XeroK00L

How about Dual VVTL-i?

I don't know. Can someone enlighten me as to why Toyota doesn't implement this obviously superior technology as widely as possible? Is it due to cost or technical issues?

Adam2562

iTrader: (2)

ya i'm driving my friends Ceilca GT-S with a few mods and when it hits VVTL-i its amazing i loveit.. car sounds angry haha and pulls very hard like a 50 shot of nitrous literally

Jeff@Longo

From my personal knowledge...

The VVTL-i project was canned due to the cost/benefit factory. This was Toyota's movement toward the "excitement you feel when driving a Honda". You have to admit, you do feel and hear the VTEC kick in... but how often do you really drive at 6000 RPM? =P

Dual VVT-i was a step toward the right direction. BMW was been using the Double VANOS system (intake and exhaust variable valve timing) for a while now and it's quite an advantage. You see the torque peak at VERY LOW RPMs and carry throughout most of the powerband as opposed to the usual torque peak at mid-high RPMs and then drop off.

I've explained VVT-i vs VTEC vs VVTL-i vs i-VTEC a few times on another forum and I think I'm getting a little better each time =P I even get to add my 2 cents regarding Dual VVT-i since the xGR-FSE engines are coming into the picture.

VVT-i: I call this the analog solution. The [INTAKE] valves vary at all RPMs using the feedback from o2 sensors, air flow sensors, etc... so you will get slight improvement across the whole powerband. VVT-i doesn't really kick in (you may feel a few 'jolts' at 3K/4.5K in some cars though...) because it's continuously working w/ the sensors.

VTEC: I call this the digital solution. There isn't much feedback in the system, just input from the emgine speed sensor (sorry, lacking the technical knowledge if there is an actual term). VTEC will kick in at a certain RPM. It opens the [EXHAUST] ports wider so more air can flow through at high RPMs. VTEC is either ON or OFF. It doesn't continously change like VVT-i. However, VTEC has a larger peak gain the VVT-i.

In VVT-i vs VTEC, VVT-i would win as the daily driver choice. VTEC would win for race technology. Honda is "Race Inspired". Rumor has it that Toyota named VVT-i (intelligence) to poke fun at Honda for just being a dummy 'on/off' system... I doubt Toyota would do anything of the sort, but it's fun for the enthusiast to laugh at

i-VTEC: Honda's answer (sort of) to VVT-i. I haven't seen too many articles pertaining to how i-VTEC works, but the ones I have read (upon i-VTEC's introduction a few years back) is that it's a multi-step VTEC. So instead of just kicking in at high RPMs, it also kicks in once at the low-mid transition area and the mid-high area then the normal VTEC kick in. The changes are much smaller to suite the range it's built for. You don't feel as big of a jolt in high RPMs, but it serves better as a daily driving technology. The torque is more available at useful ranges in the powerband now =P (A lot of my favorite jokes revolve around saying Hondas do not have torque, but now it's becoming a myth)

VVTL-i is Toyota's answer to VTEC in addition to its VVT-i technology. VVTL-i is simply VVT-i with lift at the top of the RPM range. I've only heard rumors regarding the lost technology known as VVTL-i... but, dollar for dollar, Toyota, IMO, took a step in the wrong direction. They should have looked at the Europeans for new technology ideas, not within their homeland.

Toyota learned (from what I think was a mistake) and moved to seek a new target. BMW (and other Euro brands, but, IMO, BMW was the main target). Double VANOS is a proven technology to boost overall torque (better daily drivibility) and improve emissions (added bonus). The first Toyota vehicle with this technology was the Avalon. 3.5L Dual VVT-i. To me, it felt like a supercharged 1MZ Solara. Pretty fast, but not overkill. =]

Toyota then added the Direct Fuel Injection ('S' designation in the engine code) to increase fuel economy, increase performance and decrease emissions. It was a win/win/win situation. There are a lot of other companies with VVT technology, but the 2 we hear most about are VVT-i and VTEC.

