06 BRM Jetta low RPM turbo flutter?

[gforce1108]

Buddy's car... Manual trans BRM. He had a leaking EGR cooler (exhaust leak) and I installed blank-offs and did a Malone 1.5 EGR delete tune on it. He's owned it since new and wishes he did it sooner. But... one slight issue that we can't say whether it's tune or a result of the EGR (they were driving it for a while with the EGR leak, which caused a loss of power whenever EGR was called for). Accelerating at low RPMs makes an odd vibration/noise. Almost seems like turbo surge (I've had it in my BEW with a 17/22 getting on it at lower RPMs). He has just been holding each gear a little longer and only pulling hard in the mid range.

He's selling it to a friend that is worried about it. I can log requested vs actual boost to see if it's hitting too fast. The EGR and cooler are still in place - just blanked off at turbo and inlet to the cooler.

Fairly low mile car - 140k or so. I know the "zip tie mod" is a common fix for boost issues - just haven't seen any similar issues to this.

 

[burpod]

are you sure it's boost and not timing? i would log 011-001-004 in TURBO mode. make sure to click TURBO button before clicking the log button, else you have to back out of measuring blocks to re-do it. ideally, a bit longer of a log. its not always easy to spot problem with a short 1 minute log of a couple pulls or whatnot

 

[gforce1108]

are you sure it's boost and not timing? i would log 011-001-004 in TURBO mode. make sure to click TURBO button before clicking the log button, else you have to back out of measuring blocks to re-do it. ideally, a bit longer of a log. its not always easy to spot problem with a short 1 minute log of a couple pulls or whatnot

I am completely unsure. I just know it felt like compressor surge that I’ve felt before in my own car but that was “lugging” in 5th with a larger turbo. Pulls beautifully other than 1st gear I believe. Could very well be timing. I did the timing belt a few years ago - don’t remember where torsion was last I checked. I’m working to get the car here to run some logs but figured I’d get a better idea ahead of time. Thanks!!!

 

[gforce1108]

Drove it around today some. Can only get it to do it under low RPM acceleration in 3rd and 4th. Been a wile since I drove it - more drivetrain vibration than turbo I think? I logged channel 11 though - little overshoot but doesn't seem out of the ordinary. Odd whistle sound. Last time I heard something similar was on a 1.8T that had a turbo wheel rubbing the housing. That thing smoked like you wouldn't believe. I'll see if there is a boost leak at the EGR cooler - my BEW had a bit of a squeal when the intake gasket was leaking.

Checked torsion - 0.0 at idle and goes to -0.5 when rev'd up so it seems to be working. There was a stored cam sensor code, but it cleared and didn't return.

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[Rx7145]

I’m skeptical of the torsion value. Could be correct but getting a 0.0 is kinda hard. Are the bolts on the cam pulley about in the center of the slots?

 

[gforce1108]

I’m skeptical of the torsion value. Could be correct but getting a 0.0 is kinda hard. Are the bolts on the cam pulley about in the center of the slots?

The last two PDs I've done came I got set to 0 with a slight fluctuation when bringing up the RPMs. I did this timing belt about 2 years ago. Correct cam pin and crank lock was used and had the cam bolts centered on install. I don't remember if it needed adjustment after initial install, but I'm 99% sure that it did not. I had him drive it to see if the fuel mileage was out of whack and would correct if needed. He's been running it hard ever since!

I have my own PD advanced in cam timing but I set the others to 0 or as close as possible.

I'm going to smoke test it, check the motor and dogbone mounts and make a blank-off for the intake side of the EGR cooler (may remove it, but seems way worst to do than a BEW!!!)

 

[Rx7145]

Ok, it’s probably fine.

 

[gforce1108]

Been working on a few other cars and forgot to update!. Whistle sound was a slight exhaust leak from the first blankoff. Removed and reinstalled with a better seal. All mounts tight, intake EGR connection blanked. Decided to change transmission fluid. Full drain and fill the hard way and it's noticably better. Slight bit of a groan when lugging it hard, but nothing out of the ordinary.