Ok…so I’m prolly gonna end up boosting the LS…givn the information provided by u guys…the budget I’m working with…that’s what ill prolly due…in terms of the car…its basically a street car…visits to the 1/4 mile track 1nce a month…but mainly a street car…ok so with that said…aproximately how much am I looking at to legitly boost the ls? Can I keep the parts I have now?..do I hafta change some things?..do I hafta run a different tranny when the motor is boosted?..what about internal wise?..cuz its basically stock besides obx valve springs and retainers
[QUOTE=phatcardesignz;1950539]Wow… the crap in this thread.
This is totally correct. To add to this, you canNOT put a P8R head on a 1.8L block. Yes, it flows better than a P75 due to the larger intake valves, but it also has a 84mm combustion chamber, which means that you canNOT use it on a block with a 81mm bore. Great for a B20, but useless on an LS unless you are boring or sleeving it to 2.0L. The P75 is a slight upgrade over the PR4 head that comes on the B18A, and it has an 81mm combustion chamber so that you can actually use it on your B18A. You can buy larger aftermarket valves and have it machined to get as good or better flow than the P8R.[/QUOTE]
Not true at all you can use it on a ls block with the stock 81mm bore it will just lower your comp alot.
think about what you just said the b20 p75 head has a 81cc but a 84mm bore. so why cant you use a 84cc head on a 81mm bore? V8 guys do it all the time. IE: closed chamber and open chamber heads just use the B20 HG
I dont remember anyone saying that b18a’s came with the P75 head. so yes its true.
well say he spends 2k on a turbo kit and boosts 10-12 lbs he wouldnt be able to punch it off the line the same way he would if he would have spent 2k on n/a upgrades… becuz of that power turning the axles at such a high rate… obviously turbo makes more power than n/a… so ur saying that 300hp on boost has the same effects as 200hp n/a? wouldnt the turbo setup spin those wheels more if you just gun it of the bat and smash on the throttle? IDK seems like a logical answer…
and this is just from experience and from friends experience… my friend had a g3 and he was pushing like 375hp and didnt even bother going to qualcomm or street drag cuz he said unless he eased into the first 2 gears he would spin his wheels…
Matters on what turbo you use
most turbos used now in drag spool late bcuz of this reason so you dont spin off the line. so really since the late spool it feels like N/A when taking off
My last N/A build (1998) I did for my ef i would spin tell the top of 3rd with dot drag tires and that was with a 13.1 comp b16 with less then 300whp
[QUOTE=thatblkguy;1950543]Not true at all you can use it on a ls block with the stock 81mm bore it will just lower your comp alot.
think about what you just said the b20 p75 head has a 81cc but a 84mm bore. so why cant you use a 84cc head on a 81mm bore? V8 guys do it all the time. IE: closed chamber and open chamber heads just use the B20 HG
I dont remember anyone saying that b18a’s came with the P75 head. so yes its true.[/QUOTE]
Actually, it won’t lower the compression. I did not mention anything about the volume of the combustion chamber (measured in cc’s AKA cubic centimeters). Actually, it would have no effect on compression. The B20 that comes with the P8R head has a compression of 9.2:1 and has the same pistons as the 8.8:1 engine (supposedly it has a thinner head gasket to give it the higher compression and the head has the same volume combustion chamber). The 9.6:1 engine has the same P75 head as the 8.8:1 engine, which is also the same as used on all 96-01 B18B’s. The bore in the block is 84mm on all B20’s, and the bore in the block of a B18 is 81mm. The bore in the P75 head is 81mm, and the bore in the P8R head is 84mm. If you read the link on Honda-Tech that you posted, the guy was trying to figure out how to make a P8R head work on a 1.8L block. P8R on a 1.8L block is asking for a blown head gasket.
http://www.honda-tech.com/showthread.php?t=1466416
I just spoke to my head guy ex cosworth head builder it will lower the comp a custom HG would be needed to fix any sealing issues
Head gaskets are the same for the b20 Z/B
PHK (B20Z) pistons have a -4.02 dome
P3F (B20B) pistons have a -9.90 dome
he said to think of the two heads this way P75= closed chamber and P8R=open chamber head
[QUOTE=thatblkguy;1950620]I just spoke to my head guy ex cosworth head builder it will lower the comp a custom HG would be needed to fix any sealing issues
Head gaskets are the same for the b20 Z/B
PHK (B20Z) pistons have a -4.02 dome
P3F (B20B) pistons have a -9.90 dome
he said to think of the two heads this way P75= closed chamber and P8R=open chamber head[/QUOTE]
It wouldn’t lower compression, since the B20 with the P8R head has P3F pistons and 9.2:1 CR. It either raises the compression or has a thinner head gasket, and during the extensive research that I have done on the B20, someone had measured the cylinder head volume on the P8R and claimed that it was the same as the P75. Yes, the USDM B20B and B20Z use the same headgasket, but the P8R was never offered in the US. The only way to confirm whether the P8R had the same headgasket is to get access to a Japanese parts catalog and look up the exact year of Orthia, Stepwagon or other JDM vehicle that came with one (the P8R did not come in the CR-V). Yes a P75 on a B20 is like a closed chamber and a P8R on a B20 or P75 on a B18 is like a open chamber. However, a P8R on a B18 is beyond the normal definition of open chamber. You could use a B20 headgasket with the P8R on a B18 block or even use a custom one, but you are still going to have extreme pressures on the headgasket.
