Hey guys I recently swapped out my turbosmart WGA springs from 14 PSI to 20 PSI (outer 10 PSI + middle 7 PSI + 3 PSI) and I've begun to see boost creep from 3rd gear onwards.

I'm tuned for 1.4 Bar (20 PSI) at low boost and 1.7 bar at high boost and no matter how I adjust the preload, the boost shoots from 1.4 bar to 1.7 bar (25 PSI) from 6k RPM onwards (running on WGA spring only).

I've tried adjusting the preload from tightest to zero preload (actuator arm completely loose).

With normal to very tight preloads the boost creeps to 25 PSI.

With zero preload the boost build up is lazy and slow.

I can't seem to find the sweet spot with this spring combination. Should I downgrade to 17 PSI (1.2 bar) with more preload? (Outer 10 PSI + middle 7 PSI)

boost creep didn't happen when I was on the 14 PSI spring even on maximum preload.

I also swapped my leaking HKS SQV with a turbosmart plumb back when I swapped the WGA springs. Could this have played a role in boost creep?
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If this is on a stock turbo and an electronic boost controller, the WGDC usually ramps up past 6000 to hold boost. By you adding wastage spring, it's just making more boost.

 

Thanks for the inputs! But I've been running on the WGA spring alone to ensure that I'm setting the preload correctly.

It's on a 20G that's a similar size to an FP green. I'm also running a greddy profec B spec II EBC (but in this case turned off).

Stock exhaust manifold and stock O2 housing.

 

Which O2 housing are you running? Some O2 housing like Megan needs the inside of the housing ported/opened up to help with boost creep. I had a boost creep issue and had to port the WG holes on the turbo. https://www.evolutionm.net/forums/ev...l#post11878407

 

​​​​​​I'm running the stock O2 housing.

I'm still convinced it's something to do with the WGA. I've removed the 3 PSI spring so now it's rated at 17 PSI. And guess what.. it's still boosting to 1.8 bar (26 PSI).

When I opened up the WGA to remove the spring, I noticed a small tear in the diaphragm. Would this be enough to cause a loss in pressure to move the WGA arm correctly?




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Update: I have bypassed my boost controller and hooked the line from the turbo directly to the WGA. Boost is still building to 1.8 bar instead of 1.2 bar like it should with the spring pressure. Quite likely the tear in the diaphragm is causing this. Will be ordering a replacement diaphragm.

On the flip side, bypassing the boost controller has led to my turbo spooling extremely quickly! I'm getting 1.5 bar (21 PSI) by 4k RPMs, way earlier than before when the boost pressure went through the boost controller first!! Is this typical because the air travels a shorter distance or is this a symptom of a leak somewhere within the boost controller system?

 

38mm? I had 2 of those from turbo smart and one go stuck with only 1200kms in ...and they also creeped in boost...now I'm on tials now....no more boost problems...

Also that year might be causing the issue...replace that 1st and see if that fixes your problem.

 

It's a 75mm internal wastegate. The IWG75 series from turbosmart. I'm curious..how did it get stuck? The actuator seems to be quite simple mechanically speaking. It's basically just a rod with a spring..

 

The valve started to just get stick cauing either causing unstable boost or over boost

As u can see same colour spring different size :



when we tested it upon inspection we saw the valve stem had excessive markings on it showing the valve stem was either faulty or not correct balanced. And both of my waste gates springs were different size springs altho same colour .... turbo smart I'd say not very smart lol

At this point I gave up when I mailed turbo smart either refund or change and to my sadness all they did was suck their own d**k and told me how great of a company the were and I'm wrong and they cant make mistakes...I just gave up and went with tail wastegates.

 

You're talking about an external wastegate. OP has an internal wastegate turbo, and he's useing a turbo smart wastegate actuator. So, what you're talking about isn't relevant to this discussion.

 

Most probably that tear on the diaphragm causes the creep coz the pressure that's supposed to 100% push up the spring to release boost now leaks a bit thru the diaphragm, hence the spring movement is not maximized anymore.

As for the boost behaviour thru the Profec, if you dial in your EBC setup correctly then it can also build boost quickly then hold it at your target desired boost level. I am using a 1.3bar actuator with Profec B type 2 EBC on HKS GT2 turbo. I follow the EBC setup guidelines from this forum so you can just look it up, got 2 threads and both very helpful. My target boost levels are exactly like yours, 1.4 on low boost and 1.7 on high. My setup is as follows:

Low boost

• Boost 60%
• Gain 10%
• Set Gain 1.35 bar

High boost

• Boost 80%
• Gain 10%
• Set gain 1.6 bar

Note though for my low boost it got a slight spike to just under 1.5 before it tappers and holds around 1.4 which is what I purposely want it to be like, so that the mid range punch is better. For my high boost setup it is stable at 1.7 and never spikes up. Both setups able to built max boost under 4000rpm. Maybe you can try around similar like those.

 

lol ya...true.

 

That's very interesting..how the spring sizes are different with supposedly identical spring rates. Although I have nothing to compare mine with, I hope the spring rates are true as advertised. When it was on the 14 PSI spring combo before, the wastegate flap opened dead at 0.95 Bar.

 

Thanks for the tip man! I'll give that a try..I might replace my vacuum and turbo lines running from boost controller solenoid for good measure too. They've been on the car since the boost controller was installed way back when it was first launched (probably 2 owners back and 10 years ago?). Do these silicone hoses tend to crack over time? They seem quite supple when I had a quick look at them.

 

Hmm silicone hose usually last very long. I never heard any cracking issue on them and I think I got some pretty old ones in my car too. I think if still supple then can still use, maybe just trim the ends so they will wrap the nipple tighter and add zip ties as clamps to secure. But anyway they're not expensive so if want to change then better too, at least will look nicer. 🙂