Stroked F20C is it all its cracked up to be?

[furiou5]

Hi guys,

was just wondeirng if any one could help me with an explanation or an article on why most race built s2ks run the f20c stroked to 2.2l.

I do understand that its done for the search of torque, but does it have any gains in overall power. I also know that the revlimit should be dropped down aswell.

The main reason for my confusion is due to the fact that in the past increasing displacement isn't always the best way to build a motor(ie b20 hybrids)

Am i missing something or is there another factor im not taking into account. because i was under the assumption its not normally the best idea for cylinder capacity to be more than 500ccs.

Can any one help me understand this?

BTW its just a curiousity thing, im driving a civic any ways

[aaronng]

It's to boost the F20c's torque at the mid rpm range of 5000-7000.

[furiou5]

thanks aarong, all the things i've read up on menion that but is that the only advantage of it?

plus is it actually a bad thing on having each cylinders capacity being 550cc's? (yes im aware that the h22's the same acapacity)

[aaronng]

Well, it's not as reliable if you want to keep the 9000rpm redline. One dude in Best Motoring blew a stroked F20c on the track as well.

USDM S2000 comes with the F22c, which is stroked but the redline is reduced to around 8000rpm.

[furiou5]

so the reasons y race cars would use them, is due to torque, and its feasable cos they would have the funds to sort it out if any problems occured.

would it bea good upgrade on a street car tho?

[toE]

I'll move this to Technical for now to see if we can get more replies as this seems to be a good discussion topic.

[chicken8]

i think the advantages of the stroked engine is mainly for more torque

power isnt everything as everyone well knows

the F22C has same power as the F20C (176kw) but has more torque (6% more)

torque will pull the car up a hill with better ease. which is an advantage on certain tracks

i dunno if a stroked F20C to a 2.2L would have much different characteristics to a stock F22C1

[chicken8]

F20C1 came with 206Nm torque and 179kw

F22C1 came with 220Nm torque and 178kw

the F22C1's peak torque was reached at lower rpm also

[bennjamin]

its same stroke but bigger bore for the extra 200cc's ? or opposite / both ?

[aaronng]

Same bore of 87mm. Stroke increased from 84mm to 90.7mm.

[sivic]

perhaps someone can confirm but i've heard reports that from next year the japanese S2000 as well as ours will be copping the F22C.
either way, they've found that although on paper they have the same power when stuck on a dyno the F22C equiped S2000's are putting more power down at the wheels.

[chicken8]

japan already has the F22C

doesnt matter what australia will get as only 15 or so s2000s were sold in australia in MY06

and theres every chance that the s2000 will be discontinued next year to make way for the HSC

[sivic]

there we go.
pretty sure the S2000 is staying on till 2008.
i think we'll be very lucky if the HSC is ready for production by next year

[chicken8]

yeah theres been rumours for a long time now about when the s2000 will discontinue.

majority or rumours are leaning towards 2007

Model Year Total US Sales for the S2000
1999 3,400
2000 6,797
2001 9,682
2002 9,684
2003 7,888
2004 7,320
2005 7,780
2006 4,288

Honda sells an average of 2,500 and 1,000 S2000's annually in Europe and Japan, respectively.

[saxman]

the F22C has same power as the F20C (176kw) but has more torque (6% more)
this really isn't true...

yes, honda rates the two motors at the same amount, but I recall seeing countless dynos when the f22 was released here in the states showing pretty significant hp and torque gains... quite a bit more torque than the published increase and very nice hp gains

[chicken8]

yeah more hp ATW. but at the fly there was only a 1kw difference in power. but around 14Nm difference in torque

[aaronng]

this really isn't true...

yes, honda rates the two motors at the same amount, but I recall seeing countless dynos when the f22 was released here in the states showing pretty significant hp and torque gains... quite a bit more torque than the published increase and very nice hp gains
Honda sometimes likes to surprise people.. Too bad we only get watered down versions here. Even our Accord Euro has only 187hp. LOL.

[bennjamin]

yeah more hp ATW. but at the fly there was only a 1kw difference in power. but around 14Nm difference in torque

For more hp ATW , there would be significantly more hp ATFW too.
Compensate for drivetrain loss.

[chicken8]

i read that at the fly the hp was similar between the 2. but the extra torque helped the F22C1 get more hp atw

im not sure if this was 2 engines being trialed on the same car or if it was a AP1 VS a AP2

[Weq]

i read that at the fly the hp was similar between the 2. but the extra torque helped the F22C1 get more hp atw

im not sure if this was 2 engines being trialed on the same car or if it was a AP1 VS a AP2

HP = Torque X RPM / 5252

First rule of car maths. An engine doesnt make HP, it makes torque at a given RPM.

[ProECU]

It's better to make power higher in the rev range, and allow gearing to take advantage of this fact on circuits that have long straights and high speeds and even more importantly more time spent in high rpm's

For tight circuits, you'd want more torque earlier.

[saxman]

i read that at the fly the hp was similar between the 2. but the extra torque helped the F22C1 get more hp atw

im not sure if this was 2 engines being trialed on the same car or if it was a AP1 VS a AP2
that really doesn't make sense, but I get wha tyou're trying to say


when the ap2 was first released out here, it was still rated at 240hp at the fly. On the dynos, they've been shown to make closer to 240 at the wheels.
However, if they're making 240whp, they'd have to actually be making a good bit more at the fly, despite what they're rated at.

Iirc, the tests were done on the same day, same dyno, etc, with a stock ap1 car and a stock ap2 car.

[aaronng]

when the ap2 was first released out here, it was still rated at 240hp at the fly. On the dynos, they've been shown to make closer to 240 at the wheels.
However, if they're making 240whp, they'd have to actually be making a good bit more at the fly, despite what they're rated at.

Iirc, the tests were done on the same day, same dyno, etc, with a stock ap1 car and a stock ap2 car.
I remember vtec.net's test. They tested 2002 and 2004 and found the 2004 having 26hp more atw. Although the F22C had the 6600rpm torque peak as per Honda's specs, there was a secondary torque peak at 7800rpm which just bumped up the calculated power by that insane 26hp. Power curve was still climbing without any tapering off, so imagine if the fuel cutoff was delayed by an additional 500rpm. Peak power would be even higher!