1hdt Kinugawa TD05-18G, can't reach 20psi

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So recently i decided to cheaply upgrade my turbo from the standard CT26 which has done 440,000kms. Once it was removed i noticed the wastegate port was cracked. Beside this i went ahead and fitted a new Kinugawa TD05-18g turbo with an internal wastegate which came with a 1.0Bar (14.5psi) wastegate spring.

When fitting the turbo i had to remove one of the brackets holding the steel water pipe running between the turbo and block so i could tighten up the bolts on the exhaust manifold flange. After this i went for a road test and found it only had 7 psi boost so i did some research and found this chart below:

Kinugawa Wastegate opening pressure/ preload spec.
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I received the factory yellow spring so i decided i needed to preload the hell out of the yellow spring to up the boost and i went ahead and did this and found a little difference ~2psi.

Following this i decided i wanted to run 20psi to gain more highway torque for hills and passing as 14psi from the factory CT26 was all i could possibly hope for. I went ahead and brought a 'blue' spring which had 1.5 bar (21psi) written on it and should open between 0.6bar and 1.5bar (depending on preload). Once this arrived i removed the wastegate actuator and fitted the uprated spring. This time instead of road testing i performed a pressure test using a modified tyre inflator and some hose fittings to pressurize the diaphragm, results from this showed the actuator didn't open till 12.5psi was applied. I took from this that once i fitted the new spring i would preload the actuator on the vehicle by shortening the actuator travel to obtain the correct boost between 14-20psi. The result from this was 12.5psi WOT in 3rd at 2,500 rpm.


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Next i thought what if i double the spring ratio so i fitted the factory 1bar spring aswell as the 1.5bar spring which was very difficult to fit and found now i only have 10psi on WOT in 3rd. what could i have possibly got wrong here?. The vehicle pulls hard down low but after 2,500rpm it has no balls and egt's are around 600c. This could be a fuel setting but i would have expected more boost.

Info on the truck:
1992 1hdt hdj81.
recond injector pump
recond injectors
custom intake incl snorkle
egt and boost guage Redarc.
auto with 440kms on the clock
3 inch exhaust
front mount intercooler
little to no blow-by
brand new Kinugawa TD05-18g with 11blade turbine, 6+6 cast impellor.

Below: Kinugawa turbo link


20210704_065701.jpg
 

mudgudgeon

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Setting wastegate preload with air pressure is only going to get you part of the way.

When the turbo is on boost, exhaust gas pressure is going to force the waste gate open earlier than what you have the waste gate preload set at.

You have exhaust gas pressure, plus boost to the waste gate actuator working together to overcome spring preload, and open the waste gate.


Have you done any tuning on the injection pump fuel settings?

Is you 600⁰c measured in the manifold, or in the dump pipe after the turbo?


You'll get better answers posting in the diesel tech section of the forum.

Also, loads of info about turbo's and tuning in these threads if you care to dig through them


 
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You might have a boost leak somewhere or exhaust sneaking past something
I have a boost leak, I forced air into the whole engine between the exhaust and air filter and found two major leaks. The first one was the red overboost solenoid tubing had come free and the second is the exhaust manifold (2 piece) which is leaking between the two halves. It also has a snapped exhaust stud which is hardly leaking at 8psi and using snoop to check.

After fixing the overboost solenoid tubing I got the boost upto 15psi, the exhaust manifold is getting fixed tomorrow, I'm going to remove the stud then replace all the split rings sealing the two halves.

I'm working out with help from a friend that the exhaust manifold pressure must be too low because if the leak. And subsequently not enough pressure (air speed) to spool the turbo up enough.
 
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Setting wastegate preload with air pressure is only going to get you part of the way.

When the turbo is on boost, exhaust gas pressure is going to force the waste gate open earlier than what you have the waste gate preload set at.

You have exhaust gas pressure, plus boost to the waste gate actuator working together to overcome spring preload, and open the waste gate.


Have you done any tuning on the injection pump fuel settings?

Is you 600⁰c measured in the manifold, or in the dump pipe after the turbo?


You'll get better answers posting in the diesel tech section of the forum.

Also, loads of info about turbo's and tuning in these threads if you care to dig through them


Thankyou I realize the exhaust pressure would cause that.