Variable Valve Timing Abbrevations:

BMW VANOS = VAriable NoOckenwellen Steuerung, German for "Variable Camshaft Control"
HONDA VTEC = Variable Valve Timing and Lift Electronic Control
HONDA i-VTEC = Intelligent Variable Valve Timing and Lift Electronic Control
MAZDA VVT = Variable Valve Timing
MITSUBISHI MIVEC= Mitsubishi Innovative Valve Timing and Lift Electronic Control
NISSAN CVTC = Continuously Variable Valve Timing Control
SUBARU AVCS = Active Valve Control System variable valve timing
TOYOTA VVT = Variable Valve Timing
TOYOTA VVT-i = Variable Valve Timing with Intelligence
TOYOTA VVTL-i = Variable Valve Timing and Lift with Intelligence

***NOTE***
Was it intake or exhaust that is varied? It's been a few years since I've explained this and I totally forgot... it became one of those arbitrary explanations so I forget the main points of it

Please, by all means, correct me if I've mistaken INTAKE and EXHAUST ports.
***END NOTE***

BLK13X

Ahhh... I thought there was something funky going on in my gearbox I've never driven a car with VVTi so it was quite different driving.

On the 1JZGTE VVTi update you can feel the car trying to surge at around 2500RPM (around that, usually at 1/3~mid-throttle) which you would never feel in the older 1JZ twin turbos.

And I think on the 1JZGTE VVTi the VVTi is actually the exhaust camshaft. Gotta check the Hyper Rev though, there's a pic in there.

Thanks for the info

Inabj2

Well you can though... to some extent.. as long as blocks are essentially very similar..

Take a non Vtec B20 honda engine and swap a vtec head from a b18c1-5... Or even a non vtec b18 and swap a vtec head from an earlier integras b17 vtec head.

LexFather

Thanks for the explanation!

CK6Speed

iTrader: (1)

The one thing I would add is in the end, Toyota's VVTL-i and Honda's i-VTEC are espentially the same thing. The only difference is in the amount of cam degree timing or as Toyota calls it came phase. Both systems do the same thing. The both continuously vary cam phase/timing which at one point Honda's VTEC system did NOT do, and they both alter valve lift duration. Toyota calls their system Dual VVT when it works on both the exhaust and intake, while Honda just calls it VTEC no matter. It is just understood that on Honda's SOHC VTEC or i-VTEC engines it only works on intake valves, but on all their DOHC engines it works on both intake and exhausts.

Between VVT-i, VTEC, VVTL-i, and -VTEC the only two that are really directly comparable is VVTL-i and i-VTEC as I mentioned above. VTEC and VVT-i are just a little too different to really compare. VTEC does not vary cam timing or cam phase, but offers variable valve lift duration. VVT-i on the otherhand varies cam timing/phase, but doesn't touch valve lift duration. Saying which one is better is tough because it really just comes down to which camp you are in. Not Honda vs Toyota, but if variable valve lift or cam timing is more importent to you.

I'm sure Toyora/Lexus has this as well, but Honda/Acura also uses a variable intake or induction system. It is either called VIS or VVIS depending on who you talk to. That stands for Variable Induction System, or Variable Volume Intake System. The ideal is resonant tuning within the intake manifold. There are separate butterly valves (Similar to the TB) within the intake manifold that opens and closes depening on RPM. On certain Honda cars you can really feel the VIS open up and then feel the VTEC engage.

Bottom line is no mattter what each manufacturer calls it they all use some form or another of variable valve timing. It is a GOOD thing and does offer the best of both worlds.

vwong

This isn't entirely true. The K20's found in the RSX (non TypeS) and Civic Si (not the 06), and the K24's found in the Accord and Element (I think CRV as well) are also DOHC engines but only have variable valve lift (the VTEC portion of the i-VTEC) on the intake only. The K20's in the RSX TypeS and the K24's in the TSX have variable valve lift on both intake and exhaust. Now these engines all have the cam phasing (the i portion of the i-VTEC) on intake cam only.

If you're talking about the old VTEC motors (like B16, B18C, and H22), then yes the variable valve lift is on both intake and exhaust.

CK6Speed

iTrader: (1)

Thanks for the update. I actually haven't keept too up to date on the newer K series engines.