Yeah and you drive in a parkway and park in a driveway.

You can be as specific as you want. I was just saying that SOA states that Max boost pressure from a stock car is 13.5 WRX and 14.5 STI. That doesn't mean there won't be variables, each car is different.

All the variables that you are listing have no bearing on his original question.

"what is the stock boost pressure on a 2002 wrx?"

 

13.5 PSI is the correct answer to the question: "What's the nominal peak boost pressure on a 2002 WRX?"

If the question is "What's the correct reading on my boost gauge during peak boost?", the answer is that there are lots of variables.

10 psi is too low. Something is amiss if that's your highest reading.

 

No, that's not the case. The question itself isn't specific enough. The pressure DOES vary by gear, RPM, altitude and other factors, and the person asking the question has to know those things to make any use of the answer. There actually are some 2002 WRX models that seem to have boost limited to 10 PSI in 1st and 2nd gear; my friend has one, and that's the way it came from the factory. The SOA numbers are safe estimates that are probably based on broad averages -- in which case they are about as useful as the stock coolant temperature gauge. If you KNOW a more precise answer, why not take advantage of it?

 

So are people talking about what the boost spikes up to, or what the boost holds after the initial spike?

 

That's not the pattern of boost with the WRX or STI. If you look at a dyno chart with the boost pressure overlayed, it is a rapid climb to a peak and then a catastrophic fall-off as you reach 6600 or more RPM. There is indeed a spike, but it is just before that falloff. Max boost per gear is usually around 5300-5500 RPM, but if you have your foot to the floor, you won't stay in that RPM for long. In other words, there is no steady level of boost -- if you back off the throttle to stay in a certain RPM, you quickly go to vacuum pressure again much faster than the RPM falls. The power of the turbo is literally supplied only when demanded, unlike other turbo applications such as a turboprop airplane engine.

 

Boost spikes generally don't happen on a stock WRX. They are common on cars with aftermarket boost control, or cars with aftermartket exhaust components and stock engine management.

 

When i started this thread my question should have been what is the peak boost pressure on a stock wrx in third or fourth gear and what do my fellow subaru drivers read on their boost gauges when they peak out in third or fourth. My car obviosly had a problem with the gauge because it was only hitting 11 psi peak in third and fourth. So i pick my car up tommorow with my brand new ATI pod and a new set of AWE gauges including a 60mm boost gauge that will record peak boost. So after i take out my gfb mbc i will tell you guys what i read as my peak boost on my 02 wrx wagon. I dont know if it makes the a higher or lower peak boost but i am also putting in a gutted uppipe and a helix downpipe with high flow cat.

 

Well, i got my car back today with all me new gauges so i decided to go play with them. Especially since the new 60mm boost gauge has peak boost recording. So i stepped on it in second gear and the needle shot up to 17psi. i dont think that you are supposed to run that kind of pressure ona stock turbo. I believe that tommorow i will go under the hood and tune down that stupid MBC.