[B]I want to put pr3 pistons or Civc Type R Pistons in my b18a1. I know it will raise the Compression ratio. But what will the horsepower gain be??? Anyone, please, i prefer someone who has experience in this type of issue Thank you
assuming a 3-layer headgasket, stock b18a block, stock b18a head, and factory 81mm bore:
pr3 pistons: 10.7926-ish compression
pct (civic type r) pistons: 11.6425-ish compression
it’s difficult to say what kind of horsepower numbers each will yield. there honestly are really a LOT of variables that go into it. the numbers are a good place to start though. i’m not one for calculating approximate HP numbers from compression alone. like i said…there’s a lot that factors in.
Cool,but what about NOS
I was planning on using a 2 layer headgasket and some crower cams. Is it wise to use NItrous on a semi high compression engine?
nitrous likes high compression. just don’t plan on using a fully stock fuel system. you’ll want to upgrade the injectors (unless you do direct port, which injects nitrous and fuel together into each intake manifold runner, making each cylinder get an equal amount of nitrous thus being a really safe way to run), a larger-volume fuel pump, and prolly get a new filter as well. lots of people will tell you to get like a DC or AEM fuel rail. They flow nearly the exact same amount as stock, so it’s up to you. you’ll also probably want an aftermarket ignition and you’ll want to retard your timing.
cams won’t affect compression ratio, the only thing you’ll have to think about is lift on the cams to make sure you’re not slappin the pistons silly with the valves. as long as you stay away from the stage 3 and up you’ll be fine.
with a 2-layer, you’re looking at right around 11:1 with the pr3’s and the pct’s will give you nearly 12:1. if you’re planning on having a pump-gas daily-driven engine with some nitrous on the weekend (keeping it on the track of course :p) i’d say stick to the pr3’s, just to have a bit better compatability with pump gas (here in iowa i could do the 12:1 easily, we have 93 octane premium. the poor bastards in cali only get 91, which CAN be safe on 12:1 compression, but you have some major issues to deal with and a major prayer to say if you’re drivin hard. ;))
**i’m not a guru, so if anyone wants to slap me silly or whatever please feel free. contributions from others are great, i wouldn’t ever do anything to my car without at least 3 opinions. 
Sweet
Well here in Lousiana we have 92 pump gas. I would like to run 12:1 compression with NOS.
I do make a few trips to alabama and what not. I was plaaning on upgrading the fuel system with Holley components and a stainless steel fuel line from tank to Fuel filter. :argh: Why is my car so complex?? Oh well i will do the swap. Can i use Octan booster in low octan areas??
on 92, with 12:1 you should be fine. as far as nitrous is concerned i don’t see a problem, what kind of a shot are you looking at? dry, wet, direct? there’s different variables.
as for an octane booster, i personally have never used one, and can’t say offhand that i know of anyone who has either. one of the perks of being in a 93 octane state (hey keep them hicks with their 87-octane trucks comin, just leaves more of the good stuff to boost premium up even higher! hey, maybe one day we’ll see 94 or 95 octane!!) 
one thing you might want to do (simply because i’m too lazy) if you haven’t already is pop on over to www.honda-tech.com and do a search for “high compression nitrous” or something of that sort, see what you come up with. although not necessarily fans of newbies asking questions that are answered easily and more quickly with a search, there are some REALLY knowledgeable minds over there and you should be able to find something.
i have two questions cuz im waiting on my CTR pistons to come in and i need to make sure im getting things done right.
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what good companies make 2-ply headgaskets for the b18a/b??
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when running anything about 11.1 i heard you’ll need to upgrade your igntion [MSD igintion, etc.] and dump more fuel in to go with the more spark. is this true?
thanks hopefully throwing on my pistons will go nice and smoothly
90 LS soon to be NOS and High Compression
Cool. I looked on that site. It rocked. Now, who makes a Direct Port Nitrous iNjection system, I know Nitrous express does. I eant NOS, or Zex or somebody ggod. I’m also going with the window switch. So I should have 12:1 Compression with 80 - 100 shot of Nos on CTR Pistons, and a 2 layer Headgasket. Sweet
Thanks
ahh
“cams won’t affect compression ratio”
they won’t affect static compression ratio, but they will affect dynamic CR. Big cams are holding the valves open longer, so air is running in and out and notgetting the chamber completely full. Notice that the bigger cams Spec C’s, adn JUN 3’s like 12:1ish compression ratio, since they need that to make the lost CR while running.
oh, and Nitrous does like high CR, but cylinders dont like high cylinder pressures and temps becaseu of nitrous and CR.
So I should stick with a smaller cam setup for Nos use correct??
Originally posted by 2simplex
[B]
- when running anything about 11.1 i heard you’ll need to upgrade your igntion [MSD igintion, etc.] and dump more fuel in to go with the more spark. is this true?
[/B]
I can see the merit of having a stronger spark to overcome the denser mixture for “bridging the gap”, but i don’t see any need for more fuel. The higher cr just compresses it more. Just need higher octane fuel.
that’s what i think
higher CR’s
increase cylinder temps. Adding fuel helps cool the temperature of the chamber, and prevent lean conditions…
looks like im gonna have to do some research on the whole MSD set and a good fuel pressure regulator [aem??]
but does anyone know where i can get a 2ply head gasket???
http://www.streetrays.com/catalog/index.php/cPath/142_641
that might be what your lookin for.
my question:
stock ls head
ctr pistons
shotpeened ls rods
new stock headgasket
stock fuel system (fuel rail etc.)
might upgrade fuel pump
there will be other things done but i dont think they’ll have anything to do with my question. my question is will this run correctly with the fuel setup being stock? if i upgraded the fuel rail, would a gs-r fuel rail be good enough?
holy dig up a 3.5 year thread…LOL…
i think he may have found that head gasket he was lookin for by now:)
thanks for your help. i searched, found an excisting topic for what i was lookin for to post in. rather than start a new thread. is there someone that can help me with my question?
start a new thread bro. thats prolly your best bet. yes, its been covered, but not completely…because well…you still have a question…i dont really know why that thread is still around.
I love the CTR pistons in my setup. I run 93 all the time… never tried any 89… too scared too! Yea, more fuel and better ignition are well appreciated by the 12:1. I have my fuel pressure set at 52psi for WOT, I also had to narrow my spark plug gap 0.010… It was weird dude, if your gap is too wide and you rev it up you dont get anymore spark. Mine would drop dead over 4600rpm till I changed the gap. I also have the MSD Pro Cap and Blaster 2 coil and nology wires with NGK R plugs. Now the problem with my fuel that I had was running really rich at idle to mid throttle. So I had to change my fuel with my SAFC. It’s tough to make a near perfectly running engine. Right now I’m seachin for a dyno I can get the engine tuned on around here, so if anyone knows where there’s a dyno I could tune at in the Nashville area LET ME KNOW! Thanks. Hope I helped a bit.
so would u suggest just a fuel pressure regulator and fuel pump? im petty sure the stock fuel rail is good for up to like 300hp.
Honestly, I don’t even think you need the fuel pump. Just the FPR. If you had FI then I would suggest a high flow FP.