Can I get some info on this? What is it? What does it do? What kind of performance hit can I expect? Do many people in the group have them?

 

LOL !!!
Checkout this thread for some entertainment on the subject

 

RT's fun aside, you can expect to be able to increase performance across the powerband slightly, as well as dramatically improving performance in the middle of the powerband by moving the VTEC engagement and tuning the fuel curve around it.

VTECnology stated ~15 more peak HP. My experience is that it impacts your peak HP less, but significantly improves your midrange.

Stock honda VTEC engagement points are set artificially high, presumably so you feel the "kick" when it engages. The most dramatic increase in power comes from engaging the VTEC earlier, allowing a smoother and more powerful 5-7k RPM range.

Cheers,
Ben

 

Having had one in the Prelude, I *was* a staunch advocate of it. I picked up what *felt* like a lot of midrange power just before and after VTEC, as well as at the top. Most Hondas run unnecessarily rich, especially with a few breathing mods, and leaning it out seems to help quite a bit.

I *was* and advocate, but now that I've read a little more and heard of more S2k's with them... well, it looks like the gains are less than what they were with the Prelude.

I have yet to see a dyno plot that picks up much power by moving the VTEC point. One point that corroborates this is that the Mugen and Spoon ECUs both keep the VTEC changeover at the same point. If there was more power to be had, wouldn't they have changed it?

Something else to keep in mind is that *any* mid-band gains will be dialed out by the ECU. It learns (part of the emissions controls) and will recognize any change in emissions, thus any change in a/f ratio. Since that's all the AFC does, expect those ponies to have disappeared in successive dynos days later.

One thing you can do is defeat the learning- reset the ECU regularly or clip/switch the backup power line to the ECU. On my Prelude, I had pulled that pin to prevent the ECU from remembering anything when the ignition went off- every time I restarted the car, it was basically resetting the ECU.

UL has pointed out that some learning is good, that the base programming isn't quite "complete" without a little learning. I can't vouch for this, though I've since decided that the only "right" way to fix the fuel trim is to go with a programmable management system or something that is re-mapped a little more mod-friendly like the Mugen. It's a little more expensive, though!

 

[QUOTE]Originally posted by marcucci
[B]Having had one in the Prelude, I *was* a staunch advocate of it. I picked up what *felt* like a lot of midrange power just before and after VTEC, as well as at the top. Most Hondas run unnecessarily rich, especially with a few breathing mods, and leaning it out seems to help quite a bit.