Turbo wastegate setup on L300

Balboa

Balboa

Member
Hello all,

Months later, I’m still trying to clean up the results of my 4 month visit to Nomadic Vans in Idaho.

I recently finished installing the 3rd alternator after the visit. I’m pretty confident that despite paying them labor, it’s done correctly, now, because I installed this one.

So, to the point of the post. I paid for a basic tune at Nomadic. I’m not really sure what they did, it was supposed to deliver 12 psi boost. They told me that they couldn’t get over 10 psi. It had 10 psi when it arrived.

So, it’s time to tinker. On inspection, tonight, I found the actuator rod very tight, with no retention clip. For reference, I set it slack to have a base line. I found the wastegate barely able to move, it was binding. After a bit of playing around with it, it’s freed up and moves easily. Set slack, it will make 5 psi. My question, are the actuators problematic on the 4D56? It’s probably original. I can’t get any movement from it when off. I expected that I could get some movement manually. What I’m curious to know, is possibly the actuator has failed. I’d like to get that 12 psi if possible.

Thanks for any guidance.
Bill
 
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The actuator rod is set tight at default... and it is quite hard to move by hand. IDT it has failed, if it did you would get no boost (open) or unregulated boost (closed, 10+). You can test it by applying air pressure to it with a hand pump (≤15psi)... if it moves, it's not frozen or completely blown. A blown diaphragm also tends to cause the actuator to weep a little oil.

If you still have a dump valve installed that will limit you to ~10 PSI, but they know that. It could be a very worn/tired turbo... in good condition the OEM turbo seems to max out at ~16psi. And it could be a bad boost gauge... easy enough to test with a hand pump.
 
sk66 said:
The actuator rod is set tight at default... and it is quite hard to move by hand. IDT it has failed, if it did you would get no boost (open) or unregulated boost (closed, 10+). You can test it by applying air pressure to it with a hand pump (≤15psi)... if it moves, it's not frozen or completely blown. A blown diaphragm also tends to cause the actuator to weep a little oil.

If you still have a dump valve installed that will limit you to ~10 PSI, but they know that. It could be a very worn/tired turbo... in good condition the OEM turbo seems to max out at ~16psi. And it could be a bad boost gauge... easy enough to test with a hand pump.
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Thanks for the reply! I reset the actuator rod, and I'm back to 10 psi. Interestingly, I found this fine engineering addition. I'm guessing a Mickey mouse attempt to override the relief valve. I'm shaking my head.

What do you think? Eliminate this?

Thanks for the info.

IMG20230621173902.jpg
 
Balboa said:
What do you think? Eliminate this?
Click to expand...
It does disable the relief valve. The neater way to do it is to replace it with a 1" NPT steel plug from the hardware store. It's actually BSPT thread, but at this size/service NPT is close enough the same.
But it won't get you any higher on the boost.
 
sk66 said:
It does disable the relief valve. The neater way to do it is to replace it with a 1" NPT steel plug from the hardware store. It's actually BSPT thread, but at this size/service NPT is close enough the same.
But it won't get you any higher on the boost.
Click to expand...
This is great info, thank you!

So, I re-adjusted the rod, back to 10 psi peak. What are some signs of a failing turbo? There are no glaring issues, starts and runs fine, etc.
Does the turbo just start to spool slower and weaker as it gets tired? The van runs fine, it just seems less enthusiastic than I would expect.

Thanks
 
I'd pull the intake hose off the front of the turbo and check for excessive radial play in the shaft. If you've got excessive play in the turbo shaft that would indicate a mechanically worn turbo. Any rubbing marks on the housing around the fins, excessive gunk on the front of the turbo from blowby, or any metal transfer would indicate something is up. I'd also confirm your boost gauge is reading correctly with a vacuum gauge.
 
Balboa said:
There are no glaring issues, starts and runs fine, etc.
Does the turbo just start to spool slower and weaker as it gets tired? The van runs fine,...
Click to expand...
The only thing I can think of that would restrict boost w/o any other indications would be excessively worn turbine fins (no grey/oil smoke due to bearings, no black smoke due to inadequate air, etc).
Balboa said:
... it just seems less enthusiastic than I would expect.
Click to expand...
meet the 4D56T... you may just have to temper your expectations some; the difference in performance between 10psi and even 14psi boost is pretty minimal.

BTW, the turbo will tend to generate more boost pressure at 3000rpm/30kmph than it will at 3000rpm/90kmph. So how/when you are looking for the max reading makes a difference.
 
