[bpdef29]

I have a pretty obvious boost leak, but after days of research I haven't seen logs of one quite like this yet. Running Roc Euro DCI, ER chargepipe, and MHD. 65k miles, 91 oct, Southern California.

Note that as I flash to more aggressive maps, the boost stays closer to target. Theres a 1-2 psi loss at all times across the board, but note that above 5k the stock map has a larger boost loss than stage 1 and a significantly larger boost loss than stage 1+. These big top end boost drops are very noticeable when driving. What type of leak would allow this to happen? A chargepipe/intercooler connection leak doesn't logically seem like it would be so reactive to a change in maps, and all connections are sturdy. Vac lines or could it be something even more major?

If anyone has experienced anything like this and has some input that would be awesome. Currently nursing this and have an oil filter housing gasket to replace so hopefully she'll be running strong again in a couple weeks.

These are the logs (easily repeatable with same results; none of these were a one-time test).

Stock:
http://datazap.me/u/bdefiori/stock?log=0&data=2-4-21

MHD Stg 1:
http://datazap.me/u/bdefiori/er-cp-0?log=0&data=2-4-21

MHD Stg 1+:
http://datazap.me/u/bdefiori/er-1-plus?log=0&data=21
http://datazap.me/u/bdefiori/sept-5?log=0&data=2-4-21

[Sgop335]

You have a lot of timing corrections in stock, worse than tuned! Not sure why.

[limitdown]

I'm facing a similar issue.

WGDC is very high, but boost is well below target in the low RPM's. I eventually hit 19 PSI, but it's not reaching that until around 3,800rpm.

It could be a multitude of problems including hose clamps, pipes, boost solenoid, etc.

My car is currently at my Indy's for a vacuum test to pinpoint my leak.

[Chris@BoostConcepts]

Boost leak testing is tricky on these cars. I recommend doing a true boost leak test from the intercooler inlet forward so you can actually put some decent pressure in the system and check all the major connections from the head to the intercooler inlet.

Then test from the Inlets to the intercooler inlet , this will not allow near as high pressure as you will blow the Inlets off the compressor housings.

Start there, bit it may also be a solenoid issue, bad turbo(s), split vacuum hose, tune setting. Wastegate actually interference or adjustment out. Just have to start testing and narrow it down to find the culprit.

[Mike@N54Tuning.com]

The most likely place for a boost leak is the throttle body connection on CP and the lower CP connection to the FMIC. Check those first.

Smoke test would be the next step.

Mike

[bpdef29]

Update: Target boost still not attained. Car was actually overboosting for a day (20 psi peak) after catless DP install and then went back to underboosting the next day, so the turbos aren't cooked or anything.

Upgrade/test list:
All vacuum lines redone
Wastegates tested w/ vacuum (can hear both close)
DV's tested w/ pressure
Solenoids tested at idle (10-15") - when divided by 2 enough to close both wastegates
Vacuum canisters showing standard vacuum
Pressurized system soapy water bubbles test
ER chargepipe uninstalled/reinstalled
FMIC connections rechecked

Here's another log from today w/ Ken's v6 beta:
http://datazap.me/u/bdefiori/god-dam...=0&data=2-3-20

Getting really pissed off about not being able to find the culprit . Car still feels plenty fast, but my ego as a part-time amateur mechanic is destroyed haha.

If anyone has been through the wringer with this like me and found some obscure solution that I can try, please let me know!

[TrollToll]

Originally Posted by bpdef29

Update: Target boost still not attained. Car was actually overboosting for a day (20 psi peak) after catless DP install and then went back to underboosting the next day, so the turbos aren't cooked or anything.

Upgrade/test list:
All vacuum lines redone
Wastegates tested w/ vacuum (can hear both close)
DV's tested w/ pressure
Solenoids tested at idle (10-15") - when divided by 2 enough to close both wastegates
Vacuum canisters showing standard vacuum
Pressurized system soapy water bubbles test
ER chargepipe uninstalled/reinstalled
FMIC connections rechecked

Here's another log from today w/ Ken's v6 beta:
http://datazap.me/u/bdefiori/god-dam...=0&data=2-3-20

Getting really pissed off about not being able to find the culprit . Car still feels plenty fast, but my ego as a part-time amateur mechanic is destroyed haha.

If anyone has been through the wringer with this like me and found some obscure solution that I can try, please let me know!

May be worth trying a smoke test to see if you catch anything you couldn't find with soapy water. Also, I suspect that the diverter valves can pass a boost leak test but still cause issues while driving (such as opening and closing slowly). I am on the same boat.

[limitdown]

My Indy and I rigged up a $10 smoker and found small leaks from half a dozen spots. These leaks were too small to throw a 30FF, but enough to cause underboost.
Clamps were reclamped, orings and clips were repostioned, etc.

[bpdef29]

Originally Posted by Yournamehere90

May be worth trying a smoke test to see if you catch anything you couldn't find with soapy water. Also, I suspect that the diverter valves can pass a boost leak test but still cause issues while driving (such as opening and closing slowly). I am on the same boat.

Going in on the smoke test using your thread today. If this still shows nothing, I may give up forever haha. Wish me luck.

[bpdef29]

Smoke test showed nothing . Great DIY though Yournamehere. Unplugged a DV and got it to blow rings with the pump haha. I've officially done every possible test. Time to flash stage 2 since its winter with weather in the 50s and just enjoy the car for what it is...

Edit: Stage 2 log somehow looks good! Closer to target that I've been in any log I've taken, regardless of the stage!

http://datazap.me/u/bdefiori/stage-2?log=0&data=2-3-18