Have a look at this, from the archives, it is a survey that was done some time back and this one was specifically for the CRD.

http://www.patrol4x4.com/forum/zd30-crd-engine-3-litre-82/egt-survey-crd-88474/

You never know what you might find in these places.

We normally recommend the probe to be located closer to the turbo, within 50 to 60mm. Info like this can be found when looking at both DI and CRD archives as they are still basically the same engine and share a lot of components.

 

That's completely normal for a standard setup and, ideally, the probe should be as close to the turbo as possible ie about 50mm. With the chip, you will be able to not only increase the fuelling but also boost, which will drop the EGTs significantly.

 

My crd before i modified was much the same, i could even hit 700 degrees up a very steep hill. I was shocked how hot it could get.
My gauge is the same as yours ( aubrins ), and the pyro prob is in the same postion. After my mods, 3 inch exhaust and crosscountry intercooler, with my dp chip set to 9 ( max ) , dawes set to 22 psi, i get 580 degrees up the same hill.

 

I've had mine in for a bit over a year with the standard exhaust. I have the alarm set at 650 and have heard it maybe 3 or 4 times.

I'm about 50 - 60mm from the turbo.

 

This thread actually relates to a question I was curiuos about. Until coming to this site I had never heard of egt's and its something I have been curiuos about and trying to get my head around. If the OP says he was getting these high temps just driving up a hill, then what happens for instance, when towing a two tonne van for hours and hours at a time, do the temps just get ridiculously high, should you pull over snd give the car a rest periodically etc, or is it just when accelerating or going up hills temporarily and then the temps drop down again? I mean, I hear of heaps of people towing big vans for days at a time, or towing heavy trailers through sand etc, are these prople crazy and just waiting for something to go wrong. Im curiuos because I have a stock crd and have wondered about this as Ive never worried about it with my crd ranger and I give that thing a real good going towing and sand work for a few years now,but now my patrol is the family car and my ranger is full time work ute.

 

EGTs are a reflection of the air/fuel ratio, too much fuel and the EGTs rise. But you need fuel for power ie, when under load, so it's a balancing act regarding fuel and air. Pulling over won't help, as it's not a matter of letting things cool down like with an over-heating radiator. Changing gears may help so that the engine isn't loaded up as much.

Factory ECUs should be programmed to ensure a correct fuel/air ratio, so that EGTs stay below critical temperatures, but who knows what might affect things so that is not the case. That's where EGT and boost gauges come in handy, especially when installing chips, as you can see what's happening and be aware of the need to make changes to either driving style or tune.

 

Thanks Ray. So does that mean (in theory) that if Im towing my camping trailer through the sand with my stock crd that the ECU should prevent temps getting to a critical stage? Also, in an auto whats the best way to manage the gears to help prevent EGTs, overdrive off for a start Id imagine?

 

I don't believe that the EGT should be measured after the turbo and I have never done it that way because the data you get back is pointless on its own. After the turbo is the wrong location for just 1 probe, its has to before and after. It should be measured at the exhaust manifold just between cylinders 2 - 3 and for 6 cylinder is should 3-4 and then one probe after the turbo. We use several types but the most accurate are mercury filled or aviation gauges. Also the probes used only have a life span of 12 months so after this point the temp probe is not valid for accurate readings. A good temp gauge should also come with a certification certificate. The ones in the after market car stores and the chinese versions are totally mickey mouse and not reliable or correctly calibrated.

You should really consider the option of a dual probe gauge. One in the exhaust manifold and one after the turbo. For me to measure EGT after the turbo is pointless as it already 6 to 8 plus inches away from the exhaust port valves and the turbo compression effects the reading of the temps.

Anyone who rebuilds engine for living and works with post and pre post engines temps for controlled environments knows how much difference the temps are before and after the turbo. They are generally lower after the turbo then at the exhaust manifold. When we rebuild engines and require certification from DNV and Lloyds. They always want the factory acceptance test report for the manifold EGT as issued from supplier and then the final EGT after the turbo if fitted. Our engines run the same EGT cooling system as the Apache longbow helicopter and we work to precise movements of temperature, RPM and BOOST. We all have to be certificated to do these repairs due to zone rating on and offshore if working in high risk area for hot permits. The principle is the same for all engines regardless of make and model. A professional engine rebuilder would not check after the turbo once it has been rebuilt or for testing for modifications. So as you can see if you want it done correctly you need to have two probes. Also if you don't know what the engines manufactures limits are in regards to EGT then the gauges and the data can mean anything and its all guess work. There has to be a high and low point for these gauges or data logging equipment. It could be worth digging out the acceptance levels of what this engine was built to and Nissan should be able to issue that if asked. I my just email the technical department as see what they reply with. I really like to know what are the base levels for this engine in regards to EGT and boost.

