Sup guys, quick question, whats the stock boost level on our cars from factory? (2g 4g63's) Thanks.

Boost pressure is like 14.5psi, I think, but the stock BOV leaks out anything past 12psi. You'll hit 15psi on your boost gauge, then it'll drop to 12 and stay there cuz your stock BOV is a stealing rat bastard of our precious boost pressure.

Your stock turbo might handle up to 22psi (thats killing it) But you'll never get over 12 unless you get an after-market BOV. Intercooler piping and a Greddy/HKS/Apex'i etc BOV will raise your boost between 14-17psi without a boost controller. I hit 17 with my Apex'i installed, but back to 12 cuz I have to run the stock 2G for emissions/non-rice boi reasons.

-Nick

Originally posted by NHH223
Boost pressure is like 14.5psi, I think, but the stock BOV leaks out anything past 12psi. You'll hit 15psi on your boost gauge, then it'll drop to 12 and stay there cuz your stock BOV is a stealing rat bastard of our precious boost pressure. Your stock turbo might handle up to 22psi (thats killing it) But you'll never get over 12 unless you get an after-market BOV. Intercooler piping and a Greddy/HKS/Apex'i etc BOV will raise your boost between 14-17psi without a boost controller. I hit 17 with my Apex'i installed, but back to 12 cuz I have to run the stock 2G for emissions/non-rice boi reasons. -Nick

Kinda right, kinda wrong.
Stock boost is 14.5 psi. Stock BOV leaks at like 14. The reason your boost drops from 15psi to 12psi is not because of the BOV but because the T-25 is a POS.
Also, an aftermarket BOV will not raise boost. It will merely stop it from leaking. I HIGHLY doubt you were seeing 17psi w/out a MBC.
I was seeing 15.2 with the BCS restrictor removed before I got my MBC. Maybe you were spiking to 17 but that might have have just been your setup.
Also, I wouldn't run anything more than 15-16psi on the stock turbo. You'll just be pushing hot air and will do nothing more than cause it to fail sooner.

Originally posted by eclipzGST

Originally posted by NHH223 Boost pressure is like 14.5psi, I think, but the stock BOV leaks out anything past 12psi. You'll hit 15psi on your boost gauge, then it'll drop to 12 and stay there cuz your stock BOV is a stealing rat bastard of our precious boost pressure. Your stock turbo might handle up to 22psi (thats killing it) But you'll never get over 12 unless you get an after-market BOV. Intercooler piping and a Greddy/HKS/Apex'i etc BOV will raise your boost between 14-17psi without a boost controller. I hit 17 with my Apex'i installed, but back to 12 cuz I have to run the stock 2G for emissions/non-rice boi reasons. -Nick

Kinda right, kinda wrong. Stock boost is 14.5 psi. Stock BOV leaks at like 14. The reason your boost drops from 15psi to 12psi is not because of the BOV but because the T-25 is a POS. Also, an aftermarket BOV will not raise boost. It will merely stop it from leaking. I HIGHLY doubt you were seeing 17psi w/out a MBC. I was seeing 15.2 with the BCS restrictor removed before I got my MBC. Maybe you were spiking to 17 but that might have have just been your setup. Also, I wouldn't run anything more than 15-16psi on the stock turbo. You'll just be pushing hot air and will do nothing more than cause it to fail sooner.

actually when i installed my boost guage on my stock t25 i was hitting 17psi at like 3100rpm and holding it until about 5500-6000, where it would fall to 15psi.

from factory is 12psi.....that is the size of the wastegate actuator....how do you run more then that from factory w/o a boost controller?

Originally posted by BigBald
from factory is 12psi.....that is the size of the wastegate actuator....how do you run more then that from factory w/o a boost controller?

no idea. with the mods i had(turbo back, intake, ic pipes, bov, etc) it would hit 17psi. When i installed the BC, i set it down to 15psi

Originally posted by BMPDirk

Originally posted by BigBald from factory is 12psi.....that is the size of the wastegate actuator....how do you run more then that from factory w/o a boost controller?

no idea. with the mods i had(turbo back, intake, ic pipes, bov, etc) it would hit 17psi. When i installed the BC, i set it down to 15psi

that would be a boost spike... ;)