1HD-FT what EGT’s are ok for sustained climbs? (1 Viewer)

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Post turbo EGT is near useless.

There is no way to extrapolate post turbo temp to get an accurate pre turbo.
Temperature drops as exhaust passes through the turbo. There's just no way of knowing ”right now” if it's dropped 50 degrees, or 300 degrees.

There's a huge number of variables that affect the temperature drop at any given moment
 
I hear ya.
I have an exhaust going in soon and it happens to have an EGT port, so was going to utilize it. I dont want to remove the exhaust manifold to mount the EGT, and dont feel good drilling while the exhaust manifold is in place/installed as that may introduce metal shavings into the turbo.
 
Seeing as I have all your knowledge available, there's something else I'd like to check. Fitting the EGT probe, I removed the EGR crap and used the exhaust manifold blanking plate as the perfect opportunity to position the probe (without drilling into the manifold and risking swarf up-stream of the turbo). The only issue is that technically I'm only taking a reading of the EGT of two of the combustion chambers. Is this any concern - and also, as a result, would my EGT reading be slightly lower because the probe would only be exposed to combustion strokes less frequently? I'd expect there would be a much more frequent and constant flow of exhaust which would better average out with the probe more central. Be interested to know if this is something I should consider.
Cheers, Peter

I did the same thing on mine, and was wondering how accurate the reading was so I switched it to the collector on the manifold and really did not see any noticeable difference. I was getting my turbo rebuilt so had the manifold off anyway, otherwise its a lot more work then just using the EGR spot with a plate.
 
I hear ya.
I have an exhaust going in soon and it happens to have an EGT port, so was going to utilize it. I dont want to remove the exhaust manifold to mount the EGT, and dont feel good drilling while the exhaust manifold is in place/installed as that may introduce metal shavings into the turbo.

Drilled mine pre turbo 9 yrs ago- no issue
 
Post turbo EGT is near useless.

There is no way to extrapolate post turbo temp to get an accurate pre turbo.
Temperature drops as exhaust passes through the turbo. There's just no way of knowing ”right now” if it's dropped 50 degrees, or 300 degrees.

There's a huge number of variables that affect the temperature drop at any given moment

This, but I wouldn't say totally useless. Definitely dangerous for someone who isn't aware or knowledgeable about it. You just have to understand that it's reading low and slow compared to actual EGT's. Not great for tuning obviously. Here is a video I posted previously comparing pre to post EGT.

HDJ81 Pre vs Post Turbo EGT Readings

Unfortunately, one is Fahrenheit and the other is Celsius, but a bit of math and you can see how far behind the post turbo EGT is. Post turbo EGT I think was just after the flange to the stock elbow off the turbo.
 
I hear ya.
I have an exhaust going in soon and it happens to have an EGT port, so was going to utilize it. I dont want to remove the exhaust manifold to mount the EGT, and dont feel good drilling while the exhaust manifold is in place/installed as that may introduce metal shavings into the turbo.
I'd say you're risking more damage by going with a post turbo EGT that you would be drilling your manifold.

Many many people, myself included, have drilled the manifold on the engine with zero issues.
 
I did the same thing on mine, and was wondering how accurate the reading was so I switched it to the collector on the manifold and really did not see any noticeable difference. I was getting my turbo rebuilt so had the manifold off anyway, otherwise its a lot more work then just using the EGR spot with a plate.

Thanks Loober, that's useful to know. Certainly when I need to ever have the turbo out, the probe is moving, but until then that's handy to know. Cheers, Peter
 
You'll find with more boost, even the 14-15 the stock turbo is safe to, it's much easier to keep EGT's low under sustained load as there's more air available for the same or slightly greater fuel. The greatest improvement from upping the boost is on highway manners, it's so much more comfortable at those speeds with a higher boost max. You may even get greater fuel economy as you're making more power with the same fuel, and need to use less throttle than before.

Thanks Ian B, I have been intending to up the boost to 14psi but just haven't because I haven't had time to install the front mount intercooler I have bought which is in my garage and I trip over and have to move a couple of times a week. I want the intercooler installed as a 'catch can' in case the turbo lets go, that's my pre-requisite before more boost. I was hoping for exactly that result, some slightly lower EGT to enable me to use a little more throttle on the climbs with the caravan behind this summer and possibly a little more economy. I noticed the economy fell off quite dramatically with the change to 33" MT's. It's also good to hear the standard turbo is likely to remain happy at 14psi.
 
Thanks Ian B, I have been intending to up the boost to 14psi but just haven't because I haven't had time to install the front mount intercooler I have bought which is in my garage and I trip over and have to move a couple of times a week. I want the intercooler installed as a 'catch can' in case the turbo lets go, that's my pre-requisite before more boost. I was hoping for exactly that result, some slightly lower EGT to enable me to use a little more throttle on the climbs with the caravan behind this summer and possibly a little more economy. I noticed the economy fell off quite dramatically with the change to 33" MT's. It's also good to hear the standard turbo is likely to remain happy at 14psi.

