im almost done building my 1st ls/vtec. i was wondering what the PSI per cylinder should be when i do my compression check. also what compression ratio should it be at....its just a stock b18b with a b16a2 head on it. Also i have a set of ITR pistons or B16A pistons lying around since the head hasnt been placed on the block yet would it be worth it to put either one of these sets on the LS rods? i just dont know what to expect from a stock LS/VTEC combo since im used to driving my b18c1 and I think im going to be dissapointed with this set-up. all help is appreciated.

 

Yes it will be worth it to use either of the pistons the B16's will have a tad more compression, when you do a compression test I would reall worry about the numbers as long as they're all consistent with each other since every tester test differently and some people do different methods. I hope you replaced the piston rings and bearings, and if you plan on reving over 7k rpms use ARP rod bolts

With a stock setup like you mentioned I'd be happy with about 150-160whp

 

ImportReview Re-direct take ur pic theres tons of dynos of ls vtecs in here.....put the pistons in to get the most out of the cams. as long as u dnt spend all day at 8k on ur set up ur motor should last a while. just dnt abuse it. my stock ls bottom end sees over 7k all the time n its got 100k + on it. i plan on usin it for my conversion to vtec this summer.

 

wow... only 140 hp and 110tq on a fully stock ls/vtec......hummm

 

dang by stock b-16a put 147 to the wheels...

 

Compare the torque

 

Compression should be just a bit under 10:1 with the ls pistons.
if you have the b16 and itr pistons laying around, it's a no-brainer. Use them.
Cranking pressure is a bit hard to predict and depends on what cams you are using, and where they are set if adjustable, head gasket, milling of block and head.
The ls pistons should come out to 180 to 200 psi, the vtec pistons a bit to as much as 15 percent higher, assuming all equal with the cams.

 

ya....the tq is the big difference...stock b16s barely put down 100 ft. lbs of tq.....and u have to remember the ls pistons arent gonna give u the power of the b16 pistons bc of the lower compression....higher compression pistons in an ls vtec motor = major gains in power!!!

 

yea, im using gsr cams on skunk2 adjustable gears and have arp head studs and arp rod bolts and are using an
OEM 3 layer headgasket. i just never disassembled a motor and are a little sketchy. the b16 pistons and type-r pistons are both in different motors both motors the pistons are bad.

 

uh....u can make decent power out of the stock ls pistons...get a thinner head gasket. i remember readint somewhere that the compression would b right at 10:1 with the ls bottom end (not sure where i read it tho). ive been doin research on this bc im doin the conversion soon...but ya, thinner head gasket would put u at more compression than a stock usdm gsr (if what i read was correct). i say keep addin ur bolt ons and get a tune n theres no reason why u cant get close to 170hp on stock cams.