Overboosting at high rpm . . . why ???

[coyfish]

I was doing some pulls now that the weather has gotten a little less humid / hot. Car pulled hard but I was monitering my gauges and I was hitting a boost spike around 5300 rpm. I actually felt it pull harder in that split second. I was holding about 16 psi then it creeped up to 17 psi then it jumped to 20-21 psi around 5300 until i shifted at 5500.


Why is this happening ? Even on the stock tune its odd . . .

 

[vrspeedemon]

mine does the same thing according to my dashhawk and I'm almost completely stock, figured it was due to temps dropping here in Wisconsin and colder air/more fuel mix?

 

[coyfish]

bump

thx for the response vrspeed. That seems logical. I live in florida and the temps aren't changing that much / that drastically to induce such behavior though. The ECU should adapt shouldn't it??

 

[SMOKEYS36SHOP]

it should...im no expert but make sure all your hoses are on tight...its odd when your boost is increasing in the higher rpm range when our cars are known for dropping boost at around 5,500 rpm...and if your increasing boost that much im surprised you not hitting boost cut which your computer should be monitoring because of its factory settings...didn't you recently add your turbo inlet pipe? make sure the little hose going from your inlet to your wastegate i think is still on...its just a suggestion. idk what else it could be honestly.

 

[coyfish]

Hmmm ill look into that.

 

[SMOKEYS36SHOP]

i just remember how when i changed out my stock inlet i broke the plastic nipple....and had to cut the hose off the wastegate cause it was on so tight which seemed breakable....i hope its that easy! goodluck!

 

[FORZDA 1]

I was doing some pulls now that the weather has gotten a little less humid / hot. Car pulled hard but I was monitering my gauges and I was hitting a boost spike around 5300 rpm. I actually felt it pull harder in that split second. I was holding about 16 psi then it creeped up to 17 psi then it jumped to 20-21 psi around 5300 until i shifted at 5500.


Why is this happening ? Even on the stock tune its odd . . .

I saw your thread on the other forum as well. I think you may be seeing an issue with the OEM Boost Control Solenoid sticking, or leaking vacuum/boost hose at the BCS. The ECU doesn't use boost as the ultimate indicator of load, it uses boost to hit the load target, so the max boost level seen will indeed vary with weather conditions, but it shouldn't go above the boost "limit" value set in the ECU tables, unless there is a malfunction the ECU can't detect.