818 boost pressure

[cob427sc]

The 818 I purchased partially complete and then finished has a 2004 WRX engine with unknown modifications. I know it has a different blow off valve as it now blows off to the atmosphere whenever you let off the gas. The turbo looks newer than the engine but not sure if it is stock or not and not sure if any tune has been added. I installed a boost gauge when completing the car. The gauge peak pressure is 20 psi which the engine easily hits at about 3500 rpm. Wondering what the peak pressure should be and should I be worried? My history is more with superchargers and this pressure seems excessive, but maybe not. Just don't want to blow a head gasket or worse.

[blomb11]

A stock WRX turbo engine should be around 14-15 psi and the stock turbo max is around 21-22 psi. An aftermarket turbo and supporting mods could handle even higher pressure. A tune is required any time you change the air intake, exhaust (specifically back pressure so a downpipe), and fuel system.

[Dave 53]

Does the car have a mass air flow sensor on the air intake pipe? If so, it should have a MAF tune and the blow off valve should be plumbed back the to air intake pipe between the MAF sensor and the turbo.

If there is an air intake temperature sensor near the throttle body, it's probably a Speed Density tune and the blow off to atmosphere is appropriate.

When my tuner asked how much horse power I was looking for, I answered, "keep it reliable." That equated to 18 psi.

[cob427sc]

Thanks guys. It does have a sensor (maybe temperature?) near the throttle body. It does have the different blow off valve, headers and the previous owner said he believed an "upgraded" turbo. I'm trying to get a slot with a tuner just so I know where I'm at and not cause any problems. It runs strong now, especially once you hit about 3500 rpm.