Pure stage 2+ boost oscillations (Help!!!)

[E92inSG]

Current setup:
Built engine + FBO
Pure turbos stage 2+
BMS charge pipes
EOS Billet top mount cooler
Dual WMI nozzles on cooler (cold side)
RK tunes J pipe
CSF front mount cooler
f80paul custom tune BM3

f80paul has advised I’ve got a small boost leak somewhere in my system. I’m still able to achieve target boost levels of 30psi but my WGDC logs using BM3 are always more than 90%, closer to 100%

Paul Johnson commented:

I increased the boost limit to 28psi. WGDC is definitely high for these turbos at this boost level. The JB4 uses a different unit of measure for WGDC so the two logs are not comparable.

I'm seeing some boost oscillations as well. If there is a boost leak that can be repaired this should solve the oscillations and also lower WGDC and improve power and lower IAT's.

I’m going to slowly troubleshoot the areas that could be leaking,

1. Re-install OEM top mount cooler
2. Re-route WMI nozzles to BMS charge pipes

Workshop has tried to do leak tests already but can’t find any leaks in my system

Does anyone else have any input on what could be the cause of my ultra high WGDC? The pure stage 2+ turbos shouldn’t be anywhere near capacity boosting 25-28psi which is what I run daily.

Here are some of my logs:

https://www.bootmod3.net/log?id=5e7a...0b43508e6fe1f1

https://www.bootmod3.net/log?id=5e7a...0b43508e6fe1f2

https://www.bootmod3.net/log?id=5e7a...0b43508e6fe1f3


As a very last resort, could my wastegates be faulty? It’s not Super expensive to replace both wastegates if it’s possible they could be faulty and causing high WGDC.

[Commanderwiggin]

Something on Bank 1 imo...check the charge pipe again.

An exhaust leak could be possible too at the turbo manifold-head flanges.

[BlownOne]

Check all clamps on the charge pipe couplers and make sure the pipes are fully inserted into the couplers. Check the j-pipe as well as those are the only places you could be leaking compressed air from.

[coldsteelrain]

I think I heard a guy say once that he had a boost leak because he never put the rubber o rings from his stock charge pipes to his after market ones. The aftermarket never came with the o-rings.

[rnguyennnn]

Originally Posted by Commanderwiggin

Something on Bank 1 imo...check the charge pipe again.

An exhaust leak could be possible too at the turbo manifold-head flanges.

x2. This is why i run silicone charge pipes and silicone wherever i can so plastic/metal/aluminum isn't causing issues. The boost leak could be coming from a small pinhole that you will not spot with a naked eye. It has happened to me with a brand that charges twice the price for their chargepipes. It took over 5 different ways of doing a leak down test over 2hours to find my pinhole leak.

[mike@x-ph.com]

Good luck OP and let us know once you figure it out

[E92inSG]

Appreciate the responses. Pls keep them coming.

Checking charge pipes etc all will do so definitely. These are the easy ones.

Right now my biggest worry is faulty electronic waste gates that aren’t throwing codes yet.

[E92inSG]

Originally Posted by rnguyennnn

x2. This is why i run silicone charge pipes and silicone wherever i can so plastic/metal/aluminum isn't causing issues. The boost leak could be coming from a small pinhole that you will not spot with a naked eye. It has happened to me with a brand that charges twice the price for their chargepipes. It took over 5 different ways of doing a leak down test over 2hours to find my pinhole leak.

I’m really looking to doing this as well. unfortunately i'd like to keep the option of perhaps in future locating my WMI nozzles there pre-IC

It will be a slow process changing one part at a time and re-logging each time.

But In the meantime the car seems to be running perfectly and pulling hard.

Only the logs are revealing these small issues

[E92inSG]

Originally Posted by Commanderwiggin

Something on Bank 1 imo...check the charge pipe again.

An exhaust leak could be possible too at the turbo manifold-head flanges.

what was it on bank 1 that you saw from the logs?

damn, manifold flanges would be a big job

[E92inSG]

Appreciate the replies!

[FriedPiston]

Had a similar issue, albeit with PS2 high flow turbos. Paul mentioned he noticed a slight sign of boost leak based on the logs, but nothing came up from a smoke test.

Continued to drive the car like normal, and went to the drag strip in an attempt to gather some data. Blew the engine due to a lean condition (fried piston on Cyl 4), so I never got around to diagnosing the source of the leak.

PS2 units were leaking a good amount of oil upon tear down, so it may have been a contributing factor. The aluminum J-pipe was a bit loose on the TB side, so I recommend adding this to your checklist.

[E92inSG]

I’m going to replace all screw clamps with T-bolts clamps as well to hopefully force a better seal.

[rborane]

Wow. And here I thought Pures were supposed to be the most reliable and consistent....