B.Delica said:
I'd pull the intake hose off the front of the turbo and check for excessive radial play in the shaft. If you've got excessive play in the turbo shaft that would indicate a mechanically worn turbo. Any rubbing marks on the housing around the fins, excessive gunk on the front of the turbo from blowby, or any metal transfer would indicate something is up. I'd also confirm your boost gauge is reading correctly with a vacuum gauge.
Click to expand...
Sound like a good course to explore. Looks like I’m going to be busy! Thank you!
 
sk66 said:
The only thing I can think of that would restrict boost w/o any other indications would be excessively worn turbine fins (no grey/oil smoke due to bearings, no black smoke due to inadequate air, etc).

meet the 4D56T... you may just have to temper your expectations some; the difference in performance between 10psi and even 14psi boost is pretty minimal.

BTW, the turbo will tend to generate more boost pressure at 3000rpm/30kmph than it will at 3000rpm/90kmph. So how/when you are looking for the max reading makes a difference.
Click to expand...
I’m pretty realistic about the response, I’ve put about 9000 miles on, for reference. I’m at 6000 feet, but it just doesn’t seem as perky as it was earlier. I’m curious that it can’t make more than 10 psi, regardless.

Thanks for your input!
 
Balboa said:
I’m pretty realistic about the response, I’ve put about 9000 miles on, for reference. I’m at 6000 feet, but it just doesn’t seem as perky as it was earlier. I’m curious that it can’t make more than 10 psi, regardless.

Thanks for your input!
Click to expand...
Did you just recently climb to 6k? Air's a bit thinner up there and it would probably benefit for being tuned for that altitude if it's going to be pretty normal.
 
Your van will only make as much boost as it has fuel. My Delica would not make more than 10PSI on a rebuilt turboand the waste gate wired shut. After messing about with the boost compensator to an extreme... it made 20PSI... but obviously that's to high and very inefficient for the stock TD04-10T. It made serious power... but also smoked worse than a cummins and I figured it would probably also blow up... so I tuned it was back down, and upgraded to a TD04-12T turbo w/ 5 bolt downpipe. Now it happily sits at 15PSI with an inline boost controller and a bit more fuel. No smoke and "reasonable" power... for a 4D56... (My Kei truck will still beat it in a drag race..) Higher in elevation will also have notable effects. The higher you are, the thinner the air, the less power the van will make. Going over the Tioga Pass (9,945 feet [3,031 metres) Delilah could barely get out of her own way foot to the floor.
 
sk66 said:
Did you just recently climb to 6k? Air's a bit thinner up there and it would probably benefit for being tuned for that altitude if it's going to be pretty normal.
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It’s been here most of the time I’ve had it back. It was the same at Nomadic in Idaho.

Thanks!
 
TieMyShoe said:
Your van will only make as much boost as it has fuel. My Delica would not make more than 10PSI on a rebuilt turboand the waste gate wired shut. After messing about with the boost compensator to an extreme... it made 20PSI... but obviously that's to high and very inefficient for the stock TD04-10T. It made serious power... but also smoked worse than a cummins and I figured it would probably also blow up... so I tuned it was back down, and upgraded to a TD04-12T turbo w/ 5 bolt downpipe. Now it happily sits at 15PSI with an inline boost controller and a bit more fuel. No smoke and "reasonable" power... for a 4D56... (My Kei truck will still beat it in a drag race..) Higher in elevation will also have notable effects. The higher you are, the thinner the air, the less power the van will make. Going over the Tioga Pass (9,945 feet [3,031 metres) Delilah could barely get out of her own way foot to the floor.
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Thanks for the info. Nomadic supposedly did these changes. I paid for it anyway… when I had the waste gate slack and if it made 5 psi, it did some black smoke under acceleration. Back at 10 psi, it seemed normal.

The main issue is that I don’t know if Nomadic actually made any changes. I got charged $800 for the”basic tune” but no proof the they performed the changes. My confidence in those guys is very low. They couldn’t diagnose a blown head gasket despite me telling them it was bad, and coolant shooting 6” out of the radiator neck at idle.

I drove it to St. George a while back and that’s around 2000 feet, not much different there.

I hate to start tinkering with the IP unless I know the turbo is capable. I guess that’s where to start looking.

Thank you!
 
To test how much boost your turbo is capable of, disable the wastegate actuator by clamping its boost hose (or detach the hose, whatever's easiest) then go for a drive. Your only control over the boost pressure will be your accelerator foot, so avoid holding 16psi for minutes on end. The turbo won't explode if you briefly hit 20psi.
If it's still only capable of 10psi, try shortening the actuator rod (more tension on the wastegate). A rod that's way too long/not enough tension means exhaust pressure will just blow the wastegate open. Adjust the rod until you can hit 16psi, that should get you into the ballpark where the actuator is working properly.

I don't think your pressure relief valve is the problem, despite that stunning piece of redneck engineering. A relief valve that regularly opens tends to be oily, and the noise it makes is quite alarming. You would have heard it.
 
im getting ready to plug the relief valve myself. Does it matter which type of 1" NPT plug. Theres two types at my local hardware store, black iron and galvanized. Would either work with a little thread sealant?
 
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