s2000Junky

Just to get this out there, the F22 not only makes more power then the F20 from the factory, but it responds better to the same bolts ons and tuning due to its larger displacement. One of my favorite mods for this engine besides the lightweight flywheel, is a larger 70mm TB with port match to manifold opening, and a good stepped intake with a large 6" velocity stack to get the full benefits. Response and overall power once tuned is quite good. Getting proper cold air and relocating the factory AIT sensor from manifold (04-05) to the intake tube resembling the DBW 06+ models and eliminating the hot coolant to intake manifold is also beneficial whether still utilizing the factory ecu to keep it running at full advance timing, or general performance running an aftermarket one. Ive always been happy with the factory header and a good sounding cat back, but de catting sees the most power results, if one plans on lowering vtec to the motors full potential of 3500-3600rpm. Without de catting 5300 vtec engagement is it, the engine wont respond lower then that and will actually see a power dip if tried. If your willing to spend the money and run ear plugs, some are willing to go with a proven header (mostly for weight savings) as well as a single 70mm cat back for a few more gains and weight savings. Not worth the trade off for me personally, when the other modifications yield good gains overall but great improvement in overall response and enjoyment of the motor. In theory since the only difference between the F20 and F22 head is the cam profile, one should see further high rpm benefits swapping in an F20 intake cam and gaining some usable over rev. The bottom end will take it.

Ive never run a K motor so I cant speak for how they feel, but I understand the benefits of the more modern ivtec which assist in more mid range power, but the nothing beats the flow of the F series heads. I just don't see the big deal some make over K series motors when the best one made something like 205hp from the factory. I Admittedly was never in the Honda scene/owned a fwd though so im sure I could learn something more on the line up that led to the F series, I know they are all mostly good motors, just seems like the S2k got the cream of the crop for overall performance coupled with race engine character.

miamirice

s2000Junky

230whp is typical for the mods I listed and of course with the lowered vtec at 3500-3600 rpm there is also no vtec kick, but a much fatter power curve. Id have to dig through to see what dynoes I have. I have 15 years worth mostly boosted, but not very well documented on what my mods were at the time. But shouldn't be hard for you to find some tuned F22 posted on this website.

Yeah 260whp is very healthy and impressive. Unfortunately 2.2 liters is all we get, so without cams and ITB, 245whp is about the limit on that displacement. The guys that do the 2.4 or 2.7 stokers of course yield substantially more.

miamirice

s2000Junky

?? final drive has nothing to do with the pressure plate man, the S2000 isn't a FWD

But generally I find the factory 4:10 is best when you lower vtec/tune the engine. The biggest lacking ive found that can warrant a final drive gear reduction is the ap1/f20 moving to a 4.44. With this you get more trq multiplication to help motivate this low trq engine while still being able to hit 60mph exactly at redline in second gear rather then 64ish stock. An ap2 trans in an ap1 is a nice little benefit as well if one needs to go to those lengths. The primary reduction gear in the ap2 trans is equivalent to a 4.22 rear end in the first 4 gears, and get a further over driven 6th gear. Ironically the ap1 trans due to its longer spread gives the ap2 better gearing to more closely get the one gear shift to 0-60mph and better 1/4 trap if that's your thing.

There are larger and cheaper TB out there but many of them are also fussy and unreliable, have stiction issue etc. Science of speed makes the best option which is a modified oem. Ive run the same one for years on several different motors and also inject water/meth pre tb, and no issues what's so ever. You can go to their website and read up on what they do to the TB to improve it.

miamirice

s2000Junky

Yeah I got the reason for swapping the clutch pressure plate and even doing a different final drive if you wish, just not sure how the final drive factors in to the bell housing removal since they are on two opposite ends of the car/unrelated. Maybe i'm misunderstanding your correlation there due to a run on sentence, don't know.

DavidNJ

I'm a bit confused by this discussion (other than it being off topic). On the street, how much difference is there really between 200whp, 230whp, or 250whp? I doubt a 10% difference could be detected from the seat of the pants. That small difference could occur just because of temperature, humidity, and fuel quality variation. And those power numbers are at wide-open throttle at or close to the redline. How often are you accelerating at WOT and doing a fast shift at the redline on the street? Even on the race track, unless in tight competition, do the small differences really make a difference? Streetcars are tuned for a broader power curve, as most drivers rarely seen numbers of 3500 rpm let alone 6000, 7000, or 9000.

The flywheel is very noticeable blipping the throttle on a downshift where its inertia is large compared to the rest of the engine. Maybe a bit on the upshift. However, the small difference in hp would only be noticeable in very tight wheel-to-wheel competition (e.g. Spec Miata, Spec Racer Ford, circle track racing, etc.). Note that the inertia varies linearly with mass but as the square of the radius. My stock car has a 5.5" 2-disc 'button" clutch. Even then, the hp difference is only significant at lower speeds where the rate of acceleration is high. The amount of hp consumed in rotational acceleration of the clutch is less as the rate of acceleration and ratio of engine revs to vehicle speed are lower. How many S2k flywheel/clutch setups are small diameter?

Most street cars are geared for around 40mph in 1st gear and just over 60mph in second. The later, to put the 2-3 shift after the widely reported 0-60 mph acceleration times. The AP1 did that well. The AP2 had the 2-3 shift just below 60 which is also an annoyance at many(most) autocrosses. Increasing the redline mitigates that. The goal is always to keep the engine in the part of the powerband where it makes the most power. In drag racing, that would be to maximize the last gear used just as the car tripped the lights. In the 1960s, 'muscle cars' often had 4.11 gears that limited top speed to 120 or so at their 6500rpm redline and 1:1 4th gear ratio (in a 4-speed gearbox). For road racing, the goal was the have the right combination for each straight...or as close as possible. The goal was to avoid unnecessary shifts where no power is applied. In a Formula Ford, a new and popular class in the 1970s, it was common to change the ratios in the Hewland Mk8 or Mk9 gearboxes for each track and to adjust for rain or sometimes cold weather (more power). Note that powerful cars are often traction limited in the lower gears; peak power there is less important. An example would the torque limiting feature Haltech adds to its high-end drag-racing oriented ECUs. For the street with a 6-speed transmission, is gearing really an issue?

s2000Junky

^^^ Well I realize its fun to pick things apart and be logical and practical, but keep in mind the mere act of owning a sports car at all is an impractical and illogical practice Mr. Spock. So you must allow some room for unnecessary fun.

For what its worth I can tell the difference in 10% power for sure, and more is better in my world so.

miamirice