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COBB OTS Stg 2...boost creep/overboosting?


maddoc

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Last night I installed a Perrin TBE (Catted DP, Mid, and y-pipes, stock cans). I loaded up the COBB Stg 2 93 octane OTS map on my AP and headed out. I found that as I started getting into the higher RPMs I would get a buck or shudder from the car. I immediately let off the gas. The problem is exactly the same as my old RS w/ an STi swap... am I overboosting?

 

 

I plan to ditch the AP v2 and move to an open source tune hopefully within a week or 2, but in the meantime, will I be ok?

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If you hit the boost limit, you'll get fuel cut (very abrupt power loss, almost feels like hitting the brakes) and you'll get a check-engine light. Since you didn't mention a CEL, or the flashing cruise-control light that comes with it, I'm guessing that's not what happened.

 

Before my turbo upgrade I ran for quite a while with an Invidia catted DP, Perrin's mid/Y, and stock cans. What you describe never happened to me.

 

If you can data-log with the AP, that might help troubleshoot the problem.

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No CEL, but very abrupt bucking of the car, more when the car is 75% to WOT.

 

Another thing I noticed is I'm hearing a backfire (detonation? pop-pop) that I can hear out the exhaust if I rev it.

 

I have an older tactrix cable, but I'm not sure it will work on a DBW car (I picked it up in '06 or '07)

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No CEL, but very abrupt bucking of the car, more when the car is 75% to WOT.

 

Another thing I noticed is I'm hearing a backfire (detonation? pop-pop) that I can hear out the exhaust if I rev it.

 

I have an older tactrix cable, but I'm not sure it will work on a DBW car (I picked it up in '06 or '07)

 

Backfire is not detonation, what you are experiencing could be a misfire, which is different. Have you changed your spark plugs to a one step colder plug with a tighter gap? Do you have any intake leaks? I would start looking for vacuum intake leaks as it looks like you are going way rich, not lean which is where detonation would start occuring.

 

Ever since I added a UP and DP to my car, the check engine light and flashing cruise light has come on. The code is for a front O2 sensor and lean condition. Could this be due to boost creep? I seem to lose power (or boost) over 3500rpm.

 

If you have a front 02 sensor code, that means the front 02 sensor is going bad, this is not boost creep. Replace the sensor and your car will run perfectly again.

 

Travis

COBB Tuning

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When I went stage 2 on my LGT, I had the same problem you are having. It would overboost like crazy every time I put my foot in it. FYI, I was running a Cobb catted DP, stock exhaust, and AVO TMIC. I researched the hell out of it and the ultimate solution was to get it pro-tuned. Some had mentioned changing pills, others that I should run an EWG. I ran the car for about 3 months, but just learned to keep my foot out of it as it would overboost every time. Before I got pro-tuned, I added an SPT catback and an AVO panel filter. Ever since then, the car backfires after high RPM shifting. I've heard its pretty common running a more open exhaust such as I am doing. I then had it pro-tuned by arguably one of the best Subaru tuners in the nation and have not had an overboost problem. My boost targets are spot on now. I still have the popping after high rev shifting, but have learned to deal with it and it gives the car character.
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/\ I had the same experience as you (Cobb intake, cobb catted DP, SPT CBE), after a month I was fed up with the constant overboosting and got it pro-tuned by Precision Tuning in NJ. Surprise surprise, boost targets were spot on and it ran much smoother afterwards. :)
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What is happening is your getting very brief boost spikes, On my car I've seen them as high as 22psi, I also had a catless DP, but the OTS map is terrible, I don't think anyone should use it unless it temporary. It will destroy your engine over time.

 

The buck is your car over boosting and the engine trying to compensate.

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Travis/Cobb,

 

Can you comment on the above posts whereby a catted DP was used but still they experienced over-boost? I've been following closely, and Cobb continues to deny any over-boosting when a catted DP is used.

 

they will deny it somewhat, I've talked to christian over at COBB and he said it was a catless prob. Bottom line is, dont run the OTS maps at all, they will ruin your car. Trust me, I can prove it to you.

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