Boost Creep?

RRF900RR · 04-05-2002, 07:17 AM

I've got a question about boost creep. What does it feel like? My car will start to cut out when I am accelerating hard when the rpms hit 4,000 or more. The problem seems to get more pronounced the higher the rpms get. This problem started after I installed my xbc boost controler. I have installed alot of bolt on parts in the last month so I don't know which one of the parts could be attributing to the problem any help that can be given would be much appreciated. Thanks

IPT · 04-05-2002, 11:05 AM

Watch your Aftermarket boost gauge. It should go to the level you have it set to then the boost will slowly rise. That is boost creep.

RRF900RR · 04-05-2002, 01:29 PM

thank you. I guess what is happening is not boost creep then. I guess I am going to have to break down and put the old beast in the shop to figure this thing out. Thanks for the help.

Blixx · 04-05-2002, 01:31 PM

boost creep doenst = fuel cut. Fuel cut feels like a brick wall and (mine atleast) flashes the CEL once quickly. You could be experiencing MAF overrun from the bolt-ons and higher boost level.

Blake

IPT · 04-05-2002, 01:31 PM

When was the last time you changed you spark plugs or wires?? With the mods you have been doing it puts higher stress on your ignition and a break up in the higher rpms can occur.

RRF900RR · 04-05-2002, 02:53 PM

The spark plugs and wires were done about 20,000 miles ago, but I did just go with the factory set up. I did not have any mods done at the time and was not planning on upgrades. I just heard on another thread that someone was having a similar problem. It turned out that he needed new wires. I am going to go out this weekend and pick up a new set to try it out. I figure that it is cheaper to buy a new set of wires than to let a tech figure it out. It can't hurt. Thank you for all of yall's help. woops there goes the Texan in me.

IPT · 04-05-2002, 03:05 PM

Get the plugs too. The are only $8 for a new set. (NGK's) Throw and ohm meter on the wires if the resistance is REALLY high the wire is bad. I replace the plugs in my car every couple of oil changes. I pull them out and check to see if I am running lean or rich alot!!

RRF900RR · 04-05-2002, 03:16 PM

On my way. I can't believe that I have been searching for this prblem for about a couple of weeks, putting different hoses, tightening everything down, and adding octane grade to the gas to try and get this problem to go away. I appreciate the help and I will post back after I do the repair and let you know if it took care of the problem. Thanks again for the help.

Turbocyde · 07-31-2002, 04:42 AM

what causes boost creep?

allwheelTSI · 09-14-2002, 11:53 PM

Quote:

Originally posted by Turbocyde
what causes boost creep?

boost creep is caused by either a leaky internal wastegate or when the internal wastegate can't handle the pressure you're running. an external wastegate eliminates boost creep.

Norb85 · 06-10-2003, 06:57 PM

Are there any other ways to eliminate boost creep?

jb talons · 06-11-2003, 10:52 AM

Quote:

Originally posted by allwheelTSI
boost creep is caused by either a leaky internal wastegate or when the internal wastegate can't handle the pressure you're running. an external wastegate eliminates boost creep.

I think you're a little wrong on this one. Boost Creep doesn't come from a leaky or weak waste gate. It comes from a waste gate that doesn't permit enough flow by the turbo. An external gate does fix the problem, not because it is stronger, but that it flows better.

This definition comes from Extreme Motorsports

Boost Creep
A turbocharged car is a positive-feedback system. The faster the turbo's compressor wheel spins, the more horsepower the engine makes. More horsepower means more exhaust gasses are being expelled. The more exhaust that is expelled the faster the turbine (and thus the compressor) wheel spins, and so-on until the engine explodes.

The ECU (sometimes via a boost controller) controls the boost level by opening the wastegate. Boost creep, in which the boost level of your engine continues to rise despite the best efforts of the wastegate, is caused when a fully-open wastegate can't divert enough gasses around the hot-side turbine wheel.

Boost creep can usually be eliminated by porting the wastegate opening and O2 sensor housing or by using an external wastegate. Both of these allow exhaust gasses to vent more efficiently.

flinguist · 07-16-2003, 03:54 PM

Will an internal dump O2 eliminator downpipe eliminate boost creep?-Thanks

ltvarney · 07-16-2003, 04:13 PM

Your best bet to eliminate boost creep is with an upgraded flapper, usually people use a 34mm one. They're around $40 + port work.

skj415 · 09-24-2006, 02:38 PM

my car will sputter whenever you make any kind of boost or give it gas open to any kind of ideas to fix it

DsmKid98GST · 09-25-2006, 07:55 AM

Quote:

Originally Posted by RRF900RR

I've got a question about boost creep. What does it feel like? My car will start to cut out when I am accelerating hard when the rpms hit 4,000 or more. The problem seems to get more pronounced the higher the rpms get. This problem started after I installed my xbc boost controler. I have installed alot of bolt on parts in the last month so I don't know which one of the parts could be attributing to the problem any help that can be given would be much appreciated. Thanks

I had a friend with a TSI around your year that had the same or similar problem. It felt like his car was choaking when he tried giving it any boost past 4000rpms. You might want to do a boost leak test and make sure all of your exhaust connections are secure and you don't have any big exhaust leaks.

