zeroptzero

In terms of dropping out of vtec, that refers to rpms dropping faster between shifts when the clutch is disengaged with an ap1 flywheel. Rpms can drop below the vtec engagement point between shifts but as soon as you engage the clutch the rpms are back up and vtec is re-engaged. The difference in having the vtec disengage between shifts is negligible, and I guess it depends on how fast you can shift. Not a big deal to me, and I like the lighter flywheel myself. I ran the 8 lb ACT fly on my ap1 and liked everything about it, and it is much lighter than the ap1 fly.

snmalone

I have an f22c engine with spoon flywheel and ap1 transmission. The car feels very responsive and likes to rev. You need to get used a bit taking off in first gear but other than that it makes car feel so much more alive and peppy.

B serious

The AP2 gearing is also lower.

Redline shifts put you in VTEC in any next gear.

Has nothing to do with the flywheel.

Billman250

Has nothing to do with launching.

You are correct Christian Baril. The “keeping it in VTEC” issue will only show itself on the 1-2 shift. Has everything to due with the flywheel.

The 1-2 shift will be very challenging to keep in VTEC. The rest of the gears will be easy. All due to gear spacing.

Anyone who has this mod will tell you the same.

Slowcrash_101

More inertia in the flywheel so revs drop slower when you lift. An object in motion tends to stay in motion. The heavier the object the higher its inertia.

On AP2 engine + transmission means with light flywheel you can drop out of vtec on the 1-2 shift because the revs drop slightly faster than with the heavier flywheel. 2nd gear and beyond have vtec in a wide enough range that you won't drop out of it on shifts.

Engine speed range is the same, what changes is gear ratio. 1st gear takes roughly 7.5 engine revolutions for one revolution of the tires. 2nd takes ~4.75.

02civicsi

I'm planning to install an AP1 flywheel when it's time to replace the clutch in my car.

Christian Baril

If my memory is correct I think you are the one you I learned this from reading this site 4-5 years ago.

Billman250

I had a pro-racer (Tel1sps on here) sponsored by Nitto, was able to gain one second with the AP1 flywheel and CDV removal, on tracks that he could no longer gain on.

Excellent for track, but you might loose a drag race by not catching 6000rpm in second gear.

B serious

Ok, I see what y'all are saying.

The AP2 is geared to come JUST out of VTEC from 1-2 and its on the edge at 2-3.

I was saying that no flywheel can change gear deltas. Without clutch slip or tire spinning, the gear delta determines your next gear's RPM.

But yes, the heavier AP2 flywheel would fall slower in revs and would use its inertia to spin the tires up (or make the clutch slip) enough on the 1-2 upshift to help keep the car in VTEC.

Saki GT

My plan was always to either install an AP1 flywheel, or an ACT PP with greater gripping force and an AP2 flywheel. At 16 years and 135k miles, I've yet to need to replace anything though, so I haven't had to actually choose. But for me, it would come down to an engine that revs and drops off a bit more freely, or a slightly stiffer clutch pedal and better bite.

I think everything Honda did in the revised power train was done to improve stability by reducing driveline shock and what was breaking at the time. The AP2 flywheel is such a drastic change in weight though.