f20b turbo

[Ludin203]

I'm planning my build for next year. So far with the last 2 months of research this is what I have come up with. (I'm doing this all on a shitty windows phone so bear with me lol) I'm looking for help from serious engine builders and turbo specialists.

My goal is about is to be over 350 hp (for now) with a low compression, high revving turbo f20b in the nice light chassis of a eg Honda civic as a DD.<-- that i want to be reliable!

Originally I wanted to do a f22a non vtec turbo build but after learning more about the f20b here are the pros and cons...

F20B-
An f20b has the same bore (85mm) as an f22. So after some research I found you can put f22 pistons on the f20b rods to make it lower compression.

F20b+f22 pistons yield the static compression ratio to about 7.8:1

Some rumors suggest a f20b has factory "forged" crank and rods

This motor has an AWESOME rod to stroke ratio of 1.65 so safe revving capabilities of 8000-8500 and a more reliable motor compared to the low redline and bad rod to stroke ratio of the f22.

Its dual over head cam. Better tuning capabilities.
Larger combustion chamber
Comes stock with h22 type s cams and mostly everything for a h22 head is swapable including aftermarket parts.

So. With a conservative 10 pounds of boost and revving to about 8000 rpm at an elevation of 1000 feet. I will be looking at an effective compression ratio of around 12.8:1-ish.

To my understanding, with this compression it will yield the motor to have very little torque on the bottom end... Seriously low but with the right turbo charger and the fact of the light chassis i think it should over come this issue.. I mean like a stock d16 pushes that little thing around from the factory so getting this car around town with this beast should be no issue.

Now for performance part, again to my understanding. The torque curve from vtec engagement,boost and the ability to rev the power will greatly be well over what a f22 could ever produce at its lower redline even though it is way more of a joy to drive around town with all that low end torque.. Trust me i know what a f22 turbo civic is like. Power full as hell but with around he same cost with just a switch of pistons to a different motor i see a hugeeee advantage of the dohc ability, vtec, and rev ability and future upgrading capabilities of the f20b over the f22a-b power plant in the civic.

Please share criticism and help me decide turbo sizes and anything else. Thank you.

[bmxican783]

Its gonna blow up

[Ludin203]

Obviously to keep it cost effective I will be buying my friends f22 swapped civic so mounts, axels and everything needed would be already supplied ,but just for theoretical reasons I will list everything....
Parts I would need:

F20b motor and trans.
Civic chassis
Mounts
Possibly a rear t bracket from a 92-96 prelude.. Not sure which bracket the f20b comes with?
Possibly a h series driverside engine mount bracket.. Not sure which bracket comes on the f20b yet..
90-93 Integra axels with a h or f series inner CV joint on the passenger side
H series turbo manifold
Turbo
Charge piping
Wastegate
Bov
3 bar map sensor
Wide and o2 sensor
DSM 450cc injectors <-? (probably will need to be bigger idk yet)
An injector resistor box
H or f series shift linkage
Civic half size radiator
B series wiring harness that will need to be made to work with this motor which is no problem
I have a h22 intake manifold laying around so that will be taken and hollowed out to be put In place of the f20b manifold
All the be used with a chipped ecu.

Some components like sensors and such will need to be changed since the f20b is obd2 but should be no problem as knock sensor will be deleted , and I have the tps, iat sensor, map sensor and a obd1 prelude dizzy laying around which was modified to be internal coil.

What I am worried about most is clearance ... The current f22 swap in a civic I helped build BARELY fits in the engine bay at the firewall with the h intake manifold installed but I'm sure with some persuasion and some washers at the hangars of the hood to space it up it should be fine? I mean if people swap h22s in there it should be about the same.

[Ludin203]

Its gonna blow up

Lol I hate you.

[bmxican783]

Shits gonna blow up

[2kCivicEx]

Bump for an interesting thread. It sounds like you already know what your talking about

[Ludin203]

There is ONE person I found with a similar setup which is who inspired me to do this. His name on many forums is XES. He built a 700-800 hp 4th Gen prelude.

His setup was something like this:
F20b block fully built but kept the same r/s ratio. And had it bored 2mm over to fit a 87mm cp piston. He used a h22 head on this block so I assume he did this to match the h22 combustion bore. As far as displacement is concerned, I'm sure it didn't really add much since the h22 and f20b share the same combustion chamber volume. Displacement went from 1997.0 to 2002.93

So he had around the same amount of displacement with a strengthened block.

The h22 head he used had stock cams I believe also.

From looking at his dynosheet... Its ridiculous how much power this motor makes with the right turbo and fuel.. He made 500 hp on pump gas or something around that and the hp and torque climbed up to around 7500, held it to 8, then fell off at around 8500 rpm.... With stock cams... That's amazing.

