B20/VTEC a good setup? How much HP? info please

[DownShift96GSR]

Ok ya'll, I just got done reading the B20/VTEC article in the new Honda Tuning and it got me thinking. From what I read its pretty easy to do. Well easy if you got the right place, tools and know how. Anyway, I was wondering, from people with experience with this, what the pros and cons are with this set-up? What type of potential am I looking at if I do this swap and then turbo it? Any information is greatly appreciated. Thanks to all, PEACE!!!

 

[Eviloliv3]

B20 Vtec is a nice combo
the B20 part brings a lot of torque to the table
and the Vtec part brings Hp to the table

youve got a killer midrange with a killer top end as well

the bad thing about B20/VTECS is a lot of people didnt build them right from the beginning, and thats why they get the bad rep. yes, you arent supposed to run these things up to 8k rpms all day, but they will last if you make those trips few and far between. if you get some arp rod bolts and head studs, and even shot peen the rods, then 8k is feesible, but i would still be careful.

bigger displacement = more power, thats why the LS/B20 vtec setups came around.

if i were to do it, i would get a K24 block and a K20a head...mmmmmmm

 

[DownShift96GSR]

Thanks Evil. I had a feeling you'd be one person to reply. That kinda sucks about not being able to 8k RPMs that much. I like the high rev. What about throwing the turbo on the set up?

 

[hyper98gsr]

you arent supposed to run these things up to 8k rpms all day

that is the biggest issue with the ls/vtec and crvtec. people dont understand that you simply cannot increase engine size and keep the smaller engine momentum. even the new 04 cobra revs only to @6500rpm. i think its the simpletons that rev the frankenstein motors to 8.5-9k and blow their motors that give them a bad name.

i am all for the crvtec. you get outstanding torque and awesome horsepower. and keep it in a honda. what else could you want. i also think those motors are ideal for turbo applications. you get the increased displacement and you can utilize all the power without the need to overrev.

i know a guy running 12's on an all motor b20vtec, bored over with oversized jdm itr pistons. that is really good here in co.

 

[Eviloliv3]

i honestly wouldnt boost a B20/Vtec, let alone a B20 more than 5 psi. the sleeves arent that strong. 6mm between each cylinder, not that much

but if you sleeve it, then boost the fuck out of it!!! :twisted:

 

[Baldy201]

If you want 2.0L why not bore out your GSR block? It will rev higher then the B20 and also get you very close to the same displacement. There has been a lot of convos. on LS/VTEC and B20/VTEC in the past(not on this site), and pretty much what has been said is that B20/Vtec is good for those who do not have the GSR or ITR block already. Boreing your block will even be cheaper than buying a new block and then building it and buying all the parts to get the VTEC going.

By all means go with the B20 block and slap on the GSR head and have fun. If I was the one building the engine I would stick with my GSR block and bore it out and keep my revs that will dominate.

 

[hyper98gsr]

the WHOLE point of boosting an lsvtec or crvtec is buy boring it over and sleeving it.

you could bore a gsr block over to 87mm about 2.1liters. that would be a nice boost block. but i would rather have a 2.4 liter bored out b20 block. with alot of boost. plus just as cheap.

 

[DownShift96GSR]

the WHOLE point of boosting an lsvtec or crvtec is buy boring it over and sleeving it.

you could bore a gsr block over to 87mm about 2.1liters. that would be a nice boost block. but i would rather have a 2.4 liter bored out b20 block. with alot of boost. plus just as cheap.

See I'm feelin the 2.4 liter. But on the other hand, I like the 2.0 GSR block with the same 8k rev. Man, I didn't think this one would be so hard to choose. I thought the hardest decision was to choose if you wanted a turbo, SC, or all motor. I'll definately have to think on this one.

 

[Eviloliv3]

WOAH WOAH WOAH

this thread has gotten out of hand

First, you cannot bore a GSR to 84mm. the cylinders will be way too weak. you must resleeve it with stock sleeves, or go aftermarket sleeves.

