Maverik Posted December 5, 2018 Share Posted December 5, 2018 Hi folks, So since installing my Exhaust Gas Temperature (EGT) gauge some time ago now I've been prompted to put up a query here, after some chat about turbo's and boost pins etc. I did some reserch into this and pulled up square root of not a lot. EGT's what is "normal" what is excessive and what will melt my turbocharger? - not easy to quantify due to some many veriables, but here's a few numbers below. I looked around for some technical specs for a Garret TB0242 but pretty much drew a blank, anfter doing some digging through technical papers I started seeing numbers around 750-800 degC for the upper temperature sustainable for said size of turbo - so adding some sense to the temperatures, thinking about what materials are involved, that sounds about ball park. From my own truck LR90 200tdi 150k on the clock, quite a well used engine but has a ported head, ali sports intercooler, boost sits about 8 bar, boost compansator has had the spacer removed and the pin has been tweeked. Values of course are effected by outside air temperature (deg C) but, I usually get value as per following. Idle: 750rpm: 50 - 150 degC cruising: 2000rpm 300 - 450 degC cruising: 3000rpm 450 + degC Foot down, 4th gear steep hill 650+ degC Mega steep hill foot down, I wussed out at 720 degC when I remeber feeling the engine power fadeing pretty quickly. Whats people thoughts on EGT temperatures for turbo's and whats too hot and whats not... Mav Quote Link to comment Share on other sites More sharing options...
Gazzar Posted December 5, 2018 Share Posted December 5, 2018 What is melting point of steel? Iron? How accurate is the gauge? How wealthy are you? 650+ is the conservative figure I recall from ages ago, when this was debated last. Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted December 5, 2018 Share Posted December 5, 2018 On my 300tdi... Idle - 200 Motorway cruising - 400 Giving it beans up a hill - 600 Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 5, 2018 Share Posted December 5, 2018 Nothing really matters other than the full throttle sustained temperatures. You need to check it over the full range of engine speeds as it varies. For instance, on my 200TDI, it is around 650 at 2000 rpm and rises to a peak of 720 C at 3000 rpm and then drops above that. There are obviously also variations depending on outside temperature and airflow through the intercooler. 720 C is the continuous limit set by Garret for the turbo. It seems to be safe for the engine, so there is nothing to worry about unless you sit well above that for long periods. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 5, 2018 Share Posted December 5, 2018 20 minutes ago, Gazzar said: What is melting point of steel? Iron? Iron around 1500 C, steel around 1350. But that is not something anyone would take into account. It is set based on corrosion and strength properties at temperature. The turbine metallurgy is what is setting the limit set by Garret for the turbo. Beyond the turbo, the next issue is piston temperature and the issue is mostly with fear of locking the piston or rings in the bore if it gets too hot. There does not seem to be any engine problems at the 720 C limit. I've had engines apart after sustained use and they look fine. Also many people have run massively higher before they kill something. Put in a gauge with an alarm. Alarm goes off, back off on the throttle a bit. Quote Link to comment Share on other sites More sharing options...
steve b Posted December 5, 2018 Share Posted December 5, 2018 I assume you aren't actually running 8 bar of boost but in fact 8psi ? cheers Steve b 1 Quote Link to comment Share on other sites More sharing options...
RedLineMike Posted December 5, 2018 Share Posted December 5, 2018 Some more boost wouldn't go a miss Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted December 5, 2018 Share Posted December 5, 2018 Mav My 300tdi is still a work in progress. I always thought it was fairly sprightly and after a couple of years the turbo let go big time. I fitted a new one, and looked in to adjusting the pump after articles on here. First port of call was an EGT gauge. Holy cr*p! I backed off at 780degrees C and climbing. Closer inspection showed it had already had the pump played with, as there were two witnesses marks on the boost pin. Looks like they had gone for the max, with no idea what was going on. The pump has been wound back to give a max EGT of 720 with the 3.5 tonne trailer on the back on a sustained climb. I think I found a max continuous figure of 725 C but can’t for the life of me find where. As I still have some off boost smoke, I need to try to get the pump back to standard and then start again. Presently running 1.2 bar boost. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted December 5, 2018 Share Posted December 5, 2018 I know this is about resultant EGTs but how have you achieved 1.2Bar of boost? Have you put one of those valves in the pipe to the wastegate actuator? Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted December 5, 2018 Share Posted December 5, 2018 PL i adjusted (shortened ?) the wastegate push rod. 1 Quote Link to comment Share on other sites More sharing options...
cackshifter Posted December 6, 2018 Share Posted December 6, 2018 18 hours ago, RedLineMike said: Some more boost wouldn't go a miss Yeah more boost will reduce temps I believe - correct me if I'm wrong Quote Link to comment Share on other sites More sharing options...
