shad

I found a F20B on ebay they want $1800 for the thing what are the spec on it? They say it's 200 HP at 161ftlbs the same specs of the H22a1 motor.
Is it worth getting for a prelude?
http://cgi.ebay.com/ebaymotors...=6755

sedracer

if you have an OBD1 prelude stay away from this motor. Its OBD2 and it runs like **** when you try and run it with an OBD1 p13 prelude ecu. Look into an h22. The f20b is a great motor and is a much sturdier motor stock for stock against an h22. The motor also doesn't make 161ft/lbs of torque. If its from the SiR accord it makes 180hp with 151ft/lbs and if its from the SiR-T accord it makes 196hp with 158ft/lbs of torque.

JDogg

its a good motor, it can make alot of power, but be prepaird to wait for a few parts when you blow it up... all the internals are different.

converting from obd2 to obd1 is easy.. get some uberdata and have it tuned, it will be fine.

night

that thing is kinda confusing. is it more F or H ?
when where they introduced?
its basically admitting the H wasnt all that great

SuperSlow

200/145 are the correct numbers. From Accord/Troneo Sir/ SirT.

Destroked H22. Great motor.

night

ok, thats better. that torque number makes sense now. still a nice motor though for sure.

ShaunRR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SuperSlow &raquo;</TD></TR><TR><TD CLASS="quote">200/145 are the correct numbers. From Accord/Troneo Sir/ SirT.

Destroked H22. Great motor.</TD></TR></TABLE>

No FRM sleeves either

JDogg

the f20b is sort of a cross between a f and h motor. it has the iron sleeves of the f motors, the basic block casting of the 98+ h22a4's, the head is close to the h22, it has smaller b-series size valves in what is basicly an h22 head, the ports are shaped slightly different though. it has an 85mm bore with 88mm stroke, the crank has 55mm mains like the 98+h22, with small b-series sized rod journals. the rod is long and built very beefy.. looks like an s2000 rod and has a 23mm floating wrist pin.

ShaunRR

That reminds me of something I have wondered since I first heard about the f20b. Due to the larger valves and different ports, would a H22 head swap be worthwhile on a f20b?

PreIudeSI

wonder what the r/s ratio is on that motor. What's the bore? sounds like it could be a fun motor.

JDogg

bore is 85mm, r/s is around the 1.65-1.7ish area

JBBNJ609

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">bore is 85mm, r/s is around the 1.65-1.7ish area</TD></TR></TABLE>

how is it going to have a high rod ratio like that ?? thats close to a perfect ratio, better then the b16s and way better then the stock gsr ratio of 1.58 . . .


if the ratio was that high i think honda would let it rev higher then it does . . .

JDogg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jason bouchard &raquo;</TD></TR><TR><TD CLASS="quote">

how is it going to have a high rod ratio like that ?? thats close to a perfect ratio, better then the b16s and way better then the stock gsr ratio of 1.58 . . .


if the ratio was that high i think honda would let it rev higher then it does . . . </TD></TR></TABLE>

the h22 has a 1.53 rod ratio.. the f20b has a shorter stroke and alot longer rod. b16 has a 1.75 rod ratio, b16b is even higher, f20c is in the 1.85ish area.

r/s is pretty useless number anyway, actually a shorter rod will make more power

PirateMcFred

If you search in the Prelude essential links sticky you will read that the F20B rod is 145mm. so that means that the RS ratio is 1.65. from the factory it revs to 8k but with cams people rev it to 9000 without any bottom end mods.

