dawes and needle valve for common rail?

[grimace]

g'day gents, i have noticed the dawes and needle valve kits on ebay lately and was wondering if anyone has fitted one on their common rail? also is the price they are asking about the going rate? i would put up a link if i could but my work dosn't allow me to access ebay so if anyone can help me out with that it would be great. cheers....G

[threedogs]

I paid $45 for a dawes valve from 3barracing in the states and paid $90 for a needle valve from Dependable distributors in SA.
You'll also need a provent 200 catch can. Or PM mudski he should have stock.

[Fry]

I got one of these but am yet to put it on my CRD.
Dawes Valve, Needle valve and EGR plate Nissan GU Patrol ZD30 Common Rail (http://www.ebay.com.au/itm/231112438797?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649)

[threedogs]

Yeah that's Mudski a great bloke and a sponsor as well
@ FRY what area are you in??

[mudski]

Thats me guys. Buy through here and 10% goes back into the forum. Which reminds me i need to transfer some coin across

[DSzuke]

I have got a plate I was about to install on my 2007 CRD but I got nervous about not having the Dawes and Needle valve installed yet.

Is it reasonable on the CRD motor to install the EGR block and see how the motor responds or should I just get the kit and install it anyway? (this is of course with the EGT and boost monitoring already in place).

[the evil twin]

I have got a plate I was about to install on my 2007 CRD but I got nervous about not having the Dawes and Needle valve installed yet.

Is it reasonable on the CRD motor to install the EGR block and see how the motor responds or should I just get the kit and install it anyway? (this is of course with the EGT and boost monitoring already in place).

Mine has EGR block and no Dawes or Needle valve.
I fitted the EGR then adjusted the VNT as per Chaz's bible and she's been tickety boo ever since (chipped, 3" exhaust, EGR block, pyro and scan gauge)
I bought the Dawes gear but it runs perfectly well on the ECU so never bothered so I sold the bits

[kevin07]

I have got a plate I was about to install on my 2007 CRD but I got nervous about not having the Dawes and Needle valve installed yet.

Is it reasonable on the CRD motor to install the EGR block and see how the motor responds or should I just get the kit and install it anyway? (this is of course with the EGT and boost monitoring already in place).
never going to hurt the motor buy blocking the egr

[grimace]

I paid $45 for a dawes valve from 3barracing in the states and paid $90 for a needle valve from Dependable distributors in SA.
You'll also need a provent 200 catch can. Or PM mudski he should have stock.

Why does it have to be provent? I already have a catch...I also have the boost and egt guages and notice on the boost guage under acceleration it spikes then drops off the power and keeps doing this a couple of times until it levels out and this is why I want to fit the dawes and needle so as to take away the boost control from the ecu.... cheers G

[megatexture]

Your on the right path mate

[mudski]

As you have the gauges, block the EGR and monitor how it goes. Its not a big job to remove it if your not happy.

[Lemo79]

Thats me guys. Buy through here and 10% goes back into the forum. Which reminds me i need to transfer some coin across

Hey Mudski, PM sent. This has been on my to do list, and I am about to do a service so now is as good a time as any.

Lemo

[the evil twin]

As you have the gauges, block the EGR and monitor how it goes. Its not a big job to remove it if your not happy.

What mudski said...

[patrol4life]

I have had a dawes and needle setup on mine for about two years now, with no ill effects. The ecu does a good job on an unmodifed car. But with a rail chip with no boost control, the egts can get to high. The dawes is a good way to bring egts down and gain performance when adding more fuel.

[rottodiver]

I had a Dawes and needle valve, took me a bit to install it( a lot of help from here but very very simple once you know how...maybe a 2 minute job once all hoses are cut) I have since removed them( on the side of the road on a trip) I really had troubles Setting them correctly.. They ran well in the city then when towing on the hwy I hit limp mode twice when trying to overtake on a hill. I haven't put them back in because I have had no over boosting problems at all... Although the faster spool up rate was very noticeable. I have the egr blocked with no hole in it , 3 inch exhaust, provent catch can, and chip. Have had the check engine light 3 times only(easy fix with scan guage)

Scotty

[Beni C]

I run a CRD with the EGR block, Provent and Scanguage, no massive spikes in boost, runs well.


Mine has EGR block and no Dawes or Needle valve.
I fitted the EGR then adjusted the VNT as per Chaz's bible and she's been tickety boo ever since (chipped, 3" exhaust, EGR block, pyro and scan gauge)
I bought the Dawes gear but it runs perfectly well on the ECU so never bothered so I sold the bits

Where can I lay my hands on this bible ET??

