The main change between Perodua Viva and it's predecessors (Perodua Kelisa and Perodua Kancil) would be their engines. Then it came the term of DVVT, and Perodua claiming their 1.3l DVVT saves fuel and provide power as same as normal 1.5l engines.

Let us get back to the basics, DVVT or it's full name Daihatsu Valve Variable Timing is based (copycat) on Daihatsu mother company Toyota engine, which is VVT-i (Variable Valve Timing - intelligence). We believe that DVVT is just VVT-i's engine brand name for Daihatsu cars.

DVVT and VVT-i is based by Yamaha's YPVS (Yamaha Power Valve System). Yamaha was bought over by Toyota for it's YPVS because Toyota afraid of losing to Mitsubishi's MIVEC and Honda's Vtec. Yamaha has been provinding Toyota and Daihatsu engines since.

DVVT and VVT-i engines are always put together to be compared with V-tec (Variable Valve Timing and Lift Electronic Control System), i-DSI (intelligent Dual and Sequential Ignition) that is developed by Honda earlier.

All of the Vs (DVVT, VVT-i, i-DSI, Vtec, CVCC, MIVEC, CVVT...) was meant to increase fuel efficiency which is to use less fuel and produce more power from the engine. The objective is the same, the only difference would be their methods.


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DVVT and VVT-i

Normal engines is good in the low RPM. However, when the RPM reaches higher level, the amount of power produced per fuel is lesser. This is because the air from outside the engine couldn't get into the combustion space in a short period of time. That's what Yamaha sees, and they developed YPVS, VVT-i and DVVT.

DVVT and VVT-i valve works like a normal engine while in low RPM. However, as the RPM increases, the valve timer shifts the time of opening of the valve a little bit earlier. The higher the RPM goes, the earlier the valve opens.

By doing this, air would hav enough time to go into the ignition room, thus making the fuel burning in high RPM more efficient than conventional internal combustion engine.

Vtec

Vtec have the same idea with DVVT and VVT-i. It acts like a normal fossil combustion engine in low RPM, however when the user revs until certain limit (usuall 5000rpm). The valve timer would activate (this is what people usually calls Vtec change) and produce a noisy sound.

It sounds a little bit like a 2-stroke motorcycle engine revs high. You feel like the torque suddenly increases and you have more power to accelerate.

What actually happens is that the valve intake open longer than normal. Allowing more air to come into the combustion chamber. The more air in the chamber, the more efficient the fuel burns.

i-DSI

i-DSI is a new technology by Honda. Instead of changing the valve timing of an engine, Honda put two spark plugs on each piston. The reason is the same.. to burn the fossil more efficiently.

These spark plugs however have the main and secondary plugs. The main plugs usually sparks first, followed by the secondary plugs to burn the remaining gas in the chamber.





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The interval between two sparks was calculated in such a way to its most efficient fossil burning. In the highest RPM level, those two spark plugs might sparks at the same time to produce the largest power from the engine.

Conclusion

DVVT, VVT-i, Vtec and i-DSI is a good way developed by Japanese car automaker (Toyota and Honda) to improve the burning of fossil gas. All of them have the same objective (increase efficiency) and they do achieve their goals.

For the best fuel efficiency, MyPerodua would say i-DSI would be the best choice. For power, Vtec is the best.. and DVVT and VVT-i is in between those two.

MyPerodua welcomes DVVT engines in Perodua Kelisa and Perodua Kancil replacements (Perodua Viva). We are waiting that Perodua would implement a 7-gear no gap gearbox (like Honda Jazz) in their future installments. Coz that surely would increase the fuel efficiency of a car.

DVVT & VVT-i activated when you start the engine, and has a cut-off point when reaching 4000rpm if I am not mistaken. This technology is meant more for efficiency rather than power.
V-TEC and MIVEC in the contrary are activated only when reaching certain rpm, most V-TEC and MIVEC activation at is 5000rpm. (MIVEC got activated at 3000rpm? somebody know?) They meant for high rev to maximise power and suck petrol like no tomorrow.

This post has been edited by JrRetriever: Oct 13 2008, 05:42 PM

B16B YO!

For the subject in hand, we have to separate phasing and lifting.

This is the best part like having orgasm!!!

This post has been edited by JrRetriever: Oct 13 2008, 05:49 PM

Why is vtec in that list? lol

Sometimes I really wonder why peoples say VVTI has better fc than VTEC, in fact, I don't see any significant fc difference between these 2 engines by comparing Vios 1.5 and City 1.5 Vtec.

I have a lot of friends are driving Vios, while my sister is driving City Vtec. I roughly know the figure.

mivec not in the list ? i know that the vtec comes first then mivec... and later all the vvt-i, dvvt, cvvt, vanos all pop up in the automotive industry

Variable valve lifting , variable valve timing - enough

i-VTEC is a combination of Variable Timing Control (VTC) and Variable Valve Timing and Lift Electronic Control (VTEC).

What is VTC? Do you know?

nice information,bro

actually which 1 come first in the industry? nissan dun have any name on their engine rite. even suzuki also got name for its engine d. so is nissan lag behind?

hi TS, im here just to tell u VTEC and iVTEC > all

when vtec kick in yo..it will preeeeeeeennnnnggggggggggggggggggggg all the way to 8.5k rpm and vius or vvti will smell dust

kthxbai

This post has been edited by athlonxp: Oct 13 2008, 07:43 PM

LOL

Anyway, most of the VTC technologies nowaday are pretty same, or similar.

i thought we already had a topic discussing about it??...

nissan is cvt rite? or something like this,...forget liao

This post has been edited by NTX: Oct 13 2008, 08:08 PM

There we goes again. It has been discussed again and again.

nowdays those tech all are meant to have a better FC instead of power lor i think. FC first, den power 2nd

i ve get bored with this topic d, we have this chit chat in kopitiam since the 1st myvi released last time lol

Then should ask the topic starter to refer back the old thread.

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Added on October 13, 2008, 9:02 pmHey, tongyam, same hometown weeee!! (OOpps! Off topic)

This post has been edited by JrRetriever: Oct 13 2008, 09:02 PM