Then he switched to c16 fuel and upped the injectors and maybe something else and made 779 hp and 460 lbs of torque at 9500 rpm!?!?! The torque and hp kept consistent and wanted to rise after that. He had to stop there because he ran out of injector!

That is simply crazy.
Basically this build is like having a big block turbo gsr just with bigger displacement.


Now I could go the g23 or g22 route which would produce more power and sooner.. No doubt about it but it will blow up and not remain consistent with power and is Extremely un reliable which is why I ditched that idea for now along with the f22. For now that is unless there is someone that can shed some light as to this being a waste of time.

[POS civic]

Sounds like a fun and very unique build, but I have to wonder why you're using an f series engine in the first place. I know f20b's have made huge amounts of power in accords/preludes, but it would be much easier and more attainable, possibly even more cost effective if you start breaking axles ect, if you just turbo'd let's say a gsr. If you are doing this to be unique then all the power to you, its always refreshing to see someone do something out of the "norm", but if you're trying to go cheap, in the long run I'd say there are better options. On another note I read about someone using a k series RBC intake mani on your head with an adapter plate. Not sure if this would help with clearance issues but definitely something to look into

[TypeSHLude]

the only issue with a f20b is the rods & pistons are gonna be custom through bisimoto, vs an h22 rod & piston setup which are mass produced through various companies & cost you half the price. if you gonna build an engine from top to bottom i would go with an h22, if you have aftermarket rods your gonna be able to rev it 9k+ anyway & get more torque because of the rod to stroke ratio as well... just my opinion

[bmxican783]

Fuck b series h and f all day... And its gonna blow up

[Ludin203]

Sounds like a fun and very unique build, but I have to wonder why you're using an f series engine in the first place. I know f20b's have made huge amounts of power in accords/preludes, but it would be much easier and more attainable, possibly even more cost effective if you start breaking axles ect, if you just turbo'd let's say a gsr. If you are doing this to be unique then all the power to you, its always refreshing to see someone do something out of the "norm", but if you're trying to go cheap, in the long run I'd say there are better options. On another note I read about someone using a k series RBC intake mani on your head with an adapter plate. Not sure if this would help with clearance issues but definitely something to look into

Yes I have heard about those adapter plates! That would be a big help.

As for being different then yes.. I am that guy that tries to show up to a meet with a weird ass swap under the hood. As for cost effectiveness goes. I ALWAYS buy a "new" motor if I plan on doing something like this. Which will be from hmotorsonline.com.( I can't even explain how clean my h22a was when I got it from them 3 years ago) Anyway, a f20b long block is a bit cheaper

And the fact that between me and a few friends have plenty of f and h series parts laying around.. So getting a gsr in my case I would have to start from scratch. Idk maybe I'm just a f and h series fan boy but I always remember the saying "there's no replacement for displacement" . Both motors rev as high as each other but one has a bigger displacement and makes more power so that leads me to believe that motor has more potential in the long run for future enhancements. Idk just my .2 cents

[Ludin203]

the only issue with a f20b is the rods & pistons are gonna be custom through bisimoto, vs an h22 rod & piston setup which are mass produced through various companies & cost you half the price. if you gonna build an engine from top to bottom i would go with an h22, if you have aftermarket rods your gonna be able to rev it 9k+ anyway & get more torque because of the rod to stroke ratio as well... just my opinion

Yes I understand that and agree 100 percent. I guess the over all point of this is basically in basic terms. This motor is the in between of a gsr and an h22. (stock forms)

Revs and builds power like a gsr but has displacement closer to a h22 and the same power. And has what the h22 lacks and envys... An iron bottom end.

In some aspects, it just has a slight advantage over the gsr for a mild build for boost. Better cams, stronger bottom end, bigger displacement and an ever so slightly better r/s ratio.

I guess just in my specific case, if you had the opportunity to get a car that was already setup for a bigger motor and you have parts laying around for that bigger motor that has a little more advantage over a motor that is commonly swapped in... And on top of all of this, you KNOW you can make very good power at a very small cost but you're still not planning on doing anything too crazy... What would you do then? This swap/build or a gsr turbo? ... That's just my mindset right now.

I know for a big boy fullly built project the advantage would be with the h22. But for something simple and fast I'd say this is a better route.

[Ludin203]

Fuck b series h and f all day... And its gonna blow up

Lmao did your shit blow up yet??? Didn't think so. And hell yeah h and f>b all day.

[Ludin203]

Found a few more posts on different forums with information. This one wad the most useful to un answered questions so far : http://www.wvmotorsports.com/threads/11361-F20B-Turbo

[Purple_Ej1]

Do a f22a non v single cam semi built allmotor in a crx or ef then do f2b wit typer trans and have a single cam sleeper and it'll be super reliable and you'll run low 12s all day if not break into 11s