i am thinking of doing a b18a1 motor for my other car that will be daily driven and i was thinking of raising the compression to somewheres around 12:1 and have a gas shot on it on top of that do you think it is worth doing. is there going to be good power gains from going from the 9:2 compression ratio to the 12:1 and does anyone know what itr and b16 pistons would bring the compression ration up to ,
these pistons in a LS engine will produce this compression ratio:
JDM B16b(pct) 11.4:1
JDM b16a(p30) 11:1
usdm b16a(pr3) 10.8:1
JDM typeR(p73-00) 10.8:1
usdm typeR(p73-A0) 10.3:1
If you swap to a b16a head add .5:1 compression
If you swap to a GSR head add .7:1 compression
thanks for the info
when bumping the compression up that much, like to 11.5:1, is it necessary to add fuel? if i were to get the ctr pistons, would i need a high volume fuel rail, upgraded ignition, etc.?
you would need tunning. no other parts just tunning. some crower 404’s would be a nice upgrade tooo.
The only way I would reccomend compression like that is if the car was running a alcohol injection system like SMC or Razor’s kit. Then it would be like running C16 anytime you hit the pedal and it activates your hobb switch (say its set to come on at 5psi) to start spraying the alcohol. When your outta boost your just running regular pump gas. The alcohol is cheap to buy when its down. You get it at WalMart or Shoppers Drug Mart etc for like $10. Look for the progressive one so you can add more alcohol if you hear detonation. The kits run about $410 without a 3 bar map sensor and $475 with one. Its called cheap insurance that allows you to run high boost with a colder inlet charge going to the motor on pump gas.
the engine will stay NA. no boost. it was for his DD.
that is correct this car is staying NA no boost just maybe a little bottle though i got a friend of mine that has some endyne piston for his type r motor that he is going to sell me because he is going turbo and the endyne pistons got his compression around 12:7:1 what do you think compression will be in a ls motor with those piston . plans for the block is as follows:
block post
pistons ( maybe the endyne from my friend )
eagle rods
if i put nitrous to the car i will be going with a 75 shot
the above compression ratio specs posted some of them are wrong the b16b pistons in your block will be over 12-1 compression
if you want to go all motor with an ls dont waste your time with forged rods or even block posts they dont rev high enough to stress the sleeves enough to need posts and the stock rods will be fine in most na applications the problem with the ls bottom end and why they throw rods is because of the rod bolts
heres what i would suggest for an ls build
jdm itr pistons oversized 81.25mm
shotpeen your rods and add arp rod bolts
crower 404 cams
arp mainstud kit
arp headbolts
then add a good intake manifold a good header a bigger throttle body a good intake and exhaust then have it tuned and you will see over 180whp and it will cost you less then doing forged rods and having your block posted
lets keep in mind that this is for a daily driver i already have a fully bult b16 with the works so on this motor i am not going all out just want to pep it up some since i need new piston in my ls block and i don’t see how buying a better intake manifold and throttle body and a good header would cost less then having the block post and forged rods done .
pricing your suggestion
–intake manifold between $225 and $350 depending on whether you go skunk2 or jg
–throttle body between $225 -$300
–header dc sports $225
–exhaust $550
your way would cost $1200-$1500
rods eagle $300
block post $40
my way would cost me $350 arond $400 with the post install in the block
so as you can see rods and post are cheaper and stock cams will be fine for my build.
c-speedracing.com type in the correct shit and you get 11.4:1 with a vtec head it will be over 12:1. with even 12.5:1 compression block posting is NOT needed.
the only reason i was going to do block post is some it i ever decide to do anything else to it it would be done and like i said for $40 why not just go ahead and do it . i hear it is soppose to be better than block guards
i thought the usdm b16 is a p30 and the jdm b16 is a pr3
all usdm b16a pistons are pr3’s, in japan the older b16’s came with pr3’s, the newer b16’s came with p30’s.
i was just wondering because all the jdm b16’s i have had had pr3 pistons in them
heres what i would suggest for an ls build
jdm itr pistons oversized 81.25mm
shotpeen your rods and add arp rod bolts
crower 404 cams
arp mainstud kit
arp headbolts
then add a good intake manifold a good header a bigger throttle body a good intake and exhaust then have it tuned and you will see over 180whp and it will cost you less then doing forged rods and having your block posted
so what kind of times do you think you can pull in the 1/4 mile with this setup?
Ok…first of all, with a B18a block and head with CTR (or pct) pistons, your compression ratio will be approx. 12.4:1…not 11:1 or whatever. And Crower 404’s? From what I’ve read and heard…your valve to piston clearance is already VERY close with your stock cams. And with compression of 12.4:1 your really on the verge of detonation because of the increase in compression temp. Your best best is to run 93 oct. (higher if available) and get a AFC to monitor your knock sensor so you can adjust your A/F ratio to be more rich to prevent detonation. You want to run it as lean as you can without detonating! I’m getting ready to put my engine back together with CTR pistons and and about to order ARP rod bolts. I would estimate a mid 14sec in the quarter with 180whp.
both of these statements are totally incorrect. where do you get your #'s from? I have built and tunned a gsr with pct pistons, a b16a head, and s2s2 cams. on pump gas 198whp. people float these retarted statements about CTR pistons without any PROOF. also a GSR and a LS block have the same deck height, so if a LS with pct pistons is over 12:1. how did this engine run perfect on pump gas? that would make the gsr have over 13:1 comp. please STFU. :down:
Well…according to the c-speed link you posted earlier on, your compression ratio is only 10.5:1. Thats how you can run on pump gas. And you never explained why the second statement was wrong…
shit, I just put all the correct info into the c-speed calculator, I got 11.7:1, if the gsr and the LS share the same deck height, the compression will be very similar when running a b16a head(11.9:1). This is why an LS with an LS head and b16b pistons cannot be over 12:1. also detonation isn’t caused by just A/F ratio, there are many other things invloved. The stock honda knock sensor is garbage, it won’t detect shit. This is why the honda knock sensor dosn’t save all the untunned nitrous and turbo cars that blow up. If you built and ran honda engines everyday you would know this.