This is my setup on my Type R which is mainly used for track days:

B18C5 - stock intake manifold, stock fuel rail, stock head
Mugen CAI
Taper bored TB (stock butterfly)
RC Injectors 310 cc/min - stock fuel pump and OMP FPR
Toda B cams and upgraded valvetrain (stock valves btw)
Endyn 81.5mm 12.5:1 CR RW pistons/Eagle rods/stock crank
Spoon FW/clutch
Hytech header and custom 2.5" exhaust
P/S system removed
Hondata Stage II
Runs on Chevron 94

Here is the dyno and A/F readings:





My question is: how much more power can I expect out of this setup if I p/p the head (currently stock)? Is it worth it? Or should the cams be changed first?

BPR - who is very happy - but just looking ahead

 

with a head it will make power past 9k

 

The HP curve should smooth out and increase on the top end.....

 

You will have better top end, and you will notice your engine running smoother. Just P/P My Supra.

 

That torque curve is fairly flat already, I can't see the power becomming more linear. I don't think you'd want to upgrade to a larger cam before p + p though, so I'd put my vote towards port and polish. You may not even need to go to something bigger like an M24 or a Jun3.

-edit-
Is that flat *** one a torque curve or air:fuel?

 

When you have all the mods _except_ the head like on your car, you can expect pretty large gains.

I recently had a customer with a B20 buildup and mild cams change from a stock head to a ported head and he gained nearly 20 whp peak with some level of gain from 2000 rpm to the limiter.

Depending on your porter and other variables, I think you could expect a minimum of 12 whp and max of 20 whp - just my opinion of course.

C_A_T

 

That depens if its a type r head They make preety good power
with the valves and all. It really depens on how nasty the engine is
The more compression the more it will like a great head

 

keep in mind, that max_cfm is pretty low key and doesnt boast that much

you will certainly gain good power on your whole power band. depending upon who you go with will yield different results.

im guessing you can pick up a solid 10-18whp in most of the midrange and make 8-13whp up top

just a matter of talking with a couple head porters and seeing which one treats you good and will make big power

 

CFM indicates the power potential of the head. Valve sizes will become a factor as well as cam specs, VE, tuning etc. once the flow stalls. And yes I have done head work and operated a flow bench.