[threedogs]

@ RD What do you think was the cause of the limp mode,
dawes adjusted correctly should have limited your boost to 15psi max,
with no chance to overboost

[rottodiver]

@ RD What do you think was the cause of the limp mode,
dawes adjusted correctly should have limited your boost to 15psi max,
with no chance to overboost

I was under the impression about 18 psi was ok for crd,s
It can only have been it was set too high, frustrating thing was it worked perfect ( so I thought) around town for a few weeks before the trip. It even triggered the engine light with the over boost code... I guess I am more comfortable with the ecu looking after the boost than me setting it.. If it was to over boost with out the valves I would think about re installing them but I have had absolutely no problems since taking them out..( do miss the faster spool up though... It really does improve with it). As it is I am happy with egt,s , boost, Engine temp and also auto trans temp, even the boost doesn't fluctuate too badly either so will see how they go..
Scotty

[threedogs]

I believe the Cr ECU handles the boost issues a better than the Di.
So you have a dawes set up for sale lol

[rottodiver]

I believe the Cr ECU handles the boost issues a better than the Di.
So you have a dawes set up for sale lol
Nah not for sale... I am not against having another go later... Maybe during simpson when there are some people around me that know what they are doing ( a lot more so that I) it is now plug and play, all hoses are at length etc

[threedogs]

Who knows maybe you needed to stretch the spring,
a better way is to insert SS washers, as it hard to un stretch the spring

[megatexture]

I run a CRD with the EGR block, Provent and Scanguage, no massive spikes in boost, runs well.



Where can I lay my hands on this bible ET??



here is the link to it mate its not a bad read

http://www.nissanpatrol.com.au/forums/showthread.php?89-Nissan-Patrol-Reference-Document

[rottodiver]

Who knows maybe you needed to stretch the spring,
a better way is to insert SS washers, as it hard to un stretch the spring

I believe the one I have has the heavy duty spring.... I have no doubt the problem is not with the valves but the idiot setting it..... Lol
Scotty

[patrolman123]

Mine has EGR block and no Dawes or Needle valve.
I fitted the EGR then adjusted the VNT as per Chaz's bible and she's been tickety boo ever since (chipped, 3" exhaust, EGR block, pyro and scan gauge)
I bought the Dawes gear but it runs perfectly well on the ECU so never bothered so I sold the bits

chaz's bible? where do i find this mate

[megatexture]

here is the link to it mate its not a bad read

http://www.nissanpatrol.com.au/forums/showthread.php?89-Nissan-Patrol-Reference-Document

Two post above yours is the link

[Mac53]

Hi I'm new to the forum and have a couple of questions in regards to fitting the Dawes, needle valve and blocking off the EGR on my 2012 GU 8 CRD. Where can I find some detailed instructions and photos of how to install (I also have the boost & EGT gauges)

Cheers
Graeme

[threedogs]

Pop over to the intros first Mac53 and say hello a nd tell us a bit about yourself.
Its something that the forum asks of us all as well. Then post your question in the correct area , you'll get more response that way
There are heaps of threads /post /links etc on the subject your after,,,, have you tried searching??

[apalsson]

Hi I'm new to the forum and have a couple of questions in regards to fitting the Dawes, needle valve and blocking off the EGR on my 2012 GU 8 CRD. Where can I find some detailed instructions and photos of how to install (I also have the boost & EGT gauges)

Cheers
Graeme

Graeme,

Personally I would think twice before blocking EGR on an engine still under warranty. Mama Nissan might quite likely void warranty on your engine because as far as I know, this mod isn't quite legal in most if not all States. Anyone, please correct me if I'm wrong on that point.

[Hodge]

What apalsson said.
When my nav was at Nissan the first thing they noticed is the egr block.
Not to mention a lot of common rails throw up the egr (p0401 ) code like mine. So when Nissan plug in their tool its the first thing they see.
If you do block it and needs to go to Mr Nissan take blank out. A pain to do on CRD but if its gotta be done, its gotta be done.

