Originally posted by ludeboom
VTEC is a system to improve engine breathing at higher rpms.
it is also a system that allows for a very flat torque curve.
the system was designed for NA use only and IS useable in drag racing.
DOHC VTEC has nothing to do with gas mileage.
explain why the h23a1 (non-VTEC) makes 160HP at about 6000 rpm, CR=9.8/1
and the h22a1 (VTEC) makes 190 HP at 6800 rpm, CR=10/1
both are DOHC
how did they gain 30 hp in only 800 extra rpm and .2 CR...
while losing a liter at the same time.
did the 30 HP come from better gas mileage? :fawk:
~boom
look at the lobe specs, grasshopper.
the H23's lobes have less duration and lift than the H22's VTEC lobes... therefore the H22 is capable of breathing at higher rpm's. if it can breathe efficiently at higher rpm, then more power can be achieved purely by increased rpm while maintaining torque. hp = tq x rpm / 5252
the H23 has smaller lobes to give the H23 better low end response, less engine vibration due to no idle lope, and
better fuel economy
again, VTEC is for fuel economy and low end engine response... not for high end power. if these werent valid reasons, then VTEC wouldnt have even been created as the need for a smaller lobe at low rpm wouldn't be there.