before more come in and presto over boost.
Every single person i have asked has said no you need to install an electronic boost controller as they actually take proper control of the waste gate by monitoring and controlling boost and take into account the pressure building via exhaust? What is the go?
Also i showed the people i asked the install diagram from this site and they all scratched their head in confusion as to how the Dawes valve really does much at all with regard to over boost? I am now confused as every one here says there great but i cant find any body else who will fit one or even knows what their purpose is, i am seriously thinking of going for the electronic boost control over the Dawes valve.