Dawes valve, egr block for a dummy with a crd

[rottodiver]

I know I know.... This topic has been done to death , I have read and read all about it.... Just about every topic about Dawes valve and egr blocking gets answers from almost all engine types and it confuses the hell out of me.
So a simple question for those with the knowledge on crd,s
If I install a Dawes valve and block the egr( both of which I have sitting there ready to do) do I need a boost control needle(or alike) or is it still controlled by the ecu ( which is my preference) as I understand once egr is blocked the ecu doesn't control the boost or is that on the di, and not the crd?
I know about the need for a hole in the egr( have scan gauge )but might tempt fate without it, do I need gasket or some sort of sealant for both sides of the egr plate if not which side do I place the original gasket( engine side or exhaust side?)
And if anyone has any photos of the Dawes valve done a crd it would be much appreciated.
For the record.. The boost I am currently getting on my scan gauge is 16psi tops but see the needle on my pod guage quickly spike to 18 ish for milliseconds so not sure which is correct and once I block the egr I expect things to rise.

So basically I am after dedicated info for the crd,s as this is really starting to confuse me.

Thanks Scotty

[Fry]

With regards to the scangauge boost readings I would only use it as a guide and trust your pod gauges more. I have never seen my scangauge go above 16.2PSI but I dare say that my CRD has boosted over that but I Don't know as I don't have a normal boost gauge yet.

After the reading I have done it sounds like if you do one may aswell do the others. (have to do?)

[mudski]

All the dawes valve does is limited your maximum boost. Using a needle valve in conjunction with the dawes will let you control how fast the turbo will spool up. Its not really needed to use the needle valve but you may find acceleration a bit sluggish. Using a needle valve will improve your acceleration.

[rottodiver]

Ok Dawes valve installed... 15 1/2 is the max it seems to reach now.. 2000rpm around 10-11 psi ... Do these numbers look right or do I need to wind it out more...
What damage can be done if not wound out enough?
Still got to do the egr but might get used to these numbers first..
Scotty

[threedogs]

sounds about right they are not big boosting motors, it may spike over to 20 now and again.
At 100Ks you'll need 10 psi boost as a rule of thumb which is roughly 2000rpm

[Rumcajs]

When EGR opens the ECU reduces the boost so if you are planning to "shim" it there is no point/makes no sense to retain factory solenoid control.
So the pictures are worth thousands of words look at the following pics bellow.
They show what happens when you retain factory boost control. BTW fitting just Dawes valve on CrD makes absolutely no sense.
First pic shows factory boost control (pay attention to EGTs when boost drops off) the boost is all over the place
Second pic is the same scenario (driving) but this time with needle valve and factory control bypassed. Boost is much smoother, linear and with much better torque and power delivery.
These graphs are from Di but CrD boost control solenoid principle is the same.
Cheers

These pics were kindly pilfered from this location --> P4x4.com Boost drop, EGTs rise help (http://www.patrol4x4.com/forum/zd30-di-engine-3-litre-71/boost-drop-egt-rise-help-133666/)

[rottodiver]

Ok so this is what I have noticed today after doing a bit of driving around and hwy driving(100km/h) with my Dawes valve installed( still not sure if I should have installed it) yes my egt was up a little bit but settled down at hwy speed, yes the boost does still jump around a bit and hard to get an exact reading of what boost I am getting at what speed but it is now not going over 15 1/2 psi which I believe was the whole point.... I was getting 18,s( if the gauge was reading correctly).
Does anyone know what happens if my boost is too low? Is it just the rise in egt...
Now the question is to shim the egr or not, is all this just a waste of time because it is crd?
I do appreciate the gragphs but I would like to see one for crd as it is my understanding crd ecu controls boost better that di,s

Scotty

[Jimbo4x4]

I have just fitted a egr block to my crd about 3 weeks ago, So far the boost hasn't changed max boost of about 16psi on pod gauge and the fuel economy seems to be about the same around town, haven't had a chance to do a motorway test yet. But i have noticed egt are a little lower at 100kph , just under 350" I did drill a 10mm hole in the blank plate before fitting ! and so far no error code :-)

[rottodiver]

I have just fitted a egr block to my crd about 3 weeks ago, So far the boost hasn't changed max boost of about 16psi on pod gauge and the fuel economy seems to be about the same around town, haven't had a chance to do a motorway test yet. But i have noticed egt are a little lower at 100kph , just under 350" I did drill a 10mm hole in the blank plate before fitting ! and so far no error code :-)

