First off, fill out your profile so we can see what mods you've done to your car. Since you stated that you only have the boost set to 15lbs and are spiking to 20 tells me that you have a MBC. Do you have a stock exhaust, aftermarket? My assumption is that you have an aftermarket because the boost is creeping and you're hitting fuel cut, which leads me to assume that you don't have the proper fuel requirements for higher boost. Do you have a logger to read what's going on? Try removing the MBC and go back to a stock set up and see if it continues to do it.

I'm guessing by your mod list that your car is completely stock (besides boost control and a 1g BOV), so I say it's a boost leak.

Im having simalar problems. The only obvious boost leak was at the shaft seals. Mine was set around 15psi would creep to 20 then it seems like fuel cut. Now mine will not hit 15 unless a hard launch or down shift at highway speeds wot otherwise will not go past 11. Im stummped

Sounds like boost creep and boost leaks to me. Poor turbo.

To help with the boost creep (well we need to know your mods first) you could port your o2 housing or switch to an aftermarket or evo3 one.

To help with you boost leak, do a boost leak, fix all of the leaks you can find, repeat. I've been doing boost leaks for almost a year and I'm still finding and fixing leaks. A boost leak test is not a one time thing. Also with the amount of boost that you are running, it would be a good idea to crush your BOV since it's probably on of your boost leaks.

Hope this helps!

+1 on the boost creep get a bigger exhaust first, ie o2 housing down pipe, or port what you have for now.

+0 on the big exhaust. The REAL way to stop creep is to port the wastegate hole to the limit where the flapper barely covers it and hog out the turbo inlet toward the wastegate opening. Then it will not matter what exhaust/cat/o2 housing is (or is not) on the car, IT WON'T CREEP. +1 on removing the boost controller and recheck.

Yea I hav an mbc but it looks like the knob to adjust the boost is broken.
Also there is a line on the bottom of the mbc that just fell off so and isn't connected to anything.
Its only connected to the wastegate.... I think.

gsx 1 said:

Yea I hav an mbc but it looks like the knob to adjust the boost is broken.Also there is a line on the bottom of the mbc that just fell off so and isn't connected to anything.
Its only connected to the wastegate.... I think.

Click to expand...

gsx 1 said:

Yea I hav an mbc but it looks like the knob to adjust the boost is broken.
Also there is a line on the bottom of the mbc that just fell off so and isn't connected to anything.
Its only connected to the wastegate.... I think.

Click to expand...

..Ok, remove the boost controller, throw it in the garbage, connect the wastegate hose to the j-pipe. Enjoy your functional car, assuming you haven't blown it up already.

remove that boost controller and get a new one. They are very cheap. You could even make your own.

Thanx for the help I got it 2 work... !!

Im currently running the HKS Sequential BOV and when i read boost it pops off! Very bad, its on the VRSF short route intercooler piping held on by a snap ring! What other options are there to hold that baby on there? I can't seem to find a "thinner" snap ring. The bov came on the stock intercooler piping when i had bought it, any ideas?