Understading VVT

[donjetman]

https://www.lsxmag.com/tech-stories/l8t-to-the-party-using-vvt-to-our-benefit/

 

[Marky Dissod]

At the moment, I'm getting several '404 Forbidden' across at least three different websites looking for that article.

 

[Joseph Garcia]

Excellent article, IMO. Thank you for sharing.

 

[Fless]

At the moment, I'm getting several '404 Forbidden' across at least three different websites looking for that article.

No problem here clicking on the link and getting to the site. Tried Firefox and Edge and all is good. Why are you searching for the article on different websites?

 

[Marky Dissod]

'cause the lsxmag link no workie.

For some reason, my Opera will not let me view these articles anywhere, but FireFox lets me read ...

 

[Marky Dissod]

I get what the article is saying, in principle.
Most of us are not using cam lobes so large that we can't use VVT - so why NOT use VVT?
(It's really Variable Cam Timing, but whatever.)

Say something 'dumb' goes wrong with our 'VVT' feature. Where does it wind up?
Fully advanced? Fully retarded? Somewhere in the middle?
Is it possible it could wind up 'stuck' somewhere other than 'expected'?

 

[Foggy]

In my understanding the VVT Allows the OEM's to use a smaller camshaft
(lower duration) which is basically what they've always used. So that's why
us hotrodders always went with "bigger" cams for more power... With the expense
being poor idle/low rpm behavior which the OE's can't do due to lots of reasons.
Our Gen IV engines can only "retard" the cams position in relation to the crank...
Which makes it "ACT" like a larger camshaft but when/where/how it gets retarded
is now controllable by the smart ecms.
To me there isn't really a downside to our VVT except it does add a something else
that can wrong as stated above...
That being said, if the VVT components were to get "stuck" in a certain position it
would be in the ZERO position which is default - which means no retard...
So you'd basically loose the benefits in the upper rpms.
The other benefit is that in high vacuum situation like highway driving it can retard
the cam slightly (along with fuel, timing) to lower the vacuum reversion happening
in the intake manifold. This results in better MPG at these certain conditions.
I know some of us have really looked into the actual settings via HPTuners and
understand this more than others.
Hence the need to limit the VVT actuation when installing a larger camshaft...
I'm pretty old school, but it is nice that you can have a 400HP+ engine that
idles at 600 rpm , gets good MPG AND pulls like a train to 6500 rpm !!!!
All thanks to very complicated engine management systems that are expensive
and hard to diagnose and work on though

 

[Foggy]

My above dissertation only applies to our Gen IV engines as that's my experience.
Other VVT systems are way more complicated and/or better/ worse than ours

Also to add: many engine systems are controlled by oil pressure..
That's why it's so important to always use the correct oil weight and type
and also NOT to go by the DIC or the book... Change your oil more regularly..
that's one of the major reasons why DOD/AFM engines have so many problems...
Way cheaper to change your oil more often than pony up $5000 +++ for lifters, cams
and possible a new engine. Preventative maint is soo much cheaper

 

[Noggles]

I might be in the minority here but I can't wait to get rid of the vvt in my truck. I hate how jerky it makes low rpm driving and I find it does nothing to help low end torque. It just seems like a solution in search of a problem to me.

 

[j91z28d1]

I might be in the minority here but I can't wait to get rid of the vvt in my truck. I hate how jerky it makes low rpm driving and I find it does nothing to help low end torque. It just seems like a solution in search of a problem to me.

I've never once felt anything different from my vvt 6.0 and my non vvt ls3.

are you should you're feeling the vvt work?

can anyone else feel theirs? I do have a odd by tranny in the yukon that might be hiding it?