Maverik Posted December 6, 2018 Author Share Posted December 6, 2018 i'm running 0.8bar boost - correction to my first post. Thats an interesting question I'd not considered, what is the maximum operating temp of the engine? is the 720 degC as stated above published somwhere? or is that a general reference to "engines". Mav Quote Link to comment Share on other sites More sharing options...
reb78 Posted December 6, 2018 Share Posted December 6, 2018 52 minutes ago, cackshifter said: Yeah more boost will reduce temps I believe - correct me if I'm wrong I think possibly but only to a point? At some point doesn't the compressor become inefficient so that the intercooler can't cool sufficiently and the result is higher intake temps, lower amounts of o2 as a result and then less efficient combustion and higher EGTs? I.e. there is an optimum for each setup? I am no expert, so happy for someone else to step in...! Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 6, 2018 Share Posted December 6, 2018 1 hour ago, Maverik said: i'm running 0.8bar boost - correction to my first post. Thats an interesting question I'd not considered, what is the maximum operating temp of the engine? is the 720 degC as stated above published somwhere? or is that a general reference to "engines". The 720 C is the published maximum continuous operating temperature for the turbo. This number is from Garret. Land Rover has not and would not publish a figure. As far as they are concerned, you should never be adjusting anything. Regardless. 720 is perfectly safe based on real world testing. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 6, 2018 Share Posted December 6, 2018 33 minutes ago, reb78 said: I think possibly but only to a point? At some point doesn't the compressor become inefficient so that the intercooler can't cool sufficiently and the result is higher intake temps, lower amounts of o2 as a result and then less efficient combustion and higher EGTs? I.e. there is an optimum for each setup? I am no expert, so happy for someone else to step in...! No. More boost is always more air and lower EGTs at the same fueling rates. Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted December 6, 2018 Share Posted December 6, 2018 I ran 700 but with a low boost and it highlighted cooling issues Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted December 6, 2018 Share Posted December 6, 2018 More boost is beneficial up to a point. If you get too close to the surge line the compressor stalls and air flow drops until the pressure reduces to allow delivery again. Not seen it on my Defender but on a 12,000 shaft horsepower marine diesel it certainly gets your attention! Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 6, 2018 Share Posted December 6, 2018 Surge on a diesel turbo? How? Without a throttle, there is no way to limit flow while at boost. I'm pretty sure you would need to mess up by using a mismatch compressor to the turbine. Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted December 6, 2018 Share Posted December 6, 2018 Red 90 Typically on a marine engine it is due to operating conditions changing, for example heavily fouled scavenge spaces, damaged turbine blades etc. By increasing the boost I am operating closer to the surge line. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 6, 2018 Share Posted December 6, 2018 On a turbo, though, the compressor speed is limited by the turbine choice and its map. You can only reach surge if the turbine and compressor maps are mismatched without a restriction in the system. The shaft can't spin fast enough to produce pressure and reach surge until the flow rate through the turbine is high enough. They choose the turbine and compressor on purpose to prevent any possibility of reaching surge. It is the guys that make hybrid turbos that get themselves into trouble. Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 18, 2019 Author Share Posted February 18, 2019 Just to add a bit here, after sorting out my boost gauge, i decided to tweek the exhaust gas release valve arm. I made it shorter by 2.21mm or five turns. I've now been driving the truck a few weeks and what a difference its made to the driving, very happy, it seems to have increased the boost pressure by about 0.075-0.1 bar not a huge amount but I'm not getting anything above 650deg egt, I've not tried it on the Glen Shee hill yet but its quite interesting how a subtle change has made all the difference. She's now going up hills in 5th she's never before and apparently quite effortlessly too. Quote Link to comment Share on other sites More sharing options...
monkie Posted May 8, 2021 Share Posted May 8, 2021 I've fitted a Stack EGT gauge with the probe fitted just below the turbo where all 4 exhaust outlets meet in the manifold on my 19J. I'm quite shocked. Driving at what I thought was quite normal (normal boost not going over 0.6 bar) my EGT got to 750'C and was climbing before I backed off. I'm wondering if this accounts for my melted pistons last year as I did a motorway trip without the gauge so was in blissful ignorance of EGT? The good thing about having the EGT gauge is it has made my driving style back off a bit. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted May 9, 2021 Share Posted May 9, 2021 How are you achieving the newer driving style when your maximum boost was only 0.6 Bar? I imagine that when on a hill, you are holding a lower gear for longer, as you will be using less throttle? Quote Link to comment Share on other sites More sharing options...
monkie Posted May 9, 2021 Share Posted May 9, 2021 Foot down on the A303 in 5th gear going 70mph or climbing hills. I reduced my speed just a little (60-65mph) and the EGT dropped significantly. The 19J maximum boost should be about 0.65 Bar, but I'm guessing the lack of an intercooler is resulting in the higher EGT. I'd be interested to hear if anyone else has measured the EGT in a 19J. I'm guessing this might be another reason for the lower reliability of the 19J engine if you can quite easily get the EGT high. Quote Link to comment Share on other sites More sharing options...
L19MUD Posted May 9, 2021 Share Posted May 9, 2021 200tdi, full width intercooler and 15 psi with boost pin turned round but nothing else I can get my temps to reach over 700 but only when towing up a hill again around 70. As soon as it gets to 700 i back off the tiniest fraction on the throttle and it instantly drops 100 degrees. Sensor in same place as you Quote Link to comment Share on other sites More sharing options...
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