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

[mudgudgeon]

Probably more specifically, don't assume any tune by a previous owner is safe. (Maybe don't trust a mechanic's "safe tune" either)

There's plenty of stories similar to diby's with trucks running hot

 

[diby 2000]

I am going to agree that 1200f is safe, my story is much the same. Before I touched the fueling or did any mods I installed my guages first. Same thing ...temps easily hitting 1400f if held WOT up a hill. This tune had done a couple trips to the mountins. I was loaded heavy and pushing hard on a few climbs holding it floored for minutes at a time....I can only imagine what the egt.s were.
My current tune will just touch 1200f on a long hill with the AFR around 25:1.Being slightly lean at 25:1 it stands to reason that this is safe if you are tuning by AFR. I believe 21:1 is a safe AFR from what I see posted here. What sort of temps does 21:1 AFR equate too?

There are a few things in play here such as injection timing and intercooling but I found that at 15psi a sustained 20.5:1AFR would result in the EGT sitting on the 750c mark almost perfectly. 21:1 would give about 730c. As a side note 19:1 would give about 830c.
Now I am slowly working the new MMP turbo and I am pushing about 32psi so far, and 750c is reached with 22-23:1. I have not had a chance to measure air temps yet and I'm sure this is affecting the temps. I think I might try some injection advance at some stage also.

 

[mudgudgeon]

There are a few things in play here such as injection timing and intercooling but I found that at 15psi a sustained 20.5:1AFR would result in the EGT sitting on the 750c mark almost perfectly. 21:1 would give about 730c. As a side note 19:1 would give about 830c.
Now I am slowly working the new MMP turbo and is am pushing about 32psi, and 750c is reached with 22-23:1. I have not had a chance to measure air temps yet and I'm sure this is affecting the temps. I think I might try some injection advance at some stage also.

That's helpful to have as a guide for the relationship between EGTs, and AFR
Cheers.

How does it go?

 

[diby 2000]

How does it go?

To be honest its great to have that torque when I push my foot but its a bit lazier than I expected (no worse than the CT26) but there are reasons for this that will be rectified soon.
I have discovered that I have an exhaust manifold leak beneath #6 and also out of the section where the two manifold pieces join. I have new gasket, seals, studs and nuts ready to go so I will fix that soon. I'm also convinced that I have a boost leak some where so I will have a go at finding and fixing that also.
Like I mentioned earlier, I had some help fitting the turbo as I wanted some more custom work done to allow the hot side intercooler pipework to fit and allow 4" pipe into the 90 bend onto the turbo. This meant I had to cut the compressor housing discharge pipe off and weld an alloy 90 onto the housing as well as requiring custom, custom hard lines to the turbo as the regular position that the water lines run are in the way. 4" pipe with bends take up a lot of real estate!
So anyway the bloke I had helping me is a bit of a petrol turbo guru and on inspecting the turbo we noticed that the waste gate had zero preload and there was no thread left on the actuator shaft to add some. So we pulled the actuator off to cut some new thread and then Aaron notices a large restriction in the turbine housing right at the wast gate port. We thought that didn't look right, so we ported it out to allow nice flow through the port. BIG MISTAKE! After talking to Luke and mentioning what we did there he basically said that's why its not as responsive as it should be.
Even though this was no fault of his, Luke is going to send me an entire new turbo to bolt on and send the one I have back to him to rebuild and sell again. You don't get better service than that!

For some detail on current performance though, I am only running a rough tune right now and it will achieve 15psi by 1900rpm (same as what the CT26 would do) and will be over 25psi by 2200rpm and at 32psi by 2250rpm.
I'm told that with all my issues resolved and the turbine housing and waste gate the way it was designed I should be seeing 25+psi by 1800rpm. I'm smiling right now but I'm looking forward to that type of response also.

 

[vwluv10338]

@diby 2000
I got my new silicone pieces on with the correct t bolts so I'm pretty sure I don't have any boost leaks. I have not touched the fuel yet but my turbo is not making anywhere near the boost that yours is. I'm making 10 psi at 2200 rpms. I wish I had a boost gauge on my truck when it was stock so I had something to compare it to. I had one temporarily set up once and I feel like my stock turbo started building boost at 1700 rpms and then it would shoot straight to 10psi. With this one it seems to build boost more like a petrol engine where it will starting building boost and then steady climb. Since I don't have an intercooler I am hesitant to touch the fuel but I guess I could mess with it and just watch my EGTs. Pretty sure I'm also going into boost cut above 2600rpms because there is will hit 15psi and feels slower than stock. So what's the best adjust adjustment to make to help spool? Add some main fuel screw to get more fuel to spool add some tension on the star wheel to compensate for the increased boost?