[threedogs]

highly illegal but saying that your motor will thankyou for allowing it to breathe
some say the CRD needs a hole in it to stop it throwing up errors

[patrolman123]

I think crd does need a small hole because they do have an extra sensor in the egr. It has to sense some sort of flow of air

[apalsson]

While I appreciate that people have had issues with high EGT in the past, especially in the early versions of the ZD30, I admit I'd be seriously reluctant to apply heavy handed fixes that we all agree are illegal too.
Are there any statistics available that show the percentage of these engines (year by year if possible) that actually have failed because of excessive EGT?
Even better, with the cars that blew engines, what was the configuration? (did they have bullbars without adequate openings at the front, high mount winches or other mods that might have contributed to overheating)

I guess being an engineer, I have limited imagination but like to go on numbers (facts and figures) :)

A blown engine is no joking matter but neither is voided warranty on a new engine or a defect notice from the boys in blue

[the evil twin]

While I appreciate that people have had issues with high EGT in the past, especially in the early versions of the ZD30, I admit I'd be seriously reluctant to apply heavy handed fixes that we all agree are illegal too.
Are there any statistics available that show the percentage of these engines (year by year if possible) that actually have failed because of excessive EGT?
Even better, with the cars that blew engines, what was the configuration? (did they have bullbars without adequate openings at the front, high mount winches or other mods that might have contributed to overheating)

I guess being an engineer, I have limited imagination but like to go on numbers (facts and figures) :)

A blown engine is no joking matter but neither is voided warranty on a new engine or a defect notice from the boys in blue

Also being an engineer...

Reliable figures? ... Hell no
Configuration? ... again Hell no

It is almost impossible to even find reliable sales figures of how many Patrols of a particular series have been sold.

Forums are probably one of the least reliable sources of information as regards statistics (I stress statistics) as well because they do not attract an untainted sample statistically speaking. Most people "find" a forum because of a personal interest over and above Joe Public or they have had failures... the old "search for shit and you will find it" syndrome

The vast majority of nomads, soccer mums etc tooling around in their Patrols wouldn't have a clue about blown engines, cleaning MAF's or whatever because while it keeps going they don't care.

The other BIG issue with forums is that a single post that is absolutely 100% wrong can get a cult following and become absolute concrete fact that an exponential number of people will swear is kosher purely because others have done so and it becomes almost impossible to contradict or correct.

I've seen it on other Forums and also here and I rarely even bother trying to correct it these days as you either get flamed, argued with or ignored

[patrolman123]

Agreed ^^^^^

[apalsson]

Also being an engineer...

Reliable figures? ... Hell no
Configuration? ... again Hell no


Excellent post! Must be because an engineer wrote it :)

Seriously, I have been trying hard to get some reliable data on this but it has been all but impossible. I have a good relationship with a Nissan Dealer Service Manager and discussed this with him. He obviously kept the Nissan hat on tight but told me in his time, he had seen two blown ZD30 engines, both from cars with modded fronts (as he put it). H was adamant that the ratio was low.
I suggested to him the NADS mods and he agreed with the gauges and a catch can but was mo ambivalent on the Daws/Needle Valve setup. He still agreed that und certain circumstances it wasn't a bad idea. Block EGR? His words were: "Why deliberately void your engine warranty and get the Cops on you?"

A local Diesel Service guy took a similar line but also suggested a fine extra fuel filter if you spend a lot of time Outback. H offered me a Provent and said he thought that was a good idea. He was also all in favour of the gauges.

It seems that for every two people you ask, you get three different opinions!

My old Patrol was a 2001 and was driven hard and used hard. I was diligent with the services and the car never let me down.
Because my current one is out of warranty, I don't have the same reservations against modding but as I said earli in this thread, everything in me wants data, figures and facts to go on.

I hope my rumblings make sense

[the evil twin]

What I have found is this (and my vehicles have been/are fairly heavily instrumented) but I stress it is just me and my opinions others are free to agree/disagree/plait their poo...

EGR blocking - illegal due to anti-pollution regs and has warranty implications
Gives great results in removing soot and particulates from induction and heaps less oil contamination.
On CRD's it WILL affect the spool up and you MUST adjust the VNT actuator.
If you do that adjustment you don't need a Dawes and Needle BUT you can fit them if you want some extra piece of mind and stuff to fiddle with

Bottom line - great for the engine, crap for the environment, escape clause for Nissan

Fine fuel filters -
I'm a fence sitter on this one, mainly because the CRD has no lift pump and is gobsmackingly tempermental about fuel but I reckon good idea as long as you keep a close eye on them and change regularly

Bottom Line - If they save some shit trashing the Pump, rail or Injectors which will cost you at least $5,000 then they are worth it

How many blow up?
Series 5 and up I reckon bugger all when compared to like vehicles.
My 'stock' work Ranger atomised itself at 101,500, my heavily modd'd Patrol WITHOUT NADS (just an EGR block) has nearly 160,000.
When the Ranger was in getting engine work etc there were two others the same but none of the above really proves anything.