My redarc egt is pre turbo. And I have set an alarm at 600c. When I spool up the turbo in 3rd gear I get lower exhaust gas temperatures than I would at a low rpm in 4th gear. I'm reaching 550 wot and boost is sitting roughly at 7psi during this.

I'll double check the tuning thread, I have read it in the past. I have had to reduce fueling drastically with the new turbo.
 

mudgudgeon

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I have had to reduce fueling drastically with the new turbo.

Why? Because of EGTs?
An upgraded turbo should give you potential to add more fuel

At 600⁰c pre-turbo, your leaving a lot of potential untapped. 600⁰c is unnecessarily conservative for EGTs.
 

mudgudgeon

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Good that you found some boost leaks.


When I spool up the turbo in 3rd gear I get lower exhaust gas temperatures than I would at a low rpm in 4th gear. I'm reaching 550 wot and boost is sitting roughly at 7psi during this.

Auto? Or manual trans?

To test peak EGTs, you want to load up the engine.
I used to check my EGTs after tuning on a section of this with a long steep grade. Hit the bottom of the hill at a speed that has you at ~2000rpm at the bottom in second. Accelerate up the hill WOT, rev it out to 3800-4000rpm-ish before shifting up. repeat in 3rd and 4th.
You should be seeing a lot more than 7psi in this scenario.
The idea is to pump maximum fuel through the engine under load at low RPM, WOT, and sustain tugging condition long enough to see your EGTs peak so you can assess your tune.
Don't baby it for this. Drive it like you stole it.

If you don't have a long steep hill nearby, tow a boat, or caravan, or box trailer loaded with sand etc. Peak EGTs when it's working hard are what you want to check
 
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Why? Because of EGTs?
An upgraded turbo should give you potential to add more fuel

At 600⁰c pre-turbo, your leaving a lot of potential untapped. 600⁰c is unnecessarily conservative for EGTs.
Yes, I went from a ct26 to a kinugawa td05-18g. And obviously with the different performance range and boost leaks I am not spooling 15psi the same so I have made adjustments to keep egt's under control. At lower boost I already have way more down low torque than I did with the ct26. Up high I think the exhaust manifold leak is preventing me gaining power.
Good that you found some boost leaks.




Auto? Or manual trans?

To test peak EGTs, you want to load up the engine.
I used to check my EGTs after tuning on a section of this with a long steep grade. Hit the bottom of the hill at a speed that has you at ~2000rpm at the bottom in second. Accelerate up the hill WOT, rev it out to 3800-4000rpm-ish before shifting up. repeat in 3rd and 4th.
You should be seeing a lot more than 7psi in this scenario.
The idea is to pump maximum fuel through the engine under load at low RPM, WOT, and sustain tugging condition long enough to see your EGTs peak so you can assess your tune.
Don't baby it for this. Drive it like you stole it.

If you don't have a long steep hill nearby, tow a boat, or caravan, or box trailer loaded with sand etc. Peak EGTs when it's working hard are what you want to check
Auto a442f.

If I hold it long enough wot egts will go past alarm. If I'm honest I back off and adjust the fuel to prevent it going higher. This is all because I expect the boost to be much higher than it is.

For your scenario I get to 15psi max. For my tune I must be rich as the egts will keep going up, I'm backing off the throttle when egts get to 600.
 
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Having gone through the same thing with a FT motor, it turns out my intake gaskets had a MASSIVE leak meaning I just couldn’t build boost. You need to check/change pretty much every gasket/seal...

secondly, you really want to upgrade the exhaust system... the factory exhaust crimps down to like half of 2.5” and really chokes the engine/turbo. (Remember back pressure from the small exhaust reduces the pressure differential across the turbo, meaning it’ll struggle to build boost. Also, check your air filter and make sure the engine is breathing properly. Start with those changes and then let us know how it goes
 

mudgudgeon

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If I hold it long enough wot egts will go past alarm. If I'm honest I back off and adjust the fuel to prevent it going higher. This is all because I expect the boost to be much higher than it is.

For your scenario I get to 15psi max. For my tune I must be rich as the egts will keep going up, I'm backing off the throttle when egts get to 600.

