How can you determine what the trend is when you don't have pre-turbo data?
I have the same ppd exhaust. Post-turbo bung is plugged and staying that way.
1HD-FT what EGT’s are ok for sustained climbs?
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I have the same ppd exhaust. Post-turbo bung is plugged and staying that way.
If I drive at 70MPH for 30 minutes, it's 60-70F outside, it's 5AM, and the car had been warming up for 15 minutes prior to driving, and I do that for 3 weeks in a row, and my EGTs post-turbo are consistently 500F (+/- 100F), I can consider that "normal."
Not really valuable data though. The real value of an EGT sensor is EGT data outside of normal operation - say driving up an elevation, or towing, or during acceleration. Post-turbo doesn't get you reliable cylinder temp in those situations. Even at a steady 70mph you might be unpleasantly surprised.
In the end it's your engine and nobody except you will reap the consequences.
mudgudgeon
Resident galah
It's your $10K + engine. You do you.
mudgudgeon
Resident galah
So, in that scenario, how heat soaked is the turbine housing? Exhaust manifold? How steep the hill you just climbed? Did you push to pass another vehicle before you got that hill? How quickly did the temperature in the turbine rise? How long were you at WOT passing that truck? What's your coolant temp? Did the turbine and change cool off to "normal" completely before you hit the second hill?
mudgudgeon
Resident galah
It's been proven and documented that post turbo temps fluctuate wildly.
There's video floating around of egt gauge before and after turbo simultaneously, in the same vehicle, in the same shot. Gauge readings are vastly different
Here's the video. I've messaged the dude that posted it. The gauge readings are vastly different because of the cooling that takes place when exhaust travels down 2' of pipe. What you WILL notice in the video, is post-turbo EGTs increase in-concert with the pre-turbo. (with a bit of a lag).
Monitoring trends doesn't allow you to tune to safe limits. The temp drop across the turbo varies depending on conditions, pre and post turbo readings may be be further apart under hard acceleration than cruising or vice versa, you'd be guessing if you didn't have both sensor's data, at which point you'd just use the pre-turbo data because it's superior. It's your expensive engine though.
mudgudgeon
Resident galah
Pretty sure there's other video from a different vehicle that illustrates the differences better.
I'll let you search if you want to
The temperature drop across the turbine constantly changes depending on how hot the engine is running, how hard the turbine is running and whether the wastegate is working or not.
Honestly an A/F gauge is massively better than a post-turbo EGT.
AussieHJCruza
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Having had pre-turbo and post-turbo EGT on the same vehicle (93 HDJ80 1HDT H151, 3" Exhaust, 600x400x76 intercooler etc), I can assure you that post-turbo EGT is nothing more than a useless accessory.
When I was on the dyno messing around with the tune, I could hit 900C Pre-Turbo at 2500ish RPM if I held it at WOT on the dyno brake for a while. Post-Turbo wouldn't have exceeded 550ish C which is commonly regarded as safe around these parts.
The second thing is, post turbo is so much slower to respond to changes in throttle, load etc. and you're getting data that's 10 seconds old at best. Not really a useful indication.
When I was on the dyno messing around with the tune, I could hit 900C Pre-Turbo at 2500ish RPM if I held it at WOT on the dyno brake for a while. Post-Turbo wouldn't have exceeded 550ish C which is commonly regarded as safe around these parts.
The second thing is, post turbo is so much slower to respond to changes in throttle, load etc. and you're getting data that's 10 seconds old at best. Not really a useful indication.
Yeah I’ll prolly plug the port in my exhaust and do some research as to where to place the sensor pre-turbo.
Most people put them here on the 1HD-T's. I installed mine on the engine, drilled with a 90 degree drill until just about to break through, then greased the drill bit tip and started the engine so there was positive pressure in the manifold to blow swarf out and get caught in the grease.
mudgudgeon
Resident galah
Thanks guys. Drilling a hole in the manifold scares the s*** out of me.
I don’t intend on tuning the IP, but given that this truck has 70k miles and will one day be my soon-to-be son’s, I want to make sure it lasts for years to come.
ATL Cruiser
GOLD Star
I don't have anything to add to this discussion other than that's really awesome.
mudgudgeon
Resident galah
Yeah, drilling into the manifold on the vehicle is a test of nerves for sure.
As for tuning, you're assuming that no previous owner has messed with the tuning?
The tuning on these seems to vary quite a bit from the factory. Toyota is typically conservative on the tune, There could be a lot to gain in terms of driveability without hot rodding it.
Having the tune right can mean they are more responsive to throttle, meaning your not mashing the throttle so much
Sometimes, they are over-fueled right out of the box, and running high EGTs.
Another thing to consider, if you had a 25 year old car with a carbureted gas engine, most wouldn't hesitate to have the carburettor tuned after 25 years and the timing checked, just o be sure it was running crisp and clean.
Same with your vehicle. It could be highly worthwhile to have the injection timing checked, and the IP tuned.
mudgudgeon
Resident galah
Have a read here
This was put together by well respected Landcruiser people in Australia back when your vehicle was minty fresh. It's still very much relevant
This was put together by well respected Landcruiser people in Australia back when your vehicle was minty fresh. It's still very much relevant
I’ll check it out. Certainly not opposed to learning more about a vehicle I received that’s “abundantly” used.
Thanks bud.