So would the p75 work on the b18 block? If it does…what kind of issues in terms of sealing would there b? Would I lose or gain performance from it?..and any kind of pulls made when I boost would be from a roll…iono if that matters or not.
oh ok… but i was correct although now they have remedied it…
so is this done via the computer or does the actual hardware cause the late spool?
Yes, the P75 would work on the B18A block. The 96-01 B18B comes with it. The ports might be slightly better than on the PR4, but the valve size and everything else is pretty much the same. It may be a slight upgrade, but you probably won’t notice much difference. No issues with sealing - you just use a stock B18A/B head gasket.
The reason how I know it drops the C/R and how it fits bcuz I have one on my b18a Im just waiting to send my headgasket out to cometic so I can bump it back up to around 9.2. I had to do an old V8 mod to the liners thats all I will say untill I fire it up if it works I’ll post a how to.
And the b20z kouki gasket is the same as the b20b and b20z Chuki gasket part number#12251-P8R-004
[QUOTE=thatblkguy;1951433]The reason how I know it drops the C/R and how it fits bcuz I have one on my b18a Im just waiting to send my headgasket out to cometic so I can bump it back up to around 9.2. I had to do an old V8 mod to the liners thats all I will say untill I fire it up if it works I’ll post a how to.
And the b20z kouki gasket is the same as the b20b and b20z Chuki gasket part number#12251-P8R-004[/QUOTE]
USDM - B20B (followed by a number ex. B20B4) - 126hp/133tq - 8.8:1 CR - P3R pistons - P75 head - 96-98 Honda CR-V
USDM - B20Z (followed by a number ex. B20Z2) - 146hp/133tq - 9.6:1 CR - PHK pistons - P75 head - 99-01 Honda CR-V
JDM - B20B - 126hp/133tq - 8.8:1 CR - P3R pistons - P75 head - 95-97 Honda CR-V
JDM - B20B - 146hp/133tq - 9.6:1 CR - PHK pistons - P75 head - 98-00 Honda CR-V, 99-00 Honda Orthia
JDM - B20B - 142hp/133tq - 9.2:1 CR - P3R pistons - P8R head - 96-98 Honda Orthia
Either the Orthia headgasket is .1mm thinner or the P8R head will raise the CR by .4 over a P75. Meaning it would put the B20Z at 10:1 or B18A/B at 9.6:1 if it is the head or if it is just the headgasket, it would leave them at 9.6:1 and 9.2:1 respectively. As for the “b20z kouki” comment, LOL. As you can see, there is no JDM B20Z - all are labeled B20B and the only way you can tell them apart is from knock sensors, intake manifolds, and head codes. The standard CR-V engine should have the same headgasket in the US and Japan. However, unless you have access to a JDM parts catalog to get 96-98 Honda Orthia specs, there is no telling what headgasket it has. Of course I’m always interested in seeing someone’s hybrid engine setup, but like I said before, I think it is a complete waste of time. Installing oversized valves in a P75 head to put on a B18A/B will yield the same if not better results and won’t cause sealing issues with the headgasket. P8R head with PHK pistons in a B20 block is where it’s at.
Ok so it would work if I used this head on my b18a block?..I just wanna see how it turns out. I’m gonna end up boosting the ls eventually…luckily I have a bunch of free time…and the b18a head gasket should be fine in terms if sealing?
Yes the P75 head on the B18A block is fine. Should have no issues.
Ok koo…I’m gonn do it 2m morning…well see how it goes
from some one who has a b20 with the p8r head… i dont think it makes much difference… i plan on going back to a b18a1…
[SIZE=“1”]no were near stock though[/SIZE]
[QUOTE=b20teg;1953982]from some one who has a b20 with the p8r head… i dont think it makes much difference… i plan on going back to a b18a1…
[SIZE=“1”]no were near stock though[/SIZE]:)[/QUOTE]
You don’t think it makes much difference between what? What pistons does yours have? 142hp (P8R) vs. 126hp (P75) with the stock P3R pistons.
idk…i dont think that head makes that much of a difference for him to go through the trouble of rnr work on a head…just my opinion though…
as far as i know i have a stock jdm b20b with the p8r head… a few little bolt ons and ran a 15.3 at the 1/4 mile…i have ran about the same time in a regular b18a1 motor with minor bolt ons
Oh, yes, I agree that is is not worth the effort to attempt to put it on a B18.
It is worthwhile to use it on a B20 with some higher compression pistons and a decent set of cams.