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4jg2 egt temps

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4jg2 egt temps

Postby Lukenz » Thu Aug 20, 2020 8:36 am

Hi everyone, what Egt temperatures would be considered safe in a 4jg2? going to be installing a egt Guage at the downpipe
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Re: 4jg2 egt temps

Postby geeves » Thu Aug 20, 2020 9:06 am

Its got to be pre turbo preferably where all 4 pipes join
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4jg2 egt temps

Postby Lukenz » Thu Aug 20, 2020 10:56 am

ok thanks geeves, would it work if I mounted it in my egr blanking plate on the manifold?
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Re: 4jg2 egt temps

Postby geeves » Thu Aug 20, 2020 1:10 pm

Thats what a lot of people do but it often reads a little cooler than point where the 4 pipes join. Also its slower to react to a change. Its where mine will be going though if I ever fit one
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Re: 4jg2 egt temps

Postby handymanny01 » Fri Aug 21, 2020 11:16 am

If I may weigh in... lol
The correct position for an egt probe is in one runner, in the middle of the exhaust stream, and as close to the cylinder head as possible... EGT is a TOOL to help diagnose whats going on in the combustion chamber.. its not a competition to see who can make the highest number.. placing it at a collector point will likely result in higher readings yes,, however you are wanting to reference combustion temps IN CYLINDER, not potentially in un-burnt fuel combusting in the exhaust manifold... experiencce with the 4jg2 says in this probe position, (easy due to the Exhaust recirc' port on manifold) a max of 650 c is "safe" any more and failure is immenient... (ask me how i know,,lol) id def seen 700 very briefly, but would strongly reccomend keeping to the 650 max on the indirect injection 4jg2...
Last edited by handymanny01 on Wed Aug 26, 2020 10:29 pm, edited 1 time in total.
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Re: 4jg2 egt temps

Postby handymanny01 » Fri Aug 21, 2020 11:17 am

note,, in EGR position, its important to drop probe into the gas stream, or (as Geeves notes), readings will not be correct
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Re: 4jg2 egt temps

Postby Lukenz » Sun Aug 23, 2020 11:59 am

cheers guys, installed egt Guage this weekend, I ended up installing it in my egr blanking plate, probe sits about 10mm of the bottom of the Manifold, should hopefully be in a good stream of exhaust gas! I have a 2.5" dump pipe and full system and the pump has been turned up, im seeing about 250- 300c at 100kmph and had it climb up to about 450c up a hill so far... im happy with how the truck runs, it is good to have the Guage as a reference, it is interesting watching the egts drop when more boost kicks in! it is running about 15-17 ish pounds though lol im hoping this gauge is somewhat accurate, i was expecting higher readings, with the diesel being turned up
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Re: 4jg2 egt temps

Postby handymanny01 » Sun Aug 23, 2020 9:10 pm

You've hit the nail on the head there! Read that line again "EGTs DROP as boost comes in" This is the kinda info you get from a correctly installed EGT gauge,,, What it's telling you is you are burning that extra fuel efficiently,, IN CYLINDER . As an example of what else the gauge might tell you,, if you were to advance timing, you would expect a corresponding DROP in EGTs , retard the timing, and you'd expect an INCREASE in EGTs, More boost within the "butter zone" of your compressor map will also drop EGTs, as will a good intercooler,,, more cold in equals more dense air, equals more fuel being burnt IN the combustion chamber, equals less EGT,,
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