Forge WGA - K04

[Whitedemon]

Hi all,

I've been having some issues with my boost for a while and I think I've been able to narrow it down to my WG (whole thread for this: https://www.golfmkv.com/forums/index.php?threads/loss-of-boost-spike.379914/), so I'm thinking of replacing my OEM actuator with the Forge one (yellow spring) for my K04, I've read some good reviews about it and wanted to get the opinion from someone here, @ROH ECHT I know you might have one on yours. Is it worth it over the OEM one?

Thanks in advance

 

[ROH ECHT]

I got the Forge because mine had trouble when a tuner (DM) shot for 26 to 28 psi using a 3 bar MAP sensor. Adding preload to the OE WGA did not help. Once the spring rate was reached in the OE WGA...boost just flat-lined when it was attempting to build to peak boost because the WG was opened too soon. Swapping to the Forge WGA w/yellow spring worked....even though the yellow spring's rate is 12.5 psi/0.9 bar (up to 25 psi). There was no need for me to use the Blue spring with a 17 psi/1.2 bar rate....but I have all springs if needed.

Spring rates do vary but most K04 WGA will hold the WG closed up to near 25 psi. If a tiny bit of additional preload doesn't help...then you might need another WGA to keep the WG closed. This doesn't mean a Forge will help any if the WG itself is loose or isn't sealing as it once did.

 

[Whitedemon]

I’ve physically inspected the WG and it looks good, flapper is not loose..not signs of tear either...didn’t do the vacuum test tho since I didn’t have one with me at the time...but honestly I don’t think there’s anything wrong with the WG itself since I’m able to hold boost fine and the peak boost loss it’s only like 2-3 psi..I’ve read that when the WG is bad it’s either a significant drop in boost(or no boost at all) or full boost condition...I don’t got any of those issues...which makes me believe it’s more related to the WG actuator.

Btw I also found I had a very small leak at my tb pipe where the MAP sensor sits, looks like the bung on the CTS turbo tb pipe was not sealed properly (a little too big for the o-ring) which explains why I was seeing some oil around that area, so I’m getting a slightly bigger o-ring for the sensor to take care of that issue...not sure if this would take care of the whole boost issue as well since it’s very small. Will see. if not I’d do what you recommended on the other thread, add more pre-load to the OEM WGA. Guess it’s better than spending $200 on a new WGA, especially if they both would amount to the same type of performance.

 

[ROH ECHT]

A small leak can make a difference so see what happens when the MAP is sealed.
Other conditions can also make a difference in boost; mass air, fueling, timing, CO2 etc. ...have a look at all of this data if not done since the decrease in boost was noticed.
Did I post my WG preload adjusting vid in the other thread? It's quite easy...well, easier since adding a longer coupling nut to the end so a socket can be used.