CT4-V Factory LF4 Wastegates - Spring Pressure and Thread Pitch

[BKC1]

Does anyone know whether the thread pitch on the factory turbos is 1/4" UNF or M6?

I spoke with Turbosmart last week and they identified that the IWG75 wastegate is a direct upgrade over the factory wastegate due to their greater working ratio. I should've asked them what the thread pitch was, but it slipped my mind.

For the stock spring pressure on the IWG75 you should see improvement in the torque curve and boost response, but I want to take that a step further with higher spring pressures.

The IWG75 has 3 internal springs so that by swapping in the correct combination of springs, you can adjust the effective spring pressure from 3 psi to 26 psi. If the LF4 is capable of 18-21 psi boost on 93 octane 24/7, I would think a spring set in the 12-16 psi range would be optimal.

Does anyone know what the factory spring rate is?

Linkage:

https://www.turbosmart.com/product/iwg75-universal-150mm-rod-14-psi-black/

 

[Grainofsand]

Does this make more power

 

[BKC1]

Does this make more power

No














But it makes it faster.

 

[DesertRJ]

I'd certainly be interested in an upgrade like this. Tell me more. Direct bolt on? It sounds like it. Better response would be great as I've been running autocross and any little bit of boost to on/off throttle response is worth valuable tenths for me lol. Any idea if it's going to tick off the ECU or mostly fly under the radar?

 

[WONT TAP]

Yes, those TurboSmart wastegate actuators will work with some minor adaptations. We used them on my 2018 ATS-V a few years ago when we switched over from vacuum to boost controlled actuation. I don't believe these will provide any noticeable or measurable performance improvement over the factory parts though.