CAM GUY'S , just when you though theres nothing new

[gunt]

seen this look seriously interesting for the after market ,

[midnightbluS10]

I can't watch that guy. I've seen too many vids where he was just all out wrong about whatever he's explaining. And his voice is annoying. He may be an engineer but that doesn't mean he knows what he's talking about every time.

[gunt]

YA voice is very hard on the head , but for the technology do watch it , it is pretty amazing ,

[CamKing]

That is actually pretty cool.
The cam duration in cam degrees stays the same, but it changes in crank degrees by speeding up the lobe RPM during the lift curve, and slows it down the same amount while on the base circle.
Dynamically this is a great idea. When it shortens up the duration, it is actually speeding up the effective lobe RPM, which increases the valve velocity and acceleration. This would normally be harder on the valvetrain, but it happens at lower engine RPM's, so the valve velocity and acceleration isn't any higher then it is at the higher RPM, when the duration is longer. When the system starts adding duration for top-end power, that higher RPM, requires a gentler lobe, and since the system is actually reducing the lobe RPM while it's on the lift profile, it's actually making the valve lift curve less aggressive.

This is by far, the best, most efficent system in any production engine.

[lefty o]

watched that a few days ago, definately a neat concept.

[CamKing]

One other thing. Besides the mechanism changing effective duration, it also changes centerline.
Since the rocker follower stays in the same place, and the centerline of the lobe moves, the contact point between the follower and the lobe moves, advancing or retarding when the valve reaches max lift.

[LoganD]

BMW's valvetronic is more effective. You can use it over a wider range and it allows you to throttle with the intake valve, reducing pumping loss.

[CamKing]

BMW's valvetronic is more effective. You can use it over a wider range and it allows you to throttle with the intake valve, reducing pumping loss.

Way too complex, and doesn't really change seat duration, just lift and area. It effectively just changes rocker ratio.
The problem with increasing rocker ratio as the RPM increases, the valvetrain gets less stable as the rpm increases.
This new Hyundai system slows down the valve motion, making the valvetrain more stable(or no-less stable), as RPM's increase.
The Hyundai system doesn't change lift, so you're always running the same distance from coil bind, and that's a good thing. since the system speeds up the lift curve, at lower rpms'. and slows it down as the rpm's increase, you can keep the effective lift rate the spring sees the same, throughout the rpm range.

The BMW system still needs an additional system, to advance and retard the cams.
The Hyundai system can change duration, and advance or retard the cam, all with one mechanical system.

[BobbyB]

If this technology could be used on a 350 chevy or 302 ford, how would it improve the average street strip hotrod?

[CamKing]

If this technology could be used on a 350 chevy or 302 ford, how would it improve the average street strip hotrod?

To do it right, it would need to be used on a double overhead cam engine. Something like the Ford Mod 4V engine.
With the system, you would effectively have a short duration cam for vacuum, idle quality and low-end performance, a larger duration cam for max torque, and mid range performance, and a even larger cam, for max HP and top-end performance.
I don't know all the particulars on this system, but let's say it can decrease and increase the duration of the base profile by 5% in each direction, and can move the lobe centerlines by 4 degrees total.
If the base profile has a seat duration of 280 degrees on the intake and 284 on the exhaust, you could setup the system so the cam was a 266/270 seat duration with a 106 ICL and a 112 ECL at idle, and increase to a 280/284 with a 108 ICL and 114 ECL by 4,000rpm, then increase to a 294/298 with a 110 ICL and 116 ECL by 6,800rpm.
The shortest duration would hit peak torque about 1,000rpm before the largest duration would. This would result in a very flat torque curve.
The engine would be much more efficient, over a broader rpm band.
You would have the top-end performance of a cam that would normally require a 4,500 stall, and it would pull off-idle, like a small RV cam.

[Belgian1979]

I think this is absolutely brilliant.
I would hope something like that would find it's way to our Chevy variants, but I can also see a OHC would be needed.

[BobbyB]

If this technology could be used on a 350 chevy or 302 ford, how would it improve the average street strip hotrod?

