ok i have some skunk2 pro3's for my ls-vtec.
some of the factors :
type r head,
b18b1 block
oem 3 layer headgasket

question is how high does comp ratio have to be to run these cams,

and

what pistons can i use for the right piston-valve clearance.

any help would greatly be appreciated!

thanks

 

There is no 'minimum' compression required. You will net better results and part-throttle diveability as compression ratio increases.

There is a point at which you would make more power with a smaller cam.

Depending on a variety of factors (including headwork, supporting bolt-ons, etc), I would run Pro3's on a 1.8L with 12:1-13:1 CR or higher, and as displacement increases, the need for more compression decreases. A 2.0L would do well with 11:1 CR and Pro3's with the right supporitng mods.

 

great info! thank you!

 

You might have to notch the pistons because the valves will come down so low they will tap the tops of the pistons on a high compression piston because they are such a big cam.

 

depending on the pistons valve pockets, correct?

 

Correct.

Most aftermarket forged pistons already have large valve reliefs.

I have up to +10* on the intake before P2V on off-the-shelf CP 12:1 pistons.

The only true way to tell is to carefully measure clearances.

 

Double-check if U have Arias. VERY small pockets...
Endyn Rollerwave is perfect from that prospective.

 

now one more question, are aftermarket valves needed for a cam setup like this , or is stock valves with aftermarket v/s, and retainers ok>?

 

Stock valves are fine with any cam, but you may want to consider the age of them. May be a good idea to replace anyways.

 

What would be the predicted results of a 12.5:1 B20-V with pro3's and extensive headworks, all the right supporting mods etc...

Would it be not gaining as much power as it can with a 11:1 CR?

I don't believe there is a more aggressive cam then the Pro3, unless you consider the toda killers, just trying to understand the ideal cam for this type of setup.

 

With 12.5:1 compression it would make more power than the same setup at 11:1. Most of the time you can recomend what to use based on a guideline but in the end, the engine is going to tell you what it likes through testing and comparing.

 

So when I install the S2 P2 cams in my G24, will a 12:1CR suffice or do you think that one must go higher/lower?

 

G24?

you'll be fine at that level in anything with those cams.