 

[diby 2000]

@diby 2000
I got my new silicone pieces on with the correct t bolts so I'm pretty sure I don't have any boost leaks. I have not touched the fuel yet but my turbo is not making anywhere near the boost that yours is. I'm making 10 psi at 2200 rpms. I wish I had a boost gauge on my truck when it was stock so I had something to compare it to. I had one temporarily set up once and I feel like my stock turbo started building boost at 1700 rpms and then it would shoot straight to 10psi. With this one it seems to build boost more like a petrol engine where it will starting building boost and then steady climb. Since I don't have an intercooler I am hesitant to touch the fuel but I guess I could mess with it and just watch my EGTs. Pretty sure I'm also going into boost cut above 2600rpms because there is will hit 15psi and feels slower than stock. So what's the best adjust adjustment to make to help spool?

Without knowing the position that you are in already, it sounds like you want more fuel at no to low boost to promote spool. But to start I would think that you need to know if you are going into overboost and stop that from happening first. Have you had the compensator pin out yet and if so I would recommend pulling it out and coloring the ramp you are using with a marker, installing it again and doing a few test runs from no boost to full boost to allow the follower pin to mark its travel on the aneroid pin. This will yell you if you are actually riding up the overboost section.
Depending on what this shows you, would probably dictate my next step. If you are going into overboost I would think about rotating the aneroid pin to a more aggressive ramp and add some spring preload to stop the follower from going into overboost. This means you will probably have to change the max fuel screw also and basically start tuning again. Or add a spacer under the diaphram, this will also work with less stuffing around.
If your not going into overboost you could remove some spring tension to get the pin moving into the pump earlier (with less boost) which will add some fuel to promote spool.
Or you could just add some more no boost fuel with the smoke screw. honestly Its hard to tell from here.

If you are gong to change things though, mark everything in the position they are in and write down every change you make. That way if you don't like the way it reacts you can always go back to where you are now.

 

[vwluv10338]

I have yet to touch anything fuel related. Upping the boost from 10psi to 18 I'm fairly confident I'm going into fuel cut but I guess I will have to whip out a paint pen and check. I'm more concerned about getting it to spool faster. It spins up to 10psi easily but it struggles from there but will rise to about 16psi before it hits the fuel cut

 

[diby 2000]

It may depend on whether there are any spacers beneath the diaphragm already. If there are they may not let the aneroid travel down into the pump enough for the follower pin to run up into the over boost section.

If all your your looking for right now is faster spool, as a trial I would remove half a turn, or even a full turn of preload from the star wheel (wind it down into the pump) and see what happens.
It may mean you build boost faster, then go into over boost and pull the extra fuel back out but it might prove the point at least.
If you stab the throttle when idling in neutral do you see a puff of smoke out of the exhaust?

 

[Tapage]

I really would like to know how was the factory tune .. and I mean out of the arakawa on a fresh build HDJ80 back in the day ..

 

[vwluv10338]

It may depend on whether there are any spacers beneath the diaphragm already. If there are they may not let the aneroid travel down into the pump enough for the follower pin to run up into the over boost section.

If all your your looking for right now is faster spool, as a trial I would remove half a turn, or even a full turn of preload from the star wheel (wind it down into the pump) and see what happens.
It may mean you build boost faster, then go into over boost and pull the extra fuel back out but it might prove the point at least.
If you stab the throttle when idling in neutral do you see a puff of smoke out of the exhaust?

I have no smoke at all that I can tell.

Edit to add: I adjusted my fuel rod cam plate to the most aggressive. Half a turn and I could feel more pressure. It made a big difference right there. I could hear the turbo spooling while backing down my driveway. Not trying to turn this into the fuel pump tuning thread but I wasn't happy with how the turbo was spooling but I'm amazed how a small tweak can change it. Will definitely need to do a bit of a tune and look for fuel cut but the drivability is much better

 

[Wildnlost]

That's helpful to have as a guide for the relationship between EGTs, and AFR
Cheers.

How does it go?

I have no smoke at all that I can tell.

Edit to add: I adjusted my fuel rod cam plate to the most aggressive. Half a turn and I could feel more pressure. It made a big difference right there. I could hear the turbo spooling while backing down my driveway. Not trying to turn this into the fuel pump tuning thread but I wasn't happy with how the turbo was spooling but I'm amazed how a small tweak can change it. Will definitely need to do a bit of a tune and look for fuel cut but the drivability is much better

One modification that was worth while to adjust off boost fueling was replacing the stock cam type adjuster built in the diaphram cover with an adjustable screw. @yotahed performed this mod when my pump was being rebuilt.
Before that mod was done I had removed the stock adjuster and place a washer under it too depress the pin more to increase off boost fueling. This adjustment really affects spool.

