DOHC and SOHC

[Beehive3783]

Sorry but its VVTL-i, not VVTi-L

 

http://en.wikipedia.org/wiki/Toyota_ZZ_engine#2ZZ-GE

Oops my bad

[inlinesix]

No, VTEC for K20A is implemented on both intake and exhaust. Its the VVT or CVT thats implemented on intake only.

What is the purpose of VTEC? To allow more fuel into combustion chamber. If that's the case, why do u need VTEC on exhaust valve?

 

VVT or CVT is the overall name for VTEC, VVT-i, VVTL-i & etc.

[Mini-itx]

What is the purpose of VTEC? To allow more fuel into combustion chamber. If that's the case, why do u need VTEC on exhaust valve?

 

VVT or CVT is the overall name for VTEC, VVT-i, VVTL-i & etc.

 

No, VTEC is different from VVT. VVT is basically cam phasing or timing. Your valve lift does not change. VTEC changes, your valve duration as well as lift using a seperate set of cam lobes.

 

Original VTEC does NOT have any cam phasing. Its till iVTEC then cam phasing is introduced to the intake side.

 

VVTLi does the same thing as iVTEC but added cam phasing to exhaust side as well.

 

Btw, exhaust valve timing/lift/duration is also important for producing max power out of the engine, you want exhaust gas to move out ASAP as well. And there is valve overlap.

[Krado]

what's so different?

 

I test drive Honda City last month when I send my Toyota Vios to Borneo Motor.

 

Seems that Honda City (SOHC) outbeats my Toyota Vios (DOHC).

 

Is it the power of iVTEC or higher HP?

 

SOHC = Sure Over Heat Car

DOHC = Don't Over Heat Car.

 

Therefore, DOHC is better.

Edited May 31, 2010 by Krado

[Viceroymenthol]

Aiya, just get an EG/EK can already ah! Feel the VTEC baby!!!

 

but must switch off aircon and wind down window when kui vtec

[Krado]

but must switch off aircon and wind down window when kui vtec

 

Why? Because all racing cars dun come with air con...

[SeriousGuy]

Its the higher HP but its iVTEC which provides that extra power. The VVTi on your Vios is tuned for economy rather than power.

 

You can google around for how VTEC works. Its basically having 2 sets of CAM lobs. One set for low RPM and another set for high RPM.

 

If you want extra power for your Vios, you can change your cams and retune the ECU. However, more aggressive cams will cause your low end to suffer and hence FC suffers as well.

retune ecu ? not illegal ?

Edited May 31, 2010 by SeriousGuy

[Prostcode]

but must switch off aircon and wind down window when kui vtec

Hahaha ya bro :( Miss winding down my windows and kui-ing VTEC :( Sigh.

[inlinesix]

No, VTEC is different from VVT. VVT is basically cam phasing or timing. Your valve lift does not change. VTEC changes, your valve duration as well as lift using a seperate set of cam lobes.

 

Original VTEC does NOT have any cam phasing. Its till iVTEC then cam phasing is introduced to the intake side.

 

VVTLi does the same thing as iVTEC but added cam phasing to exhaust side as well.

 

Btw, exhaust valve timing/lift/duration is also important for producing max power out of the engine, you want exhaust gas to move out ASAP as well. And there is valve overlap.

Variable valve timing includes both cam phasing (VVT-i) & cam changing (VTEC).

[Zangetsu77]

Aiya, just get an EG/EK can already ah! Feel the VTEC baby!!!

 

Yeah EG and EK used to rule the streets, esp after they lub on a supercharger and over-bore the pistons to 2.0L displacement heehee...

[999]

DOHC has two cams. One for the intake, and one for the exhaust. With two cams, you are able to fine tune the timings for the intake and exhaust valves seperately, as they are controlled by two different "arms"

 

 

SOHC has one cam. It controls both the intake and the exhaust valves. This way, both the intake and exhaust timings are the same. You cannot increase the duration of one without increasing the other too. They are controlled by the same arm.

 

In engineering, some people believe that DOHC can produce more power. Although the company Bisimoto has came up with a SOHC setup that can rival many DOHC in drag races, DOHC in general still gives more power per cc when tuned up.

CamSHAFT not cams.

[Japan96]

Wan POWER and FUEL ECONOMY take the Volkswagen TSI Engine.

1400CC got 160BHP leh

Fuel: 16.5km/L

but expensive near 100k or can say 100k

but V-TEC not easy maintain. Ferrari all use V-TEC but higher

V-8, V-12 ALL THOSE EXPENSIVE ONES.

[Itsec]

Wan POWER and FUEL ECONOMY take the Volkswagen TSI Engine.

1400CC got 160BHP leh

Fuel: 16.5km/L

but expensive near 100k or can say 100k

but V-TEC not easy maintain. Ferrari all use V-TEC but higher

V-8, V-12 ALL THOSE EXPENSIVE ONES.

 

mai anyhow smoke lah...

 

[Phluvcat]

i think it's not rpm. but load factor.

 

12v are used for fuel saving mode.

be it at 50kmh or 100kmh as long as you are cruising at constant speed it's 12v.

for my ride, it has a eco light to let u know its 12v

 

cam thingy explained as well

http://paultan.org/2006/03/13/2006-honda-c...-i-vtec-engine/

 

yo u driving a EK3? or the iVTEC also got this ECONO light feature???

[Mini-itx]

Wan POWER and FUEL ECONOMY take the Volkswagen TSI Engine.

1400CC got 160BHP leh

Fuel: 16.5km/L

but expensive near 100k or can say 100k

but V-TEC not easy maintain. Ferrari all use V-TEC but higher

V-8, V-12 ALL THOSE EXPENSIVE ONES.

 

No, Ferrari does not use VTEC. What Ferrari uses is even more advance than plain old skool VTEC. They use a fully variable valve timing lift system. ITs like valvetronic and valvematic but tuned for performance.

[Mini-itx]

CamSHAFT not cams.

 

Err.... its the same thing lar. Cams is like the short form of camshaft. I am very sure most people who frequent car related forums know what is are cams.

[Mini-itx]

retune ecu ? not illegal ?

 

Tuning ECU is fully legal except it may void your warranty if your car is still under warranty.

[Zangetsu77]

No, Ferrari does not use VTEC. What Ferrari uses is even more advance than plain old skool VTEC. They use a fully variable valve timing lift system. ITs like valvetronic and valvematic but tuned for performance.

 

In the good old days of the EG/EK VTEC, you will note that a stock 1.6L B16A engine is good for 160HP and a stock 2.0L Type R is good for 200HP. In terms of HP : displacement ratio, it does come close to matching the stock Modena 360, which was the latest Ferrari then, so you must not under-estimate the sophistication of the VTEC.

 

Tuned 1.6L rides were good for well over 200HP without resorting to forced induction or NOS, and when coupled with forced induction, 400HP could be achieved.

 

And if we go back even earlier, do note that Honda and not Ferrari won the F1 races.

Edited May 31, 2010 by Zangetsu77