it doesnt release compression... the reason it leaves the intake valve open to compensate for pump lose when the TB butterfly closed during cruising. this helps the R18 be very efficient with fuel while the TB is closed. during pump loss compression is maintained not released and no inertia is lossed.
it has oil squirters "oil piston injectors/Jets" so it can run 10.5 compression pistons in this application not because of fuel porpoises directly. since the compression is still low its able to run 87 octane efficiently. the ignition and fuel delivery is tuned for this.
Technical Overview of Honda's new R18 i-VTEC Implementation
i think you read it wrong
vtec = wow
others = whatevers
are u kidding me? the ivtec in r18s and k20s are totally different and are there for different purposes.Excellent discourse, but I think we can all agree that while i-Vtec is different from what other manufacturers offer, it does not represent a paradigm shift. It's like how American English is different from British English, but it's not a different language, just a variant. Not the same, but not different enough for it to be in a different class.
vtec = wowOk...
vtec = wow
VVT (or whatever variable valve timing) + turbo = bye bye Si
It all comes down to torque and Hp. I dont really care how they get it. I would rather have a nice flat torque curve over a big RPM range than a burst of power at a certain rpm and above.
I like my civic. I didnt buy my civic for i-vtec, i bought it because it was a Honda.
lots of false information on here. . . for starters theres alot of people here thinking VTC = VTEC. . . NO. . . VTC refers to systems like VVT, VVT-i, etc. . . VTEC is unique in the "EC", the Electronic lift Controller. . . VERY few systems function in this form
a little bit of history, Toyota came out with a VVT/VTC system first, I think it was called T-VIS. . . and from there they went into heavy VVT research and now havfe their Dual VVT-i to show for it, constantly variable valve timing on intake and exhaust valves independently. . . the first people to think and try research on a variable lift motor was GM, but their efforts proved futile and they canned the project, Hondas engineers picked up the project and in 1989 gave the world VTEC. . . their research went there and now theyve got things like the R18's i-VTEC SOHC, and their traditional DOHC i-VTECs. . . and soon enough VTEC Advanced
another little tidbit, up until 2000 TOyota didnt have a working idea of the variable lift system, then the came along with the 2ZZ-GE, their first. . . and only. . . venture into the variable lift stage, mechanically it was almost identical to VTEC. . . then later on the HOnda side the VTEC system gained it's "i". . . with the introduction of continuously variable valve timing along with the standard lift controller. . . Toyota gets the lift from Honda after its patents go out, and Honda gets continupusly variable timing when toyotas patent on it goes out. . . if it works well, and has proven itself, why not implement it yourself. . . and I will admit my brother's old Celica GT-S was awesome once that cam kicked over, but its not smooth like a Honda cam transition, which could present a problem in some circumstances
Toyota dropped out of the category in 2005 when the 2ZZ powerplant was canned due to its requirement of modification to pass euro spec emissions. . . Mitsubishi has MIVEC, and have had it for a good long while, its similar to VTEC, bit different enough that it didnt violate Hondas patents on the technology. . . and since, nissan is now running it as what they call Neo VVL on their SR20VE motor, Porsche is using it as they call it Variocam Plus. . . fact is, the technology is catching on, its more horsepower in less displacement, whats not to like
Regarding i-VTEC,im going to have say this over and over...
vtc changes the valve timing
vtec controlls higher lift on valves
Actually first production car with variable valve timing wasBeen discussed. Honda is Unique as it was the first to come out with it! B16's OBD0 GSR motors.