p8r head on a b18a1 block questions

[Senko]

Lets start simple,

What is the compression ratio of the p8r head on a factory b18a1 block??

Does any have experience mating these two together??

Are there any special considerations to take when Mating the two together? IE thicker head gasket, different sized head bolts, etc.

Is this setup better for boost or NA?

Will this give me much power over factory?

Am I an idiot for asking these questions and not just "finding out"?


Thanks in advance and let the flaming begin!

[xero_xero]

a p8r head has the same combutsion chamber as the pr4 or p75. the only advantage is the bigger valves and more duration on the cams.
it builds monster torque and can flow really well.

guys on boost should be chasin this head.

as far as the head its self, it came on the b20z (only about 5% of the total engines were these) so they are a bitharder to find. verry similar castings to the pr4 and p75, just bigger valves and cams for torque.

[Infamous_1]

no p8r head is 84 mm combustion camber with vtec size valves and cams are the same as p75 fyi. You'll only make more power cause of more airflow. Also it out flow better then a pnp p75 head and flows almost the same as a b16 head

[xero_xero]

b18c5/b17/b16 have just under 43 cc combustion chamber
b18c1 has just under 42cc combustion chamber
b18a1/b1/b20b/z have just under 46cc combustion chamber

all of this is an average of everything i have gathered and measured myself.

the difference between b20z and b20b are:
b20b has p3f pistons and p75 head
b20z has phk pistons and p8r head
the only difference is higher compression piston and bigger valves in the b20z.

[Infamous_1]

http://ht-archive.org/showthread.php?t=1467903

[xero_xero]

Originally Posted by Aquafina
P8R = 47cc
P75 = 45cc


i cc'd my p8r head today and i came up with the same numbers...




you really should read this if you are going to post it up. above contradicts what i said and measured on myheads and i believe it to bo wrong.





you indicated that your b20b engine had stamped on its cams, R1 exhaust, and R2 intake. Your b20z had R3 ex and R4 in. All 4 were stamped p75, and both sets had different specs.


from another post, telling you the cams, intake and header are different.