 

[mudgudgeon]

I really would like to know how was the factory tune .. and I mean out of the arakawa on a fresh build HDJ80 back in the day ..

I think it varies quite a bit, but was generally conservative (typical of Toyota).

You should be able to reproduce a factory tune with a good diesel shop if you really wanted it

 

[diby 2000]

I have no smoke at all that I can tell.

Edit to add: I adjusted my fuel rod cam plate to the most aggressive. Half a turn and I could feel more pressure. It made a big difference right there. I could hear the turbo spooling while backing down my driveway. Not trying to turn this into the fuel pump tuning thread but I wasn't happy with how the turbo was spooling but I'm amazed how a small tweak can change it. Will definitely need to do a bit of a tune and look for fuel cut but the drivability is much better

It is amazing the difference a tune will make. It's so much easier (and cheaper) if you can do it yourself.
Just be aware that you may have more fuel at full boost now also. Just watch it and see how the temps look.

 

[vwluv10338]

Removed the lock collar on the main fuel screw and gave it about 1/8 of a turn. Just enough that I got a quick puff of black if I did a stab at the pedal in neutral. This raised my idle to around 1000rpms so I will have to adjust that now. Now I can't boost to 20 psi and a run down the highway I could only get the temps up to about 1230F. Hard pulls in second and third gear seem to be around 950f. More power and better spool again. Not bad for no intercooler. I think I'm done messing with it for now until my intercooler and downpipe are done. I'm much happier with how it runs now. Way better drivability than when I first installed it. On my way to work this morning, before I even touched the main fuel screw, it would start boosting at 1200 rpms. I will try and get some better numbers on the way home tonight because I did this work at lunch and was only able to do a short drive.

 

[IanB]

Removed the lock collar on the main fuel screw and gave it about 1/8 of a turn. Just enough that I got a quick puff of black if I did a stab at the pedal in neutral. This raised my idle to around 1000rpms so I will have to adjust that now. Now I can't boost to 20 psi and a run down the highway I could only get the temps up to about 1230F. Hard pulls in second and third gear seem to be around 950f. More power and better spool again. Not bad for no intercooler. I think I'm done messing with it for now until my intercooler and downpipe are done. I'm much happier with how it runs now. Way better drivability than when I first installed it. On my way to work this morning, before I even touched the main fuel screw, it would start boosting at 1200 rpms. I will try and get some better numbers on the way home tonight because I did this work at lunch and was only able to do a short drive.

Be aware, that if you're able to hit 1230F accelerating on the highway, once you get onto a long grade and get things heatsoaked you will very likely have to back out of the throttle to keep EGT's in check. It's really tough to tune for the mountains when you live on the prairies, pretty well need some dyno time.

 

[vwluv10338]

Be aware, that if you're able to hit 1230F accelerating on the highway, once you get onto a long grade and get things heatsoaked you will very likely have to back out of the throttle to keep EGT's in check. It's really tough to tune for the mountains when you live on the prairies, pretty well need some dyno time.

I'll keep an eye on it. It needs to be tuned to tow my boat anyway. I was just tying to make it more drivable.

 

[gerg]

If you can get that high egt accelerating you can add like 150F on a sustained hill in hot weather easily.

 

[diby 2000]

Removed the lock collar on the main fuel screw and gave it about 1/8 of a turn. Just enough that I got a quick puff of black if I did a stab at the pedal in neutral. This raised my idle to around 1000rpms so I will have to adjust that now. Now I can't boost to 20 psi and a run down the highway I could only get the temps up to about 1230F. Hard pulls in second and third gear seem to be around 950f. More power and better spool again. Not bad for no intercooler. I think I'm done messing with it for now until my intercooler and downpipe are done. I'm much happier with how it runs now. Way better drivability than when I first installed it. On my way to work this morning, before I even touched the main fuel screw, it would start boosting at 1200 rpms. I will try and get some better numbers on the way home tonight because I did this work at lunch and was only able to do a short drive.

I'm glad it's working better for you.
Boosting from 1200rpm sounds more like what you want it to do.
Careful, now that you know what sort of difference a small tweak of the fuel pump can do, that you don't get addicted!

 

[Wildnlost]

.

I'm glad it's working better for you.
Boosting from 1200rpm sounds more like what you want it to do.
Careful, now that you know what sort of difference a small tweak of the fuel pump can do, that you don't get addicted!

More is always better. Right. LOL

 

[mudgudgeon]

.
More is always better. Right. LOL

More is never enough!