Hi all,
I've got a MK 7.5 GTI. I was tuned with EQT (ECU stage 2 + TCU). I am running a Forge blow off valve, turbo inlet and the integrated engineering intake, amongst other mods. I had been running the blue spring for the Forge BOV (23-30 PSI) since EQT stage 2 peak boost falls within that range.
I changed over to Unitronic stage 2 ECU/TCU last week.
Since then, I've been noticing some faint turbo flutter on letting off the throttle under very light load (most often has been in 2nd gear when releasing the throttle around 2000-2500 RPM).
Found this video on youtube, this is exactly what I'm experiencing.
When I hear the turbo flutter the BOV does not vent (i.e. closed throttle compressor surge).
I have a mechanical boost gauge and it's typically still reading vacuum or just under 0 PSI when this happens (i.e. I'm not in boost). Doesn't happen when on throttle at all, and doesn't occur if I let off the throttle after hitting boost (e.g. even 5 PSI, if I let off I can hear the BOV venting properly).
I don't think the BOV is stuck since it operates normally when venting off when > 0 PSI. But I am wondering whether the spring is too tight to vent under light engine loads.
Just curious if anyone else has noticed turbo flutter on throttle let off with Unitronic? I'm seeing posts about this with other tuners like APR and IE, but generally people haven't noticed it with EQT. Maybe I'm just not used to it?
I'm planning on swapping back to the yellow BOV spring (15-23 PSI; I'm told Unitronic stage 2 peak PSI is 22) but can only get the car in to a garage in over a week. I'm reading closed throttle compressor surge isn't really harmful to modern turbos (although not ideal I know), as opposed to open throttle compressor surge (that definitely can damage turbo bearings). Given it's only happening at very load engine load/off boost, should I be OK?
Also reading the comments in the attached youtube video above and it seems that when the OP had switched back to the stock DV it still fluttered. I'm suspecting it's more of a tune issue than the spring being really too strong, since it'll blow off consistently the minute I hit > 0 PSI and consistently when doing a pull and then letting off the throttle.
I've already read up on BOV vs DV extensively and not looking for advice on BOV vs DV given the MK7 GTI has a MAP sensor.
Thanks in advance for any help!
I've got a MK 7.5 GTI. I was tuned with EQT (ECU stage 2 + TCU). I am running a Forge blow off valve, turbo inlet and the integrated engineering intake, amongst other mods. I had been running the blue spring for the Forge BOV (23-30 PSI) since EQT stage 2 peak boost falls within that range.
I changed over to Unitronic stage 2 ECU/TCU last week.
Since then, I've been noticing some faint turbo flutter on letting off the throttle under very light load (most often has been in 2nd gear when releasing the throttle around 2000-2500 RPM).
Found this video on youtube, this is exactly what I'm experiencing.
When I hear the turbo flutter the BOV does not vent (i.e. closed throttle compressor surge).
I have a mechanical boost gauge and it's typically still reading vacuum or just under 0 PSI when this happens (i.e. I'm not in boost). Doesn't happen when on throttle at all, and doesn't occur if I let off the throttle after hitting boost (e.g. even 5 PSI, if I let off I can hear the BOV venting properly).
I don't think the BOV is stuck since it operates normally when venting off when > 0 PSI. But I am wondering whether the spring is too tight to vent under light engine loads.
Just curious if anyone else has noticed turbo flutter on throttle let off with Unitronic? I'm seeing posts about this with other tuners like APR and IE, but generally people haven't noticed it with EQT. Maybe I'm just not used to it?
I'm planning on swapping back to the yellow BOV spring (15-23 PSI; I'm told Unitronic stage 2 peak PSI is 22) but can only get the car in to a garage in over a week. I'm reading closed throttle compressor surge isn't really harmful to modern turbos (although not ideal I know), as opposed to open throttle compressor surge (that definitely can damage turbo bearings). Given it's only happening at very load engine load/off boost, should I be OK?
Also reading the comments in the attached youtube video above and it seems that when the OP had switched back to the stock DV it still fluttered. I'm suspecting it's more of a tune issue than the spring being really too strong, since it'll blow off consistently the minute I hit > 0 PSI and consistently when doing a pull and then letting off the throttle.
I've already read up on BOV vs DV extensively and not looking for advice on BOV vs DV given the MK7 GTI has a MAP sensor.
Thanks in advance for any help!