Thanks jimbo,
Do have have a chip and exhaust upgrade( I run a 3 inch exhaust and tunit chip) or Dawes
Scotty

[Rumcajs]

Ok so this is what I have noticed today after doing a bit of driving around and hwy driving(100km/h) with my Dawes valve installed( still not sure if I should have installed it) yes my egt was up a little bit but settled down at hwy speed, yes the boost does still jump around a bit and hard to get an exact reading of what boost I am getting at what speed but it is now not going over 15 1/2 psi which I believe was the whole point.... I was getting 18,s( if the gauge was reading correctly).
Does anyone know what happens if my boost is too low? Is it just the rise in egt...
Now the question is to shim the egr or not, is all this just a waste of time because it is crd?
I do appreciate the gragphs but I would like to see one for crd as it is my understanding crd ecu controls boost better that di,s

Scotty

Look, laws of physics apply, you'll need to lower the boost to be able to feed exhaust gases back in to intake. Low boost equals high EGTs = bad news for diesel engine. Yes, ZD30 CrD engines are much better at handling higher EGTs than Di but that doesn't mean that it is good for them in the long term.
CrD control system is much more sophisticated than primitive/rudimentary Di control. Boost of 18 psi is normal on CrDs.
CrD not only uses MAF but also MAP and MAT to correctly calculate optimal AFR. (not really doing a great job there though)
Again that doesn't mean Jack if you are feeding crap down your intake mixing it with oil vapor from crankcase ventilation layering the intake manifold and restricting the airflow.
This has consequences in reduced engine life and increased maintenance costs including fuel consumption. So if you are planning to keep Patrol for 4 years (or while under warranty) max on lease like plan than don't bother fiddling EGR, Dawes, boost control EGTs what not.

Current emission control tech punishes you the consumer with higher costs and reduced reliability. Basically car makers are making it your problem while handsomely profiting from it by selling you crap cheap technology which makes you to fork out more and more often. Its a win for them and oil companies because these techs also increase fuel consumption.

You want to effectively reduce emissions you need to reduce fuel consumption. You will reduce it by making the engines more efficient and powerful at the same time while reducing their size.
So variable camshaft timings or even camless engines, variable hybrid turbo compound chargers, cylinder switching off technologies, water injection etc.
Instead of outdated technology which costs users fortune like DPF, SCR, EGR, AHI and whatever these assholes would do anything but making better efficient engines.
Did you know that common rail diesel injection patent was applied for in 1911. It took 80+ years before we started using that technology, for Nissan even longer they started putting that tech in their ZD30s in 2007 :icon_bonk:

Its your choice. There is no point for Dawes valve alone on CrD. ECU has the boost under control quite well. There is a point for Dawes and needle valve if you want better torque down low, improve power delivery and tractability.
Would I do it on mine if it was CrD, hell yeah. The difference is phenomenal on Di so it will be even better on CrD me thinks I'd at least try for the cost of it. ($150)
Have you ever wondered why CrD has the same power and torque output as Di. It makes no sense when D40 2.5L (Navara) has more power and torque than 3.0L.

[rottodiver]

Look, laws of physics apply, you'll need to lower the boost to be able to feed exhaust gases back in to intake. Low boost equals high EGTs = bad news for diesel engine. Yes, ZD30 CrD engines are much better at handling higher EGTs than Di but that doesn't mean that it is good for them in the long term.
CrD control system is much more sophisticated than primitive/rudimentary Di control. Boost of 18 psi is normal on CrDs.
CrD not only uses MAF but also MAP and MAT to correctly calculate optimal AFR. (not really doing a great job there though)
Again that doesn't mean Jack if you are feeding crap down your intake mixing it with oil vapor from crankcase ventilation layering the intake manifold and restricting the airflow.
This has consequences in reduced engine life and increased maintenance costs including fuel consumption. So if you are planning to keep Patrol for 4 years (or while under warranty) max on lease like plan than don't bother fiddling EGR, Dawes, boost control EGTs what not.

Current emission control tech punishes you the consumer with higher costs and reduced reliability. Basically car makers are making it your problem while handsomely profiting from it by selling you crap cheap technology which makes you to fork out more and more often. Its a win for them and oil companies because these techs also increase fuel consumption.

