From what I have read in all other forums and from personal experience and knowledge, I will post up a list of what mods will cause FUEL CUT in possibly all gears while going WOT.

Any DP catless with stock catback <40 degrees C

Any DP catted with stock catback <35 degrees C

Any DP catted with 3" catback and <40 degrees C

Any Full turboback exhaust (catted or not) and <45 degrees C

If you add any sort of intake it will also increase the amount of boost creep.

These are approximations I made from my own experience and what I've read on numerous forums. So basically if you ever plan on modding your STi and especially the temps are low in your area, you need a wastegate port.

I had horrible creep and fuel cut ~19psi was the highest I let it go (it was still climbing but I backed off the throttle). This caused concern not for fear of damaging the engine, but that the vf39 is not safe to run at pressures greater than 17psi. For example one member on clubwrx had premature turbofailure because he was running an MBC at 17psi.

A EBC or MBC will not stop boost creep. You can lower the boost which will help by activating the wastegate earlier, but it will still creep up to unsafe levels, especially in the higher gears 4th+.

A fuel cut defender is not a smart idea since you take away the safeguard (fuel cut) and allows the turbo to spin to even more unsafe levels.

So the only 2 options are, porting the wastegate OR upgrading to a different turbo.

I had a friend with experience do it for me. He's been working for SOA as a mechanic for 6+yrs and he's gone to STi mechanics school as well. It took him ~1.5 hrs to do the whole thing and no more creep. Boost was capped at .11mpa (~15psi) and this was in 5 degree weather.

 

Oh, I just made a website for my friend. He is a really good guy and knows what he's doing. I highly recommend him if anyone has boost creep issues or needs something installed. He's more experienced (in subarus'), faster and cheaper than any other mechanic I've been to.

He said he is willing to offer wastegate porting for $50 +shipping. You can mail the exhaust housing to him and he'll promise a 1 day turnaround from when he recieves it.

If anyone is in the area (NY, northern PA), he can do the wastegate port for $90 which includes taking off the turbo, port and reinstallation.

I'm not making any money off of this, just thought I'd help a friend out and bring a good deal to the Subaru community.

Oh: a small website I just made-

http://hometown.aol.com/__121b_0Kc/u...oIQ/wXVOM4d4k=

 

if you buy a TBE and you do not get boost creep, then the TBE is not worth getting. Because the only reason you get a TBE is for a more free flowing exhaust.

All free flowing TBEs will give you boost creep period.

The cheapest way to get rid of boost creep is to make the wastegate hole bigger (port the wastegate hole).

 

any BC doesn't work mario.. unless you defy the laws of physics.

A TBE + cooler weather seems to be the main cause of boost creep. Since cooler air is more dense it has a harder time escaping though the wastegate especially as the heat from the turbo expands the molecules. I haven't heard of any real issues with boost creep (I mean fuel cut!) in hotter climates (above 65 degrees year round)

 

Whoops, I meant to say fuel cut. I'll modify it. Do you guys get fuel cut in HI?

The main point I'm trying to illustrate is that as the temp goes down, the air molecules are more dense. Then as it passes though the hot engine it expands causing greater boost creep. So lower temps. = increased effects of boost creep.

What kind of peak boost pressures are you getting down in HI and what gear, mario?

 

Wow, guess the wastegate hole is really inefficient. Hopefully SOA will fix it for 2005 model. Wonder if anyone has gotten fuel cut w/ a stock exhaust? If so, wonder if they will recall them if it happens stock?

The highest psi I had was when it was ~15 degrees out I pushed the pedal to the floor in 5th gear while trying to pass someone. I was at 2800-3000rpms and the needle instantly swung up to .13mpa (19psi+) and kept climbing up so I let off the gas right away. I guess the effects must be bad enough to get fuel cut in warm climates, but probably less extreme than my boost creep in cooler climates.

 

TSX downpipe (no cats), Borla Hush cat-back, snorkel removed, and Perrin panel filter all added to my boost creep.

I don't know if stock cars get creep since all of my power mods were installed before October...

Ro

 

I have my WG done and I even hit fuel cut on a 10 degree day here in NJ.

The Xede and upcoming UTEC will have featurs to prevent fuel cut from happening.