80 series 1hz turbo / boost cut issue

[phantom snail]

Hi guys,
new to the scene
Just got myself an 80 series rig
Its a factory diesel 1hz with a turbo kit on it
Not sure on what brand setup it is, but it's running what appears to be a factory turbo? [pics attached, can someone please confirm what kind of turbo / setup / manifold etc it is running]
Its been "tuned" and max egt I've seen is a touch over 500*C on full song up a hill at about 8-10psi [has a turbosmart manual boost tee combined with a 3" turbo back exhaust system]

So the issue I encountered on the drive home after purchasing it and after owning it now for a few days is what appears to be like a boost cut?
Doesn't matter what gear I'm in (1st through to 4th) - ONLY when WOT and up around 2500-3000rpm odd the turbo cuts out ... boosts to about 6-10psi (depending what gear its in) and then all of a sudden it cuts out, boost gauge reads minus pressure, engine speed decreases - there's no power at all. Clutch in and the boost goes from minus pressure to zero, clutch out and all good again, engine and turbo picks up ...
If I'm not on WOT, so even up to 90% open throttle, it'll rev out the whole rev range no issues or problems

Does anyone know what the issue is? Why is this happening? How do I rectify it?

Any help is greatly appreciated

Cheers

 

[dadinabarrel]

Looks like a stock Lancruiser C26. Great turbo, sounds to me like your wastegate or actuator diaphram is stuffed, or maybe just worn and needs adjusting, try clamping the boost controller completely shut, to see how much boost it really gets without the signal line telling the actuator to lift. You may have to adjust the actuating arm so it doesn't lift so easily. When it's worn it'll lift easily and can also creep (leak) when you're spooling up, robbing your response.

It's quite possible you are generating a lot more heat than 500'c as I can see that your EGT probe is post turbo. You really want to change that to pre turbo.

Just unbolt the turbo and put a plate/card inbetween the flanges, drill and tap into the exhaust manifold behind the mounting bolts and make sure you blow the crumbs out of the flange/gap, not through your turbo.

You'll see a very big difference between your pre and post temps.

Post turbo EGT temps are always lower as the air pressure created by the turbo has a cooling effect so it reads a lot lower, this has caused many a damaged engine, whereas you can rely on pre temps, keep them below a sustained 650'c (some say 700'c) and you're safe as houses.

 

[phantom snail]

^ You sir are a legend, thanks for the insight
Will definitely look into the wastegate and also the EGT probe
With respect the the EGT probe, do you have a pic of where the optimal position should be?

I know you say the C26 is a great turbo, however is there a better option out there? Will the gains be worth the money or will it be negligible?
I found up a steep hill, I struggled to keep the rig at 80km/h with temps a touch above 500 - otherwise 90% of the hills I have encountered I have been able to keep it at a comfy 90-100
Plus having something more powerful would be good ... however I guess I'm too use to my petrol motors =/

 

[Tapage]

Not sure it's a CT26 .. that down pipe does not look right ...

plus it must say CT26 on the cold section ...

my pre turbo EGT probe ..

 

[dadinabarrel]

Thanks Dude, I only know a little but I'm glad it helps. Here's mine.

I've put a Gturbo Grunter Extreme in mine. Absolutely unbefxxxinglievable compared to the stock after market unit I had previously. Boosts up to 28psi on a 1HZ

 

[dadinabarrel]

Of course the correct ARF is more important than the total boost, big boost with not enough fuel is a waste of energy. You have to find a balance between AFR/boost/EGT

There's lots of good info and some very smart cookies on here mate, check some of these out:

https://forum.ih8mud.com/threads/gturbo-racing-1kd-ftv-1vd-ftv-1hd-fte.820131/

https://forum.ih8mud.com/threads/performance-diesels.753727/#post-8668815

https://forum.ih8mud.com/threads/gbentink-turbo-upgrade-users-thread.505371/

https://forum.ih8mud.com/threads/the-official-1hd-t-ft-fuel-pump-mod-tuning-thread.728533/

https://forum.ih8mud.com/threads/th...1hd-ft-gturbo-alternative-tech-thread.802797/

https://forum.ih8mud.com/threads/the-official-1hz-1hd-t-1hd-ft-airbox-intake-mod-thread.731686/

https://forum.ih8mud.com/threads/the-official-1hdt-intercooler-thread.514067/

https://forum.ih8mud.com/threads/1hd-t-intake-manifold-modifications.651365/

That should keep you busy for a while

 

[Hulsty]

It is a aftermarket setup of some type, check all you intake pipework, some might be collapsing under load.

 

[Neil826]

X2 on collapsing intake pipe.
Most probably the elbow that is attached to the front of the compressor housing.

 

[SeaJay]

x3 on the intake elbow collapsing, try putting a hose clamp around it where it bends as a temp fix, the turbo looks like a schwitzer with that clamp setup on the outlet?

 

[phantom snail]

thanks for the help guys, turned out to be the intake pipe collapsing under load - now replaced with new silicon item and its boosting and driving awesome

 

[arnott1t]

So that tells you something....


You need a better air box. The intake collapsed because the pressure was so low inside it!