You want to effectively reduce emissions you need to reduce fuel consumption. You will reduce it by making the engines more efficient and powerful at the same time while reducing their size.
So variable camshaft timings or even camless engines, variable hybrid turbo compound chargers, cylinder switching off technologies, water injection etc.
Instead of outdated technology which costs users fortune like DPF, SCR, EGR, AHI and whatever these assholes would do anything but making better efficient engines.
Did you know that common rail diesel injection patent was applied for in 1911. It took 80+ years before we started using that technology, for Nissan even longer they started putting that tech in their ZD30s in 2007 :icon_bonk:

Its your choice. There is no point for Dawes valve alone on CrD. ECU has the boost under control quite well. There is a point for Dawes and needle valve if you want better torque down low, improve power delivery and tractability.
Would I do it on mine if it was CrD, hell yeah. The difference is phenomenal on Di so it will be even better on CrD me thinks I'd at least try for the cost of it. ($150)
Have you ever wondered why CrD has the same power and torque output as Di. It makes no sense when D40 2.5L (Navara) has more power and torque than 3.0L.

Wow.. Some great info, I do t really understand how to use the needle valve, do you have to continually adjust it, does it just boost at the same psi all the time? How does the needle valve actually work.... I am pretty keen to give it a go..
Thanks again
Scotty

[Hodge]

Bloody hell. This Rumcajs bloke just answered a crate of questions I've been pondering for a long time, in a single shot! You seem to know your stuff mate ... First time I've ever seen a bloke here, use a graph to prove a point. And it absolutely made sense. Hats off to you buddy. :049:

I've got my gauges fitted a week ago, so I'm monitoring what the engine is doing, before I apply the NADS. I've scored the whole CRD Nads kit from Mudski a while back, but really haven't had time to toy around with it till now. My trol needs it now more than ever, especially after fitting the 33's.
I think I'll bite the bullet and give the dawes, and needle valves a shot sometime this weekend or the week after. My plan of attack is to, fit the valves, adjust to suit, and then later on blank the EGR just to see what difference it makes.

I'll be honest and say that all in all, I haven't got a bloody clue what I'm doing. I've got a general idea of the principle of the dawes and needle, how it works before and after. And all that was learnt through threads here and a informative chat with Mudski when I picked up the bits.
But there is an in-experienced , un-educated side of me when it comes to "under the hood" kind of stuff in these CRD's that's got me just a tad concerned. I'm approaching this with a "what if this and what if that" attitude. Put it this way I'm yet to even have a look for and trace the vacuum lines needed for the task ahead.

But hey you only live once, onwards and upwards. lol

[Rumcajs]

There is no need to keep adjusting it (needle valve) constantly unless you are one of those types who keep constantly fiddling, never happy. Mine is fitted under bonnet is now almost fully close because I use dual stage boost control as well.
Essentially needle valve is continuously bleeding waste gate like control for the VNT actuator. The valve allows vacuum (its being used to open the vanes up) to be bled off so vanes are backing off thus reducing the rate of turbo spool up. So more vacuum is bled the less are the vanes open the slower the turbo spool up in simple terms.
Basically you are turning your variable geometry turbo charger into fixed geometry with added bonus of having very fast spool up indeed much faster than you would on fixed geometry turbo. Once predetermined boost is reached Dawes is than dumping vacuum backing the vanes off and that in turn slows the turbo charger down reducing boost. That's basically it really simple rudimentary device. I admit power is great but fuel consumption can also increase especially cruising at higher boost hence I have dual stage boost control with two Dawes one set at max 11 psi and one set at 18 psi. Have the control both automated via accelerator pedal position and voltage switch as well as having manual overide to choose what mode low/high. Great fun. These gems are really of the Patrol4x4 guru Chaz's invention I think he deserves all the credit.
I'd preferred programmable PWM controller utilizing existing boost solenoid which would allow even better control but this is so far working and is simple.
You could technically do away without needle valve but it is a piece of mind to have some sort of a spool up control otherwise compressor surge might occur.
The reason why some people fiddle with needle valve in the cab is so they can adjust the spool rate depending on conditions like towing etc. I was happy to get right compromise between spool rate vs safety and basically it was set and forget type.

[mudski]

Its your choice. There is no point for Dawes valve alone on CrD. ECU has the boost under control quite well. There is a point for Dawes and needle valve if you want better torque down low, improve power delivery and tractability.
Would I do it on mine if it was CrD, hell yeah. The difference is phenomenal on Di so it will be even better on CrD me thinks I'd at least try for the cost of it. ($150)
Have you ever wondered why CrD has the same power and torque output as Di. It makes no sense when D40 2.5L (Navara) has more power and torque than 3.0L.
True dat...
As for the EGR, all EGR's on diesels need to be blocked. Period.


