what would be the requiered comp ratio for running these cams

i have 11:1 now but i know ill need more ..it is a strret car so the most i would go is 12:1 but id rater a bit lower as i only have 91oct available

the motor is an f20b with 42mm itbs

thanks guys

 

bump for thread cuz i need to know also w/ my 402's in my b16/P72 head

 

Static CR is kind of vague on what octane you can run on the street. More agressive cams drop dynamic compression. So if you are running 12:1 static CR and ping with a conservative ignition map then you will have better luck with a more agressive cam instead or retarding the ignition or swapping pistons. I would go at least 12:1 static on those cams. But honestly you want to go as high as you can without detonation. Higher compresison makes the engine more efficient which means more torque, which means more power and you'll get better mileage while cruising on the highway.

People are running 12.5+ static CR on 91oct at sea level. Just tune it and you'll be fine.

Pirate


Modified by PirateMcFred at 12:30 PM 6/7/2005

 

thanks pirate ...i just need to find a thin HG and mill cause i cant afford pistons for the f20b..ill try to get as close as possible to 12:1
i can get 94 here but it just doesnt seem to liek my car much ...but that could change with more comp

 

any help on the rocker mods needed for these cams ..i didnt think they were that big

 

I would get the recommended Crower valvetrain and then do a quick install and see if the rockers even need to be machined. IIRC you should have at least .030" clearance between the outside edge of the retainer and the underside of the rocker arms. You'd make the measurement when the follower is on the base circle of the cam (i.e. not at any valve lift).

Pirate

 

ohh so this is a clearance problem with the retainer hittin the inner bottom part of the rocker ....thats not a big deal really

i was thinking about rocket valve train

 

Go with any reputable VT. Rocket has a Lifetime warranty IIRC. Just check the clearances and you'll be good to go. Did you go with the Crower st. 3's because they were on sale ($500)? I have only seen one dyno of Stage 3's and they only made like 215whp. But that was with a POS DC header with a colletor mod.

BTW do you have the low cam specs on the 3's? I am interested in an H23 comparison for ***** and giggles.

Pirate

 

they only list the big cam specs but iam going to phone them in a min

yes ther eon sale that pretty much the only reason im considereing getting thme
need to sell my type s cams first to make the jump

i hope with a good header (rmf smsp ect) and the itbs(i now ill be limiting with my 42mm itb) i could see around 230whp with the 12:1

i have faith in the f20b

 

so am i right in where the clearance issue is .

is it the retainer contacting the bottom of the rocker when on the peak of the lobes?


thanks again pirate always helping

 

You are half right. the clearance issue is at zero lift. At gross lift the retainer is pretty far away from the rocker's underside, but when the valve is on the seat the retainer is much closer to the rocker.

this guy had the issue that I am talking about:
https://honda-tech.com/zerothread?id=1240002

another topic:
https://honda-tech.com/zerothread?id=1266132

Picture of the rocker mod from Endyn (b-series):
http://www.theoldone.com/artic...2.jpg

You just have to waste more time on HT and this crap just presents itself

Pirate

 

thanks ..makes sens its when theres no lift on the cam ..i understand now

 

have the oppertunity to get some skunk 2 for about the same price as the crowers but there used and i havent seen them yet ...

what would be the better cam for me