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Discussion Starter #1
Hi everybody,
This is my first post although I have been a keen reader of this site for sometime and found the information very helpfull. I have a 2007 CRD manual patrol (Approx 10,000km) with a 2" lift (koni 88's & polyairs), EGT ( probe in the bend in the dump pipe after the turbo) & Boost gauges, 84% crawler gears(Marks) and Front Locker(ARB).

I recently completed a trip to the Cape via the OTL, Frenchmans track etc in a convoy including a 2005 auto Patrol Wagon and a 4.2 manual Patrol Trayback.

This trip raised real concerns about longevity of the 3.0Lt CRD engine and I wondered if anyone else has a CRD with an EGT gauge fitted or if anyone could offer a comment on the problem: the EGT got to 638c when cruising at 95km on the blacktop and accelerating to 105km/hr to overtake a truck using gentle acceleration so as not to overfuel. It also increased to 627c climbing a slight incline about 1km long. On the Cape Development Road that had heavy rain on new laid clay surface(very sticky) the temp reached just on 700c in 4th gear at 90km/hr. There were many other occasions when the temperature exceeded 600c yet the boost remained normal at about 12 to 14 and a max of 16.8psi. I did notice that by dropping a gear and bringing the RPM up to around 3000 to 3500 under the same conditions the EGT was about 20 to 30 degrees lower. The other shock was the fuel consumption, which for the CRD manual was around 20-25% worse than the 2005 Auto Patrol with a similar and roof rack load and about 30% worse than the 2004 trayback in most 4WD situations.

If my observations are normal then I have grave concerns for the longevity of the 3.0lt CRD engine, and certainly won't be putting a power upgrade computer chip in it as I understand that increases the EGT.

The other mods worked very well . The Koni 88 shocks are great with virtually no fade over severe corrigations, the front airlocker proved to be just as good as a L/Cruiser with dual lockers, and the crawler low range gears outstanding for being able to keep the engine on the turbo at 1800-2000RPM uphill whilst keeping the speed at less than walking pace to save damage to the truck and down hill control far exceeded anything that anyone on the trip had seen before.

RussTNQ
 

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600 is proberly not to bad. however with sensor after the turbo you don't get accurate readings due to how the turbo operates.
 

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bit cold out it seems
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calibration of your temp gauge may not be accurate too. sensors and gauges arent perfect (look at your standard temp gauge...cold...normal...cracked head :p).

CRD's arent melting around the place like the old engine, so far the only issues i've ever heard reported from them is high fuel consumption and pump/injector problems caused by bad fuel.

thats not to say it won't happen though. infact i think they will start to show piston and head/gasket failures in due time like pretty much all the modern turbo diesels are. only takes one bad batch of fuel and injector to start dripping for a speed hole to develop.
 

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RussTNQ said:
There were many other occasions when the temperature exceeded 600c yet the boost remained normal at about 12 to 14 and a max of 16.8psi.

RussTNQ
Hi RussTNQ, pretty good for a first post :bigthumb: , can you please let us know what tyres you are running.

Could other manual CRD member that have boost / EGT gauges confirm if 12-14psi cruise and 17psi max is the norm? I seem to recall some manual Di owners saying that their cruise boost was above the 20psi mark and they wanted to use the Dawes valve to bring it down.

I have recently had the pleasure of meeting up with Matt_GU who also has a manual CRD and his boost was behaving the same as RussTNQs, so was the fuel consumption :confused:

Cheers,
Whitie
 

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Why do you guys have you EGT's so far away from the exhaust port?

Why would you want to know the EGT post turbo? what value does this add?

I have my EGT probe set up close as possible to the exhaust port on #4 cylinder. No EGT as yet but the fitting is all set to go.

I have run EGT's on V8's / 2 stroke jet skis where the probe was set up in the bend of the headers as close as possible to the port.

On a turbo vehicle it is important to have the EGT prior to the turbo, not after it. A turbo can "soak up" over 100*c. The closer to the exhaust port the more accurate the temperature, it will always be cooler closer to the turbo.

At the exhaust port 900*C is not uncommon, I used to run at 1050*c in the V8.

Just my 2 cents worth .....
 

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titanium said:
Why do you guys have you EGT's so far away from the exhaust port?

Why would you want to know the EGT post turbo? what value does this add?
Hi titanium, I copied one of OldMavs posts which I think explains it well for the diesels:

Quote:
Originally Posted by Fox Shooter
In talking to a couple of deisel mechanics and the internet, from what I can find it is better to fit the EGT sensor before the turbo. A more realistic temp reading on whats coming out of the combustion chambers.
I do like the guage pod where can I get one for myself ?

Posted by OldMav
That is true but all data is related to just after turbo. That being 550 deg C for good engine life. this value spec is the value Cat, Man, Iveco, Cummins, Volvo, to but name a few of the engines i have fitted to boats and it dosn't matter if they are 40 hp to 2500 hp on a turbo motor value is the same 550 to 600 deg C Max. To have the sensor on the engine side a complete set of data values need to be found for that particular turbo motor and position. The temp varies greatly as you move along the manifold can be 150 deg C in 100mm, after turbo temp is constant for about 150mm past turbo. This is why engine Manf check temp after turbo as before turbo readings are unreliable and misleading with one probe.
If you want to read Temp before turbo to see which injectors are working and distribution etc etc, you have a probe or sensor at every exhaust outlet in the same position this will give you good readings and info on combustion etc, but tells you sh*t about what the turbo is doing. MTU motors 2000 series have both exhaust outlet temp max 950 deg C, turbo outlet max temp 580 deg C under full load. Save your money put one probe in just after turbo set your max fuel for 550 deg C and your motor will last. Your diesel mechanics are misleading you, the idea of the EGT gauge here is to monitor not to tune the engine, the VDO gauge is not what you use to tune your fuel system

Cheers,
Whitie
 

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whitie said:
Hi RussTNQ, pretty good for a first post :bigthumb: , can you please let us know what tyres you are running.