Chips -
Mine has a DP and goes ganbusters on 7. It also has a big exhaust

Warranty,
Mine is just out now but Nissan never blinked at anything including new intercooler etc. even with the Chip etc and yes they knew about the EGR block. We just chose not to ever speak of it. Other Dealerships may not be so uuuummmm accomodating

[teach]

I know this thread is a little old but I am in similar boat with my 2010 GU8 CRD. Just recently had intercooler replaced under extended warranty by Nissan (it was leaking after 4.5 years) so I am looking at the NADS etc and trying to put together in my mind a plan of attack. Here is my thinking thus far.

1. Install catch can. I have purchased Provent 200 already (still yet to install). Thought this will help engine etc run cleaner and less blockage.

2. Install boost and EGT gauges.

3. Install exhaust. Reduce EGT and some minor performance increase. Install Dawes valve (and needle valve??) as exhaust will change boost in engine.

4. Block EGR (in 18 months time when warranty over). Get ScanGauge to clear fault codes.

Now likely to do steps 1-3 at same time as I don't feel I am mechanically mined enough (used to work on my 186 motor in my Torana in younger days but CRD much different kettle of fish), don't have all the tools to do myself (esp. welding bungs in dump pipes etc), and the obvious time factor to do it myself, hence pay diesel mechanic to do it. Plus saves paying exhaust shop $120 to fit bung in the stock exhaust dump pipe to fit EGT probe if gauges fitted same time as exhaust.

So my questions I can think of are:
* Is this the way to attack the issue? Have I missed something?
* Who would be a suitable diesel mechanic (Brisbane Southside - I live at Morningside) to approach to install these bits and pieces
* Is Dawes and needle valve required for CRD? I know Dawes limits boost and needle works on spool up of turbo, but does CRD manage this much better than Di and makes them not required.

Thanks in advance for any useful advice I receive.

[mudski]

I know this thread is a little old but I am in similar boat with my 2010 GU8 CRD. Just recently had intercooler replaced under extended warranty by Nissan (it was leaking after 4.5 years) so I am looking at the NADS etc and trying to put together in my mind a plan of attack. Here is my thinking thus far.

1. Install catch can. I have purchased Provent 200 already (still yet to install). Thought this will help engine etc run cleaner and less blockage.

2. Install boost and EGT gauges.

3. Install exhaust. Reduce EGT and some minor performance increase. Install Dawes valve (and needle valve??) as exhaust will change boost in engine.

4. Block EGR (in 18 months time when warranty over). Get ScanGauge to clear fault codes.

Now likely to do steps 1-3 at same time as I don't feel I am mechanically mined enough (used to work on my 186 motor in my Torana in younger days but CRD much different kettle of fish), don't have all the tools to do myself (esp. welding bungs in dump pipes etc), and the obvious time factor to do it myself, hence pay diesel mechanic to do it. Plus saves paying exhaust shop $120 to fit bung in the stock exhaust dump pipe to fit EGT probe if gauges fitted same time as exhaust.

So my questions I can think of are:
* Is this the way to attack the issue? Have I missed something?
* Who would be a suitable diesel mechanic (Brisbane Southside - I live at Morningside) to approach to install these bits and pieces
* Is Dawes and needle valve required for CRD? I know Dawes limits boost and needle works on spool up of turbo, but does CRD manage this much better than Di and makes them not required.

Thanks in advance for any useful advice I receive.

To your questions.
*1 Your pretty much on the money....
*2 Can't help you there. I'm a Mexican.
*3 The dawes and needle isn't required for the CRD's or the Di's.
*3 pt.2 The CRD's does manage this better than the DI's but if you see a before and after shot of a dyno run. You will definitely put the two valves in. Just because the ECU in the CRD's handles things better than the Di's. Still doesn't mean its doing its job right. I'm not saying it isn't mind you. But every driver is different, every driver wants their car to perform to the way they like it. Running the two valves gives you the driver the opportunity to adjust things and make the car drive the way you like it. You want more boost? Sure! You want a quicker spool up rate? No worries!
Some people just don't care and like how the car drives out of the crate. Thats fine too. Its their car.
But in all honesty, there is no point in just doing the Dawes valve and NOT the needle valve. Thats like taking a dump and holding your pee back. Doing half a job. Its a hole half an hour longer to fit up the needle valve and really enjoy what you have just done and really benefit from it. Your are bypassing one part of the boost control solenoid with the Dawes. Why not by pass the whole thing? I have fitted countless valves to these donks, Di and CRD, and have seen in person the difference it makes.