You'll see a huge difference in EGT's with adding the IC, I would do a bit of driving before turning the boost up just so you can appreciate the difference each mod makes. At some point you'll want to start adding some more fuel, as you'll have so much more capacity to burn more fuel with all that added efficiency and air!
 
Seeing as I have all your knowledge available, there's something else I'd like to check. Fitting the EGT probe, I removed the EGR crap and used the exhaust manifold blanking plate as the perfect opportunity to position the probe (without drilling into the manifold and risking swarf up-stream of the turbo). The only issue is that technically I'm only taking a reading of the EGT of two of the combustion chambers. Is this any concern - and also, as a result, would my EGT reading be slightly lower because the probe would only be exposed to combustion strokes less frequently? I'd expect there would be a much more frequent and constant flow of exhaust which would better average out with the probe more central. Be interested to know if this is something I should consider.
Cheers, Peter


I know I'm late to this party, but my probe is installed in my EGR blanking plate as well. I think temperatures change and fluctuate so much during operation that even if there was a difference, our simple human minds wouldn't catch it.

To echo what others have said about temperatures, just last weekend I had a full load of camping gear, two adults, two children and a canoe on the roof, on a truck with lift and 35s, fighting a 50kph headwind and I was burning along the highway at 1100f for about 3 hours straight, hitting 1250-1300 on quite a few hills. Truck just kept driving :meh:
 
I hear ya.
I have an exhaust going in soon and it happens to have an EGT port, so was going to utilize it. I dont want to remove the exhaust manifold to mount the EGT, and dont feel good drilling while the exhaust manifold is in place/installed as that may introduce metal shavings into the turbo.
The port in your exhaust pipe is likely for an O2 sensor as they are positioned post turbo. I drilled and fitted my egt bung without pulling the manifold. I put grease on the tap and cleaned it several times. There is splitter in the manifold that I ran into while drilling.... I couldnt see it until my manifold was off for rebuild. If I was to drill again it would be a little bit lower to avoid the splitter.
Pre turbo as everyone has stated is the only reliable pickup point for an EGT probe.
Cheers
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For those with digital coolant temps, what kind of temps are you seeing on the engine at those EGT's #'s
 
I have an analog gauge, but I only see a maximum of 85-86 C coolant temps on longer hill climbs and I run 650C on pre-turbo EGT. I'm also running a FZJ80 radiator which I believe is slightly bigger than the original HDJ81.
 
That is what mine usually stays around, this weekend the outside temp was 37+, and I was seeing upwards of 95 on longer hills, which quickly dropped down to 85 once cleared the hill. The only reason I noticed is because of my digital gauge, the stock analogue barely moved from its normal 1/4 position, which i know does not mean much. But brings up the question of what is a safe coolant temp.
 
I have also seen coolant temps up to 100c in sustained 750c pre pulls with 35c ambient temps.

For reference, I have done the factory temp gauge mod to remove the dead spot and with this mod the temp gauge is still reading about 1/8 below the red zone and the air conditioner has not cut out.
This tells me I'm still safe. Ymmv.

I have also done the can clutch mod and can hear it roaring when it's getting hot.
Normal coolant temp is 78 - 82c
 
Theoretical safe coolant temp is anything below boiling point.

With glycol and pressurised radiator, that should be around 102-104°c maybe more.

With my hdj81 I saw the stock gauge creep above normal only once and that was after repeated sustained WOT hill climbs in 40+°c ambient with EGTs in excess of 850°c
 
15psi pressurised cap raises your boiling point to around 120°C.

100°C is in the normal operating range and no cause for concern.
 
I'd say you're risking more damage by going with a post turbo EGT that you would be drilling your manifold.

Many many people, myself included, have drilled the manifold on the engine with zero issues.
PPDperformance manufactures 3" exhaust systems for 1HDFTs with a pre-drilled EGT bung...

Edit: the pre-drilled bung is specifically for an EGT port.

I've got a note out to PPDperformance to pick their brain on pre vs. post-turbo EGT sensors as I've fitted their pre-drilled hole with a sensor. I live in coastal Texas (hot & humid). Cruising, that sensor reads anywhere between 400F-600F depending on ambient temps.

It was particularly hot & humid this morning, so I saw 800F at WOT, but back down to 500F at ~110KMPH.

I understand a pre-turbo sensor is more accurate at reading exhaust gas, but if I can determine a baseline based off regular driving (pre-turbo), I can view deviations as abnormal.
 
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I understand a pre-turbo sensor is more accurate at reading exhaust gas, but if I can determine a baseline based off regular driving (pre-turbo), I can view deviations as abnormal.
You can't be sure the temperature do across the turbo is the same in all conditions. It's not.
It'll give you a half assed vague indication at best.
Fine if you're running a really conservative tune, at which point, and EGT gauge is a useless accessory.
 
You can't be sure the temperature do across the turbo is the same in all conditions. It's not.
It'll give you a half assed vague indication at best.
Fine if you're running a really conservative tune, at which point, and EGT gauge is a useless accessory.
It's not tuned.

You can call trend-monitoring a "half-assed vague indication at best" if you'd like. Not the hill I'm gonna die on.
 

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