Which gauge do I believe

[Spanky2324]

Alright I have been noticing that my stock boost gauge in my gsx starts creeping up. Not slowly but at a moderate speed. I also have an aftermarket boost gauge that stays where my boost is set(11 psi). So I don't know which one to believe because I don't wanna push my car and come to find out I had boost creep or if that stock gauge is faulty. What do you think?

 

[turbosax2]

The stock gauge is completely useless.

 

[oldman]

I smell boost leaks, not boost creep.

 

[turbolover10]

Agreed^^
If your still on stock fuel and you have boost creep you'll most likely have fuel cut...
But definitely don't trust your stock boost gauge.. Plus if you still have the stock turbo "t-25" I havent heard of it creeping..
www.vfaq.com build a cheap boost leak tester trust me your going to need it.

 

[Spanky2324]

Thank you. That has been bugging me and I haven't had the time to post anything because I've been so busy working. Alternator went out and door actuators ceased up Fixed now. Now it's time for brakes and boost leaks

 

[oldman]

If your still on stock fuel and you have boost creep you'll most likely have fuel cut.

Hitting fuel cut has little to do with your fuel delivery capability, it's a function of airflow.

Now it's time for breaks and boost leaks

Brakes.

 

[turbolover10]

Hitting fuel cut has little to do with your fuel delivery capability, it's a function of airflow.

Ahh, kind of missleading by the name.

 

[turboglenn]

neither one is 100% accurate...the only true reading is to be had from a GM MAP sensor through a logger..but if you have to choose go with the aftermarket one..the stock guage is junk

 

[oldman]

Ahh, kind of missleading by the name.

Indeed, "boost cut" would have been more appropriate. The purpose of "fuel cut" is to guard against defective wastegate/BCS, it does this by cutting fuel when the pre-programed amount of airflow is surpassed, hence the term "fuel cut", also the reason why boost leaks is the number one cause of "fuel cut" although you're running pig rich.

OP, your stock boost gauge does not measure real pressure, it guesstimates boost level using several sensor readings, mainly the MAF sensor. Boost leaks can inflate the MAF reading because you're losing metered air, the reason your mechanical boost gauge is holding steady is because your turbo is working harder (spinning faster) to overcome the leaks.

 

[Artago]

Could it be an incorrectly installed (tapped) boost gauge?