Honda's VTEC.

[beef_bourito]

oh, i saw a picture of one and i only noticed 3, it was a picture from the side

[ChEvYgRuNt]

Good work Kris nice article
Although i already new the basic operation of vtec it was nice for someone to be able to decipher and explain all the various types of vtec applications and their differences.
As for everone arguing about the comparison between vtec and turbos. Think of this "A Sequential Twin Turbo setup mounted onto a Vtec motor". With the second turbo staged at the point just before the wild lobe cuts in. This as i see it would be the ultimate setup!! Economy down low, and BULK AMOUNTS OF TOP END!!!!!!!

[TRD2000]

DAMN THATS A LOT OF READING... BUT INFORMATIVE...

1. I'M GLAD SOMEONE CORRECTED THE HONDA F1 RECORD CAUSE THEY HAVE TRADITIONALLY KICKED ASS.

2. I'D SAY RENAULT SHOULD BE ON THE LIST FOR TURBO EXPERTS.. AFTER ALL IT WAS THEM WHO MADE THE DAMN THINGS EFFECTIVE IN F1.

3. OK MAYBE I'M MISSING SOMETHING, CHRYSLER TURBO? "EXPERT???" HUH?

VALVE OVERLAP... I CAN UNDERSTAND WHY IT STUFFS FUEL ECONOMY, AND WHY YOU NEED IT FOR NA CARS, AND WHY ROTORS HAVE THE SAME EFFECT. WHAT I WANT TO KNOW IS IF I TAKE A BEAMS 3S-GE VVTL-i ENGINE AND WHACK A TURBO ON IT SHOULD I CHANGE THE CAM? OR CAN THE ADVANCE/RETARD ON THE VVT SYSTEM ADJUST TO REDUCE OVERLAP? WHAT ELSE WOULD NEED TO BE CHANGED TO MAKE THE TURBO WORK EFFECTIVELY?

[TRD2000]

The Advantage Is The Engine Length.

[TRD2000]

I'M GLAD SOMEONE MANAGED TO ACKNOWLEGE BMW HERE.
The VANOS and double vanos systems have been used on BMW's for quite a while now and were barely mentioned... the fact mitsubishi's mivec was a copyright thing from vtec... toyota had vvt and vvtl-i.. vvt being purely duration and vvtl-i being lift and duration CONTINUOUS!!! VVTL-I is the most advanced system in use at the moment! and vvt has been fitted to more than just a celica and a corolla! its been on the supra, SW20 mr2, MRS (MR2 spyder) two celica generations, corolla, caldina, the ALTEZZA, and a bunch of others!
saab used to be up there on turbos, but have been baught out by GM and have been working on things like variable compression engines, Volvo used to be up there on turbos but they got baught out by ford, chrysler had their stuff done by mitsubishi.... Japanese company's are where its at with turbos and they are moving away from them cause of the US market! so unless you can afford something like a porsche or ferrari forget it...
vtec's nice... my girlfriends FTO really gets moving round 5000rpm... but my turbos already got me up the road!! anyway thats enough bitching for now, i still want to know about the turbo and VVTL-i!

[Moppie]

Originally Posted by TRD2000

i still want to know about the turbo and VVTL-i!

Then start another thread about it, preferably in your car models forum, or the forced induction forum.
This thread is about VTEC, it dosn't need to be filled with advice on how to turbo your car.

[Moppie]

I have removed several off topic posts.

This thread is about VTEC and related or similar systems used by Honda and other manufactors.


If you want to discuss W engines, or Turbos, or phased cam timing systems with out relation to altering valve lift and duration then please start a new thread, after useing the search feature to make sure it hasn't already been covered.


Any further off topic posts will also be deleted, including any refering to the deletion of posts.

[jinz_s]

can i ask, isn't a v-tec engine same as vvt-I engine used in toyota?

[TRD2000]

nope...IVTEC and VVTL are very close...

V-tec basically adjusts the lift of the valves... at a certain point in the rev's it will swap to a different cam labe.. meaning more lift and possibly different duration.

VVT uses one cam lobe, and a hydraulic actuator where the cam gear is (on the end of the camshaft). the actuator actually rotates the cam forwards or backwards by a certain amount to change the timing of the engine throughout the rev range.

IVTEC and VVTL are the next generation, combining both these functions. so they are pretty similar.

[crazzysol]

Not to bad of a forum

[jinz_s]

ok i understand that part, but just to make things clearer. vvt i also does the same thing as v tec. it also adjusts the lift of valves. it basically controls the valve to actuate at diff time.

by this then only it is able to control the fuel economy. i used to attend a course on vvti engine from toyota and lexus. do u have a site to where i can go? to further make me understand about the vtec system

thanks

[jinz_s]

another thing.....visit my blog and tell what u think about it
http://torque_nm.blogspot.com/

[Moppie]

Originally Posted by jinz_s

do u have a site to where i can go? to further make me understand about the vtec system

thanks

If you take the time to read this thread several times it should give you almost all the information you need.
To get any deeper into the topic you would need to find a Honda Technical Manual with all the enginering spefics, and that would require a trip to a Honda dealer and a deep understanding of the enginering involved.

[CBFryman]

Originally Posted by Polygon

There are two, one for intake and one for exhaust. Granted they aren't valves in the sense of most combustion engines more that they are two holes and are both open, or uncovered for a very short period of time allowing exhaust gas to be mixed in with the fuel and clean air causing stinky exhaust and poor gas mileage.

That is what I meant, and yes this is a vtec guide but it is also talking about turbos, I was out to correct some misconceptions about turbos stated in the guide, that is all.

yep, just as in a 2cycle gasoline engine, even thought i know of no 2cycle gasoline cars...so this is irelevant....just thought id ad this in....i know of some 2cycle diesels (sp?) though...

[choboi86]

So I understand VTI-E stands for Economy...

but what does VTI-S stand for??

and is there a difference between the two?