I've checked on the Nissan computer and it does not measure EGT for DI and highly doubt it does on the CRD. The ZD engine is still very basic and outdated in regards to how much data logging can be done by the ECU.

I also don't agree with some of the NADS and all that spool up rate stuff as posted on several web sites as some of it is just guess work with very little facts to support it. But don't get worked up about, its only my view.

 

I don't believe that the EGT should be measured after the turbo and I have never done it that way because the data you get back is pointless on its own.

Not really the whole story, and this has been written many times, placing the probe close to the turbo flange, 50-60mm, is a simple and very effective method of getting an overall view of what is happening in the engine, the reaction time is very quick so you are getting positive feedback instantly.

In the archives we have a significant database of temperatures in this position that can be used as a reference, so going to all the trouble of fitting it in a manifold and possibly having one cylinder being dominant does not make a lot of sense, sure a correctly positioned probe in a manifold will be more accurate but why go to that trouble when 50mm from the turbo flange works just as well. We use 550C as a maximum for a DI (a little higher for a CRD) and many of us can achieve significantly better with a bit of work, in reality we are only after something to guide us and based on existing data,,,,, we do, simple as. I cruise at 210-240C on flat at 100k at 9psi and rarely see over 450C, this is down from 700C+ when I first fitted an EGT gauge but had no other NADS gear.

Now if I was building an engine or for some reason had to remove the manifold then I may just take the time to fit a probe in a carefully selected position, but for the masses who won't be doing this, 50mm from the Turbo flange is very good option.

 

geeyoutoo, I don't see how it can be measured correctly due to all the patrols on the road been so different in regards to engine compression, load up, ambient, altitude, fuel, fuel pressure, road conditions, temp of coolant, boost and all that other stuff. The only way is to do before and after to get some sort of true reading. I understand its a swine to fit one at the exhaust manifold but is it not just guess work now. If I said the ZD patrol standard boost is 28 PSI can any one show me a document from Nissan stating in black and white that that level of boost is to high or to low. So how can we guess what it should and shouldn't be. Its difficult one to I know and maybe even nissan have no real level of what EGT is ok apart from what heat the engine can displace.

 

As said we have collected data over a period of time with the objective of putting together as "safe a guide as possible" for the average punter, remember it's the average punter that we are concerned with here, those of us that have mechanical skills and background can please ourselves what we do, sure all engines are slightly different in various conditions but not that different, run a DI constantly over 550C (CRD's higher) in any conditions and you are closer to a failure than at 500C and you are not leaving much room and inviting a problem.

Even just a few years ago if someone had said we will all run our DI's at 18psi, it would have been almost impossible for the average punter to achieve, through guy's playing around collecting data and writing it up almost anyone can achieve it now without spending thousands, so what we have gained in knowledge has come from the roots of the forum and experimentation, the same as a safe EGT limit, it may not be written up in a glossy magazine but that doesn't detract from the quality of the info across the spectrum (that is the key), remembering it is a safe limit guide, that is really quite easily achieved.

 

Looking at the ZD30 engine I feel the root course of high EGT on this engine stem from multiple issues and they all need addressing when fitting a Ex Gas temp. What limits this little engine is the amount of EGT it makes and so we could be limiting the power all because were taking a lower reading. Is it not worth a little bit of extra time and doing both? I expect the ZD can run 850C at exhaust manifold with ease and 650C after the turbo for long periods of time. The OEM pistons are built to handle no more then 1200C for very limited period.

 

But this is changing your original point that post turbo EGT is not effective and that manifold readings are the only effective measure.

I go back to the point this was put together for the average punter, all measurements are subjective but when you have a data base that put's readings into a perspective and the EGT survey's go a fair way to doing that I feel, why should the average punter go to all that trouble removing manifolds to get a temp that he can already cross reference with other users in the same position.

I don't think we are robbing our engines of HP by aiming low, it's more important in how you aim low, you can pump plenty of fuel in as long as you are pumping in a corresponding amount of air, I have no problems with how much grunt mines got, it's way over std and as said my temps are hundreds below what I had and what I had was a significant contributing factor in the demise of my first engine, simple as.

Surely it makes sense to aim low than to aim marginal and run the risk of doing it all again?

I agree with you dbsep, the location and readings are largely irrelvent. BUT it will show a trend in its action. If you usually see 300*C cruising and then see 700*C, you know the motor is underload, the actual number could and does vary significantly to each vehicle, but the temperature change will always mean the same thing.

Isn't this exactly what I've been saying (just a little differently) that something to trend against is what the average punter needs, not having to remove manifolds (bloody helll the heat shield is hard enough).