[E92inSG]

That’s what I thought as well! I don’t want to be so quick to blame the turbos. I’ll update with findings in this thread as I go along.

Again, the car is driving well and delivering good power at the current moment, and on a relatively “safe” tune from f80paul

[jpy1980]

Originally Posted by FriedPiston

Had a similar issue, albeit with PS2 high flow turbos. Paul mentioned he noticed a slight sign of boost leak based on the logs, but nothing came up from a smoke test.

Continued to drive the car like normal, and went to the drag strip in an attempt to gather some data. Blew the engine due to a lean condition (fried piston on Cyl 4), so I never got around to diagnosing the source of the leak.

PS2 units were leaking a good amount of oil upon tear down, so it may have been a contributing factor. The aluminum J-pipe was a bit loose on the TB side, so I recommend adding this to your checklist.

Ah jeez. What did you end up doing? Building the motor? Going with a different turbo brand?

[DanMpower]

Originally Posted by FriedPiston

Had a similar issue, albeit with PS2 high flow turbos. Paul mentioned he noticed a slight sign of boost leak based on the logs, but nothing came up from a smoke test.

Continued to drive the car like normal, and went to the drag strip in an attempt to gather some data. Blew the engine due to a lean condition (fried piston on Cyl 4), so I never got around to diagnosing the source of the leak.

PS2 units were leaking a good amount of oil upon tear down, so it may have been a contributing factor. The aluminum J-pipe was a bit loose on the TB side, so I recommend adding this to your checklist.

How did you run lean on #4? Tune related? Injector clogged?

[FriedPiston]

Originally Posted by rborane

Wow. And here I thought Pures were supposed to be the most reliable and consistent....

Pure turbos are probably as reliable as the OEM turbochargers. After all, their units re-uses the factory turbo housing. Things just have a higher tendency of breaking, or not go as expected when it comes to performance applications.

No brand or product is 100% resistant to failure. There's an MTBF to just about every mechanical part ever made.

[FriedPiston]

Originally Posted by jpy1980

Ah jeez. What did you end up doing? Building the motor? Going with a different turbo brand?

Yes

Originally Posted by DumbAS55

How did you run lean on #4? Tune related? Injector clogged?

Unfortunately, there's no log data that would help explain the engine failure. The tune was relatively safe like OP's situation. I should add I was running a 50/50 split (99% meth) feed on the J-pipe (cold side) that happened to have a loose fitment, and another one on the hot side charge pipe. Cylinder 4 is closes to the TB, so something clearly went wrong with the setup.

[E92inSG]

https://www.bootmod3.net/log?id=5e7f...0b430c46472b95

https://www.bootmod3.net/log?id=5e7f...0b430c46472bc4

I got another couple of fresh logs on BM3 running my 28psi map.

2nd log was a 100-200kmh run of 6.1s, which is decent for 93+meth @ 28psi, but clearly my WGDC is still super high and suffering boost oscillations.

Troubleshooting starts on Monday when workshop opens.

[Commanderwiggin]

Originally Posted by E92inSG

what was it on bank 1 that you saw from the logs?

damn, manifold flanges would be a big job

Looking at this again the bank 1/2 have quite a deviation of STFT. It could be that the meth flow is imbalanced to each bank as well in this scenario. I'm actually leaning more to an exhaust leak probably. I take back the Bank1 thought on the charge pipe.

Bank 2 is pulling more fueling out when compared to Bank 1 which could either be more meth going to Bank 2 or less air/less exhaust scavenging (overall less flow) in Bank 2.

[E92inSG]

Originally Posted by Commanderwiggin

Looking at this again the bank 1/2 have quite a deviation of STFT. It could be that the meth flow is imbalanced to each bank as well in this scenario. I'm actually leaning more to an exhaust leak probably. I take back the Bank1 thought on the charge pipe.

Bank 2 is pulling more fueling out when compared to Bank 1 which could either be more meth going to Bank 2 or less air/less exhaust scavenging (overall less flow) in Bank 2.

Yes, that was one of f80paul's initial comments about the uneven fuel trims might be due to uneven meth.

so 1st step tomorrow will be to move WMI nozzles to charge pipe pre-IC and revert back to stock TMIC, so try and isolate boost leak,

[Commanderwiggin]

Originally Posted by E92inSG

so 1st step tomorrow will be to move WMI nozzles to charge pipe pre-IC and revert back to stock TMIC, so try and isolate boost leak,

That seems backwards imo, you want the meth injected after the intercooler for maximum affect. The intercooler will do more work with a greater delta T (difference in temp) and then you inject the meth post intercooler. This provides max benefit.

Has your shop done a pressurized smoke test with a smoke testing machine? This should identify any leaks quickly.