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Boost fluctuations and hesitation: APR Stage 1

thatspsychotic

thatspsychotic

Ready to race!
Blaznjoe said:
I'm GIAC Stage 2 tuned and started getting Boost fluctuations after a hard track day (road course) this past August. I chased for boost leaks and found nothing. Bought a new OEM n75 valve and replaced it two days ago with no other changes. Problem solved for me. No more fluctuations or hesitations. :thumbup:
I will say that replacing this little valve was a royal PITA :mad0259: Very little space around it. I highly recommend very long needle nose pliers. Maybe even long angled needle nose pliers. Also, upgrading to the USP turbo delete could make the job easier as well. (I kinda wish I did this.) I had to remove my turbo muffler in order to get my hands in there.

Other statistics:
53k miles
Chipped/Tuned for 40k+
Pump and Race file did not change hesitation issue
Still on original PCV
ECS CatchCan for about 10k miles
old n75 had oil in it. (Similar to DV)
Click to expand...

Thanks for the feedback. I'm considering having the dealer replace it for that reason... I wonder how much labor they'd charge. I'm pretty sure this is the culprit for what I'm experiencing. Shame that such a cheap part is such a PITA to replace.
 
Roadrunner_GTI

Roadrunner_GTI

Drag Racing Champion
Any update OP? I'm experiencing the exact same boost fluctuation issue with APR Stage1 v2.4 file. No codes, new rev D DV, new N75 valve, no improvement.
Starting to run out of ideas.
 
F

FriggenT1

Banned
Ronnie_B said:
Any update OP? I'm experiencing the exact same boost fluctuation issue with APR Stage1 v2.4 file. No codes, new rev D DV, new N75 valve, no improvement.
Starting to run out of ideas.
Click to expand...

Perhaps it's just in the software itself? Not a knock on the APR, but I've seen a lot of complaints about the new software since it came out, however I can't say I keep up with it either to say it it was resolved or not. I wouldn't just throw parts at it though. Unless you can flash back to stock I'm not sure how to say for certainty if it is or is not the software. You have any places close by that are not APR that might be weilling to flash their software to check it? Perhaps the APR dealer where you got your work done will flash it back to stock or stage 1 t o help diagnose the problem?
 
Roadrunner_GTI

Roadrunner_GTI

Drag Racing Champion
FriggenT said:
Perhaps it's just in the software itself? Not a knock on the APR, but I've seen a lot of complaints about the new software since it came out, however I can't say I keep up with it either to say it it was resolved or not. I wouldn't just throw parts at it though. Unless you can flash back to stock I'm not sure how to say for certainty if it is or is not the software. You have any places close by that are not APR that might be weilling to flash their software to check it? Perhaps the APR dealer where you got your work done will flash it back to stock or stage 1 t o help diagnose the problem?
Click to expand...

I flashed back to stock earlier today, no boost fluctuation issues...so it's definitely in the APR software. After looking at the N75 duty cycle in the logs, the gain on the PID Loop is set too high, causing the boost to overshoot and oscillate as it tries to meet setpoint. This is definitely software related.
 
F

FriggenT1

Banned
Ronnie_B said:
I flashed back to stock earlier today, no boost fluctuation issues...so it's definitely in the APR software. After looking at the N75 duty cycle in the logs, the gain on the PID Loop is set too high, causing the boost to overshoot and oscillate as it tries to meet setpoint. This is definitely software related.
Click to expand...

Have you contacted APR ?
 
E

Erick666

Passed Driver's Ed
I've had a similar problem. Turned out to be a faulty rev D DV. Switched back to the rev C I originally had in the car and it seemed to fix the issue. When I pulled the rev D out, it didn't come out in one piece (the cage portion was easily separating from the rest of the DV). I assume it was leaking, being that it was loose enough to come apart like that, causing the pulsing.
 
hbrown0509

hbrown0509

Go Kart Champion
Blaznjoe said:
I'm GIAC Stage 2 tuned and started getting Boost fluctuations after a hard track day (road course) this past August. I chased for boost leaks and found nothing. Bought a new OEM n75 valve and replaced it two days ago with no other changes. Problem solved for me. No more fluctuations or hesitations. [emoji106]
I will say that replacing this little valve was a royal PITA :mad0259: Very little space around it. I highly recommend very long needle nose pliers. Maybe even long angled needle nose pliers. Also, upgrading to the USP turbo delete could make the job easier as well. (I kinda wish I did this.) I had to remove my turbo muffler in order to get my hands in there.

