Overboosting problem

[Jayros]

Hello,

I wanted to know why my 2005 STI would be overboosting. It has a TD05H 16G turbo, a Grimmspeed MBC, and a Grimmspeed intake manifold. Everything else is pretty much stock on it. When I'm driving it and stepping on the throttle my COBB access-port reads that I am pushing 23.96 PSI boost. At around 6k RPMs in 2nd, and 3nd gear I hit a power loss, this also continues through the rest of the gears just at different RPMs. I put a Grimmspeed MBC on it, and I was still overboosting. We had to manually open the wastegate and leave it open so that it would stop overboosting. I think its the tension spring in the wastegate, because was very hard to pull and open. Not sure what else it could be. Wanted to post here and see if someone else has had this problem, or knows how to fix it. Thanks for your time.

 

[IGOTASTi]

Does your STi have a custom tune?

 

[Jayros]

Yes, I've put a 93 low wastegate tune, from COBBs access port.

 

[Spamby]

Stage one or two?
OTS map or protune?
Downpipe catted or not?

 

[IGOTASTi]

What he said.

 

[Alin]

Yes, I've put a 93 low wastegate tune, from COBBs access port.

Stage one or two?
OTS map or protune?
Downpipe catted or not?

So, that leaves the questions being: Is it Stage 1 or Stage 2? Catted or catless?

 

[Jayros]

Its a stage 1, OTS map from COBB, and its stock downpipe.

 

[Alin]

Then, there is the underlying problem. That OTS map is meant only for stock intake/cobb intake + any CBE. Nothing else. That's why the fuel cut/power loss. Everything is way out of sync. You need to get a protune or an open source tune.

Refrain from wide open throttle from now on until you get a proper tune going. We wouldn't want any damage done to the car.

 

[IGOTASTi]

You need a protune asap.

 

[Jayros]

Would going with a VF 48 turbo help at all ? Got a buddy with a 2015 STI and he is going to upgrade everything and willing to give me his stock turbo.

 

[IGOTASTi]

Just get a etune. We do that for premium members.

 

[Jayros]

How much do you guys charge ? And where are you located ? Also with a protune, do I have to get it tuned every time I put something new on my car ? Because I'm saving for an HKS Hi Power exhaust and a HKS downpipe right now. But in general I will be putting on all bolt on stuff first before I mess with internals.

 

[Alin]

Would going with a VF 48 turbo help at all ? Got a buddy with a 2015 STI and he is going to upgrade everything and willing to give me his stock turbo.

You have the TD05 turbo, the boost controller, and different intake manifold. Those are all great contributing factors that are drastically different than what is required for the OTS map.

How much do you guys charge ? And where are you located ? Also with a protune, do I have to get it tuned every time I put something new on my car ? Because I'm saving for an HKS Hi Power exhaust and a HKS downpipe right now. But in general I will be putting on all bolt on stuff first before I mess with internals.

With Platinum membership, you get free tunes done by a very intelligent and knowledgeable tuner that we have here. He does extraordinary e-tunes with safety and reliability in mind first. :tup:

 

[danosrk]

Tune is free for premium members and you just need to send them data logs. And yeah every time you add a power mod you need a new tune.

 

[Jayros]

Aaa ok, thanks for the help guys appreciate it. Also what sites do you guys use to order your parts of ? I've been looking at JSC, Ebay, Amazon, and Evasive Motorsports.

 

[Spamby]

Oh dear Jesus I just caught that your NOT running the stock turbo with an OTS map. If you plan on driving the car, stay out of boost.
As Alin stated, the OTS maps are very specific to only a few mods; stage one for cat back exhaust and nothing else. Stage two for a downpipe (usually catted) catback exhaust and sometimes a cold air intake. These maps are intended for using only and exactly the stated mods.
Your fueling, timing and turbo dynamics, wgdc the whole shebang is wrong at this point for what you've got.
An mbc will throw it off since boost profiles will be different especially when compared to the factory solenoid.
Given your use of a different turbo, that is going to be the big issue. You must have a custom map made for this. This is why your having issues.
A VF48 will not help resolve this. It will only hurt unless you tune for this, as well.
Essentially, if you bolt something onto your engine that is different from the factory piece or what you have been tuned for, you will need a retune.
These cars are very picky when it comes to changes and retunes are often needed.
An aftermarket downpipe will also be needed when you do your tune with your aftermarket turbo. The factory downpipe is a major restriction.
I would say park the car until you get it all sorted out.

 

[IGOTASTi]

[MENTION=3605]Jayros[/MENTION] our Vendors here give nice discounts for parts, but you need this guy [MENTION=9]HolyCrapItsFast[/MENTION].

 

[HolyCrapItsFast]

I don't think that any of this has anything to do with the tune because he tried it with a manual boost controller, which could care less what the tuning parameters are. This should have fixed your problem, or at the very least, tested that the problem is tune related. Also the fact that you manually opened the waste gate and the boost level subsided, indicates a mechanical issue. It indicates boost creap wich could be caused by a sticky waste gate or to small a waste gate which can often be fixed by porting and polishing the waste gate port.

To test the waste gate properly I suggest you get a stand alone pressure source like a hand pump and observe the waste gate to open upon applying pressure.

When you manually opened the waste gate how did you do that? Did you remove the diaphragm and actuator arm from the waste gate itself first? The concerning statement in your original post was that you had difficulty moving the waste gate. With the actuator arm in place, this is the case. But with the arm removed the watse gate should move freely with out any resistance.

George.

 

[HolyCrapItsFast]

Would going with a VF 48 turbo help at all ? Got a buddy with a 2015 STI and he is going to upgrade everything and willing to give me his stock turbo.

If all else fails this would be your best bet. A much better turbo than the 16G

 

[Jayros]

We adjusted the arm on the wastegate so that the wastegate flap valve would be open a bit. Thats how we were able to reduce my boost. Idk I was thinking it was the tension spring in wastegate actuator. Because the older owner had different mods on it, and I dont know how much boost he was pushing. Sadly my budget limits me to only do so much. Otherwise i would get all the bolt on and put it on, and go down to Austin and get it tuned. But I'm pretty sure either my wastegate tension spring is really stiff, or my wastegate is just bad/worn out.