MIVEC's three profiles
Jun 1, 2005, 11:48 AM
#16
Evolved Member
iTrader: (2)
Join Date: Apr 2004
Location: Sherbrooke, Qc
Posts: 2,297
Likes: 0
Received 0 Likes
on
0 Posts
-
Actually, the diagram seems to represent one typical lift cycle and shows the low and mid lift curves overlapping. That would mean that only one cam profile is used under 3,500 RPM: one valve is practically closed and the other is half open. So in essence, I think the confusion (mine at least) stems from the fact that MIVEC has three different valve lift settings, but it actually uses them in only two seperate modes of operation.
So my conclusion is this: MIVEC only has two working states (or modes), high or low intake valve lift, depending on wheter the engine revs over or under 3,500 RPM. So nothing changes somewhere around 1500 or 2000 RPM or wherever... it's only a misconception amongst some people (and even journalists if I recall correctly) who were (myself included) mistaking "lift settings" for "operating mode".
I think I get the whole picture now... thanks again to everybody who contributed to my growing knowledge of mecanics, especially PR_Mivec!
-
Actually, the diagram seems to represent one typical lift cycle and shows the low and mid lift curves overlapping. That would mean that only one cam profile is used under 3,500 RPM: one valve is practically closed and the other is half open. So in essence, I think the confusion (mine at least) stems from the fact that MIVEC has three different valve lift settings, but it actually uses them in only two seperate modes of operation.
So my conclusion is this: MIVEC only has two working states (or modes), high or low intake valve lift, depending on wheter the engine revs over or under 3,500 RPM. So nothing changes somewhere around 1500 or 2000 RPM or wherever... it's only a misconception amongst some people (and even journalists if I recall correctly) who were (myself included) mistaking "lift settings" for "operating mode".
I think I get the whole picture now... thanks again to everybody who contributed to my growing knowledge of mecanics, especially PR_Mivec!
-
Jun 1, 2005, 03:46 PM
#17
Originally Posted by tuffguy
That makes a little more sense.
However, I noticed something when I disabled MIVEC. Even at idle or at low RPMs, that metallic raspiness disappeared. Assuming that I was not imagining things, would someone like to guess what's going on at that point?
PR_Mivec - You've probably seen this, but just in case you haven't:
http://www.technogeeky.com/ralliart/Stuff/mivec_01.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_02.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_03.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_04.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_05.gif
However, I noticed something when I disabled MIVEC. Even at idle or at low RPMs, that metallic raspiness disappeared. Assuming that I was not imagining things, would someone like to guess what's going on at that point?
PR_Mivec - You've probably seen this, but just in case you haven't:
http://www.technogeeky.com/ralliart/Stuff/mivec_01.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_02.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_03.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_04.gif
http://www.technogeeky.com/ralliart/Stuff/mivec_05.gif
thats the document i quoted
Jun 1, 2005, 05:44 PM
#18
Evolved Member
Join Date: Aug 2004
Location: A
Posts: 929
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by WoRkZ
-
Actually, the diagram seems to represent one typical lift cycle and shows the low and mid lift curves overlapping. That would mean that only one cam profile is used under 3,500 RPM: one valve is practically closed and the other is half open. So in essence, I think the confusion (mine at least) stems from the fact that MIVEC has three different valve lift settings, but it actually uses them in only two seperate modes of operation.
So my conclusion is this: MIVEC only has two working states (or modes), high or low intake valve lift, depending on wheter the engine revs over or under 3,500 RPM. So nothing changes somewhere around 1500 or 2000 RPM or wherever... it's only a misconception amongst some people (and even journalists if I recall correctly) who were (myself included) mistaking "lift settings" for "operating mode".
I think I get the whole picture now... thanks again to everybody who contributed to my growing knowledge of mecanics, especially PR_Mivec!
-
Actually, the diagram seems to represent one typical lift cycle and shows the low and mid lift curves overlapping. That would mean that only one cam profile is used under 3,500 RPM: one valve is practically closed and the other is half open. So in essence, I think the confusion (mine at least) stems from the fact that MIVEC has three different valve lift settings, but it actually uses them in only two seperate modes of operation.
So my conclusion is this: MIVEC only has two working states (or modes), high or low intake valve lift, depending on wheter the engine revs over or under 3,500 RPM. So nothing changes somewhere around 1500 or 2000 RPM or wherever... it's only a misconception amongst some people (and even journalists if I recall correctly) who were (myself included) mistaking "lift settings" for "operating mode".
I think I get the whole picture now... thanks again to everybody who contributed to my growing knowledge of mecanics, especially PR_Mivec!
-
3 different lifts, but 2 of them are used AT THE SAME TIME (<<<<key point)
Jun 3, 2005, 05:01 PM
#22
Newbie
Join Date: Apr 2005
Location: Houston
Posts: 28
Likes: 0
Received 0 Likes
on
0 Posts
Fayettenam is probably the same place it was back when you were there. I was 82d INF. I'm in Houston now. Thanks for your comments on my Toyota. It's fun to drive around and so is the Ralliart. My g/f wants a new Eclipse, but I dunno about that.
Jun 3, 2005, 05:40 PM
#23
Evolved Member
Join Date: Jan 2005
Location: Nanty Glo, Pa
Posts: 744
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by TrialMR-S
Fayettenam is probably the same place it was back when you were there. I was 82d INF. I'm in Houston now. Thanks for your comments on my Toyota. It's fun to drive around and so is the Ralliart. My g/f wants a new Eclipse, but I dunno about that.
Tell her if she pays for it.
Thread
Thread Starter
Forum
Replies
Last Post
Gruppe-S
Evo 'For Sale' External Engine / Power
5
Sep 28, 2005 04:36 PM
Vivid Racing
Evo Vendor 'Group Buy / Specials' Classifieds
4
Oct 21, 2003 01:11 PM
24, 4g64, 4g69, beneficial, cam, catalyst, efficiency, gdi, hydraulic, kick, mivec, noise, profile, rpm, sohc, technogeekycom, volumetric