Other statistics:
53k miles
Chipped/Tuned for 40k+
Pump (91oct) and Race file did not change hesitation issue
Still on original PCV
ECS CatchCan for about 10k miles
old n75 had oil in it. (Similar to DV)
no check engine light or error codes (I have VAG-COM)
Click to expand...



Sorry i know this is an old post, but also stage 2 GIAC and getting and getting the exact same issues. Been chasing it for months back and forth to my tuner shop. Boost leak free, new stock DV, turbo muffler delete, among basic bolt on mods and getting the oscillations. Similar to the video that was shared but worse. I’ve been wondering if the n75 has been the culprit? My shop has done many logs a dyno day and still think it could be software related. Race file doesn’t fix my issue either. Only problem now is that his dyno is down for a while for some part and won’t be able to get all the logs done. Almost tempted to just buy a new n75 and see what happens.

To the APR people having this issue, at least you guys aren’t alone whether it’s software or a hardware related issue. I’ve been dealing with mine for ever it seems and am exhausted by it. Car is not even fun to drive past 3rd gear.

Sent from my iPhone using Tapatalk
 
F

FriggenT1

Banned
hbrown0509 said:
Sorry i know this is an old post, but also stage 2 GIAC and getting and getting the exact same issues. Been chasing it for months back and forth to my tuner shop. Boost leak free, new stock DV, turbo muffler delete, among basic bolt on mods and getting the oscillations. Similar to the video that was shared but worse. I’ve been wondering if the n75 has been the culprit? My shop has done many logs a dyno day and still think it could be software related. Race file doesn’t fix my issue either. Only problem now is that his dyno is down for a while for some part and won’t be able to get all the logs done. Almost tempted to just buy a new n75 and see what happens.

To the APR people having this issue, at least you guys aren’t alone whether it’s software or a hardware related issue. I’ve been dealing with mine for ever it seems and am exhausted by it. Car is not even fun to drive past 3rd gear.

Sent from my iPhone using Tapatalk
Click to expand...

I'm surprised giac has not done better to solve the problem, but I know they do revisions and can adjust the tune.

The n75 is not an easy part to swap out.

Honestly, the ihi turbos have had wastegate flap issues, where the cleavis pin (i believe that's what it's called) causes the flap to rattle and even cause boost issues. If I were to check anything, I think I would do that next, simply because you can just unbolt the DP, move it to the side, and check that flap. If the flap opens, the ecu will sense it, thus compensate for it, which could POSSIBLY cause your issue.

See the end of this video (although it's only 1:30 or so)
https://youtu.be/Cl4AuMc8zfg
 
V

Verserk-MK6

Ready to race!
This is Great information, ive been struggling with this issue for awhile now.
At first the APR update seem to fix it, after a few months the issue was back.
 
hbrown0509

hbrown0509

Go Kart Champion
FriggenT said:
I'm surprised giac has not done better to solve the problem, but I know they do revisions and can adjust the tune.

The n75 is not an easy part to swap out.

Honestly, the ihi turbos have had wastegate flap issues, where the cleavis pin (i believe that's what it's called) causes the flap to rattle and even cause boost issues. If I were to check anything, I think I would do that next, simply because you can just unbolt the DP, move it to the side, and check that flap. If the flap opens, the ecu will sense it, thus compensate for it, which could POSSIBLY cause your issue.

See the end of this video (although it's only 1:30 or so)
https://youtu.be/Cl4AuMc8zfg
Click to expand...



Hey sorry for the late response but thanks for the informative feedback. The weird thing is I don’t get any fault codes or underboost codes/go into limp mode. Yeah I don’t understand how it’s been this difficult of a diagnosis. They’ve gotten so many logs you think they would have found the issue. Still on the holding pattern from the shop since his Mustang AWD dyno is down. He prefers this route for logging since the area the shop is at doesn’t have many spots to do third and fourth gear pulls. I did ask about the wastegate and was told there isn’t any play in the shaft. Honestly the car hasn’t been fun at all to drive this year and making me hate it. If I had the coin I’d try another tune but that’s kind of a dumb decision if it’s just something GIAC can revise in my tune.