Thats my 2c. Some will agree some will not. The beauty of the internet forum...

Cheers.

[teach]

Many thanks for the advice. It is greatly appreciated. Looks like it would best to fit catch can, gauges and exhaust. Drive the car for awhile and learn how it's performing with changes. Then fit Dawes and needle valve to suit.

[PerthGuy]

hi there, Im New to Patrols (searching for my first actually) looking for late model CRD.

My question (newbie) is what is the difference between installing an EGR block and a catch can? maybe im missing the purpose of the catch can, if you have the EGR block in place? Sorry if this is a newbie question

[pollenface]

An egr block is a physical barrier to stop or reduce exhaust gasses entering the throttle body.

A catch can is to condense the oil vapor from the crankcase vent to minimize the condensed oil in the intake system (turbo/intercooler/throttle body)

[growler2058]

hi there, Im New to Patrols (searching for my first actually) looking for late model CRD.

My question (newbie) is what is the difference between installing an EGR block and a catch can? maybe im missing the purpose of the catch can, if you have the EGR block in place? Sorry if this is a newbie question
G’day mate welcome aboard

[mudski]

hi there, Im New to Patrols (searching for my first actually) looking for late model CRD.

My question (newbie) is what is the difference between installing an EGR block and a catch can? maybe im missing the purpose of the catch can, if you have the EGR block in place? Sorry if this is a newbie question

Two totally different things mate.

The EGR block. Blocks the exhaust gases that are recirculated back into the air intake via the EGR valve. A catch can, filters( filters as in cleans the gases of the oil) the crank case vapours that are recirculated from the rocker cover and back into the air intake.

Two totally different things.

[chandkumar3g]

I have had a dawes and needle setup on mine for about two years now, with no ill effects. The ecu does a good job on an unmodifed car.

[PerthGuy]

Hi all, thanks for your responses and apologies for the delay in coming back here.

are the air paths totally different. ie should you do one or the other, or both? the catch can cleans the air that goes in and the EGR block stops it from getting into the air intake completely.

If worried about the air intake, would the EGR block be sufficient. Maybe the catch can stops (reduces) particulate deposits elsewhere in the engine?

Just bought a 2015 GU ST, 50,000km and am loving the car so far. So much potential and certainly different from the prado!

[nipagu7]

when the car is on boost and you then take your foot off the throttle , the pressure blow back in the air intake carries engine blowby gasses back past the MAF sensor , after a while this builds up on the MAF sensor and causes it to give false readings . A catchcan greatly cleans up the blowby gasses which in turn keeps the MAF sensor cleaner longer . although it is still advisable to occasionable clean the MAF sensor with MAF sensor cleaner spray occasionally ( i do mine when i do oil changes ) . if the egr is not blocked the catch can does go someway towards helping keep the inlet manifold and valve intake ports clean , as the blowby gasses combine with the egr gasses to stick and clog them up .
if you block the egr it would stop the crud buildup occurring in the first place , and most people would get better fuel economy and more power although you may need to look at a dawse and needle valve arrangement to help control the turbo , which has benifits of allowing higher boost ( more Power ) and better driveability ( more power at lower RPMs )

[PerthGuy]

Ok Thankyou. That’s kind of what I was guessing. Block it off then don’t need a catch can.
Do you have to do the Dawes and needle valve if you have blocked the EGR?

Thanks again for helping a newbie out

[phdv61]

Boost is not what is needed by your engine.
Only airflow matters ( MAF voltage represents an estimate of the quantity of air pushed by the turbo inside admission and your cylinders.

It is a common but wrong belief that all you need is boost.
Take a garden hose. Close it. open the tap. You build pressure in, but you get no flow.
Make a very little hole in it. You'll get pressurized water, but no flow/quantity of water pouring.

Now take you dawes. it blocks any flow until it opens. As a result, the vanes are closed, the turbo spins, but exhaust gaz can't exit the cylinders fast enough. All you do is build-up back pressure, and therefore boost, but very little flow.

