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Tuning APR K04 wastegate

GTIAPRK04

Cam Follower Replacer
Location
Maryland
Firstly, I know there are other threads about K04 wastegate tuning. I've read many of them and picked up little snippets of info here and there. So, I'm not trying to start a huge wastegate tuning discussion thread. Only trying to get some suggestions from the gurus out there for my particular situation. Of course, as many others, it may hopefully assist others, too.

Details:

So, I have an early 2006 GTI, 158K on the clock, stock internals (head redone with new cams @ 130K), 170-180 compression on all four bangers. It has the APR Borg Warner K04, APR K04 tune, APR HPFP, S3 injectors, full APR turboback exhaust, Eurosport intake with ITG filter (I also have the APR Carbonio stage 1 and stock engine cover), stock intercooler, rev D DV, IE PCV blockoff, and New South boost gauge.

After 45K on K04, I found I was having oil burn and too much shaft play on the turbo. Got a new genuine Borg Warner K04-0064 CHRA and rebuilt the turbo. No leaks and all is well. Even threw in a new Pierburg Rev D DV while I had it out.

The Problem:

So as many others have found, I tried to set the wastegate with the turbo out but sure enough it was way off. First time driving the car hard in 93 program I hit 30+ psi spikes both on my gauge and maxing out in VCDS. Terrible turbo flutter/surge from 3-4K RPM. My boost graph looked like a roller coaster. So I backed off the wastegate 3 turns, after which I saw spikes of 28-29psi and holding 25-24ish. Still surging/fluttering and VCDS looking funky. I backed it off another 2 turns and I am now seeing spikes of 26-27 psi and holding 22ish psi. A little less fluttering/surging but still present.

My wastegate connector with the jam nuts is now about 3/5 to 2/3 of the way down the actuator rod (towards the end of the rod). Also, just to test, I put the car in the stock program and it was spiking 15-16psi and holding 12ish, a bit above what it should be, and indicating the the software is not the issue.

My question:

Am I on the right track working the wastegate down little by little? Any guess how many more turns I might possibly need?
 

clockwise33

New York Giants Fanatic
Location
NJ
When I did mine, I came at it from the other direction. I turned it down 6 turns right off the bat and slowly adjusted it up.

Be extremely careful with how many times you boost to 30 at such a high mileage. Others around here have popped motors that way.
 

GTIAPRK04

Cam Follower Replacer
Location
Maryland
Yeah I'm running stock program now until I get the WG sorted out to be gracious on my rods. Just hit 17psi on a wot 3rd gear pull in stock today, so I'm still well off lol. One turn of the WG nut equals about 1.5psi, correct?

In other news, probably going to rebuild the bottom end of the motor this summer. Thinking about some IE forged rods 50% for the heck of it and 50% in case I ever get around to going stage III. Are forged pistons worth it, too? Or just drop in rods and a rering?
 

clockwise33

New York Giants Fanatic
Location
NJ
Yeah I'm running stock program now until I get the WG sorted out to be gracious on my rods. Just hit 17psi on a wot 3rd gear pull in stock today, so I'm still well off lol. One turn of the WG nut equals about 1.5psi, correct?

In other news, probably going to rebuild the bottom end of the motor this summer. Thinking about some IE forged rods 50% for the heck of it and 50% in case I ever get around to going stage III. Are forged pistons worth it, too? Or just drop in rods and a rering?
I'm also preparing to do IE drop ins hopefully in the coming year. If you're going to DIY post pics and experiences. Contrary to popular opinion around here, I don't think stock rods are guaranteed safe w/ K04.

Also, please provide info on the process of obtaining / installing the replacement CHRA for the forum knowledge base.
 

larcic

Ready to race!
Location
Tampa, FL
i dont think you should be comparing k04 stock tune boost levels to k03 stock tune boost levels in order to adjust your wastegate.. I'd use the tune and contact apr in order to find out what boost you are supposed to be running and adjust to that. also I'm gonna be doing stock internals and k04 so many people have it with no issues and I dont beat my car up that much. I was gonna ask for a low torque tune though...
 

GTIAPRK04

Cam Follower Replacer
Location
Maryland
I could totally do a DIY on the turbo removal/rebuild/reinstall. I unfortunately didn't take too many pictures, but I could do a good write up. And if I do the engine rebuild, I will certainly do a DIY.

I did contact APR the other day and they said the car should be spiking to 24 and holding about 20 on the 93 program. All of my WG tuning is being done in 93. I only put the car in stock mode to verify it was overboosting there, too, and to keep my engine safe until I could find the time to tune the WG further.

As I had mentioned, the car has been K04 for 45K miles now with no issues whatsoever. So the stock rods are fine with K04. Just, at this mileage I would like to go ahead and pop the motor open and see what looks good, what needs replacing, what needs machining, and to go ahead and replace the rings and all seals before I encounter any issues. And while I have it open I may as well grab some IE rods as future insurance, especially at the price of $550 rifle drilled.
 

GTIAPRK04

Cam Follower Replacer
Location
Maryland
So, tonight I turned my WG back two more turns, however, I found that it was loosened to the point that the WG wasn't even held closed. So I tightened it 1/2 turn back to hold the WG closed snug.

On a quick test drive, I found the car to hold about 25psi spikes and settle to about 20-21 in a couple quick 3rd and 4th gear pulls. Mind, these are boost gauge numbers and I understand they can be a little on the high side. A WOT in third from about 2.5K RPM gave about 99% less boost flutter/surge sound, almost completely gone.

It seems this setup is not meant to have any WG preload? I'll have to run VCDS soon to verify that all is correct but it does seem to be!
 
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