I have always wanted to destroke a 89mm H22 with 12.5:1 and longer rod/shorter piston combo. But that is awefully $$$

Pirate

rjay8604

Also rod stroke ratio isn't the single-most important factor in revving ability, the plain old stroke is largely a determining factor. Thats why most motorcycle engines, weedeater,chainsaw, etc. can rev to the sky.

machine4321

the only reason the f20 was made was honda nad mugen needed a 2.0 liter to race in the jtcc or what ever it is lol
they only had the h22 before that and at 2.2 liter was not allowed ..

thats whythe motor seems to be build better then the h22 and have a higher reving capabilites ..

i also heard it was some what of a test bed foor the s2000 f20c....but thats not 100%

tougeEGsies

I actually found something online once about the f20b being the starting point from which the f20c was designed. They were tryint to reach a certain hp per literl.
It only breifly mentions the f20b, but it's in writing so it's gotta be true.

heres the link.

http://www.itepsa.com/samples/SIET199907_ES.PDF

cbmprelude

What is a rod ratio?

cpforyou

H22A = 87mm Bore cs. 90.7mm Stroke
F20B = 85mm Bore vs. 88mm Stroke

F20B is a motor few GOODIES!

200HP, 145 FT-LBS
It's shorter stroke and better R/S ratio make it more suitable for higher RPM out of the BOX! The stock block revs up to 9000RPM w/o any problems except for normal wear and tear.

It also comes with 11.0:1 Compression.

I was present at the dyno itself, on a DynoJet at the reputable R&D Dyno. The motor made 199WHP w/ JUN3 Cams & an RMF Header on stock bottom end!

After adding the R&D CNC Ported Head to it, it made 213WHP. Quarter mile runs on BFG Drag Radials in a Civic Hatchback with interior were consistent 13.1 - 13.3s. With slicks, the setup would be high 12s for sure.



My opinion, the F20B is a great build for those who would like to keep the block stock, and just build the head with a nice P&P job and nice set of cams.

Maybe not even P&P! Just get a RMF Header, add the JUN3 cams, and you're pratcially around 200WHP. It's the 11.0:1 Compression that helps a lot with the gains.

If you plan on building the block and going to put all that money into it, I would say to stick w/ the H22A.

machine4321

that dyno has been my driving force lol

i saw good thing in my head from this motor and i love it ..it works so well even with my shitty diy itbs....i loves to rev ,even on the stock header ..

i cant wait for cams and a header ..i really think i need to step up to atleast 50mm .

im leaving the bottome end stock and gonna try for a bit more comp from h/g and milling but not much

well see what it does..in the mean time i cant wait to see jdoggs when its done ,its gettign all the right touches

cpforyou

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by machine4321 &raquo;</TD></TR><TR><TD CLASS="quote">that dyno has been my driving force lol

i saw good thing in my head from this motor and i love it ..it works so well even with my shitty diy itbs....i loves to rev ,even on the stock header ..

i cant wait for cams and a header ..i really think i need to step up to atleast 50mm .

im leaving the bottome end stock and gonna try for a bit more comp from h/g and milling but not much

well see what it does..in the mean time i cant wait to see jdoggs when its done ,its gettign all the right touches </TD></TR></TABLE>

Only reason I don't run it is because F20B cannot be legalized in California.

machine4321

iot could become a b20 very easily lol alittle engraving

cpforyou

B20B is not legal in California also. You are not allowed to put an SUV motor into a car.

The only way it can be "legal" for the cops is to swap in an F20 (from the Accord) into a CRX. Have the inspector certifiy it as a 2.0L engine in a CRX.

Then you take it out, and put in an F20B and shave off the DOHC VTEC. The cops pop the hood, if they see no funny business, they see it's supposed to have a 2.0L engine in it, they see the F20B, they won't know. You're good to go.

I've thought about it, but I don't have a CRX, and it's too much work for just an F20B.

Back on topic, the F20B is a great motor. If bought as a complete swap, it usually comes w/ an LSD Tranny, and it's cheaper than a Euro R.

cbmprelude

will mods like a header, cams, intake manifold yeild gretter results on an f20 or h22?

machine4321

hard to say ..but i think the f20 would "respond"better to those mods ..i tihnk more overall power can be made with the h22 ..

liek i said the f20 has a stock 3 angle valve job larger cams more compression a type r like port casting (extremly smooth )

and the fact that the r/s ratio cams compression naturally like a higher power band and the f20 shines up there