Boost creep / fuel cut

[testes1010]

yb normal07 thanks for all the time you put into this.this is great info i have an 02 with fp16g with tbh 3in all the way im gona go with the catted dp to build my back purssure.im gona have an exhusth shop weld on a high flow cat on to my invida dp.from what i read this should cure boost creep/ fuel cut right? this will work on the 2.0 right?thanks for all the help and eveyone else too.

A properly tuned a 2.0L should not creep, even with a catless TBE. This is mainly a problem w/ the 2.5L engine w/ small hotside turbos. I would look into the tuning a bit more, who tuned your setup?

[edrosswrx]

topspeed in atlanta tune it for me in winter. about a mouth after it started boost creep. but at the time i had a stock intercooler,which i replace with a front mount and it still does it.this was last winter.i plan on getting retune in about 1mth.after i put on a high flow cat on the dp hopefully this will take care of the pro.anyone else having trouable with boost creep on the 2.0 motor.

[YBNormal07]

yb normal07 thanks for all the time you put into this.this is great info i have an 02 with fp16g with tbh 3in all the way im gona go with the catted dp to build my back purssure.im gona have an exhusth shop weld on a high flow cat on to my invida dp.from what i read this should cure boost creep/ fuel cut right? this will work on the 2.0 right?thanks for all the help and eveyone else too.

As testes pointed out, boost creep is usually associated with the 2.5 platform, not the 2.0. I honestly don't have enough experience with 2.0 engine to comment on this. Perhaps it has to do with the FP16G you have on it? I am assuming it has an internal wastegate? If so, it should be properaly sized for the turbo, regardless of outlet piping. Testes has a lot of experience with the 2.0, so I would trust his experience on this.

[edrosswrx]

i have the same problems as the 2.5L you described in this thread. the problems are exactly as you described them. so i figured i needed the catted dp.does this make sense to you? how do i get in touch with testes?

[edrosswrx]

Will A Prodrive 3-port Boost Control Solenoid Work With The Trouble I'm Experiencing? Thanks For The Help

[testes1010]

i have the same problems as the 2.5L you described in this thread. the problems are exactly as you described them. so i figured i needed the catted dp.does this make sense to you? how do i get in touch with testes?

I am the testes...

the problem w/ the creep is more than likely just poor tuning. The boost controller won't fix it if it is actual creep issue; if its tuning a problem, you'd still have to get the ecu reflashed to run the BCS.

[edrosswrx]

sorry for not paying attention testes thanks for the reply, i got it tuned professionlly at top speed they are big into subarus and evos, they are located in atlanta. thats really the only good shop i known. i know if i got the prodrive i would need a tune but im stumped on what the problem is. since you guys think its not the exhaust im gonna try the pro drive, get it tuned, and ill let you know. it will be about 4 weeks till i can get it done.till then ill be sreaching for an answer. what are you running on your 2.0? how big of an exhaust do you have, any cats on it?

[testes1010]

what are you running on your 2.0? how big of an exhaust do you have, any cats on it?

Deadbolt TD05H-20G w/ 38mm EWG & meth injection, no cats, no boost creep. I'm putting down 350whp/340wtq on 93 octane, 371whp/355wtq on meth injection.

[edrosswrx]

wow! nice set up last time i got tune i made 275hp 250tq with stock intercooler and sti catback ,now i have a front mount and full tbe.hopefully with the prodrive and a tune i can get her running good with about 290-300hp.what do you think? ill start there and maybe that will fix it.

[mycologist]

I was slightly confused by the discussion of divorced wastegate DPs. Getting the exhaust out of the wastegate as quickly and smoothly as possible is supposed to help prevent boost creep according to some manufacturer. Theoretically, while that may reduce the back pressure some, if the actual change is due to a proportional change in the amount of exhaust being diverted through the WG it could have a larger effect and more direct effect on reducing creep than the total pressure or flow change. Hence it seems like the wastegate tube should not be restrictive. I have no idea if this works, but maybe it should not be dismissed on a strictly theoretical basis. It seemed worthwhile to clarify this because I saw in a recent thread that people are concluding that a DWG would have no benefit based on the information here.

One manufacturer/designer employs a highflow cat with DWG and the wastegate gasses re-enter after the cat. This would possibly allow more out the wastegate while also increasing back pressure in the system. They advertise explicitly that the DP will eliminate boost creep and it sounds like a valid additional saftey measure.

[YBNormal07]

I was slightly confused by the discussion of divorced wastegate DPs. Getting the exhaust out of the wastegate as quickly and smoothly as possible is supposed to help prevent boost creep according to some manufacturer. Theoretically, while that may reduce the back pressure some, if the actual change is due to a proportional change in the amount of exhaust being diverted through the WG it could have a larger effect and more direct effect on reducing creep than the total pressure or flow change. Hence it seems like the wastegate tube should not be restrictive. I have no idea if this works, but maybe it should not be dismissed on a strictly theoretical basis. It seemed worthwhile to clarify this because I saw in a recent thread that people are concluding that a DWG would have no benefit based on the information here.

One manufacturer/designer employs a highflow cat with DWG and the wastegate gasses re-enter after the cat. This would possibly allow more out the wastegate while also increasing back pressure in the system. They advertise explicitly that the DP will eliminate boost creep and it sounds like a valid additional saftey measure.

It makes sense theoretically, but if the causal issue is the size of the wastegate, everything done downstream or via programming is just a band aid to mask the issue. Porting, external wg, or getting a different turbo with larger wastegate are the only true fixes. Introducing backpressure works, but again, you loose some performance (very small imho, but have no numbers to support this).

[mycologist]

Just a friendly suggestion - because the title of this sticky contains the creep/fuel term it is very hard to search for. E.g. if you search titles for "boost creep" or "fuel cut" it doesn't come up. "Boost cut" will fetch it though. So, a couple of spaces in the term as in "creep / fuel" would really help.

[YBNormal07]

Just a friendly suggestion - because the title of this sticky contains the creep/fuel term it is very hard to search for. E.g. if you search titles for "boost creep" or "fuel cut" it doesn't come up. "Boost cut" will fetch it though. So, a couple of spaces in the term as in "creep / fuel" would really help.

good suggestion. I'll fix that now.

[bbjoy]

This has happened 3 times.....all about 1 month apart. if im pushing it in 4th and shift to 5th get up to about 4000rpm and the boost will dump with throttle, the car will lurch forward but not shut off and then the CEL will come on and cruise will flash but after the lurch it will be right back to normal. Just wondering what could be done to fix this...im guessing this is fuel cut but if im wrong correct me. Im running Cobb tbe with HF cat, SPT heatshield, Cobb SR intake, and Cobb AP stage 2. Im just confused because it seems this shouldnt happen with the HF cat.

[jorgee17]

So basically i have a 2007 subaru wrx with a full turbo back exhaust a new intake and maf, i'm getting ridiculous boostcreep and i was wondering if anyone had specific suggestions on what to do next...

i'm fairly new to subarus and could use some helpful suggestions.