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Went KO4...What's Wrong?

S

sschultz

New member
Location
Chicago
Hey guys, looking for some experienced advice. I installed a KO4 two days ago with S3 injectors and GIAC tune. I have the following other mods Forge/BSH DV relocate, Neuspeed TOP, BSH charge pipe, APR HPFP, Intake, BSH PCV revamp, 3" exhaust, full intercooler.

First off, I'm only getting about 15-16psi of boost. Switching out the yellow and red springs for the DV doesn't change anything. The boost spikes there and stays there. Sometimes in 3-4gear if I hold the throttle to 6k rpm the boost will climb a few psi after holding 15 for a bit. GIAC says I should be getting about 20-22psi.

Honestly, I can't really tell much of a difference in power with the KO4 over the stage 2 tune. Am I missing something here?
 
ROH ECHT

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
If the DV is fine and there are no leaks...then seems like it's the WGA calibration. The Yellow spring is in a Forge DV? I run the GIAC K04 HO tune with the RS4 FPRV. When I got my K04...the WGA calibration was off as well. It boosted to only 17 psi.

I doubt it is the N75 or boost frequency controller valve, because boost would act quite weird when it fails. If N75 is failing, boost will not build to its max psi and drop off about 50% suddenly before building up psi again.

You can check the WG preload...I have a vid for it. I prefer loosening it up, both 10mm nuts, and pressing the WG linkage so to be closed (towards the WGA diaphragm). Then bring the inner 10mm nut up to and just touching the linkage and then back it off three full turns towards the WGA diaphragm. Then tighten the outer 10mm nut up to the linkage and its new position. Fine tuning may be needed but it is just a starting point. Seems your K04 was still set for stock preload.

https://www.youtube.com/watch?v=EyzS-vvuFmA&t=325s
 
Last edited:
S

sschultz

New member
Location
Chicago
ROH ECHT said:
If the DV is fine and there are no leaks...then seems like it's the WGA calibration. The Yellow spring is in a Forge DV? I run the GIAC K04 HO tune with the RS4 FPRV. When I got my K04...the WGA calibration was off as well. It boosted to only 17 psi.

I doubt it is the N75 or boost frequency controller valve, because boost would act quite weird when it fails. If N75 is failing, boost will not build to its max psi and drop off about 50% suddenly before building up psi again.

You can check the WG preload...I have a vid for it. I prefer loosening it up, both 10mm nuts, and pressing the WG linkage so to be closed (towards the WGA diaphragm). Then bring the inner 10mm nut up to and just touching the linkage and then back it off three full turns towards the WGA diaphragm. Then tighten the outer 10mm nut up to the linkage and its new position. Fine tuning may be needed but it is just a starting point. Seems your K04 was still set for stock preload.

https://www.youtube.com/watch?v=EyzS-vvuFmA&t=325s
Click to expand...

Thank you! I hope it's just a boost leak. I'll make a tester tomorrow and check. The WGA that you have is from forge. Will your adjustment recommendation apply to a stock WGA? And yes, I have a forge dv and they make different springs for it (different than the WG springs obviously).
What kind of boost pressure are you getting with the HO tune?
 
ROH ECHT

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
sschultz said:
Thank you! I hope it's just a boost leak. I'll make a tester tomorrow and check. The WGA that you have is from forge. Yes. Will your adjustment recommendation apply to a stock WGA? Yes...I would do the same with the oem WGA before I installed the Forge. And yes, I have a forge dv and they make different springs for it (different than the WG springs obviously). Yep.
What kind of boost pressure are you getting with the HO tune? Right now, with the yellow spring, I have it set to peak at 23 psi...but with more WG preload it will boost over 25 psi. With the Forge WGA, and the yellow spring set with zero WG preload, it will still peak boost at 20.5 psi.
Click to expand...
But yes, first make sure there are no leaks and the DV is good. The intake manifold must be sealed as well as all of the boost plumbing. If you find nothing else causing the low boost...and need encouragement to do the WG preload increase...I can help. But yeah...do not do it until all else is ruled out. :thumbsup:
 
S

sschultz

New member
Location
Chicago
Okay I did some logs. Boost gauge says I'm getting 15psi. Logs say around 20psi requested and close to that for actual....N75 duty cycle is perpetually 0%. This means I have a bad N75 valve correct? If the duty cycle is 0%, should I be getting any boost?...I don't get, I put a brand new one on when I installed the turbo...
 
ROH ECHT

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Can't comment accurately because not looking at the full pull from 2k rpm to redline in a single gear...
...but with zero wgdc it will still make boost...just no what it should make.
There is no actuation of the N75 at 0% wgdc and it is likely due to inability to control boost. Check the vac tubes connected to the N75. Perhaps they weren't sealed well when installed. Or, the WGA rod is loose at the WG linkage.
 
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