[evo_killer]

Yo, I just install my helix dp the other day and I has been running fine. I even got the cel fix too, the O2 extension. Anyway I got on it to test it out and I don't feel that much of a differance in power. Not to mention I still have my stock exhaust, but I do have an intake. I got on it not to long ago and it was about 35 degrees outside and before I knew it I saw on the boost gauge that I went two notches past .1 and not thinking stayed on the gas. Then I hit fuel cut and then the check engine light and cruise light came on. I pulled into a gas station and just reset the ecu and everything was fine. So I take it that I boost creeped? Then I played with it some more to check on things and I can't get past 5k rpm's without going over .1 on the boost gauge. If I gradually get on it, it won't go over. Will EM help me out in this situation?

[Ol'SaltyBastard]

EM might help, but really isn't much of a fix. I'm catted, so I don't have to worry about creep, but if I did, I would yank the turbo, clean up the WG inlet (not the hole, the inlet) and be on my way.

[evo_killer]

I thought catted or not you would still get boost creep without EM?

[offset]

EM is not the (proper) solution. There is only one solution on the stock turbo, porting.

offset

[evo_killer]

How do I do that and can I do it myself without messing anything up?

[evo_killer]

You know what? I think the problem just might be because it's cold out and I mean like 30 degree cold. For like a week after I put it in it hasn't creeped at all and now that it's really cold it does it. I just thought about that and that might be the reason.

[donmei]

Repost from one of my old posts.

Don

Boost creep can NOT be cured with engine management.

Boost creep happens when the wastegate is all the way open, but it can not flow enough to divert enough exh gasses around the exh turbine. The result is that even thought the waste gate is open, the turbo continues to make more boost than is requested.

There are 2 solutions to this. 1) increase flow through the wastegate 2) decrease flow through the turbine (not something youwant to do since this reduces power at lower revs and increases lag.

A turbo works because of the difference in pressure between the intake side of the turbine and the outlet side of the turbine. By putting ina free flow exhaust you are are decreasing the pressure onthe outlet side. Thus increasing the pressure differential and the boost available at a given rpm and load.

Engine management will only try to open the wastegate more, but if its already open, the only way to decrease boost is to increase flow through the wastegate.

Don

p.s. I intentionally omitted another significant motive force on the exh turbine, which is the actual expansion of gasses while in the compressor housing. Either way, their effectiveness at driving the turbine also increases when exh flow at the exit side in increased.

[donmei]

Repost from one of my old posts.

Don

Boost creep can NOT be cured with engine management.

Boost creep happens when the wastegate is all the way open, but it can not flow enough to divert enough exh gasses around the exh turbine. The result is that even thought the waste gate is open, the turbo continues to make more boost than is requested.

There are 2 solutions to this. 1) increase flow through the wastegate 2) decrease flow through the turbine (not something youwant to do since this reduces power at lower revs and increases lag.

A turbo works because of the difference in pressure between the intake side of the turbine and the outlet side of the turbine. By putting ina free flow exhaust you are are decreasing the pressure onthe outlet side. Thus increasing the pressure differential and the boost available at a given rpm and load.

Engine management will only try to open the wastegate more, but if its already open, the only way to decrease boost is to increase flow through the wastegate.

Don

p.s. I intentionally omitted another significant motive force on the exh turbine, which is the actual expansion of gasses while in the compressor housing. Either way, their effectiveness at driving the turbine also increases when exh flow at the exit side in increased.

[USAF_STi]

EM might not be a cure but it sure as hell helps. i also ran in to boost creep issues when i had my catless downpipe on since then i have been running cobb's accessport and i am right on target with the target boost and have not had an issue since. for me it works so i will not bother with porting.

[buschurs_STi]

Same as him. I've got my boost tuned to run 18 lbs. So i haven't had any problems with creeping.

[jt_binary]

TBE = Boost Creep, with or without EM. Engine Management solutions can tune around it to some extent, but point is that if your car breathes really well, you'll see boost creep.
http://forums.nasioc.com/forums/show...hreadid=477715

Solutions? Some retreat back to axleback, others port (reduces ability to make boost), others try to tune around it (tuning must then produce more conservative curve), other live with it and plan to replace turbo...

[drdome99]

Originally Posted by evo_killer

I thought catted or not you would still get boost creep without EM?

I have helix catted w/ borla hush and max out at 1.2bar even on days in the single digits.

[jt_binary]

I still get creep... others don't; CAI + catless TBE is your sure-fire way of seeing it.

Not sure of the percentage breakdown of those that do vs. don't, but there are some that certainly still get it. Probably most... I'm in South FL and I still see it; coldest temp my car has ever exprienced is around 55 deg. I'm dynoing at 300whp so I'm certainly not complaining about something that is relatively simple to fix... just haven't gotten around to it.

[donmei]

If stock is 16 psi and it creeps to 18 with a dp with the wastegate wide open, then you install engine mgmt where the TARGET boost is 19 psi, "creep" is gone in theory. But if the ecu tries to pull boost for some reason it then won't be able to.

Don

[jt_binary]

In theory yes, since tuning moves the boost target higher... 'raising the bar' [pun intended], but I'm reaching that too. Boost shoots up and stays at .13 / .14 bar for a few moments... then cutoff. I don't even need 100% throttle in 5th to make it happen. Simple fact is that it's still happening, post-tune... with what many regard as the best parts available, and best Subi tuner in Southeast...

As a matter of fact happened since I wrote my last post, and it's 75 degrees out. Mastro not pleased, and indicating they want me to take off turbo wrap. Sorry, it ain't the turbo wrap, and they admit that it's not the cause but might be aggravating the situation some... but they stop short on recommending porting... Why? Maybe their rationale is that it introduces an uncontrollable variable... as in "do at your own risk - we know it's a documented solution but..."

I knew this going into CAI + catless TBE; even after tune, that the setup might still produce boost creep situations. If we could take a poll of folks with that setup, majority will definitely tell you they've seen it & had to port wastegate.

Moral of the story is that tuning your car & installing aftermarket parts -- even the best parts & best tuners -- introduce variables you need to be prepared to handle... not every car behaves exactly the same either.