VTEC vs VVVL-i

[SolReaver]

Aren't they the same? If not who is better?

[SolReaver]

Oops one too many V

[enzo@af]

I've heard that the VVTL-i is better. People say because it has "lift intelligence"

[gang$tarr]

well vtec is kinda an old technology, soon there will be vtec-i..... juss like VVTL... into VVTL-i
it's vtec with inteligence, or whatever
it'll be way better than VVTL-i :frog:

[enzo@af]

Of course, doesn't Porsche use a continuously variable VTEC-like system? That would kick either of those's arses.

[Jay!]

is "more advanced."

VTEC has two sets of lobes for each valve, and the valve levers would switch over at the predetermined threshold. (FYI: the NSX engine had three cam positions.)

VVTL-i is "continuously variable," meaning that it doesn't choose between two settings, but rather it can move to any setting in a range. I'm sure that the computer choreographing the changes is super sophisticated.

I always heard that turbo-charging a VTEC engine was troublesome. I wonder if the VVTL-i technology will be more adaptive...

[gang$tarr]

yeah silver but the VTEC-i will kick the vvtl-i :rocket:

[Jay!]

I guess we'll see. Anybody know what H-car is planned to get it first?

[gang$tarr]

prob prelude or s2000

[Jay!]

Actually, I'll put money on the RSX having the first to hit the street. AutoWeek printed a picture of it this week; it's the first picture I've seen of an i-VTEC engine in a car.

[SolReaver]

How about the new Civic hatchback with a new 170hp engine. It has i-VTEC.

[Jay!]

I think I heard that, too. But it won't be here until late next year, is that right?

Doh! Where'd I read that?

[texan]

Silver S2000- VVTLi does use multiple camshaft lobes, and is very similar to Honda's VTEC (which uses 3 cam lobes to every 2 valves, not 4). It's biggest advantage (aside from changes in cam phasing through electronically adjustable cam gears) is not having a third rocker arm and third lobe for every two valves, which saves weight in the valvetrain. Of course this is also it's biggest disadvantge to VTEC, since only having one lobe active per set of intake or exhaust valves means it's not able to stagger valve lift and duration between the valves at lower RPM like VTEC setups do (which prevents the easy introduction of swirl and tumble to the mixture).

If you ask which is tuned better though, all VTEC motors are currently setup better than Toyota's Celica GTS motor. The Celica's VVTLi motor has a hiccup in the power curve at 6000 RPM (where the big cam kicks in), and doesn't possess enough RPM potential to keep you on the big cam during upshifts. Which partially counteracts the whole point of having variable valve lift and duration in the first place, and I think was a cost cutting measure on Toyota's part. If you extened the redline another 500-600 RPM, you could stay on the big cam once you reached it in first gear, and the car would definitely better the B18C1 in power output and accelerative ability.

gang$tarr- The Prelude is gone, no longer produced, the damn dirty RSX Type S is both the Integra and Prelude's replacement.


enzo@af- Porsche's Variocam Plus setup is nice, but currently only used on the intake side of the motor (if memory serves me correctly). Variocam Plus has 3 cam lobes per valve, and uses an adjustable hydrolic lifter to facilitate different cam lobes being in control of the valve. It is two stage (just like the others), very compact and simple in actuation. Regular Variocam is just changable cam phasing, and is no big deal.

[JD@af]

(applause for texan)

I didn't realize that VVTL-i discouraged swirl through unified cam lobes below the VVTL-i range.

Inspiring excellence as always.

[VTEC V6]

i got a video of hte new porshe 911 turbo and they talk about the engine and all sayin it gots something similar to honda's VTEC system but it can actuate anytime not like honda's fixed timing as in 5500rpm on a civic