Back then I didn't have the knowledge i do now so we didn't perform a boost leak test or check for exhaust leaks. Good luck, let us know what's up.

zippyshoe · 09-25-2006, 10:38 AM

Quote:

Originally Posted by RRF900RR

I've got a question about boost creep. What does it feel like? My car will start to cut out when I am accelerating hard when the rpms hit 4,000 or more. The problem seems to get more pronounced the higher the rpms get. This problem started after I installed my xbc boost controler. I have installed alot of bolt on parts in the last month so I don't know which one of the parts could be attributing to the problem any help that can be given would be much appreciated. Thanks

When you checked your aftermarket boost gauge as IPT suggested, what was it showing? If your boost quickly rose to a very high boost pressure, than what you have is uncontrolled boost. If this is the case, I would check and make sure your MBC is connected properly - one port of the MBC should be designated as the boost source connection, while the other port of the MBC is designated as the connection to the wastegate actuator. If you have these connected backwards, this will probably result in uncontrolled boost.

EDIT: Wow... I just noticed that this thread began back in 2002!

vaboys2ndgen · 09-30-2006, 12:18 AM

im running a 14b on my 2g gsx. 3" dp and exhaust no cat. boost creep is killing me bad. its not even a slow build up of boost. i had it set at 11psi today and hit fuel cut around 21psi.. trying to test out the fmic.. but didnt wanna blow anything up.. so do u think by porting exhaust manifold(which i have) and a ported o2 housing would cure it?

SaiyanFury · 09-30-2006, 04:58 AM

Boost creep can also result from low performing cams from my research. If your turbo is pushing too much air, but the engine can't do anything with it, you might simply have too much boost. Just a thought. Cams can address this problem. It's not a fix, but perhaps a possible solution.

oldman · 11-14-2006, 02:19 PM

Quote:

Originally Posted by SaiyanFury

Boost creep can also result from low performing cams from my research. If your turbo is pushing too much air, but the engine can't do anything with it, you might simply have too much boost. Just a thought. Cams can address this problem. It's not a fix, but perhaps a possible solution.

That is what is called "compressor surge", not boost creep.

Speed_RacerGSX · 05-14-2008, 06:27 PM

Quote:

Originally Posted by skj415

my car will sputter whenever you make any kind of boost or give it gas open to any kind of ideas to fix it

Sure wish someone would have given this guy an answer. I have a similar issue. It idles slightly rough, but I can pull it in and out of the shop fine. But if I try to take it out on the street it just boost spikes to the moon, hits fuel cut and such. I take good care of my car, but it does have 230K on the clock. It has recent iridium plugs, ngk wires. Its a mostly stock 95 gsx, with upper ic pipe, greddy bov, ported t25, aftermarket stainless exhaust mani. injen air filter, home depot mbc. I have comped it, and its all good, no exhaust leaks, no vacuum leaks (that I've found) tested the waste gate actuator, replaced it with a known good one. My MBC is plumbed off the bov vac line to the T at the compressor housing. Tried running the stock BCS (restrictor removed), still boost like mad. I don't have an aftermarket boost gauge in it tho.... Any help is appreciated. Im a tech, but I don't get alot of free time to mess with my own stuff, and have been pretty frustrated.
Thanks.

BOC Jason · 06-18-2008, 02:13 PM

Quote:

Originally Posted by Speed_RacerGSX

Sure wish someone would have given this guy an answer. I have a similar issue. It idles slightly rough, but I can pull it in and out of the shop fine. But if I try to take it out on the street it just boost spikes to the moon, hits fuel cut and such. I take good care of my car, but it does have 230K on the clock. It has recent iridium plugs, ngk wires. Its a mostly stock 95 gsx, with upper ic pipe, greddy bov, ported t25, aftermarket stainless exhaust mani. injen air filter, home depot mbc. I have comped it, and its all good, no exhaust leaks, no vacuum leaks (that I've found) tested the waste gate actuator, replaced it with a known good one. My MBC is plumbed off the bov vac line to the T at the compressor housing. Tried running the stock BCS (restrictor removed), still boost like mad. I don't have an aftermarket boost gauge in it tho.... Any help is appreciated. Im a tech, but I don't get alot of free time to mess with my own stuff, and have been pretty frustrated.
Thanks.

How do you know that your getting boost creep without a Boost gauge?
Either way though, you need a boost gauge.
IMO dsm's should have came equipped with them

As far as diagnosing the issue, do another boost leak test. (another one never hurt) Check your BOV, make sure the diaphragm in there is good and isn't leaking any air out. Also check around your throttle body and around you injectors. You may find a leak near the insulators. One easy way to try and help fix boost creep is by porting your O2 housing by allowing a better path of flow for you exhaust.

But first's first, Leak test. Let us know any findings.

Oh yeah, check you LICP just for kicks