The 2H/12H-T/1HZ/1HD-T/1HD-FT Gturbo Alternative Tech Thread

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Yep the boost is plugged. No exhaust leaks. One thing I could do is put some RTV on the intake manifold to make sure there's nothing leaking there.
 
410Nm / 129kw!!!

You can read and see my set up and results here:
 
410Nm / 129kw!!!

You can read and see my set up and results here:

That's about 1999 stock 1HF-FTE power/torque but you're also smokey. Why are you running such low boost?
 
because the engine has 430thsd km on its clock!
why should I squeeze more out of it?
It runs good as it is and has decent torque and power.
No reason for me to get more as it is now

Here in South Africa the engines are rare and a complete rebuild is pretty expensive
 
bit more boost = less smoke + less egt
 
My EGT are fine, running low.
Boost maybe, the actuator I use is not acurate (Mamba rubbish!)
I pushed the car up on the local mountains here without getting worried about high egt´s
And I can easily overtake a slower car now.
As I said, its ok for now, much better what I had befor
 
My EGT are fine, running low.
Boost maybe, the actuator I use is not acurate (Mamba rubbish!)
I pushed the car up on the local mountains here without getting worried about high egt´s
And I can easily overtake a slower car now.
As I said, its ok for now, much better what I had befor

You are smoking which fills your oil up with soot. A retune with more boost and less aggressive boost compensator will be much, much, kinder on your engine.

Where is your EGT probe and does it reach mid-stream?
 
Hi guys, I've installed an arashi td05-16 large on my 1HDT and it's seems awfully slow to spool, doesn't hit full boost of 19psi (I've installed a boost tee.) Till after about 2100rpm and even drops boost between 3rd and 4th which cause egts to spike up. Max egts under load on a hill are about 685 pre .
I've done injectors 3 inch exhaust and big end bearings recently. Any ideas please?
 
Hi guys, I've installed an arashi td05-16 large on my 1HDT and it's seems awfully slow to spool, doesn't hit full boost of 19psi (I've installed a boost tee.) Till after about 2100rpm and even drops boost between 3rd and 4th which cause egts to spike up. Max egts under load on a hill are about 685 pre .
I've done injectors 3 inch exhaust and big end bearings recently. Any ideas please?
What exhaust housing and turbine wheel do you have?
 
Hi guys, I've installed an arashi td05-16 large on my 1HDT and it's seems awfully slow to spool, doesn't hit full boost of 19psi (I've installed a boost tee.) Till after about 2100rpm and even drops boost between 3rd and 4th which cause egts to spike up. Max egts under load on a hill are about 685 pre .
I've done injectors 3 inch exhaust and big end bearings recently. Any ideas please?

Yeah the TD05-16G large (48.5mm inducer) is too large and always runs in an area of low efficiency. You need a better sized compressor. 16G small (46.5mm inducer) is better but still not a good fit for these engines.
Also 7cm turbine housing is way better than 8cm.
 
Hi guys, I've installed an arashi td05-16 large on my 1HDT and it's seems awfully slow to spool, doesn't hit full boost of 19psi (I've installed a boost tee.) Till after about 2100rpm and even drops boost between 3rd and 4th which cause egts to spike up. Max egts under load on a hill are about 685 pre .
I've done injectors 3 inch exhaust and big end bearings recently. Any ideas please?

FYI, your choice of text colour is totally unreadable for anyone who uses the dark screen option for viewing Mud
 
They're arnt a bunch of modified Toyota diesels around here for me to compare it to but I got to say I think the holset he250 8cm and twinscroll manifold is a great match for these motors. Pretty much no lag at all, driving my truck and a stock one w/ boost gauge back to back mine is in boost quicker and still doesn't feel like it's choking the engine from back-pressure at higher RPM. I've only gotten it up to 25psi so far. Stock wastegate is set to 30 so it hasn't even opened yet. Very mild tune right now for break-in haven't hit 1000f egt yet, still pretty quick.
 