The point of the test above is finding your peak EGTs as a tuning tool. It gives an indication of overall tuning, and whether you have tuned in too much fuel, or not as much as possible.

Backing off at 600⁰c result defeats the purpose of this test.
Your essentially trying to apply maximum load, maximum fuel at WOT for as long as possible to see what the tune peaks at.
A dyno tune is essentially trying to recreate this in a workshop.

I think you could re-evaluate what safe EGTs are.

Its widely accepted that 750⁰c pre-turbo is conservatively safe. GTurbo has said 850⁰c is a safe sustained maximum EGT in these engines.
I personally tuned so sustained WOT saw EGT of 800-850. But I was comfortable seeing this peak to 900 for short moments.


I think Feistl is right about intake manifold gaskets. They are known to leak a the rubber deteriorates. Easy enough to change them, you just need the hands of a7 year old to reach all the nuts.

Upgrading the exhaust along with the turbo is the biggest perforate upgrade you can do for these.
 
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Having gone through the same thing with a FT motor, it turns out my intake gaskets had a MASSIVE leak meaning I just couldn’t build boost. You need to check/change pretty much every gasket/seal...

secondly, you really want to upgrade the exhaust system... the factory exhaust crimps down to like half of 2.5” and really chokes the engine/turbo. (Remember back pressure from the small exhaust reduces the pressure differential across the turbo, meaning it’ll struggle to build boost. Also, check your air filter and make sure the engine is breathing properly. Start with those changes and then let us know how it goes
I have pressuresed the whole engine from the air intake to the end of my 3inch x-force custom exhaust, the only leak was where the two exhaust manifolds joined
 
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I was going through the same thing when I put a mamba on mine, fiddled around with springs for awhile, then just disconnected the wastegate and drove around, went right to 20psi(right what I was hoping for) and left it disconnected.
 
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I was going through the same thing when I put a mamba on mine, fiddled around with springs for awhile, then just disconnected the wastegate and drove around, went right to 20psi(right what I was hoping for) and left it disconnected.
I was contemplating that, might try it out.
 
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I have done some trial and error and found it is getting to 19spi at approximately 4000rpm. I have come to a conclusion that the timing needs increasing from 1.32 to 1.35mm stroke to give me more top end and in addition to that my android pin needs resetting and smoke screw turning up.

Question is for 20spi will the star wheel adjustment be strong enough to prevent the follower pin hitting the over fuel zone. I know some of you will think I'm lazy for not looking in the 1hdt tuning thread but I'm not going through 120pages of debate to find the answer. I have read from page 40 onwards multiple times.

Thank you.
 

mudgudgeon

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Best to remove the pin, mark it with paint, reinstall, test the aneroid with 20psi with a bike pump etc, remove and check the travel on the pin.

You can install shims/spacers at the start wheel to prevent the pin travelling deep enough to go into fuel cut.
Some injector pumps had spacers in the boost compensator assembly already, early ones did not.

If you remove the pin, you need to grind a bevel on the bottom edge to get it back in part the follower pin or
remove a plug, pin and spring to reinstall the fuel pin, then reinstall the oil,spring,plug. Easy enough to do, just hella fiddly in a tight space
 

mudgudgeon

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Also, in a long thread like the tuning thread, sometimes it helps to search within the thread with key words, and skin through the posts to find relevant stuff.
Hit the search button, type key words, and select search within thread.

There a load of good info in that thread, but it does take some digging that's for sure
 
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Best to remove the pin, mark it with paint, reinstall, test the aneroid with 20psi with a bike pump etc, remove and check the travel on the pin.

You can install shims/spacers at the start wheel to prevent the pin travelling deep enough to go into fuel cut.
Some injector pumps had spacers in the boost compensator assembly already, early ones did not.

If you remove the pin, you need to grind a bevel on the bottom edge to get it back in part the follower pin or
remove a plug, pin and spring to reinstall the fuel pin, then reinstall the oil,spring,plug. Easy enough to do, just hella fiddly in a tight space
Hi, thanks for this. I have done it and have got 25psi!
 
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Hi, thanks for this. I have done it and have got 25psi!
Hi, I was wondering if you're still running a Yellow and Blue spring together? What is your current wastegate spring?
I'm thinking of going with the same turbo.
 

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