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Boost creep issues


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Hey guys,


I'm in the process of tuning my set up and im having really bad boost creep issues. I'm only on the first revision of the set but I want to help my tuner by looking at things from my end, is there anything that could cause this ? air vacuum leaks ? I seem to hit max boost at like 2800 rpm, and then it shoots back down to like 12 and takes until close to 5000rpm to hit max again. Very strange. Anything that I should be taking a look at ?




grimspeed ebcs

dp (cat) / up / mid / catback

cobb air intake


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hey guys, i left a c clamp on one of my lines because it was too troublesome to get it off. do you think could be pinching my hose too much ? It doesn't look like theres much pressure being applied to the hose from it ... its not sitting on any fitting or anything
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If I did have a big boost leak issue, what places should I check ?


My throttlebody hose to tmic connection, maybe It's not tight enough ? I just don't want to snap that sucker ... what did you guys do ?


tmic to bov connection, prone to big leaks?

turbo to tmic connection, prone to leaks ?


also, how do i do a boost leak test?

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Did you have any runs at 0 wgdc? You should log less stuff..I would not log coolant and intake temp, fuel trims, injector pulse width, afr.


Also..Is your MAF properly scaled? Based on the boost you are hitting and how it relates to injector duty, I do not think it is. That much boost in the high end could lean you out badly on stock injectors. I know your injectors are showing 98% max..but if the maf scale is not correct, you could be running super lean.


I would check to make sure the WG opens freely and does not contact anything.


Good luck.

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i just baught a new vf 52 with the actuator, doubtful that its the actuator ... and my stuff ran fine before i did the new avo tmic / grimspeed ebcs plus the tune ... so doubtful its my actuator ... hmm


I dont know if the maf is scaled right, isn't that all done in the tuning ? What about a dirty air intake cone ? Ive had mine on for like 15k now and never cleaned it ...


You don't think its a boost leak or vaccum leak? No one is town has a boost leak tester, but they do have what they call 'smoking' . I guess to see if there are any vacuum leaks. I dont think that will help because it would be a high pressure leak only right ?

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A few things.. :)


When you put the turbo on, did you get a custom tune to rescale the MAF table?


Generally, leaks cause behavior like you are experiencing. The turbo works hard to hit the target boost, it reaches it, and then a bunch of air comes out the leak and the pressure in the system drops so the turbo has to make up that ground again.


On my car, I had a leak where the TMIC meets the turbo. I got a MrGasket aluminum gasket and used some RTV to seal that joint. After doing that, my boost leaks went away.


You can test for leaks with the smoke test. I tested mine with an aircompressor, soup can, tire stem fitting, and soapy water. Drill a hole in the can and securely fit the tire stem fitting. Then, I took my intercooler off and stuck the can in the throttle body hose and clamped it down. I pressurized the system and had a few people spray soapy water at different hoses and joints to check for leaks while I watched my boost gauge to make sure the pressure wasn't too high. Some of the hoses going to my BPV were leaking, so we re zip-tied those and fixed the leaks.


Pull a learning view for the car and tell us what your AF correction is at. That's probably a good start. Since fixing my leaks, my correction is within 2% after rescaling the MAF.



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Your IAT is 15F, my buddies 09WRX (which comes stock with a VF52) also had a MAJOR boost creep problem, we had to port the turbine housing of the turbo. I suspect in the end you will have to do the same if you drive it at WOT in the cold.


Your boost control is all screwed up in the first place, but in the log I can see WGDC going down to 0 but boost still hitting 20 psi.


Do all the checks:


-actuator works

-no leaks



in the end you may have to port it, or risk running much higher boost when it is -20 outside!

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I had my vf52 installed a few months ago, and had a custom emap tune done then. This week I installed an AVO tmic and grimspeed ebcs with a custom emap tune. Since the installation of the tmic and grimmspeed ebcs, I have had this problem. I can noticably hear the boost leak around 10 psi i believe.


I tie wrapped all my vacuum connections, and I torqued all my connections to spec (turbo to tmic 21.6 nm, bov 8.8nm). It doesn't feel that tight though ... Also, maybe i could tighten to throttle body to tmic hose clamp connection? I just dont want to break it ... how did you guys do that connection ?


actuator worked fine before the install, im sure it works now ... im going in for the smoke test today, then i'll see what i need

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my ebcs should be connected properly, i followed the instructions


port 1 goes to to air inlet port

port 2 was the wastegate actuator

port 3 was turbo compressor


I was thinking of going back to the stock 2 port actuator after work today, reloading my old map and seeing if i have the same leak issues, then we will know for sure right?


How is the stock one hooked up ? which port goes to the "T" and which one goes to the air intake inlet hose ?


also, its getting smoked right now.


also, my tuner was confused about the logs and was asking me about how i connected the EBCS... I've checked to make sure everything was connected as to how i just said there.

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not sure what that comment is about ... I guess i could have used the stock system with a different pill ... that's an option. I used the stock pill with my vf52 tune and i was overboosting way too much.
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