To do it right, it would need to be used on a double overhead cam engine. Something like the Ford Mod 4V engine.
With the system, you would effectively have a short duration cam for vacuum, idle quality and low-end performance, a larger duration cam for max torque, and mid range performance, and a even larger cam, for max HP and top-end performance.
I don't know all the particulars on this system, but let's say it can decrease and increase the duration of the base profile by 5% in each direction, and can move the lobe centerlines by 4 degrees total.
If the base profile has a seat duration of 280 degrees on the intake and 284 on the exhaust, you could setup the system so the cam was a 266/270 seat duration with a 106 ICL and a 112 ECL at idle, and increase to a 280/284 with a 108 ICL and 114 ECL by 4,000rpm, then increase to a 294/298 with a 110 ICL and 116 ECL by 6,800rpm.
The shortest duration would hit peak torque about 1,000rpm before the largest duration would. This would result in a very flat torque curve.
The engine would be much more efficient, over a broader rpm band.
You would have the top-end performance of a cam that would normally require a 4,500 stall, and it would pull off-idle, like a small RV cam.

Well, now you know what we want!

[LoganD]

BMW's valvetronic is more effective. You can use it over a wider range and it allows you to throttle with the intake valve, reducing pumping loss.

Way too complex, and doesn't really change seat duration, just lift and area. It effectively just changes rocker ratio.
The problem with increasing rocker ratio as the RPM increases, the valvetrain gets less stable as the rpm increases.
This new Hyundai system slows down the valve motion, making the valvetrain more stable(or no-less stable), as RPM's increase.
The Hyundai system doesn't change lift, so you're always running the same distance from coil bind, and that's a good thing. since the system speeds up the lift curve, at lower rpms'. and slows it down as the rpm's increase, you can keep the effective lift rate the spring sees the same, throughout the rpm range.

The BMW system still needs an additional system, to advance and retard the cams.
The Hyundai system can change duration, and advance or retard the cam, all with one mechanical system.

The current versions of valvetronic can completely vary all aspects of valve events including duration. I think you're referencing older systems.

I'd also consider Honda's current "iVTEC" or whatever they call it on their latest motors superior to the Hyundai system. The main benefit of the Hyundai system is that it's easier to add/remove from an engine design than either of those systems, you don't have to design an engine completely around it.

~Sincerely, someone who has physically tested all three.

EDIT: VVT is more important/useful for performance than any of the variable duration and lift systems, that's what the aftermarket should be trying to add to older engines.

[CamKing]

EDIT: VVT is more important/useful for performance than any of the variable duration and lift systems, that's what the aftermarket should be trying to add to older engines.

Not even close.
Being able to reduce the duration, to control port velocity past the valve, is much more important then moving centerlines.
VVT won't allow you to close the intake valve earlier, without having to open the intake valve earlier, and that can cause problems

~Sincerely, someone who has spent 37 years designing cams for almost every form of racing, performance and production application, and does prototype development for one of the largest OEM's in the world.

[LoganD]

EDIT: VVT is more important/useful for performance than any of the variable duration and lift systems, that's what the aftermarket should be trying to add to older engines.

Not even close.
Being able to reduce the duration, to control port velocity past the valve, is much more important then moving centerlines.
VVT won't allow you to close the intake valve earlier, without having to open the intake valve earlier, and that can cause problems

~Sincerely, someone who has spent 37 years designing cams for almost every form of racing, performance and production application, and does prototype development for one of the largest OEM's in the world.

For performance. Performance operation is in a narrow range, you aren't worried about idle or 2000 rpm operation when you're trying to make more power. The better response time of modern cam phasers than any of the lift/duration systems makes it far, far more useful and effective at high engine speeds and in situations where revs will be rising and falling very rapidly.

How many combustion systems have you designed that use any type of cam timing/lift/duration control? How many cylinder heads or valvetrains have you designed, from scratch, with any of that? I don't doubt you can spec a good cam, but it's pretty clear you aren't familiar with the real world control limitations of these systems. If they could move to any position instantly that'd be one thing, but they all have cycle time and that HEAVILY limits what you can do with them.

If you're going for pure engine efficiency, lift is BY FAR the most important aspect to control because you want to rid yourself of the pumping loss from a throttle body. Throttling a gas engine with the intake valve is the holy grail of engine efficiency outside of lean burn. This is much, much more effective than varying duration from an efficiency standpoint and it's why valvetronic is better for fuel economy/emissions.

EDIT: If you do work for the US OEMs, you should give me a shout next time you're in the area. I would be very interested to understand why you think duration is superior for efficiency, and it' be fun to show you around.