I just bought and installed a boost gauge on my 2001 a4, 1.8t obviously. and I do have the GIAC stage 1 chip on there so it boosts more than the stock 9-10 psi. But i put on the gauge and it says and or records that i am only getting 12 psi when i absolutely punch it to death. now i know this cant be right because if i were only getting 12 psi my car would be much slower than my friends exact same car who gets 18 psi, but no i can smoke him. so i was wondering if anyone knew what the problem may be.

thanks