hmmm i wonder, i dunno if honda ever made a v8, but could you imagine a v8 with vtec, or maybe a custom made , block with two vtec head on. now that would be some hellish engineering dont ya think?

Nissan V8's after the Y series all had VTC on them, even my 1992 VH45DE.

The newer VK ones they do have continually variable cam timing on both sets of cams I think. Can't remember the model but it'll be VK50xxx, use in the new infiniti saloons, very nice bit of kit. Its kinda odd how Honda sell so much on VTEC yet most manufactures use similar technology. The new fiat/alfa multi-air engines are a great bit of tech too, one of those ideas so simple you wonder why nobody has done it before.

BMW v8's M62tu onwards have fully variable valve timing, they also have valvetronic which varied the intake valve lift - jolly clever!

i have the Vanos on my 325 too...same principle init:wink:

variable cam timing isnt quite the same as v tech, the v tech has basically 2 different cam profiles so at switch over you get a different profile so you get different lift,duration and timing/overlap. so you get the best of both worlds ideally, a smooth low down grunt profile and a screaming race cam.

 

most other systems just vary the overlap

 

the nsx used a v6 v tech

There seem to be a few different approaches now.

Saw some drawings of the nissan system ages ago and from memory it uses followers on a moveable shaft as part of the linkage presumably to give variable lift and duration, can't really remember exactly how it looked.

The multi-air has a cam with basically the biggest profile that doesn't make the valves hit the pistons then uses hydraulic actuators between the cam and the valve to control the valve movement. Pretty sure they even do multiple valve openings at low revs to give higher velocity / increased swirl.

 

Didn't honda do a V12 at one time in some limos too, wonder if that had VTEC?

My mistake, the V12 is I think the toyota one.

variable cam timing isnt quite the same as v tech, the v tech has basically 2 different cam profiles so at switch over you get a different profile so you get different lift,duration and timing/overlap. so you get the best of both worlds ideally, a smooth low down grunt profile and a screaming race cam.

 

most other systems just vary the overlap

 

the nsx used a v6 v tech

 

technically speaking, v tech is a childrens toy.

variable cam timing isnt quite the same as v tech, the v tech has basically 2 different cam profiles so at switch over you get a different profile so you get different lift,duration and timing/overlap. so you get the best of both worlds ideally, a smooth low down grunt profile and a screaming race cam.

 

most other systems just vary the overlap

 

the nsx used a v6 v tech

 

standard vtec is a two stage thing. More modern solutions to the problem, such as i-vtec, vanos, vvti are continously variable systems which provide even MORE of the best of both worlds.

Should be interesting to see when the camless engine finally becomes a reality. Not until 42v electrics at least. Koenigsegg apparently have one on the bench running. Pretty sure it had a rev range of something mad like 100-10k rpm!

Will certainly take a while to map, continuously variable is bad enough!