Little quantity of air, small MAF voltage seen by the ECU. The ECU requests a small quantity of fuel to your IP. And you get little torque/power down low.

The way the vanes of a VNT MUST be managed ( and this is the way the ECU manages the VNT for a full STOCK configuration is as follows :

keep the vanes closed until the exhaust turbine spins fast enough. At 3psi, starts opening the vanes as boost is building up, until mid-aperture is reached. This vanes position ( mid-aperture / mid-closure) is the position at which the turbo provides its best efficiency !!
Stay in that position / open very slightly vanes as boost continues to build-up until you get close to max boost, then open vanes more rapidly to keep max boost under control.

Good luck with valves. As a minimum, set 3 ( yes THREE : one dawes TWO needles ) valves as follows :
get the dawes to open at 3-4 psi. put a needle behind the dawes to regulate the positive flow which is going to open the vanes.
The outstanding issue is that you will not be able to stop the vanes from opening at mid aperture. Only a proper electronic control can provide the exact positioning of vanes at all times, depending upon your Patrol configuration.

So you will have to compromise, and will never be able to get the right cruise boost that you wish to have, at 80 or at 110 km/h.
Only one position of the vanes at all loads/Revs provides the maximum airflow (and maximum power). I called this the 'turbo map'.

I have spent two years studying an analysing in detail what my 2000 Patrol was doing, and why. And found the solution to accomodate properly my EGR being blocked and my 3" exhaust (less back-pressure ), with the best spool-up, torque down low and power.
Only the MAF value matters. Believe me.

As soon as you touch anything to your stock Patrol, your ECM is lost and can't manage. There are many work-arounds, but none is perfect, and some worst than others (one dawes one needle). Sorry to be so blunt, but I spent so much time trying to understand it all.
I wished someone had explained all this to me 2 years ago when I was scratching my head, and bumping it against the wall.

[growler2058]

Boost is not what is needed by your engine.
Only airflow matters ( MAF voltage represents an estimate of the quantity of air pushed by the turbo inside admission and your cylinders.

It is a common but wrong belief that all you need is boost.
Take a garden hose. Close it. open the tap. You build pressure in, but you get no flow.
Make a very little hole in it. You'll get pressurized water, but no flow/quantity of water pouring.

Now take you dawes. it blocks any flow until it opens. As a result, the vanes are closed, the turbo spins, but exhaust gaz can't exit the cylinders fast enough. All you do is build-up back pressure, and therefore boost, but very little flow.

Little quantity of air, small MAF voltage seen by the ECU. The ECU requests a small quantity of fuel to your IP. And you get little torque/power down low.

The way the vanes of a VNT MUST be managed ( and this is the way the ECU manages the VNT for a full STOCK configuration is as follows :

keep the vanes closed until the exhaust turbine spins fast enough. At 3psi, starts opening the vanes as boost is building up, until mid-aperture is reached. This vanes position ( mid-aperture / mid-closure) is the position at which the turbo provides its best efficiency !!
Stay in that position / open very slightly vanes as boost continues to build-up until you get close to max boost, then open vanes more rapidly to keep max boost under control.

Good luck with valves. As a minimum, set 3 ( yes THREE : one dawes TWO needles ) valves as follows :
get the dawes to open at 3-4 psi. put a needle behind the dawes to regulate the positive flow which is going to open the vanes.
The outstanding issue is that you will not be able to stop the vanes from opening at mid aperture. Only a proper electronic control can provide the exact positioning of vanes at all times, depending upon your Patrol configuration.

So you will have to compromise, and will never be able to get the right cruise boost that you wish to have, at 80 or at 110 km/h.
Only one position of the vanes at all loads/Revs provides the maximum airflow (and maximum power). I called this the 'turbo map'.

I have spent two years studying an analysing in detail what my 2000 Patrol was doing, and why. And found the solution to accomodate properly my EGR being blocked and my 3" exhaust (less back-pressure ), with the best spool-up, torque down low and power.
Only the MAF value matters. Believe me.

As soon as you touch anything to your stock Patrol, your ECM is lost and can't manage. There are many work-arounds, but none is perfect, and some worst than others (one dawes one needle). Sorry to be so blunt, but I spent so much time trying to understand it all.
I wished someone had explained all this to me 2 years ago when I was scratching my head, and bumping it against the wall.

Soooo what have you done?

