What if you used an F20C shortblock in a DBW chassis with Flashpro? I suppose this is kinda what some markets in Europe, etc, got. But not here in USA. I know FP makes a version for those other markets. Does it allow as much tuning potential as the FP for US market ECU?

For US market, the F22C added lower end torque, at the expense of redline and power band. But the use of Flashpro, and a HFC (or *gasp* a tp), allows lowering VTEC rpm, which probably does a much better job of increasing lower end power than the added displacement (and other changes) associated with F22C did.

Is there potential for a best of all worlds here?

If you had a DBW car, & replaced engine with F20C shortblock, used the ap2 head (or would it be better to use an ap1 head?), use a HFC, lower VTEC using FP and bump redline back to 9k. Now you got an even bigger high cam powerband, like 4k-9k, you got most possible stratosphere rpm fun. But you also got a nice bump at the lower end (perhaps not as big a low end bump as the same changes applied to an F22C, but likely worth it due to those other benefits.) Combine best of F20C & F22C.

In virtually all markets outside USA, 2004-2005 cars retained the F20C (then Japan got the F22C '06+, while Europe and some other places kept the F20C for al years). However many (most, all?) of the manufacturing improvements that came in '04 F22C were also done to these '04+ F20C's. Hopefully that included the use of a torque plate during bore & hone process (which is responsible for dramatic improvements in oil consumption). Hopefully someone knows? If so, no F20C oil burning penalties if you use an '04+ F20C block.

What are potential drawbacks to this concept? What did I miss?

 

Well...the drawback is that an equally tuned F22C will still make more torque and HP for a larger portion of the power band.

Even if you broaden the F20C power band to flatten it out over a larger area than a F22....overlaying a F22 graph would show a larger gain at any RPM. One's flatter. One's fatter.

Ain't no displacement for replacement.

or...aint...displaced any...refreshment...

man whatever you know what I mean.

The advantage is stretching power another 1K RPM. Maybe if you use the correct gearing, you end up with an equally fast car.

 

Oh, of course. I should have been more clear about the goal. More about enhancing the cars character, less about trying to make it something its not (a truely fast car).

Sprinkle some of the magic 9k pixey dust onto the ap2. While still retaining most of the F22C/dbw benefits, filling in some of the low end torque deficit, improved reliability, oil consumption, ability to easily/cheaply tune, etc.

 

I can't remember what year car you have...

I have a MY00 and a MY07. I can share my opinion for the sake of discussion.

If I blew up the F22C, I don't think I could live with the F20C as a replacement (apples to apples). From a perspective of driving enjoyment...the F22C just seems way more "alive". I would probably try and find another F22...or K swap it.

Strangely enough, on the flip side, if I blew up the F20C, I would have a tough time deciding whether I wanted to replace it with a F20 or F22. The 9K redline isn't experienced as often as the low RPM liveliness of the F22. But if I had to live without it...could I really call it living? Not sure.

I think its a case of not wanting to get rid of it once you've had it (in both cases).

Your proposal is intriguing. Best of both worlds. Not sure if a tuned up F20C would feel like a stock F22. If it could...shit...the world has a solution to all it's 1st world problems.

Or maybe the world already solved that problem with the K20A lol.

 

'04+ F20C's. Hopefully that included the use of a torque plate during bore & hone process
correct from 04> in UK, also yes a deck plate was used when machining

 

You can tune a 00-05 that's not FlashPro but that's not the question.

You'd want a F20C block+head for the conversion but a DBW Valve cover with the right cam sensor. You'd have to remove the front cover and replace some parts like the K-Pro kit recommends. Then swap out to a DBW throttle body.

Really the gains are just a tuned F20C with an AP2 trans and diff which have a shorter 1-4 effective gear ratios

With a HFC, AP2 reduction gear, and a piggyback tune you can have the same build for an AP1 the you want for less. You'd get the AP1 steering rack too!

 

The concept is from pov of someone that has a dbw car, and it needs an engine (which many of us will eventually face). Assuming you already have FP and hfc, which is a better choice for replacement block?

The 9k redline is always brought up in the which is the better car argument, ap1 vs ap2. The counter argument is the larger motors low end. So a way to combine some of the attributes of both seems a worthy pursuit.

The question is how attainable that is.

 

Anyone have a link to the AP1 and AP2 engine power graphs overlaid on each other? A comparison of power under the curve?

The AP1 engine does not really rev to 9000rpm (unless you round up from 8900) nor does the AP2 engine cap at 8000rpm (unless you round down from 8200). This exaggeration seems common among AP1 owners claiming something magic about "9000rpm" and the "extra 1000 HP." Doubt I've ever read any magic about an extra 700rpm, it's always 1000. I'm sure the AP1 engine can squeeze out a couple hundred more rpm and I know my AP2 engine will easily rev to 8400 which is where my Flash Pro rev limiter is set. But these are "so what?" numbers since few ride the rev limiter. And both engines (in stock form at least) produce the same max power at WOT. Since that's moot the difference in power curves should be interesting.

AP2 gearbox is lower geared (secondary final drive) which is beneficial for acceleration albeit a deficit to top speed when the AP2 engine runs out of revs.

-- Chuck

 

I have a F20C and if I wanted the more powerful engine I would pick the F22C to replace it for a DBW car. Less converting needed and like Chuck said, you can get an F22C to rev to 8400-8600 safely which actually has a higher piston speed than the AP1 engine at 9000rpm which I verified with OBDII at least. With my E-Manage I can bounce off fuel cut around 9100-9150 so it's not a wall of no power.

With a proper tune an AP2 will have a VTEC range of 3600-8600rpm which is more than enough to play with at the higher power numbers. If he wanted to as well, the AP2 transmission can have an AP1 secondary final drive (reduction gear) swapped into it so you have a higher top speed per gear. In certain autox classes it's the combination most people prefer.

If it were me, and not built for a race class, then I would do a F22C DBW swap. You can easily convert a 04-05 engine if one is found much cheaper too. Throw in an AP1 flywheel, AP1 slave cylinder, and do the return style fuel system conversion. HFC+tue and now you have about the best of the best parts from the S2000s. If you want, you can throw in a CR steering rack to really have it all.

 

I don't really understand the argument that you can get the F22C's benefits by tuning a F20C. That's comparing apples to oranges. If you tune the F22C in the same way it will still have even more low end.