b20 stock boosted

does anyone know or have any experience with a stock boosted b20b low compression version? i dont want to do anything crazy 8-10lbs would be plenty maybe like 250whp. the block is completly stock and is from japan with not even 50k on it. please dont post any neg about the b20 sleeves i know theyre weaker the the 1.8 but i know you should be able to boost to a certain level within its limits and not crack them. i dont plan on revving past 7k either so help if you can thanks ahead. i also already searched but there is no good info on the b20 stock boosted to 250whp direct me to articles specificaly about the boosted b20 only thanks


Sounds like you have done your homework. The B20 is the same as the 1.8, with a bigger bore. The sleeves are the big thing, and that is problematic. If you plan to rev to 7K think about getting some ARP rod bolts, as stock B20’s rev to 6500. I’m sure it will hold the power, but spend some money on a good tune. Unfortunately I’m not sure what the B20 block is capable of, the LS are capable of 300+whp on stock internals.

yea… i guess not many people risk it i might just hone out my b18 to freshen it up a bit and use stock components until i can get my b20 sleeved. if anyone has any first hand experience feel free to chime in.

I would juist be sure to invest in a good tune and software. I personally think your 250hp goal on the B20 is definitely achievanle without much of an issue. You just want to have a nice conservative det free tune which will help tremendously with the known sleeve “issue”. I’d also do as suggested and look into adding the arp studs and rod bolts.

what 1/4 mile time would u look at with 200whp? on something like that

what head r u using im starting the same project… got the block need a head atm…

i have the stock head but i can get my hands on a pr8 head so i might use that since it flows so much better. idk i think i might just use my b18 block and just get some arp hardware so ill still have a reliable b20 incase somthing happens and get the b20 sleeved down the road. with my luck something always comes up lol.

what is the PR8 head off of…its flows better than a PR4??

its the only non vtec head that has large valves and has the same flow charactoristics as a vtec head. it came on some of the jdm b20’s like the orthia or somthing just type pr8 in the search and you find all you need to know

I see! thanks

It’s P8R not PR8.

whatever same diff.

What kind of turbo are you planning on using?

ya a boosted b20b would need a very very good tune. i have a prototype b20b in mine, and only got 7k original miles on the motor, but i feel that boost would put stress on the cylinder walls even during DD that i dont’ want. i’m actually looking into spraying and getting that tuned just right for the bottle but is starting to look like a big pain in the arse. a 55 shot being sprayed maybe like once or twice a month seems reasonable.

if u do consider boosting ur b20b. change the pistons to some aftermarket ones, and get some arp rod bolts. considering u wouldn’t ever boost high on the block, u don’t have to look into rods. but if u can prolly drop the compression down a bit, that would put less stress on the walls. with that tho u can up the boost to something more practical like 8-12 lbs depending on what ur tuner figures out. all u’ll need to consider after is all the other stuff, and won’t need to worry about the walls so much.

ic but upon research the walls really arent that big of a concern its the detonation that causes the walls to crack. i was really lookin to get some feedback on this from an experienced boosted b20 head so if there are any, or anyone you know of that has a definate answer get at me

its NOT the detonation that causes the cracking of the walls… its that the DESIGN!!! that is flawed. pressure of one cylinder puts enough pressure on the cylinder wall of the NEXT cylinder(s) which then happens again once the other cylinder fires.

basically… the pressure in #1 puts a big load on the #2, and when #2 fires it puts pressure on #1 & #3… and so on. this normally doesn’t happen with like a b18 block. the walls aren’t that much thinner, just designed different. thats why even resleeving the b20 block doesn’t exactly get rid of the issue, it just decreases the likely hood of it cracking.

makes me think if i used a ridge reamer… put a slightly larger taper near the top of each cylinder… if that would decrease that weak spot. it would make the wall a lil thinner, but maybe the slight alteration in shape would be enough to make it last longer. :think:

yea i think ill just go the b18 rought and leave the b20 stock for a backup just wish i had a little more power and top end from it.

yea i’d suggest building an LS instead. if u have a good reliable b20 leave it alone unless u got the funds and the capability to do so. its a lil easier and less stressful to build a good motor while it isn’t in the car. cuz that way u have less of a tendency to cut corners and do it right cuz u’ll still have ur ride functional and driveable.

I have a b20b block a si head with ctr cams and adjustable cam gears had it tuned and made 175 to the wheels. I plan on boosting mine next winter. I’ll be getting new pistons, rods, springs and retainers. And I was told by a shop that I could use a block guard and. And after all that depending on boost I’ll be looking at 350-400 to the wheels. Has anyone had experience with block guards? Or any idea how much sleeving would cost

sleeving is gonna cost around a stack ($1000) to do plus cost for the labor i would def recommend sleeving before you boost the b20. do you have a stock bottom end? do you have arp hardware? and how much did you spend on this mild build

Yeah stock bottom end for now at least. The cams and gears install and tuning was 900. I don’t remember how much the swap was of the top of my head, do you know how much a b20 swap like this normally runs?