Bloody hell. This Rumcajs bloke just answered a crate of questions I've been pondering for a long time, in a single shot! You seem to know your stuff mate ... First time I've ever seen a bloke here, use a graph to prove a point. And it absolutely made sense. Hats off to you buddy. :049:

I've got my gauges fitted a week ago, so I'm monitoring what the engine is doing, before I apply the NADS. I've scored the whole CRD Nads kit from Mudski a while back, but really haven't had time to toy around with it till now. My trol needs it now more than ever, especially after fitting the 33's.
I think I'll bite the bullet and give the dawes, and needle valves a shot sometime this weekend or the week after. My plan of attack is to, fit the valves, adjust to suit, and then later on blank the EGR just to see what difference it makes.

I'll be honest and say that all in all, I haven't got a bloody clue what I'm doing. I've got a general idea of the principle of the dawes and needle, how it works before and after. And all that was learnt through threads here and a informative chat with Mudski when I picked up the bits.
But there is an in-experienced , un-educated side of me when it comes to "under the hood" kind of stuff in these CRD's that's got me just a tad concerned. I'm approaching this with a "what if this and what if that" attitude. Put it this way I'm yet to even have a look for and trace the vacuum lines needed for the task ahead.

But hey you only live once, onwards and upwards. lol
You still got my number mate? Give me a ring if you get stuck bud. A coupla beers and we'll have here done...:)

[rottodiver]

Needle valve on its way, expressed, should have it by end of week or early next....

Scotty

[Jimbo4x4]

Hi rottodiver, Yes i have a Roo systems chip & 3' exhaust, I have just fitted a cross country intercooler and fan today, I do a lot of towing with the camper and the egt was hitting 650 degrees up hill and on the beach .


Thanks jimbo,
Do have have a chip and exhaust upgrade( I run a 3 inch exhaust and tunit chip) or Dawes
Scotty

[rottodiver]

Ok egr is now blocked, to be honest I didn't really notice much difference in egt but I did notice the turbo boost is a little erratic now, this will hopefully be fixed when my needle valve arrives, hopefully tomorrow.
Scotty

[93patrol]

i am glad you asked the question Scotty because there is alot of fantastic info here that just blows my mind and can help if i ever need to give Fry a hand to fit his when he gets it

[rottodiver]

Ok egr is now blocked, to be honest I didn't really notice much difference in egt but I did notice the turbo boost is a little erratic now, this will hopefully be fixed when my needle valve arrives, hopefully tomorrow.
Scotty

Ok, needle valve is here..... I am trying to work out the instal of this.....
On the solenoid with the 3 hoses it looks I remove all the vacuum hoses from that solenoid.. Is this correct?

Scotty

[Rumcajs]

Yes. Use short loop to connect between two of the ports and block the third with another short hose and small screw jammed in the other end of the hose.
The hose from solenoid which is going to resonator box (under the solenoid) will connect to outlet on the needle valve. vacuum hose coming from the pump needs to "T" pieced in to VNT line with Dawes and needle valve.
Cheers

[rottodiver]

Thanks rumcajs,
does it matter if the middle one is not blocked( the one that went to the actuator originally), I have looped other two.i have tried to follow Chaz's instructions but do notice the "damper" is on the vacuum pump line where as on the crd it is on the actuator line( I changed it to the vacuum pump line as per his drawing.. Is that right?

I seem to now get a max boost of 18.6 on the scan gauge( which reads 18 on my pod gauge), would that be too high or just right.

Now for adjustment of the needle, I think I got it right.... I idled the engine with it wound all the way in then as I watched the actuator arm I wound the needle out until I saw the arm drop slightly, then I wound it back in again until it was just about to hit the stop again.. Sound right?
I have notice exactly what you said, the boost does not fluctuate now it is steady, but now at 2000 rpm it sits on about 16( when doing a touch under 100 km/h).

Thanks in advance... It is a little nerve racking doing this for the first time..

Scotty

[Rumcajs]

Thanks rumcajs,
does it matter if the middle one is not blocked( the one that went to the actuator originally), I have looped other two.i have tried to follow Chaz's instructions but do notice the "damper" is on the vacuum pump line where as on the crd it is on the actuator line( I changed it to the vacuum pump line as per his drawing.. Is that right?


I'd blocked all ports on the solenoid so as not to get it filthy, you never know when you want to re use it again. The damper is the same on Di as well, when you change over to needle valve it is on the vac line.



