Toyota's Dual VVT-I Vs Honda's I-VTEC DOHC (K Series)

[Shouyi]

Hi,

 

with the rumours of a new 1.8L Dual VVT-I corolla, I am wondering what are the major differences b/w a Dual VVT-I unit and a I-VTEC DOHC unit. And which is more advanced. Let's discuss!

[Normal_aspirated]

wow, seems like the trend of japs & koreans upsizing their engines for new models.

[EventH]

Donno about which being more advanced.

The old Dual VVTi Altezza produce some 210hp (6MT) from 2L with 21kg.m torque. That is nearly a Honda "R" engine spec.

The new Dual VVTi V6 2.5L in the Mark X (6AT) does 212hp from 2.5L but had 26.5kg.m torque at just 3800rpm.

 

Actually toyota just need to put the 1.8L VVTLi from the SS2 Celica into the Corolla and the thing will also fly.

[Chenqien]

eh dual vvt-i means cam phasing in both intake and exhaust valves...

 

i-vtec in the k block integra type R engine uses cam phasing only on the intake but has cam changing ( the traditional vtec where there is a wild cam ) thingy.. same concept as the vvtl-i.. the rest of the i-vtec i not so sure...

 

both are good.. but for everyday driving there is no really need for a wild cam..

[Gary84]

sorie...correct u abit...Mark X churning out 215bhp...

[Odyssey02]

i think i'll say honda produces better engines. they're renowned for it. maybe this'll be a biased viewpoint. furthermore, there seems to be some sludging problems with some toyota engines.

[Tanjkp]

Pardon me, you mean the dual VVTi also have the higher cam lift as the the Honda Vtec ?

[W210k]

I don't think all Dual VVTi engines have the wild cam. It's dual because its required for the V6 engine's setup (quadcam vs DOHC for in-line engines).

 

Toyota's VVTi-L is more akin to Honda's i-VTEC. Both have phased valve timing and lift control.

[Webbyboy]

Donno about which being more advanced.

The old Dual VVTi Altezza produce some 210hp (6MT) from 2L with 21kg.m torque. That is nearly a Honda "R" engine spec.

The new Dual VVTi V6 2.5L in the Mark X (6AT) does 212hp from 2.5L but had 26.5kg.m torque at just 3800rpm.

 

Actually toyota just need to put the 1.8L VVTLi from the SS2 Celica into the Corolla and the thing will also fly.

 

 

There's Corolla XRS in USA with 2ZZ-GE engine but tuned to 170bhp only. on Celica GT-S/SS2 is 190bhp. add in toyota supercharger it will be bout 215bhp. adding blitz supercharger can go till like 270bhp.

[Tanjkp]

O, thks, got it. So all make now want to boost more power so as not to fall behind KR starting with DVVT.

[Watwheels]

VVTI-L

 

Sallah spelling lah! It's VVTL-i

[Watwheels]

Sigh! So many fancy terms, what wild cams lah ....what lift control.

 

Pls lah dun confuse readers can or not?

 

@ high rpm the air intake valves will move deeper to allow more air to enter the combustion chamber (i.e when ECU detect more air hence add more fuel to produce more power). The idea is to let in more air into the combustion chamber.

 

But there's a limit, the cams (shaft with offset lobes) cannot move the valves too deep or else they will hit the piston head.

 

It's the same concept which u learn in secondary sch on combustion nothing fancyful like u guys mentioned. More air + more fuel + ignition = bigger combustion.

Edited June 22, 2006 by Watwheels

[EventH]

I can still remember the advert where the sheep out run the race horse.

 

I think the main problem with the VVTLi and wild cams vtec is that the power and torque come in (shiok feeling) at rather high rpms (5-6k) That is like the redline for a regular car. Quite tiring to drive like that day in day out.

[Tanjkp]

For those who ever read about 3 stage Vtec will know what is all about.

Not necessary need to ram to red line, 2nd stage lift came in at around 2K RPM.

[Iforu]

3stages vtec is not for racing 1.

3stages = save fuel, 2k+ switch 12 to 16valves.

[EventH]

The 3 charts are manufacturer figures for SS1, SS2 and USDM 2006 Civic Si respectively.

 

If you look at the charts, for cruising (at 3000rpm (110km/h?), both 1.8L Celicas had around 60hp while the 2.0L Civic Si had around 80hp.

 

All the engines produce around 90-100hp at 4000rpm.

Even at 6000rpm, both SS1 and SS2 produce around 140hp

while the 2006 Civic Si had around 160hp.

 

Off course the SS1 run out of power at 6k while the rest goes all the way to around 8k rpm.

 

But who drive at 6-8k all the time ... even when overtaking?

Edited June 22, 2006 by EventH

[Tanjkp]

Post: 3stages vtec is not for racing 1.

3stages = save fuel, 2k+ switch 12 to 16valves.

 

That's right, that's how it sells with economy + power.

[Tanjkp]

Thks for the charts, they are talking about max torgue, max power.

The Vtec lift don't kick in at high RPM only.

 

Most drivers will hardly use up to that high power / RPM.

Edited June 22, 2006 by Tanjkp