99-00 b20b block with P8R head questions...

[bRiAnMcIvIcS]

The 99-00 b20b is rated 9.6:1 C/R. 146 hp and 133 ft-lbs torque. What would the compression be with the P8R head(honda orthia head) on a 99-00 spec b20b? What headgasket would you use? An Ls headgasket(81mm combustion chambers) would'nt match up with the p8r 84mm combustion chambers. Supposedly the p8r heads flow almost as good as the vtec heads due to the 33mm intake valves and bigger 84mm combustion chambers. What size are the exhaust valves? 28mm? Also are the b20b 99-00 spec oem cams an upgrade in the p8r head?
I've searched honda-tech but not much info. I guess its not a desirable setup.
Sorry with all the questions im just curious.

[blackhatch99]

thats a lot of numbers the best thing to do is call batlground

[cardesignz]

Basically, if you are asking that question, you probably know more than 95% (or more) of Honda tuners. Really, there is more bad info out there on B20’s than anything else. Most people with B20’s have 126hp 8.8:1 JDM B20B's that they spent $1000+ on after installation at a shop.

This is coming from someone who has done extensive research and has a 2001 USDM B20Z that made 146whp/137wtq with the P75 head with only I/H/E (well, the AEM cam gears were turned a little as well - I didn't have any way of adjusting them when it was tuned, so I don't know if that helped or hurt).

The P8R head is said to have "VTEC-sized" intake valves and an 84mm combustion chamber (I don't remember if the exhaust valves are different or not). All B20's use a 84mm headgasket regardless of the head (a 81mm LS headgasket will not work). Here is the breakdown on engines/cams:

1. USDM/JDM 96-98(ish) CRV - 8.8:1, P75 head - 126hp/133tq. Block labeled B20B in Japan and B20B followed by a number in the US. Usually has a very tall LS style intake manifold that is often referred to as a "giraffe" because of the really long runners. (cam specs in the chart below)

2. JDM (the specs listed are from a Honda Orthia - multiple cars came with B20's over in Japan, so there could be other variations) - 9.2:1, P8R head ~ about 143hp/132tq from converting from PS and NM figures that I found in some info on the Orthia. Block labeled B20B. Usually has an LS style intake manifold. Same cams and pistons as the 8.8:1 compression engine based on research done by some guys on nonvtec.com a while back - can't find it now since all of the old stuff got deleted when something happened with the site (was a big sticky with extensive information and actual measurements).

3. USDM/JDM 99-01(ish) CRV - 9.6:1, P75 head - 146hp/133tq. Block labeled B20B in Japan and B20Z2 in the US. Intake manifold looks like an LS manifold with a large funky looking box on the top. Will also have a knock sensor. More lift on intake cam - exact same cams as in the 96-01 Integra B18B (specs in the chart below).


*chart taken from the USDM Honda CRV factory service manual (commonly referred to as a Helm's manual, since they make them)


Basically, all of the exhaust cams are the same, and you want to run a B20Z/B18B intake cam. From what I understood in my research, the engine with the P8R head comes with a special thinner head gasket (2 layer vs. 3 layer) that raises the compression to 9.2:1. If it is truly just the head gasket that accounts for the increase in compression, then you would still have 9.6:1 on the 9.6:1 block. If the head itself raises the compression, then you would end up with 10:1. Get me a P8R head and I'll give you all of the info you could ever wish for including dyno numbers... LOL! If I could find a P8R head (and for a reasonable price), I would do in a heartbeat.









This was with:
2001 USDM Honda CRV B20Z2 (9.6:1cr) engine
YS1 transmission (long-geared 1992 LS) - (now running a Y1 B16 tranny)
K&N cone filter
DC Sports 4-2-1 header,
Thermal R&D catback
Fidanza 8lb flywheel
dyno tune with Chrome
146whp/137wtq ON 87 OCTANE!!!
I got 31mpg with the LS tranny and now get 28-29 wth the B16 tranny and driving the hell out of it on back roads or stuck in traffic.

[cardesignz]

Oh, before anyone else tells me I need to change my intake manifold, according to the second person I have ever seen to keep the resonator box, it is responsible for my my nice clean dyno graph and LS manifolds tend to create a gap or drop in the midrange.

You're welcome for more B20 information than has probably ever been or will be posted on this site again. Someone needs to retitle the thread and sticky it somewhere.

[Vteckidd]

The p8R head has VTEC sized valves, and the ports are as big as a VTEC head.

The combustion chamber is 84mm, but i dont think that matters because:
1) There are guys running Stock VTEC heads on 84.5mm blocks with 84.5mm Headgaskets. I dont see them blowing headdgaskets all the time.

2) I believe the headgasket would seal fine 84mm with a 81mm headgasket.

Let me think about this one an run some numbers aka talk to Don.

The cams are not that different, an i wouldnt classify them as an upgrade anymore than the 01 ITR Intake cam vs the 98 ITR intake cam (3 deg difference)

P8R should be 33mm Intake valve and 28mm Exhaust Valve, same as any VTEC head.

[Vteckidd]

or you could just put oversized valves in the stock LS head with a little port work and have the same thing lol

[bRiAnMcIvIcS]

Thank you sir, very informative. With a 10.1 c/r b20b, im guessin the motor should put out around 160whp and some impressive torque. I was just thinking logical, 84mm combustion chambers on a 84mm block(it just sounds so right.lol). It just seems like it would flow SO much better than a p75 head. Would you use vtec valve springs and retainers? Im thinking about this as a possible turbo setup.

Thanks cardesignz.

[bRiAnMcIvIcS]

I just bought a P8R head for $80. YAY! It has around 30k on it. Now i just gotta get a b20b block then golden eagle resleeve to 84mm, cp pistons 9.5 c/r, eagle rods, and then boost the fuck out of it. I will probably use the gt2871r. I figured id go the non-vtec route. haha. Besides id rather boost a b20b rather than my poor little b16a2.
Lookin to get 300+whp.