Got Over 400kw Atw?

[bigmikespec]

No, it's not closed loop. But that's a weird question

Why? How would you know exactly how far the cam has moved if all you have to go by it oil pressure? Cold day, thicker oil... and so on. If you can't check where the cam is you are just assuming it has moved going by the oil pressure you want via signal to the solenoid.

[SS8_Gohan]

i was also under the impression the exhaust side was only really an emissions thing, not necessarily performance related - but if the rb25 VCT is up to say 5000rpm, you could then fiddle with the exhaust side from then onwards for a little more top end perhaps?

[Rolls]

BMW must have seen benefits to controlling both cams as they changed from single to dual vanos with the s54.

It is for emissions, that is mainly why they vary the exhaust.

i was also under the impression the exhaust side was only really an emissions thing, not necessarily performance related - but if the rb25 VCT is up to say 5000rpm, you could then fiddle with the exhaust side from then onwards for a little more top end perhaps?

You can change the VCT set points to whatever you want

Edited July 8, 2011 by Rolls

[HYPED6]

Why? How would you know exactly how far the cam has moved if all you have to go by it oil pressure? Cold day, thicker oil... and so on. If you can't check where the cam is you are just assuming it has moved going by the oil pressure you want via signal to the solenoid.

Umm, There is a stop point where the cam stops. Regardless of oil temp/flow/pressure.

Its not closed loop as there is no feedback needed.

Its on....... or off........ The computer all ready knows this.

If it was a full variable system where the cam was infinitely adjustable (by the degree) then yes most defiantly a closed loop system would be needed.

So the system is open loop.

[Walk510]

Umm, There is a stop point where the cam stops. Regardless of oil temp/flow/pressure.

Its not closed loop as there is no feedback needed.

Its on....... or off........ The computer all ready knows this.

If it was a full variable system where the cam was infinitely adjustable (by the degree) then yes most defiantly a closed loop system would be needed.

So the system is open loop.

big mike has vipec therefor it makes it a VCAM not just the normal nissan switched !

[Rolls]

big mike has vipec therefor it makes it a VCAM not just the normal nissan switched !

No it doesn't, it can still only be switched on or off.... unless you tried pulsing it on and off to get some degree inbetween, but I wouldn't like the chances of that working properly.

Edited July 8, 2011 by Rolls

[The Dan]

BMW must have seen benefits to controlling both cams as they changed from single to dual vanos with the s54.

The benefits are as stated above. The principle is to increase and decrease the overlap of the camshafts by changing the valve timing on one side. By doing both sides, you are still increasing or decreasing overlap, just in a different way. I'm not going to spend thousands making a system to do both sides as the benefit would be nil or minimal.

[Walk510]

No it doesn't, it can still only be switched on or off.... unless you tried pulsing it on and off to get some degree inbetween, but I wouldn't like the chances of that working properly.

LMAO

[N1GTR]

What size engines has this been tried on so far?

^^^ Elite ?

[The Dan]

^^^ Elite ?

oh sorry, standard bore RB26

[N1GTR]

Ok thanks!

[bigmikespec]

Umm, There is a stop point where the cam stops. Regardless of oil temp/flow/pressure.

Its not closed loop as there is no feedback needed.

Its on....... or off........ The computer all ready knows this.

If it was a full variable system where the cam was infinitely adjustable (by the degree) then yes most defiantly a closed loop system would be needed.

So the system is open loop.

Ok, misunderstood... on or off. That makes it a lot easier to control; they did not try very hard when Nissan developed it

I thought it was a fully variable, in that case the Vipec could control with PWM signal. At least Walks510 thinks its funny.

[Walk510]

Ok, misunderstood... on or off. That makes it a lot easier to control; they did not try very hard when Nissan developed it

I thought it was a fully variable, in that case the Vipec could control with PWM signal. At least Walks510 thinks its funny.

i believe the new series of nissan v8's run closed loop vvt the vk56vd engine

[TiTAN]

they arent early 90's RB technology.

[Walk510]

they arent early 90's RB technology.

and you probably couldn't run them with a vipec either.

[Rolls]

and you probably couldn't run them with a vipec either.

If the vipec has PWM control that can be mapped to a rev table l I don't see why you couldn't. Eg revs vs PWM output, just be a simple 1 dimensional table.

Edited July 8, 2011 by Rolls

[Walk510]

If the vipec has PWM control that can be mapped to a rev table l I don't see why you couldn't. Eg revs vs PWM output, just be a simple 1 dimensional table.

may run out of digital inputs ?

[HYPED6]

Really? you don't have a 32x32 table that you can PWM over any axis then 4 2D tables under that 32x32 table for variable adjustments of any input into the computer?

Bugger,

[Rolls]

may run out of digital inputs ?

You don't need any physical inputs, you just need the PWM output and use RPM as your input.

[The Dan]

You don't need any physical inputs, you just need the PWM output and use RPM as your input.

For it to be closed loop it will need a signal input from the camshaft position sensor that you will need to install. You can't just use RPM as an input for closed loop as it's unrelated to what you are adjusting