Difference b/w Twim Cam & Vtec Engines?

[F1]

Tell me What is the difference b/w Twim Cam & Vtec Engines ?

[codernaut]

Twin cam engine is just engine have two cams. Where as vtec is a variable valve timing and lift technology. A name given by honda to changing cam and valve profiles based upon rpm. There are many valve technologies such as vvti by toyota, mivec by mitsu vanos and double vanos by beamers, there is a new technology by honda know as i-vtec which isntead of having two or three cam and valve timing profiles for low and high rpm, makes continuous adjustment. See the prvious posts, there is a post dedicated to just vtec and also another post the honda edge.

[sali2002]

hello!!
twin cam means there are two cams for valve lifting and Vtec is a tehnology by honda which has 16 valve or say twin cam but vtec(variable valve timing and lift electrical control) means that valve timing is variably setted in such a manner that on low rpm fuel consumption is automatically lowered by engine by closing on valve and on high rpm where speed is required so the closed valve is open and all this is contolled electrically...i thinks it is controlled by ECU.....
huge diff b/w twin cam and Vtec...
Thanxxx

[tauseef]

well twincam and vtec r totally different as described by my bros. i think twincam and DOHC r the same.
correct me if i m wrong.

[sali2002]

yeah its same!! some said it twin cam like Nissan and some said it DOHC like toyota etc..but they are same

[tech_wiz]

Twin means two
Dual means two, so
Twincam and Dual Over Head Cam (DOHC) are the same things!

while VTEC, 16 valve, 4 valves per cylinder, 2 valves on intakes, 2 on exhaust.
in VTEC below a specific RPM, 1 intake valves stays closed for economy on every cylinder, so the car acts like 12V, when u push the pedel the other intake valve comes to life, and the car is not 16v, with prolonged intake valve open times! more fuel, more combustion, more power! thats VTEC.

SOHC VTEC is more or less of the same performance of a DOHC,
DOHC VTEC now it has DOHC plus the VTEC system, designed for power, then there's this I-VTEC.

[sali2002]

yes!!
tech_wiz rite......
now i known what is I-vtec...thanx
but what is This Vtec-III..?
any info??
Thanxxx

[codernaut]

i-vtec is hyrdaulicaly operated where as vtec is mechanically operated through oil pressure. I-vtec continuosly adjusts timing and cam positioning. Where as vtec has profiles based on rpm. Vtec operated on both intake and exhaust valves, i-vtec only operated on exhaust valves. i-vtec produces more smoother power curve. vtec iii is just a three stage vtec where we have a profile for low, mid and high rpm instead of just low and high rpm as in vtec.

[sali2002]

Hello!!!
thanx for telling

[ZXMCO]

ASA.i think, i can explain it in 1 pic.KHUDA HAFIZ

[tech_wiz]

@sali2002
VTEC-III is jsut the a generation engine name like,

1)the 95 had a vtec engine worldwide (not lauched in pak) it was considered as VTEC-I by honda fans

2)then the 96-2000 vti oriels, probably the best hondas ever had VTEC-II

3)and now this generation of civic
2001-2005 have VTEC-III engine

BUT technically speaking VTEC-III is more powerful than VTEC-II of 99vtis
but the reason for 99vti being faster is not tht they had faster engine or less weight, BUT has SHORTER GEAR RATIOS!!!

[ZXMCO]

ASA.nice work "tech_wiz" i think u have great knowledge about cars.nice work,keep it up.KHUDA HAFIZ