B18 or B20 Vtec???

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Smurf_CRX

New Member
Sadly at the moment I'm driving an '87 CRX but here in a couple of weeks I'll hopefully have an EG hatch. My question to anyone interested in answering is, once I have it should i throw in a B18 or B20 and Vtec it? let me know what you think
 
do a b20 vtec with a b16 crank and some high compression pistons bore/hone it out to 84.5mm and use a gsr block girdle, it'll give you 1736cc and a rod stroke ratio of 1.77, you'll be able to rev it pretty high and with the great r/s ratio and block girdle you'll have a bullet proof bottom end
 
Alright sounds good. So I guess my next question is which would be better for forced induction in the long run? Wouldn't I just have to lower the compression all over again later if I did all the high compression stuff. Please correct me if I'm wrong..I truly don't plan on keeping it all motor so the help would be great.
 
keep the stock stroke and compression. Its up to you if you want to buy new forged stuff. i did and i love it. If you serious about boost just keep the comprression low. and save till your able to boost. There no point in building an all motor only to go turbo later. Tear the motor open once.

hey tarty, why b16 crank? isnt the whole point of building a b20vtec for torque/displacement? If your putting a b16 crank in it, wont you defeat the purpose of building a b20vtec? I have an lsvtec so i know why i have the b18block........torque. why the hell would i put a b16 crank/rods in a 1.8l block. Its about displacement when building an lsvtec. IMO. sure you can rev high but thats what the vtec head is for. please elaborate. i'm not dissagreeing with you i just dont understand why a b16crank.
 
smurf, sorry i didn't know you wanted to boost it eventually if you want that then yea forged internals and if you do a b20 sleeve it becasue the sleeves are kinda thin

umm well you can build a ls/vtec or b20vtec for whatever you want, the limiting factor in revibility with a motor is the rod stroke ratio and for a ls/vtec or b20vtec the rod/stroke isn't all that great (1.54), you end up with essentially the same redline you have with a regular b18a/b block, the head doesn't let you rev higher. building an engine like the one i described is essentially a type r but better (r/s ratio 1.77), its an over square engine layout which is where the bore is greater then the stroke of the crank, formula one engines are designed this way, and let you rev much higher, and in a vtec engine, vtec usually engages at higher rpm's and your power band is much higher then in a non-vtec block/engine, i've never actually used this set up in an engine yet, (thats my next project) so i don't have much to claim about how great it is besides the good r/s ratio(no hp or tq numbers to show sorry fellas), but most of the time people rev their ls/vtec too high and end up destroying the bottom end, to me this is an all oem solution to it... kinda

umm other then that in my opinion its just a good set up...
 
tartymctang2357 said:
smurf, sorry i didn't know you wanted to boost it eventually if you want that then yea forged internals and if you do a b20 sleeve it becasue the sleeves are kinda thin

umm well you can build a ls/vtec or b20vtec for whatever you want, the limiting factor in revibility with a motor is the rod stroke ratio and for a ls/vtec or b20vtec the rod/stroke isn't all that great (1.54), you end up with essentially the same redline you have with a regular b18a/b block, the head doesn't let you rev higher. building an engine like the one i described is essentially a type r but better (r/s ratio 1.77), its an over square engine layout which is where the bore is greater then the stroke of the crank, formula one engines are designed this way, and let you rev much higher, and in a vtec engine, vtec usually engages at higher rpm's and your power band is much higher then in a non-vtec block/engine, i've never actually used this set up in an engine yet, (thats my next project) so i don't have much to claim about how great it is besides the good r/s ratio(no hp or tq numbers to show sorry fellas), but most of the time people rev their ls/vtec too high and end up destroying the bottom end, to me this is an all oem solution to it... kinda

umm other then that in my opinion its just a good set up...
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The sleeves are fine on the B20. There's no need to sleeve it if you're staying within reasonable (300-400whp) power goals.

The stock stroke is fine too. If you're going to go through all the trouble of resleeving a block, why bother with the B20 casting? Just get a B16 and sleeve it to 84mm. It's much easier than playing with all the VTEC conversion crap, crank swapping, oil lines, dowel holes etc.

If you want to build a B20, build a B20. They can take quite a bit of abuse. Just don't cut corners and complain if you blow it up.
 
if you put a b16 crank in it would take a custom rods or you would have a like 3:1 CR because the piston at tdc would be like a inch in the hold and it could veryeasly come out the botom with stock b16 rods
 
actually it'd be like 5.71 mm lower, which could be made up with some race pistons with an increased compression height, and thats using stock (137mm) rods, sorry i guess origionally i didn't specify, i ment use the stock (137mm) rods or after markets of the equivelant length
 
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why that would be going aginst the puting the crank in you want to run a poston with the wristpin as close to the top as possible this is not an easy task and should not be advised unless you have a good builder or are experienced in engine blueprinting/setup
 
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