I was recently talking to some co-workers and they seem to know a little bit about cars. I told them the highest iv ever gotten my almost stock 00 civic si was to about 107mph. They told me if i install an ECU chip or something and a speedometer something(im guessing to unrestrict it) i could probably top at 140 or so. So could someone possibly tell me more information on this. Im still Very new when it comes to talking about cars. My engine is a b16

 

Not sure about the si, but the gsr has a rev limiter programmed to cut fuel at a certain rpm. If there is a way to find out if the si has a rev limiter that is gear specific, check it out. I installed a hondata S100, which will be same for civics, with this you can set the rev limiter and even remove secondary O2 sensor. If you have a local tuner who knows anything about Si's then contact them.