im going to build an ls/vtec, so hopefully i dont blow it up, but in order to do this i will get pistons and rods, rod bolts, and all of the other nessasary parts, but to hopefully make it lastm, and to boost it. to do this i am going to sleeve it, what i want to know is how to get the most power out of it. the b20 block cilinder is 84mm and the b18a/b is 81mm would it be worth wile to bore the ls block to a 84mm or 85mm to match that of a b20. would that be a substantial amount of power gain or not. is it even possible? thanks

no its not worth it.

the b20 has a longer stroke wich gives it a much larger displacment.

and this is my opinion, take it or leave it:

the lsvtec/b20vtec is not a reliable motor to begin with. sure you can fully build it do all the other things that people do. but it will never change the fact that the motor will NOT have great reliability. how many blown ls/b20vtec motors have you seen? too many. not to mention you are adding boost. i had a friend that ran a b20vtec for over 30,000 miles, 2 cross country trips AND he road raced it. 2 weeks after he put a turbo on it, it blew.

once again thats my opinion from what ive seen, i dont care if you take it or leave it.

ok thats where your wrong, the b18a/b and the b20b/z share the same crank and rods whick means that the stroke is the same, the only thing that changes the displacement is the bore of the cilinder, the b20's bore is 84mm when the b18a/b has a 81mm bore, there for you have a 2 liter engine and a 1.8 liter engine there is no difference between the two beside the oil pump. now from the long research that i have been doing the only reason that the b20 blows is because people over rev it and the stock sleeves are to week to handle it, also since there is such a long stroke on both the b20 and the b18a/b BECAUSE they share the same crank and rods, it put alot more stress on the rods because of vtec. and ls and crv rods are just as weak as any d series rods. so one your friend should have sleeved his block, or got after market rods, and rod bolts. then he might not have blown it up. two, now anyone that knows what their talking about, and that dosent feel like just adding their opinion about a topic they havent explored enough, please help me with my question thanks

i stand corrected on the crank my apologies but do NOT talk down to me like i have no idea what im talking about OR comment on how my friend should build his engines jackass.

im sorry, i dont mean to come off as an ******* it just seemed that you where attacking the principles of adding a vtec head to a non vtec block when you were not completely positive about the statements you made and your knowledge on the subject especally after the mistake you made. and as for your friend i have no idea if his block was sleeved, no idea if he had after market pistons, rods bla bla bla so on. it just seemed that for running boost on a sleeved block after replacing the only things that are said to give a ls/vtec, b20vtec problems and still having it blow up, after two weeks of boosting seems unlikely. also 30,000 miles is usually around the time that ls/vtec's and b20/vtec's blow up when running stock internals.so when you said that after 30,000 miles he boosted for two weeks and it blew up, that left me with the conclution that he was running stock internals. i hope we have a better understanding now, and im sorry if i was acting like an *******.

no worries man

he was running stock internals only because the series he was racing in dosent allow a modified bottom end (away from OEM parts). that motor was a beast. i still cant belive it did over 15 2 day race weekends 2 cross country trips and god knows how many street races before it finally gave in. drove the **** out of that motor..

anyway ill give you a suggestion about your bore question. YES. if you are gonna sleeve it with darton/GE/anyone that has a good sleeve the more displacment the better. displacment = torque. "theres no replacment for displacment" thats why im putting in a 2.5 liter 6 cylinder and with a huge thick set of sleeves you wont have to worry about cracking a sleeve barring a horrible tuning accident or a bad set of sleeves.

now is that too much torque? hehe wheelspin is bad.

cool man, big up's for admitting that your boy was on stock internals, most other people, would still be too subborn to admit that, and swear that their friends motor was worked. dude that was cool.

on the another note, i appreciate your advice on what sleeves to use, and will keep darton/Golden eagle in mind,i still need to hear some prices though,when i go to the websites they dont post any prices, and i dont feel like emailing them haha.As far as desplacement goes, i was pritty sure that boring it to a 84,84.5mm or a 85mm would give me more torque but i wasnt sure if it was worth doing it to that extreme, or if it was possible on the B18a/b. i know that on a b20 84.5,84,85mm even 87mm(not smart)is no sweat, but i wasnt sure how much space could be taken away off of a b18 to the point where the walls are to thin.
thanks man for the advice, if you know anymore, or have anything else to share go right ahead

if anyone else has any opinion,advise,or anything please share