i have a b18a1 block and head. im building my motor and whant to know if 12:1 or 12:5 cp is to high. its my daily driven car and im going to be using 93 octane every time. below is the set-up im going to be using.

b18a1 block bored .25 over stock sleaves
ls crank
ls rods
ctr pistons .25 over
ls head (how much do i need to mill to get to 12:xx cp?)
oem headgasket (maybe remove the middle layer to get to 12:xx cp)
crower 404 cams

im going to be using a hondata to tune it and will i need bigger injectors? which ones (its still obd-o)
if anyone needs more info about my set-up let me know and ill provide you with it.thanx

 

bump

 

93 octane should be fine as long as you dont run to much advanced timing. Your lucky you have the luxury of pumping 93 at the pump, here in Ca I have to go to a racetrack and pump 96 @ $3.58 a gallon just to drive my car, 13.5:1 cr isnt very nice on 91 octane which is what we have at the pumps here.

 

yeah i get 93 for about 2.05/gallon. and do you know which one would work the 12:1 or 12:5?thanx

 

You could get away with either depending on what kinda of tuning your will be doing. I would go with the 12.0:1 simply because then you can run some more timing. The power your gonna gain w/ that extra 5 points of compression is gonna be lost when u have to pull timing.

Another thought is what kind of cams, big *** cams with alot of overlap are going to allow you to run a higher static compression. The overlap will in a sense "bleed off" some of the compression resulting in a dynamic compression ratio that is lower than the static.

 

It really depends all on how you tune it, my friend has a 2.0l GSR with 13:1 cr running on 91 octane, his ECU is hondata tuned for 91 so he runs it that way it all depends on what you want.

 

i'm doing alright as of now with 12.4 on 94 daily driven