I seem to now get a max boost of 18.6 on the scan gauge( which reads 18 on my pod gauge), would that be too high or just right.

That's perfectly OK for CrD, I get that on mine (Di)



Now for adjustment of the needle, I think I got it right.... I idled the engine with it wound all the way in then as I watched the actuator arm I wound the needle out until I saw the arm drop slightly, then I wound it back in again until it was just about to hit the stop again.. Sound right?

Yep that's your initial setting.



I have notice exactly what you said, the boost does not fluctuate now it is steady, but now at 2000 rpm it sits on about 16( when doing a touch under 100 km/h).

Do you have Dawes fitted? 16 psi at 100km/h under cruising (not under hard acceleration/uphill) is a little too high, maybe 11-13 psi is more ideal under reasonable load, you'll get better eco. I'm guessing yours is an auto by the revs@100kn/h

Now I think its time for trial and error tuning. Try open the needle valve a slightly and see what boost you'll get than.

Cheers

[rottodiver]

Rumcajs,
Thanks so much for the time you are taking with me on this...
Yes I do have the Dawes valve fitted, currently I have egr blocked Dawes valve, needle valve, 3 inch exhaust, tunit chip, provent200.

Ok I will open it up the needle valve a touch, how do I know When I have gone too far? Can I do any damage?

Scotty

[Rumcajs]

Well, you'll know alright, the boost spool up will be slower and car sluggish/slower to accelerate. No real damage from slower spool up. You need to do it in small increments. Did you observe spool up rate under partial load/accelerator pedal? So boost bellow 6 psi under 1500 RPM, 10 psi under 2000 RPM etc. Those are general rules for Di. For CrD it might be slightly higher.
CrDs can easily spike to 20 psi under full load (over 2500 RPM) with no issues apart from possible reliability. Don't forget that you might have to reign in the max boost with Dawes as well. Its a balancing act now to try finding a sweet spot between power and eco and safety.

Cheers

[rottodiver]

Yeah at 1500 rpm I was getting about 7... I am thinking I am getting close then, if I wound it out slightly wouldnt that raise my 2000 rpm boost?

Scotty

[Rumcajs]

Yeah at 1500 rpm I was getting about 7... I am thinking I am getting close then, if I wound it out slightly wouldnt that raise my 2000 rpm boost?

Scotty

No, wounding it out aka opening it will reduce spool rate which slows down the turbo response which lowers down the boost. Wounding it in aka closing it makes it spool up faster with higher boost at lower RPM that gives more power (better response) but can be more dangerous to the turbo/motor.
Cheers

[rottodiver]

Awesome... That is my next plan then.... Will be my first job in the morning,
Thanks again, it is really appreciated...

Scotty

[Rumcajs]

Look you can do an experiment where you fully close the valve (engine can handle that for limited time) to see what figures you'll get so you can establish your max baseline and than start scaling back to what you feel is a right balance between power, eco and safety...
If yours in an automatic it will be keeping up higher boost across gear changes which can lead to higher boost levels and much quicker spool up rate. So in that case you might need to get Dawes valve adjustment to reflect on that too (reducing the max boost level).

Cheers

[rottodiver]

Yes it is an auto....

[rottodiver]

I might adjust the Dawes slightly, I have got that pretty sussed now... That also doesn't need much adjustment..
Scotty

[Rumcajs]

I might adjust the Dawes slightly, I have got that pretty sussed now... That also doesn't need much adjustment..
Scotty

Remember one adjustment at the time otherwise you'll be getting misleading info. Do use some marking implement to record the positions of the valves.

Cheers

[rottodiver]

well just a little update, i seem to have the dawes and needle valve in a comfortable position.. the patrol has a bit of get up and go now... and it is now that i am noticing the drop in egt (when i fitted the egr plate i didnt notice it but one the needle valve went in i certainly have also i never got the error code (from not drilling a hole in the egr plate) but since the needle valve has gone in i have had it up 3 times!!!! might be coincident!!

Scotty

and a massive thanks to Rumcajs... i definately would have struggled more without the one on one info from him..... i cant think of anywhere else you could get that help..

Thanks heaps

[Heinzy]

Is there any place in Perth that can do this

[4bye4]

Is there any place in Perth that can do this

Don't know if you are in Perth mate but you might consider joining the Western Patrol club, details below. We do have maitanence days from time to time to do things like NADS. I will certainly be doing mine in the next couple of months.