155 MPH With Few Mods....

Me: 2007 Chevrolet Cobalt SS/SC
Mods: Stock tune (put it back stock so my buddy would have a fair match)
Magnaflow Cat-back exhaust
9" Power Adder Cone air-box mod

My buddy: 2007 Honda Civic Si
Mods: Unbolted, and removed 3rd (last) resonator

So I was running a couple errands to Oakland and back when my buddy hit me up and asked if I wanted to follow him to get his lady's car (1980s Datsun 280zx) aligned. I said, 'what the hell?', and I met him at his place. Chatted for a little bit and then we headed on the freeway. He decided that early morning racing would be appropriate so we were weaving in and out of light traffic at 110-130mphs....

An opening finally appeared 4 miles long (equivalent to 5 exits), 2 lanes wide so we jumped on it from 80 mph. We stood dead even till 115mph and then I started to take the lead. So I kept going and going watching my gauge go to 120, then to 130, then I had to shift to fifth. I saw it go to 140, almost the fastest I have EVER got my car to. Then I saw the needle pass 147mph which then was fastest my car saw. By that point, I was in front of my buddy's Si by maybe 3 bus lengths and still pulling!

Then the most surprising thing happened. I had a little grade going downhill on the freeway (maybe 1%) and my speedometer needle went to 150mph and made my jaw drop, and kept going. My rear spoiler at that point was vibrating furiously (which is why I want to get rid of it) and I looked down one more time and my needle was at 155mph and still climbing but I ran out of room so I had to stop.

Now I know my speedometer is right because when I drove to LA one time, I had my GPS read 130 the same time my speedo read 130. It couldnt have changed that drastically because I KNOW what 150mph feels like. Remember, I down tuned my car back to stock and I saw 155.... The Cobalt SS/SC is claimed to be limited to 143 (bunch of BS!)