Overboosting

[08SPEED3Veteran]

ok, break it down barney style for me...i have cai, inlet pipe, tbe (no cats), fmic, denso step colder plugs, and the AP on the mscai map. first and second gears are perfect boost, but third through fifth at wot the boost hits the supposed max boost for the map but then slowly rises into the twenties and stays as long as im hard on the gas. I dont drive the car hard because it is my daily driver and i dont go wot hardly at all, but when i do i have to pay attention to the boost gauge and lay off the gas when these scary boost levels occur. what am i experiencing, and can I take the car to a cobb pro tuner and have this tuned out? or should I just get a catted DP and get rid of the non-catted one? any advice is greatly appreciated!

 

[MSMS3]

I'm not a Cobb AP expert, as I am on stock tune. I am running catless dp/rp. I think you are seeing true boost creep.

To me, your options are: (1) get the wastegate port opened larger, or more simply (2), see if you can go with a less aggressive tune on your AP and set your target boost lower, recognizing that your free flowing exhaust will cause it to rise a couple pounds above your target.

And yes, if you are holding at WOT above 18 psi, you are likely to soon join the zoom, zoom, boom club if you push it. It is wise that you are recognizing the problem from the creep.

AP users? Chime in here?

 

[hugador]

Keep your DP. Either learn to use ATR or get help on tunnig. If you can take it to a tuner that you trust by all means do it!

 

[08SPEED3Veteran]

AKUMA MOTORSPORTS is in NJ and the closest cobb pro tuner. it was started by a former cobb tuner and they tune speeds so i think im going to just take it in and let them work magic with the AP and ATR. after all a membership to the zoom zoom boom club is out of my price range at this point. I have too many mods to not have a good tune anyway.

 

[matsuda]

Question: is your your boost creep test parameter of stock 15.6 PSI still applicable for those of us running catless dp/rp, or should we expect to see the boost to rise and hold a bit higher, maybe two more pounds?

If the boost pressure is > 15.6 PSI with the wastegate solenoid valve disconnected (valve closed), there essentially is no control of the boost pressure by the ECU and the mechanical wastegate itself would be "maxed out".

I'm sorry for the late response. I missed your question when you posted it.

 

[MSMS3]

Thanks, Matsuda. Now to run the test. Since I'm just quickly spiking at 21 and then holding at 17, I don't think it's really an issue for me (hopefully), but I want to know.

I really don't want to remove the turbo to port the wastegate unless absolutely necessary, given the work involved in remove and reinstall.

 

[Double Dspeed]

i have the same problem and just planned on getting a new turbo preferrably the gt2871r that ATP offers since the seals in mine are shot from running catless. even though its still internal wastegate would it be better then stock? or should i go external?

 

[Darth Vader]

Mine just won't hold. Even with an MBC set super loose, it will eventually creep up to the cut in high gears (Corksport DP and RP). I'm hoping it's just a winter foible and will fade as the weather warms in the spring. If not, I'm going to have to reinstall my second cat to calm it down, as this is really dangerous.