Vvtli Vs Dual Vvti Vs Vtec Vs I-vtec

[ZZa]

HI everybody.. i always been wondering whats the difference between VVTLi, VVti, V-tec and I-Vtec...one of my friend told me that VVti is nothing like Vtec... the only thing produed from TOYOTA that perform like V-TEC is VVTLi... and after the test drive of a SS 2 celica ive found VVTLi do give me more 'push my back feelin' and seemed slightly faster than our Alteeza... so to find out whether our dual vvti is that bad or not.. i had a drag battle with my friends accord sir-T... but the accord was no match for us all the way up to the 3rd gear...after that i test drive my friends accord... than ive found his V-Tec do give me a similar feel as VVTL-i too.. but how come his car is even slower than mine??

so im pretty much confused abt which is better... and y there is Dual vvti but not dual VVtli or Vtec? and when does our 2nd VVti actually goes on? i can only feel the car do go faster from ard 4800rpm - 6000rpm..

can any1 tell me plz thz

[Turbo tezza]

Dual vvt-i on the tezza.

This means that both the intake and exhaust cams are varible, to opimise air flow thru the valve train.

(Varible valve timing with intellegence)

Vvtl-i is varible valve timing with lift and intellegence. This has varible timing on the intake ( i think) and the cams have extra lift over about 5500 rpm.

I'm not sure how v-tec works :(

Corey

[voiceinsideyou]

VTEC has lift control as well, I presume it's roughly the same as VVTL-i.

However, there's so many other variables involved that I doubt you can really say one is 'better' than the other. I'd definitely say that VTEC is more 'sophisticated' than plain VVTi, but that doesn't necessarily mean its effect on performance is better.

AFAIK, VTEC is only intake though? (could be wrong!)

[Sirnixalot]

VTEC has variable lift on both cams

iVTEC is similar to VVTLi - it has variable cam timing on the intake

Im not sure if both systems have a set timing advance or retard on the intake cam or if its "infinately" variable as in the DUAL VVTi which we have.

[SSML]

1G-Fe 6 cylinder engine only has VVTi, for inlet valve only :(

nearly every major car maker has similar feature as VVTi, or Vtec, but just with different names, e.g Vanos, double Vanos for BMWs,

SSML

[Thunderbird2]

Im not sure if both systems have a set timing advance or retard on the intake cam or if its "infinately" variable as in the DUAL VVTi which we have.

Yes, this is the big advance here. VTEC is like an on/off switch, and VVTi feels much the same in this regard (such as in the new Celica above 6000rpm)

I believe iVTEC is Honda's continously variable version of VTEC, however it still operates on two distinct profiles. The DC5 Type R also has a 'stepped' feel to the power delivery.

More here - Valve Tech

[silverr171]

Yep VTEC is variable timing with lift, where the amount of extra lift is fixed. this is normally tuned to `step in' at a certain rpm.. eg for the 1998+ accords you will notice a pickup in delivery and change in engine note at 3800rpm, most other models this happens at ~5500rpm-6krpm.

i-vtec is vtec plus variable timing control on intake, which allows valve overlap to be infinitely variable. What this means is that the engine can breathe better at higher rpms (by having both intake and exhaust valves simultaneously open for a longer period of time) while still maintaining a smooth idle and better low-down torque (less overlap).

afaik BMW's VANOS system works in a very similar way.

[Sirnixalot]

Yep VTEC is variable timing with lift, where the amount of extra lift is fixed. this is normally tuned to `step in' at a certain rpm.. eg for the 1998+ accords you will notice a pickup in delivery and change in engine note at 3800rpm, most other models this happens at ~5500rpm-6krpm.

i-vtec is vtec plus variable timing control on intake, which allows valve overlap to be infinitely variable. What this means is that the engine can breathe better at higher rpms (by having both intake and exhaust valves simultaneously open for a longer period of time) while still maintaining a smooth idle and better low-down torque (less overlap).

afaik BMW's VANOS system works in a very similar way.

VTEC doesnt have variable timing....only iVTEC does and its only on the intake cam

[silverr171]

VTEC doesnt have variable timing....only iVTEC does and its only on the intake cam

Actually yes it does.. VTEC does create a larger valve overlap.. it's just not continuously variable like iVTEC is...

[RESIST]

It has been so long since i looked at all the V-TEC technology. But what I can tell you is that after 2 years of having a V-TEC it does have greater kick than the 3S-GE, in saying that I did have full extractor exhaust system fitted.

The other thing you will notice is that when you hit V-TEC (in my case 4500RPM) you will notice noise increase and higher octive. The best part is with after marked exhaust you have substantial noise gain and at quiet a nice frequency! It is the one thing that i do miss, the Altezza's just dont have the same frequency change :(

Check out www.honda.co.nz for link to iV-TEC technical info.

[Sirnixalot]

VTEC doesnt have variable timing....only iVTEC does and its only on the intake cam

Actually yes it does.. VTEC does create a larger valve overlap.. it's just not continuously variable like iVTEC is...

the over lap changes between the cam profiles. If you look at VTEC cam gears or pulleys you will see they are not adjustable like the iVTEC or VVTi ones.

thats what i mean. VTEC does not have variable cam timing. VTEC has 2 cam lobes with profiles for each pair of valves on the same cam. Of course the specs will change between the different lobes, that is the point of the technology. But the ECU cannot variate the timing of the cams.

[Sirnixalot]

It has been so long since i looked at all the V-TEC technology. But what I can tell you is that after 2 years of having a V-TEC it does have greater kick than the 3S-GE, in saying that I did have full extractor exhaust system fitted.

The other thing you will notice is that when you hit V-TEC (in my case 4500RPM) you will notice noise increase and higher octive. The best part is with after marked exhaust you have substantial noise gain and at quiet a nice frequency! It is the one thing that i do miss, the Altezza's just dont have the same frequency change :(

Check out www.honda.co.nz for link to iV-TEC technical info.

the reason is because the altezza cams have one profile and not 2. If you put some Toda or TRD cams in your 3sge you will hear a similar sound at high revs

[RS200TEZ]

Whats MIVEC then? :P

[ZZa]

THZ everybody.. ive learn alot of stuff from u guys..

[ldc]

It's all about economy vs performacing turning. Dual vvti allows for extra fuel economy and better emission.

I was abit dissappointed that the is250, with it's new engine lineup didnt come with Lift.

Vtec is still my fav. with the s2000 toping the list of affordable performace cars.