 

I agree with you dbsep, the location and readings are largely irrelvent. BUT it will show a trend in its action. If you usually see 300*C cruising and then see 700*C, you know the motor is underload, the actual number could and does vary significantly to each vehicle, but the temperature change will always mean the same thing.

 

But I see dbsep's point and reflect on what I was saying the otherday. The advice being given from this site is a reflection on individual vehicles, setups, circumstances and personal preferences. Just because I see 600*C doesn't mean my car has something wrong with it because someone else sees 400*C. When calibrated or calculated from EGT position, any precombustion treatment, gear, load, etc. You'll probably find they are the same or could be hugely different. So what is gained by saying EGT should be either 400*C, 600*C or anything in between at a given rev or speed?

So even when we survey and get a variation of 200*C, vehicles anywhere on that scale could either be running ok or sht, we just don't know because the comparison is not the same.

 

This discussion is going nowhere so after this I'll stop, you believe what you want and I'll believe what I do, our members can make up their own mind based on our experiences and data, that is the choices a good forum gives, I have put forward the EGT surveys as a reference point for our "average punter", and I see no "evidence" (structured or anecdotal) to rule it out as a guide, I can live with that no worries.

If you read the survey (and I have read every single one in great detail) you will notice we had a lot of questions re mods etc to give the guy's something to compare too for their vehicle.

 

Thats the problem here sometimes and its like been stuck in the ways of its this way or no way. Its shouldn't be like that as its a general topic and all sorts of angles should be discussed or else it never really gets covered or updated. The last 5 years have seen the diesel engine transform from something very outdated to now been used in the Lemans and hot rods. We should always be looking for improvement even in the 4x4 Patrol range. What was once set as a bench mark may now be out of date and should be reviewed.

Im not saying the guide is wrong. It could be time to maybe review it. Data from 5 or 6 years ago may not be suitable for 2013 and forwards. The 4.8 and 5.6 Patrol has also under gone several changes and its important to keep up with whats been changed.

I was reading somewhere tonight and I lost the page that I wanted to post. It was a review from the US navy about temp probes. They were testing several different probes to measure EGT. Both had a variation of temperatures due to what material was used in the construction of the probe and I really wanted to recall what was the correct material to be used.

For me if I was fitting a probe to 3.0 I would go manifold and not after the turbo. It may take a little longer but its worth it in the long run.

 

I've read something like that before, when I was looking at processes temperature control. The info I found was for temp recording of motors for work/reliability/maintenance monitoring.

But we're not after degree accurate probes, it doesn't make a difference and we probably have even less accuracy in the guages anyway. None are calibrated units. The tolorence could be out by 10% or more.

 

I know heyhey. Thats way over the top for this motor. I was just interested to find if that probe was the same as used in aviation engines. More for my own interest than anything else.

 

Same probe design, less QA

 

Thanks to everyone for your replies

 

Update. I finally figured out what the culprit of the high egts were! Pre snorkel was also pre egt probe but fuel economy was good. Then I fitted snorkel and egt gauge in one weekend. Ever since have been having what i believed was high egts and poor economy even after injectors and rail replaced, but blamed the chip as that went in only a tank or two after snorkel and probe. That was 15 months ago.

After reading about 50 pages of thread "snorkel head foward or backwards" (and having a good ole chuckle at the 116 page debate it started) it got me thinking it was at the time of fitting the snorkel that my issues started. AND my snorkel was second hand with the head having no mesh. I fitted a piece of window mesh and thought nothing more of it. So this week I pulled off the snorkel head to try....guess what. ....more torque, more power and egts dropped on hwy by nearly 100c, sitting around 400-440 @100kph with the chip and standard no muffler exhaust. Next I pulled the mesh out and put the head back on, still low egts. I had finally found the culprit. It had been starving for air, the mesh was obviously to restrictive.....fuel economy has also improved. Have thus ordered new head from nissan.

So to everyone thanks for all your replies in the many threads on here. It is amazing just how much you learn from others! I am finally a happy camper with both power and economy with low egts....

 

If it was starving for air would it have not thrown an error code?

 

Evidently not. Perhaps it wasn't blocked enough. I forgot to mention that boost at 2200rpm(o/d) has increased by 2psi and 3100rpm has increased by 3psi... so it was definitely affecting air fuel ratios

 

Zip Nip, you shouldn't need to buy a new one , just go to an auto shop and get some cheap mesh that the racer boys use in their grill. I knocked the mesh out of mine with a low flying bird and so modified the snorkel head and fitted new mesh. See page 12:
http://www.patrol4x4.com/forum/zd30...or-housing-airbox-factory-snorkle-upgrade-feel-like-new-car-121322/index12.html

 

Thanks for that geordie, unfortunately I have already paid for the new one after trying everywhere to find the right mesh....