[mudski]

Ok Thankyou. That’s kind of what I was guessing. Block it off then don’t need a catch can.
Do you have to do the Dawes and needle valve if you have blocked the EGR?

Thanks again for helping a newbie out

you don't have to have any of them, they are all there to help improve your engine performance and longevity, to some extent. in my opinion, you need a catch and block the EGR, on any diesel engine. The EGR simply blocks up your intake system with soot and mixed with oily crankcase vapours from not having a catch can will make your intake block up like cholesterol...

Boost is not what is needed by your engine.
Only airflow matters ( MAF voltage represents an estimate of the quantity of air pushed by the turbo inside admission and your cylinders.

It is a common but wrong belief that all you need is boost.
Take a garden hose. Close it. open the tap. You build pressure in, but you get no flow.
Make a very little hole in it. You'll get pressurized water, but no flow/quantity of water pouring.

Now take you dawes. it blocks any flow until it opens. As a result, the vanes are closed, the turbo spins, but exhaust gaz can't exit the cylinders fast enough. All you do is build-up back pressure, and therefore boost, but very little flow.

Little quantity of air, small MAF voltage seen by the ECU. The ECU requests a small quantity of fuel to your IP. And you get little torque/power down low.

The way the vanes of a VNT MUST be managed ( and this is the way the ECU manages the VNT for a full STOCK configuration is as follows :

keep the vanes closed until the exhaust turbine spins fast enough. At 3psi, starts opening the vanes as boost is building up, until mid-aperture is reached. This vanes position ( mid-aperture / mid-closure) is the position at which the turbo provides its best efficiency !!
Stay in that position / open very slightly vanes as boost continues to build-up until you get close to max boost, then open vanes more rapidly to keep max boost under control.

Good luck with valves. As a minimum, set 3 ( yes THREE : one dawes TWO needles ) valves as follows :
get the dawes to open at 3-4 psi. put a needle behind the dawes to regulate the positive flow which is going to open the vanes.
The outstanding issue is that you will not be able to stop the vanes from opening at mid aperture. Only a proper electronic control can provide the exact positioning of vanes at all times, depending upon your Patrol configuration.

So you will have to compromise, and will never be able to get the right cruise boost that you wish to have, at 80 or at 110 km/h.
Only one position of the vanes at all loads/Revs provides the maximum airflow (and maximum power). I called this the 'turbo map'.

I have spent two years studying an analysing in detail what my 2000 Patrol was doing, and why. And found the solution to accomodate properly my EGR being blocked and my 3" exhaust (less back-pressure ), with the best spool-up, torque down low and power.
Only the MAF value matters. Believe me.

As soon as you touch anything to your stock Patrol, your ECM is lost and can't manage. There are many work-arounds, but none is perfect, and some worst than others (one dawes one needle). Sorry to be so blunt, but I spent so much time trying to understand it all.
I wished someone had explained all this to me 2 years ago when I was scratching my head, and bumping it against the wall.

Not sure about your first comment. When I had my ZD di, there was a massive difference in performance from 15psi of max boost, to what I ended up setting it at to 25psi of max boost with 18 psi cruise boost. The main issue was getting around the 16psi boost limit the ECU had, once I got rid of that I could do anything I wanted and the not worry about limp mode.

[phdv61]

Don't get me wrong.
I am not saying you do not need to have more boost to get more air in.
But boost is not all. What you need is to maximize the quantity of air getting in your cylinder, as measured by the MAF voltage.

There is not limitation at 16 psi boost on the Di. The MAP sensor is not used.
I can get 20 psi if I wish, although, beyond 18 psi, the increase of air you get is little are you are getting beyond the efficiency zone of the 2052 garett turbo.

Getting a lot of boost down low is only creating backpressure, and little air is coming in. In other terms, you reduce the power/torque you can get from this engine. If you let it 'breathe' properly, it becomes another "animal".

To move the 2.5T, you need torque down low, which you don't get if you keep the vanes closed too long, and beyond what is needed to get the initial turbine spin. You need to free the exhaust gaz, or you build too much back pressure preventing the cylinders to get rid of the exhaust gaz, making room for more fresh air + fuel. And you have reduced torque and ... driving pleasure.

[mudski]

On my old Di the boost limit was 16psi, yes not via the MAP sensor as you say, just thats when the stupid thing would just a have hissy fit and go into limp mode, at 16psi, or 14psi if I wound in the needle valve for faster spool up. After changing out the MAF housing for a high flow housing, no limp, no hissy fits, nothing, I wound the boost out to 30psi and still nothing. Drove great.