hallo everybody, me also from italy playng with upgrade on my two ct26. first step of my adventure was step up from 5+5 to 6+6 keeping all original parts of ct26 block. @the moment the car is stopped for swapping turbo and other job, soon i will test it on road. I need only a little more air flux to low rpm, from 1000 to 1600. When original 5+5 ct26 will be mapped on test bank, i will comprare diagrams with upgraded 6+6. next step is to try another step up by using aluminium 11+0 48,3-64,89 wheel on the original aluminium part of ct26 coming from toyota supra,larger than ct26 oh hdj80.
thanks a lot for your marvelous topic.

6+6 ct26 original.webp


6+6ct26 original1.webp


6+6ct26original2.webp


6+6ct26original3.webp


11+0 ct26 48,30-64,89.webp
 
They're arnt a bunch of modified Toyota diesels around here for me to compare it to but I got to say I think the holset he250 8cm and twinscroll manifold is a great match for these motors. Pretty much no lag at all, driving my truck and a stock one w/ boost gauge back to back mine is in boost quicker and still doesn't feel like it's choking the engine from back-pressure at higher RPM. I've only gotten it up to 25psi so far. Stock wastegate is set to 30 so it hasn't even opened yet. Very mild tune right now for break-in haven't hit 1000f egt yet, still pretty quick.
What are the wheel measurements on the HE250 and which engine is it off?

hallo everybody, me also from italy playng with upgrade on my two ct26. first step of my adventure was step up from 5+5 to 6+6 keeping all original parts of ct26 block. @the moment the car is stopped for swapping turbo and other job, soon i will test it on road. I need only a little more air flux to low rpm, from 1000 to 1600. When original 5+5 ct26 will be mapped on test bank, i will comprare diagrams with upgraded 6+6. next step is to try another step up by using aluminium 11+0 48,3-64,89 wheel on the original aluminium part of ct26 coming from toyota supra,larger than ct26 oh hdj80.
thanks a lot for your marvelous topic.

One big problem with the Toyota turbos is no published compressor or turbine maps. But we can estimate them pretty well from measurements. The biggest problem with the CT26 turbos are old, inefficient, turbine designs and large turbine housings. Those need improved to get good response and more boost sooner.
 
What are the wheel measurements on the HE250 and which engine is it off?
turbine: 59mm/ 49mm
compressor: 69mm/50mm
looking up the part number on parts.cummins.com it says it's used on a 8.1L in china.

i bought mine from ebay china but benzforce has them now.

from what i can look up seems like its a newer design came out in about 2020 or so.

I also have a 6cm with the same size wheels for another project and I've seen a 9cm (not sure what size wheels)
 
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Toyotone was taken out of service a few days ago for a series of maintenance operations, including the replacement of the original turbine with its twin, upgraded with a 6+6 impeller. The first thing worth noting is that the dismantled CT26, with 500,000 km on the clock, is in excellent condition, with absolutely minimal mechanical tolerances. This turbine operated at peaks of 1.1 atm thanks to an extra valve that partially closed the waste gate. It was a pressure that was rarely reached, but during some long climbs I was able to read that value for a few seconds, then lift my foot off the pedal after indulging my desire to read the pressure gauge. The turbine now fitted has a 6+6 impeller but is identical to the original in terms of dimensions and my desire to fill a slight gap below 1400 rpm where the engine struggled a little to rev up in gears 3-4-5. The turbine works at the pressure of the original waste gate, which should be 0.74 or 0.84, I don't remember, I have to reinstall the pressure gauge, but in any case about 0.4 atm less than the original turbine. Despite this difference in pressure, the benefit is noticeable because the smoke between 1000 and 1400 is greatly reduced, gaining responsiveness and a linearity that was previously unknown to me. Let's be clear, it hasn't become a Celica. Continuing to drive uphill and downhill, I noticed a slight decrease in engine braking and a noticeable but not excessive increase in intake noise at the snorkel mouth with a slight whistling sound during gear changes.
 
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