Variable Timeing

[AmErIcAnPrIdE05]

I would like to know why US cars dont use variable timing considering you get better miles to the galon.

[pimento]

US engines are lazily engineered and cheap to make. VVT costs money. Also, I dunno how possible it is with pushrodders. I presume it would be...

[Quiggs]

That's a really broad generalization. A Viper crate motor alone would cost more than some small cars.

Anyway, variable timing setups cost more to develop, more to produce, and the average buyer looking for a $30,000 toaster doesn't care about some high tech engine component. It doesn't make sense for them to use it.

[pimento]

I'm a broadly general kinda guy. As far as $30,000 toasters go, doesn't the Toyota Echo have VVT?

[Sweeney921]

I'm a broadly general kinda guy. As far as $30,000 toasters go, doesn't the Toyota Echo have VVT?

it does, but only to get better mileage.

the volvo 850 we have has it, but of course it's a swedish inline 5. weird engine. it has sport and economy modes.

[spi-ti-tout]

What is VVTi?

I've seen it on Toyota's but I don't know what it means.

[Sweeney921]

What is VVTi?

I've seen it on Toyota's but I don't know what it means.

It's a contraction for Variable Valve Timing. It's when the camshafts adjust as the RPM's increase, to either open the valves for a more aggressive fuel/air mixture, or to make the engine run leaner to increase mileage.

[AmErIcAnPrIdE05]

[QUOTE=pimento]I'm a broadly general kinda guy. As
No they dont

[pimento]

the volvo 850 we have has it, but of course it's a swedish inline 5. weird engine. it has sport and economy modes.

We have one too. Well, we're on our second one, the current one is a T5. The sport and econ mode just alters where it changes gears, sport holds them longer to stay within the powerband.

[Slicks]

I would like to know why US cars dont use variable timing considering you get better miles to the galon.

Alot of them do, they just dont brag about it with large stickers V-TAK!!!!!!!
And pushrods can have VVT, they generally dont need it though being that they are made to have a powerband that can be used. GM is developing a VVT system for their OHV 3.9L V6.

[gregvl52]

If you have an engine that is being used over a relatively narrow rev range, then there is no need (or at least, not as much of a need) for VVT.

[Matra et Alpine]

Not much benefit if the engine is big and a long stroker.
Vairable timing comes into it's own to better control the gfas flows in and out at diffreetn engine speeds to optimise the low end and high end characteristics.
With cu.in it's less of a need. BIG valves, BIG heads, BIG pistons, longish strok

[ScionDriver]

My Scion has VVTi, its a cheap car, and as all of you say it helps with fuel economy, which my car gets great. Maybe it will be like many technologies we see these days and costs will come down and it will become more commonplace on engines in this country.

[SupraMan22]

This kid doesn't know what variable timing is. This is the same kid with the V12 viper thread, cept he made a new name....agian. He asked a brit jackass what he should put on here to make him sound smart. Hey Gay Pride, what is variable timing anyway. If you made the thread you must know..right?