[phdv61]

On my old Di the boost limit was 16psi, yes not via the MAP sensor as you say, just thats when the stupid thing would just a have hissy fit and go into limp mode, at 16psi, or 14psi if I wound in the needle valve for faster spool up. After changing out the MAF housing for a high flow housing, no limp, no hissy fits, nothing, I wound the boost out to 30psi and still nothing. Drove great.

This is a non-sense mate.
reducing the MAF voltage makes the ECM believe there is less air than real. So, the ECM requests less fuel to the pump.
Pushing boost, when reducing the MAF voltage, results in increasing the AFR by reducing the fuel injection.

The only way to get the most of our 3.0 motor is to control the MAF value at all times by using the RPM signal, and manage the turbo vanes directly to maximize the MAF value. I explained all this in details on a Patrol site, and many abandonned dawes+needle for dawes + 2 needles, and now the magic box. That one makes an unbelievable difference.
I am just sharing here the result of the 18 months I spent full time of deep analysis and development to overcome once for all the limits of my own Patrol owned for 21 years now.

The problem with beliefs which have been going on for so long, is that it is hard to believe they were just wrong. I have been misled myself, so I know what it is ! I have been running my home made electronic VNT controller including a LIMP avoidance function, and my old lady became a young girl, climbing like never, to the top of the highest mountains I have around.

[MB]

Crikey, if you Two Legends can agree I’m for sure reconsidering going back to a 3.0L [emoji41][emoji106][emoji106]
By far the zippiest Patrol we’ve ever family owned, unfortunately had to get rid of it humanely clutch hauling Nags in our hills and had to revert back to a sluggish TD42T, did I mention SLUG [emoji222][emoji23][emoji106][emoji106]


Sent from my iPhone using Tapatalk

[mudski]

Crikey, if you Two Legends can agree I’m for sure reconsidering going back to a 3.0L [emoji41][emoji106][emoji106]
By far the zippiest Patrol we’ve ever family owned, unfortunately had to get rid of it humanely clutch hauling Nags in our hills and had to revert back to a sluggish TD42T, did I mention SLUG [emoji222][emoji23][emoji106][emoji106]


Sent from my iPhone using Tapatalk

Haha! I'll agree to disagree. I only supplied maybe 5000 of these kits worldwide and fitted maybe a couple of hundred during my time with the shop. But yes the ZD is quite zippy. Easier to drive than the TD in the burbs, but thats all its got going for it.

[phdv61]

Making the ECU believe there is less air coming through by enlarging the inlet, or by simply adding one or two schottky diode in serie (costs only 10 cents each) with the MAF signal to reduce it by 0.15V or 0.30V have the same dual effect :
1/ it suppresses the limp modes as the MAF voltage is reduced
2/ it also reduces the fueling and therefore the power/torque as the ECM makes use of the MAF voltage to request the correct amount of fuel per stroke to the IP. Believing otherwise is just wrong. Just put a voltmeter on your MAF signal wire, and you will just see with your own eyes what I am saying here.
And if you consider the MAF 'characteristic response' in volts to quantity of air in g/s , which is a 'log' curve (available on the net), you will see that missing 0.3V ( ie measuring 3.7V instead of 4V) makes the ECM believe there is 30% less air (!!) and therefore the ECM will ask 30% less fuel to the IP.

Unless you go for a remap which increases the well known limp thereshold values, to suppress them, the alternative is to use the RPM signal to clamp the voltage just below the limp threshold(s) until the RPM goes above the associated RPM limit, after a delay of around 2s. Only electronics and software allows all these "subtilities".

With the magic box VNT, and by managing the garett vanes properly, I can get more than 3.65V below 2000RPM ( limp at 3.55 ), and well above 3.88V below 2500RPM, 3.98V below 3000... etc. Never any limp, immediate spool, and max power and torque out of my engine at all Revs.

Historically, people with limp used to screw the limiting screw to decrease the initial spool-up (same effect as adding a needle), but at the expense of getting a 'sluggish' Patrol. Some went on modifying the MAF enclosure (just to reduce MAF voltage which you can get with a simple non-expensive diode).

People who have now moved to Magic box in several countries do get a full control of their turbo 'map', maximize the airflow at all Revs (and therefore the Torque and power) with boost under control, no peaks - no holes.