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Hi Guys, my first post on this site.


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I have owned a 2008 CRD ZD30 Patrol for about 14 months and have been following your posts on NADS etc.


Have partially blocked EGR with a home made blank (1.2mm Zinc anneal steel plate) with a 9mm hole to stop any code errors. The EGR on the 2008 troll has a cooler (Water/Coolant Jacket) pre egr valve I have put the blank between the flanges post cooler - pre egr valve. After doing the partial egr block i turned the vnt adjustment screw down about a third of a turn. At this stage no boost guage fitted and adjusted the vnt just in case i introduced higher boost pressures.

Have fitted a Redline mechanical boost guage now.There is a cast alloy/aluminium tube splice/joiner that is approx half way between intercooler and inlet manifold (after intercooler) which has a 7 mm thick wall at the center where it is at its thickest. It is here that i drilled and tapped a 1/8th BSP hole and fitted a nipple to connect the boost guage tube. When starting the engine for the first time afer guage fitting i noticed the guage showed very little pressure only when reving up to 2500rpm did it rise to 5 psi. I have since readjusted the vnt to its original position and the boost guage still only reads 5psi at approx 2500 rpm. I meassured voltage from MAF and at idle and i got 1.75 to 1.8 volts which according to some of the posts on this subject appears in the normal (non block egr) range. So it would appear partial block on this crd has little or no effect on MAF voltage, I did not check MAF voltage proir to the partial block so i cannot say for definite there has been no affect on MAF voltage only that it seems to be in the expected idle range. Sprayed a soapy solution over Intercooler and boost pipe joints at first start up to see if there were any obvious pressure leaks, didnt spot any.


I know that the ecu on post 2007/8 crd vehicles is supposed to have a lot more control over boost/fuel levels than previous models. Can anyone please tell me what boost pressures i shoud expect to see and at what rpm and should the engine be under load or not?


Thanks in advance






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Hello, welcome to the forum.


Firstly, using E*R shim will not influence MAF voltages noticeably.


Secondly, it is unwise making any changes without actually been able to read/check with either gauges or a scan tool as to what effects the changes made have.


I personally suspect that the boost gauge you are using is not displaying data correctly either because the the boost tube has a restriction/kink in it or it needs to be calibrated perhaps I'm not that familiar with mechanical boost gauges. Is there a significant lack of power as well?


Because yours is CrD 08 model you could actually use the OBDII adapter and app if you have a smart phone for example to access the engine ECU sensors like MAF and MAP (boost sensor) instead of additional mechanical boost gauge. Or you could obtain OBDII scanner like "Scangauge" or OBD software with OBD adapter to use with a notebook for example. You've got choices there.

I'd certainly not hesitate to purchase Scangauge (~$170 AUD) or at least a cheap OBDII bluetooth adapter and a smart phone app as a minimum (under $50 AUD) because it will allow you to access vital info on the engine ECU including added features like fuel consumption data, DTCs (Diagnostic Trouble Codes) readout and clearing/deleting the codes instead of going to Mr Nissan to get fleeced.


The boost levels on CrD are definately higher than 5 psi however it is all relevant to the engine load and throttle pedal position. average boost is around 10-15 psi with max spike to 22 psi are not uncommon. It is uncommon to have a need for VNT stop screw adjustment on CrD ZD30 as well, they handle higher boost easily unlike the Di units.


Free (without the load) reving the engine will not achieve higher boost levels maybe around 5-8 psi max from my experience with turbo Diesels.



Edited by Rumcajs
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Thanks for the advice and info.


From your last comment about the boost levels it would seem that the guage is working correctly as i have only just fitted the boost gauge. The 5psi i saw was when the car was static and was a "free" reving reading. Will drive the troll and let you know what readings i see under load.

 I have also fitted a ProVent 200 and Oil pressure guage (sender not mechanical tube)


Will look at scanguage as my next aquisition.

You will have to bear with me on the new technology as i am a bit of a dinosaur. I remember when everything could be repaired not replaced and most things could be adjusted with a screw driver or a spanner.


Thanks once again

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Provent is the most important addition IMHO,and oil pressure gauge is nice to have for added safety.

After the Scangauge perhaps consider exhaust gas temperature (EGT) gauge as another important piece in your NADS armory.

Other than you should be fine until you start modding the Patrol even further, LOL.


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Only went for a short drive, but the boost pressures were as you suggested averaging 10 psi to15 psi.


Looked on the net for the OBD scanners, there is a few of them but the " Scanguage " you mentioned seems to be a very comprehensive diagnostic tool.

The EGT guage is also an item for near future.


All the Best

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