How does the mivec cam get oil pressure? I can't figure in my head how it could be oil pressure controlled. The oil whould have to go through the center of the cam. Yet in the pics online of the cutaway evo9 in japan, the cam is still hollow. This suggests the cam gear is mechanical.

Anyone know for sure how this cam operates?

Hope everyone gave what they wanted for Xmass.

 

The Mivec is oil pressure switched, not directly operated by oil pressure which means that there is a pressure switch that, like an oil pressure gauge sender, senses oil pressure to tell the ECU to switch the relay that operates the Solenoid that operates the MIVEC and so on and so fourth.

There's something called an OCV or Oil control Valve that opens and closes given a certain amount of oil pressure. Open is zero voltage, closed is 12v. High oil pressure will derive higher performance for a given engine speed and load based on the interaction between the OCV's switch and the ECU which will tell the mivec to increase the lift and duration.


. (this is my understanding)


-Alex

 

Nevermind.

 

The Mitsubishi Innovative Valve timing and lift Electronic Control (MIVEC)
http://www.mitsubishi-motors.com/cor...e/e/mivec.html

On the EVO 9 the mivec is two part. First part is "the lift electronic control" dual rocker arm modes which is definately controlled via an oil pressure solenoid. The valve lift is low below 3500rpm and high lift above 3500rpm. The second part of the mivec is "the innovative valve timing" where lobe separation is small for good low end torque. At high rpm the lobe separation is increased for better top end torque. There is no reason the second part cant be mechanical. If it is I can use this gear on early 4g63 cars. I wish someone would answer this question for sure. The cam gear lists for 350. Dont want to order one just for kicks.

 

https://www.evolutionm.net/forums/sh...light=cut-away

There are pics in this thread of the cam gear. All someone has to do it remove the fours screws on that four clover leaf and see whats under the cover. can someone with an evo 9 help me out here?

 

interesting.. thanks for the engeneering lesson ..

 

Everything I have read on the Evo 9 indicates that it does not use the variable lift part of the system, only the variable cam timing. Of course, anyone who has taken the valve cover off would know for sure...

The link you posted was not in reference to the Evo 9 system.

 

Thats a good possibility too. The evo cutaway pic suggests this as you cant see a variable rocker system. If there is no variable rocker sytem then how are the evo9 cams different from the evo8? It would also mean the cam gear is oil fed as you can see the oil control solenoid on the head. But at the same time you can see the intake cam is still hollow. So how the heck do you get oil pressure to a spinning cam without going through the center of a the cam???

sure would like to get to the bottom of this.

 

i want to know why it took them soo long to make the system.. honda has it first then eveyone jump on board..

 

Mitsubishi has been using MIVEC for quite a while (The Mirage Cyborg, which we didn't get used it in the mid 90s), it isn't a new technology at all for Mitsubishi.

 

The MIVEC in the Evo 9 is NOT AT ALL like VTEC. It's more like Toyota's VVT-I system. So it does not change lift at all, just duration. Here is a VVT-i vs VTEC system comparison written by Bill Sherwood from Club4ag.com. I'd expect the MIVEC works similar to the VVT-i.

 

That's what I thought too, until I actually got off my butt and looked up MIVEC on Google. (Hence the edit.) I have no idea if the Evo's (4G63) system works anything like this. But this is how the MIVEC works on the 2.4L 4G69:

MIVEC: http://www.mitsubishi-motors.com/cor...e/e/mivec.html



-Adrian

 

i believe oil is fed into cam where it attaches to the cam gear. the cam is hollow but this part is separated from this oil passage in the cam that feeds the sprocket. i believe that solenoid works at different duty cycles to achieve different retard/advance through oil pressure similar to the honda k20a. i could be wrong though.

 

Yeah, the MIVEC on the Lancer Ralliart and JDM MIVEC systems of yesteryear were/are very similiar to the VTEC system. I think that's where a lot of the confusion comes from. doesn't seem to differentiate between the two like honda (VTEC/i-VTEC) and Toyota (VVT-i/VVTL-i)

 

That would be interesting to put a turbo on the 4g69 mivec Grandis