I just finished my brothers B16 swap and I noticed vtec activating @ 4,500 RPMS. It seems to bog down alittle then around 5,500 take off alittle better. Is this the normal point or do I have a modded ECU? Also how much power can be gained from changing out the stock OEM exhaust system with a higher flowing setup? I must say the car doesn't feel very fast. But then I am comparing it to my Turbo B18B.

 

umm...my stock pr3 ecu has a 4800 rpm vtec switchover point. 4500 is a little low, it might be chipped like another ecu i used to own. you can check it out by SLOWLY (well, not TOO slowly--about 25% throttle) accelerating from 4400 rpm to like 4600 rpm and if you hear a switchover, you most likely have a chipped ecu. if you can't hear it, then you have a stock that opens up pretty early...and you should get a bigger exhaust system...personally, i had a stock b16 with oem piping and did 15.3's in the 1/4, when i switched to a catback 5zigen fireball, i was runnin easy 15.1's...the gains are better when you're at highway speeds

 

theres a chance its not a chipped ecu, it may be an auto trans ecu....
the a/t ecu switches over between 4300 and 4500 rpm and the fuel cutoff is around 7500
i swapped my a/t out for a m/t ecu and the vtec switch changed to 4800 and my fuel cutoff is now @ 8000