Could other manual CRD member that have boost / EGT gauges confirm if 12-14psi cruise and 17psi max is the norm? I seem to recall some manual Di owners saying that their cruise boost was above the 20psi mark and they wanted to use the Dawes valve to bring it down.

I have recently had the pleasure of meeting up with Matt_GU who also has a manual CRD and his boost was behaving the same as RussTNQs, so was the fuel consumption :confused:

Cheers,
Whitie

At 110-120 Kph, I have boost from 10-16 PSI max, when i lift off Boost drops to 6psi or even lower, MY EGTS have never gone over 500 yet ,

Around town 40-80 Kph its around 320-350 Deg C

On a long run up a hill, She may hit 480 Deg C at say 90 Kph

Ive pushed her to 140 kph on a straight freeway fully loaded, boost never went above 16 Psi and EGT never went above 500 Deg C in fact more like 450 Deg C a slight incline at that speed she does nudge 480 Deg C

Cheers
 

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GU5STS said:
At 110-120 Kph, I have boost from 10-16 PSI max, when i lift off Boost drops to 6psi or even lower, MY EGTS have never gone over 500 yet ,

Around town 40-80 Kph its around 320-350 Deg C

On a long run up a hill, She may hit 480 Deg C at say 90 Kph

Ive pushed her to 140 kph on a straight freeway fully loaded, boost never went above 16 Psi and EGT never went above 500 Deg C in fact more like 450 Deg C a slight incline at that speed she does nudge 480 Deg C

Cheers
Thanks GU5STS, those figures look real good. I assume that you are running on the standard 275/65/17 tyres?

It seems that the way to achieve Euro IV compliance is to lower the boost whilst possibly keeping the old EGR values.

RussTNQ, it appears that there is a lack of oxygen getting to the cylinders, this could be because there is too much EGR going back into the intake, or the aftercooler is not getting good air flow, the swirl valve is not opening etc. I would normally add to check the EGT probe (how far it is in the pipe) as this may alter the readings however the fact that you are also experiencing higher fuel consumption indicates that it is probably ok.

There is a process that Nissan can do to re-set the EGR (get it to re-learn its parameters - open, close, midpont etc.), it could be worth a shot.

I'm still keen to find out what size tyres are on the truck as you have it kitted out well.

Cheers,
Whitie
 

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Discussion Starter #9
Hi Whitie,

I am running LT 265/70/R17 Wild Spirit ATR's and had no problems on the trip (3800KM) to the Cape. Not a well known brand but about $100/tyre less than Coopers/MT- suppose to be made in the same factory as Coopers. There were several 4WD's with Cooper ATR's, in our convoy and they suffered more lug damage and one with a double sidewall stake. The Wild Spirit's were no noiser and worked as well or better in mud and on gnarley rocky terrain. The GPS indicates the speedo is now spot on at 60, 80 and 100k/h instead of underreading by 2k/m at 60 and 80 and 3k/m at 100 with the factory Bridgestones. I think that makes them about 10 to 15mm bigger in diameter.

Thanks for all the comments about the EGT over temp, it really has me concerned for the long term, I will be replacing the MAS in a few months (when I get back from driving an old Disc from the top to the bottom of Africa) even though I don't think that was the problem as the first time the EGT went to 630c the Patrol had only done 8500km with no offroad !

It would seem some CRD's mave real problems including high fuel consumption and very high EGT's. I found an earlier post where someone said they had 600c on a CRD. Perhaps if CRD owners could post there own info as more install Boost and EGT gauges we may be able to determine the extent of the problem.

For those with new CRD Patrols I might sujest removing the bonnet protectors as just doing this reduced my temp by about 10-15c under similar conditions at cruise speed.

RussTNQ
 

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whitie said:
Thanks GU5STS, those figures look real good. I assume that you are running on the standard 275/65/17 tyres?

It seems that the way to achieve Euro IV compliance is to lower the boost whilst possibly keeping the old EGR values.

RussTNQ, it appears that there is a lack of oxygen getting to the cylinders, this could be because there is too much EGR going back into the intake, or the aftercooler is not getting good air flow, the swirl valve is not opening etc. I would normally add to check the EGT probe (how far it is in the pipe) as this may alter the readings however the fact that you are also experiencing higher fuel consumption indicates that it is probably ok.

There is a process that Nissan can do to re-set the EGR (get it to re-learn its parameters - open, close, midpont etc.), it could be worth a shot.

I'm still keen to find out what size tyres are on the truck as you have it kitted out well.

Cheers,
Whitie
Hi Whitie,

yes mate standard tyres, mate.... i didnt see the point in going bigger , seeing im only on the black top

Cheers
 

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RussTNQ, Just slightly off subject. Thanks for the tip on bonnet protectors. I was thinking of getting one this week. Is your 84% crawler gear OK, was thinking of getting only 43% reduction?
 
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