Sent from my iPhone using Tapatalk
 
hbrown0509

hbrown0509

Go Kart Champion
FriggenT said:
Honestly, the ihi turbos have had wastegate flap issues, where the cleavis pin (i believe that's what it's called) causes the flap to rattle and even cause boost issues. If I were to check anything, I think I would do that next, simply because you can just unbolt the DP, move it to the side, and check that flap. If the flap opens, the ecu will sense it, thus compensate for it, which could POSSIBLY cause your issue. [\QUOTE]



Does the DP have to be unbolted to check the WGA?


Sent from my iPhone using Tapatalk
Click to expand...
 
F

FriggenT1

Banned
hbrown0509 said:
FriggenT said:
Honestly, the ihi turbos have had wastegate flap issues, where the cleavis pin (i believe that's what it's called) causes the flap to rattle and even cause boost issues. If I were to check anything, I think I would do that next, simply because you can just unbolt the DP, move it to the side, and check that flap. If the flap opens, the ecu will sense it, thus compensate for it, which could POSSIBLY cause your issue. [\QUOTE]



Does the DP have to be unbolted to check the WGA?


Sent from my iPhone using Tapatalk
Click to expand...

Well, you can feel play in the WGA rod sometimes I think, but they are fairly tight, humble mechanic did a YouTube video on it and on the fix, but said it wouldn't ultimately fix the issue entirely.
Click to expand...
 
hbrown0509

hbrown0509

Go Kart Champion
FriggenT said:
hbrown0509 said:
Well, you can feel play in the WGA rod sometimes I think, but they are fairly tight, humble mechanic did a YouTube video on it and on the fix, but said it wouldn't ultimately fix the issue entirely.
Click to expand...



Yeah I watched the video you shared and noticed that it was him, so legit source, and luckily for him the turbo was off the car making it easy to show. I did notice sometime ago that the clip is already on the actuator so VW must have put it on at some point either beforehand buying it or during service. Last month I had it at the tuning shop and he performed the smoke test which found no leaks. I made sure to ask about the WGA then and was told that he did check it to find no play in it.

I still want to check it as well. Just haven’t had the time recently.


Sent from my iPhone using Tapatalk
Click to expand...
 
Blaznjoe

Blaznjoe

Drag Race Newbie
hbrown0509 said:
Sorry i know this is an old post, but also stage 2 GIAC and getting and getting the exact same issues. Been chasing it for months back and forth to my tuner shop. Boost leak free, new stock DV, turbo muffler delete, among basic bolt on mods and getting the oscillations. Similar to the video that was shared but worse. I’ve been wondering if the n75 has been the culprit? My shop has done many logs a dyno day and still think it could be software related. Race file doesn’t fix my issue either. Only problem now is that his dyno is down for a while for some part and won’t be able to get all the logs done. Almost tempted to just buy a new n75 and see what happens.

To the APR people having this issue, at least you guys aren’t alone whether it’s software or a hardware related issue. I’ve been dealing with mine for ever it seems and am exhausted by it. Car is not even fun to drive past 3rd gear.

Sent from my iPhone using Tapatalk
Click to expand...

I'm just reading your response now.....I would recommend buying a new n75 and replacing it yourself, if possible. I know I stated it was a PITA but as long as you have patience and mechanical know-how, you can do it. Especially if you tackled the Turbo muffler delete (you were half way there to swap out the n75).
I also thought my waste gate was bad and also threw no codes during the fluctuation issue. And...I cleaned my MAF and MAP senors thinking these could be the problem but the issue was still there and very apparent/annoying. (MAP was oily.) I ordered an OEM n75 around $75 shipped then took my time and changed it. (Car battery remained plugged during the swap.) The fluctuation was gone immediately during the test drive and I've been fluctuation free for over a year now. :thumbup:
Definitely not saying our issues are the same but a n75 relatively inexpensive in comparison to a new turbo (or K04) so it might be worth a try.

Good luck!
 
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