Second, even if you bore a GSR to 84mm, youll still only have a 1933cc motor. not 2 liters. (honda rounds up and calls it the next liter size even if its only 1 cc over 50, Example: 2153ccs would be 2.2L)

anyway, the most you can bore a Bseries motor to is 87, after that, you have to worry about sleeve thickness to the outer block clearance, along with some other things. plus if you used that 87mm wide bore with an aftermarket crank (95 is the highest ive seen), youll still only have 2259ccs. which will dramatically lower your redline (you SHOULD lower your redline whenever you increase stroke). no revving past 7k in my opinion.

also, the reason people use a vtec head on a nonvtec block, is for the crank and displacement. if you put a LS crank in a GSR with LS rods, youll have more displacement, which means better power. i think its a lot easier than the LS vtec cause youve just gotta change out rods and crank, and everybody still thinks its a gsr

anyways....... ive talked too much

 

[Baldy201]

Boreing out a GSR block to 84mm is not going to be a problem. The B20 is basicly an LS bored out to 84mm. So boring out a GSR will give you no more problems with wall thickness than a B20.

Granted that the GSR crank will with the 84mm bore will not get you to 2L it will still increase displacement by almost a full .2L, and in my opinion is excelent for the GSR since it lacks down low. Also you will not get the same low end grunt of the B20 "Frankin" engine but you keep the higher redline, and to me that is the whole reason of running VTEC in the first place. A 8000 RPM redline is low for a the Vtec Cams especially if you upgrade to Jun stage 2 or Toda B cams.

 

[hyper98gsr]

the most you can safely bore out the bseries block to without sleeving is 81.75. so of course i had sleeving in mind. any time you build a motor FOR boost you should sleeve it for added protection.

 

[Baldy201]

exactly.

to evilolive: the most you can bore out the bseries block to without sleeving is 81.75. so of course i had sleeving in mind. any time you build a motor FOR boost you should sleeve it for added protection.

Dont you mean 84.75?

 

[hyper98gsr]

nope 81.75

 

[Baldy201]

Since, boring out makes the cylinder walls thinner and weaker in an open deck, the use of nitrous and forced induction is NOT recommended for bores > 85 mm , even if they are re-sleeved. Rules are meant to be broken but this is a general common recommendation at this time by people who build engines.You are limited by how far you can bore to. The maximum bore on a B series is 87 mm. Why?:

The cylinders are siamesed meaning they are joined together. The "deep channel" between 2 cylinders is approx. 3mm thick. Once you bore past 6 mm above stock, you are into the next neighbouring cylinder. The walls are too thin. For race only "throw away" 10 pass blocks 87mm bore is fine but in road racing or street/race setups that need to last much longer, there's no point in pushing to 87mm bore.

The cheapest way to get 2.0L is swapping for a CRV engine completely in the case of LS/SE owners . The cheapest way to get 2.0L for GSR and ITR owners is to bore out to 84.5-85 mm and purchase JE or Wiseco 84.5-85 mm off the shelf pistons.

For those of you you dont know who MD is, he is the engine tech guru over on Team-Integra.net who has taged along with tons of racing teams and has tons of knowledge on Honda engines.

 

[Eviloliv3]

Boreing out a GSR block to 84mm is not going to be a problem. The B20 is basicly an LS bored out to 84mm. So boring out a GSR will give you no more problems with wall thickness than a B20.

Granted that the GSR crank will with the 84mm bore will not get you to 2L it will still increase displacement by almost a full .2L, and in my opinion is excelent for the GSR since it lacks down low. Also you will not get the same low end grunt of the B20 "Frankin" engine but you keep the higher redline, and to me that is the whole reason of running VTEC in the first place. A 8000 RPM redline is low for a the Vtec Cams especially if you upgrade to Jun stage 2 or Toda B cams.

please dont post bullshit like this anymore.

The MOST you SHOULD bore a stock block is 1mm over. after that, you are severly decreasing the amount of miles you can get out of your engine. Yes, i know who Mike is, and yes i know hes on racing teams, but ask him what size bore he has in his car, ill be you its a stock bore.

and the B20 is not basically a bored out LS, its got different sleeves. the sleeve thickness is the same in both motors. meaning the b20 ones are just wider. if you bored a LS out to 84.5, i dont think you would get more than 5 passes at the track.

i bored my B20 to 84.25 and the diameter between the cylinders is 6mm.... and that 6mm is a weaker iron material. if you bored a LS to 84.25, youd probably have around3-4mm.... waaayyyyy too little. once you get those sleeves up to normal operating temperature, youll crack that shit like a cracker.

the GSR with 84mm bore will only get about .15 more displacement. not .2, it may seem like a lil, but every difference in Hondas is HUGE. think about how big a difference it is when changing your timing, you may not have even moved a cm, but you can advance the timing by 5 degrees.