I spoke with Vince (Trifecta) today and was surprised to find out that the sensors in the stage kit are not needed (regardless of your tune) unless you upgrade your turbo. The stock sensors are rated for the max boost that the stock turbo can produce. It appears as though gm added these sensors to make the tune harder to duplicate.

Anyone considering the GMS1 tune should speak with Vince first. He can create a tune with all of the same parameters of the GMS1 for alot less $$$$.

08 BLACK AUTO - ZZP catted DP, IC piping, KN intake, custom Trifecta tune

 

but with out that nice 100k mile powertrain waranty.

 

That warranty is the sole reason I went with GMPP Stg 1.

 

Hope you guys have good service departments with REALLY good turbo techs then. I've had nothing problems with my GMTU...and they can't figure what is wrong with it without the CEL. They said that since the CEL isn't coming on...it's not covered under warranty.

I wish I could go back in time...because regardless...my car obviously isn't under warranty...even with the GM installed GMTU

 

I got the stage 1 for the warranty too. however, i haven't had a single problem with my tune, in about 3 1/2 years.

side note, though related...i've seen it a lot. when did everyone start calling the stage 1 tune a GMTU? it's not a Turbo Upgrade, nor does GM even offer one...i know i took a nice long break from these forums (i logged in about 5-8 times a day...figured i'd break that habit lol), but before I left it was still referred to as GMS1 as the OP used. i know it sounds stupid for me to be asking this, but the new term seems dumb and misleading...just my opinion

 

Users on here made up the GMS1 name. Turbo upgrade is the "official" name used by gm.

 

Found these names in the paperwork:
1-Soltice,Sky,Cobalt and HHR LNF Turbo Upgrade Kit
2-Turbo Upgrade Kit
3-POWER UPG
4-Power Upgrade Kit(on the shipping box)

 

not one issue. and i drive the bawls off it.

 

your one of the luck ones then

 

Yup with stg.1 it's a hit or miss but 3bar is only good for bigger turbo which as soon I due my taxs that will be next project on the list. You'll will find the problem soon my friend.