So I have just recently bought an evo x. And I'm new to the engine setup, but the original boost is set at 15psi. But when full throttle, in fifth gear, it shoots all the way to 25psi. But when drive normal it doesn't. Does anyone have any idea on what the issue can be? I recently talked to one of my fellow friend, and he said it can be the waste gate. Not so sure. If any info. That would be a great help. Thanks.

 

Also, it is a aftermarket boost controller, doesn't say what brand, but my friend said it can be the gauge itself.

 

First of all is it stock? If not, it's most likely tuned for 25psi at full boost(normal). The original boost for the evo X is not set at 15psi either in stock form so I'm not sure where you got that information. You might want to list out the mods on your car so we can help you figure out if you really do have a problem.