vtec compression?


now i could be wrong but I'm sure I'm not but v-tec is in the head right? Compression is in the pistons and bore size right? So if thats the case what does v tec have to do with compression?

Just asking, not busting anybody, just making sure I got my s**t right

 

Compression is measured from the displacement above the piston, which includes cylinder diameter, cylinder length, cavity size in the head or piston.
A Vtec engine can have a compression ratio of 10.2:1 where a non-Vtec might only have a ratio of 9.4:1

 

what he said...

 

yeah, its not actually the VTEC itself that causes the problem, its the higher compression that VTEC engines have. but power is based on FINAL compression. i am not sure of the equation, but it goes something like:


atmospheric pressure=14.7=X

boost=boost psi over atmosphere=Y

CR=base compression ratio=Z


it goes like this:

[(X+Y)Z]
------------
X




i believe thats it. it shows the effective compression ratios after boost has been introduced. so you can see how higher compression and lower boost in otherwise identical engines could give more power than a low compression-high boost setup. and if you add in the variable valve timing and lift characteristics of VTEC, you can see why VTEC engines have a bit of an advantage over the nonners. let alone the stronger built motors.