Danlp6 said:so how does the vvt work on these? is it like an automatic vernier pulley? lookin at those pics, its not like the vtec sysem where it has a hi-lift lobes on the cam.
Riker said:Thanks Ben, I knew you got the answer, you always had one...thumbs up!
That's your grunt or?
BenR said:Your on the right tracks.
The cam is a normal cam, with a single lobe per valve. In OE trim the timing of each valve per cylinder is a few degrees different to aid swirl and efficiency, but i junk that offset on my cams.
The VVT pulley has vanes on the inside, once you reach a certain rpm/load trigger point (1450rpm @+800mb) then a VVT plunger is activated, which opens an oil galley into the centre of the camshaft, which then supplies oil pressure to the pulley. The oil pressure is directed to one side of the vanes which changes the relative position of the pulley to the cam, advancing the cam 16 degrees. Its not too fancy and basically is an on/off setup. But the same pulley is basically used on the constantly variable system on newer renualts, but the plunger recives a pulsed signal which will affect the amount of pressure on either side of the vanes so you can advance/r****d the cams by however much the ecu decides is correct.
Danlp6 said:you say is a 1450rpm, whats the kick at 5000? i rememer someone sayin that was the vvt?
Also, how much are your cams?
Cheers!
BenR said:Difference between the std cam and the one your running, duration wise, is very little......its not a wild cam. The gains are made by very very rapid valve acceleration rates, but with a lift curve that minimises valve float and bounce. SO basically your getting the valve off the seat faster, running peak lift for longer, reducing the 4th and 5th order harmonics so that natural frequencies dont set themselves up in the springs, which leads to poor valve control and float/bounce.
Essentially your making alot more torque across a much wider band because the dynamic compression ratio is higher than stock across all those areas, its all about holding great volumetric efficiency for as long a period as you can.
BenR said:ah ok, it was a customers engine.
glad i can help.