MIVEC tuning
It's not physically changing the lift of the cam, it just makes the max lift happen sooner or later, depending on your mivec map. Does that makes sense?
Let's say the intake cam has a max lift of 10.6 (i'm pulling this out of my ***). This is with the lobe fully upright. What Mivec is doing is changing when that max lift is happening, either sooner or later, depending on what is in the mivec table.
Let's say the intake cam has a max lift of 10.6 (i'm pulling this out of my ***). This is with the lobe fully upright. What Mivec is doing is changing when that max lift is happening, either sooner or later, depending on what is in the mivec table.
Last edited by Mr. Evo IX; Jun 7, 2008 at 05:15 PM.
Sorry for my long explanation. I'm not a very good teacher. So now we get at what I wanted to get at. (which I tip-toed around in my last post
EVO MIVEC does NOT change lift or duration. It only changes cam timing. As long as everyone understands this fact.
EVO MIVEC does NOT change lift or duration. It only changes cam timing. As long as everyone understands this fact.
so. Could I shut off Mivec? lol. like by inputting -1.2* everywhere? I would like to see how the car performs. Would it be like an VIII?
I want to try and shut it off by about 5000rpms and see how that works. Thats where I am having a hard time dialing it in for my setup.
Anything less than the max before 5000rpms, then my load starts to drop. I have seen it drop, then build again with 28.2*, then drop again w/ 24.0*
And Bryan, I never have confused Mivec timing w/ ignition timing..
I want to try and shut it off by about 5000rpms and see how that works. Thats where I am having a hard time dialing it in for my setup.
Anything less than the max before 5000rpms, then my load starts to drop. I have seen it drop, then build again with 28.2*, then drop again w/ 24.0*
And Bryan, I never have confused Mivec timing w/ ignition timing..
You could shut off MIVEC but cams straight up is not -1.2 like Scott mentioned. It would not be like an VIII because the IX cam profiles are application specific as are the VIII profiles. The VIII has a conventional cam design that has to make the best of a single cam profile. The IX has VVT and the lobes are designed to take advantage of this.
Last edited by Mr. Evo IX; Jun 7, 2008 at 11:44 AM.
Correct, Its impossible for Mivec to change lift, however, I believe the duration is sometimes shorter/longer. Right? Thats the point of Mivec, to keep the valve open longer/shorter, hence the name Variable Valve Timing.
The Duration is a variable with Mivec.
Mojo Rising is right from mechanical point of view. The cam lift and duration are unchanged. My post is also correct but I didnt really know exactly how it worked until after I posted it because I wasnt sure what was creating the additional lift / duration.
It's already there, the lift and duration that is, it just tones it down for idle and economy and to reduce turbo back pressure caused by the more aggressive profile. The way it tones it down is through pressure differentials that can be changed with cam timing that affect airflow. I had to think a little. Thanks for questioning my post.
Conventional cams are always a trade-off, if you go with higher lift longer duration profile you have low speed drivability issues. Mivec allows the cam timing to be toned down for idle and economy mode, high lift long duration with overlap for spoolup and maximum torque and then they can retard to reduce the overlap caused by the higher lift long duration profile.
It's already there, the lift and duration that is, it just tones it down for idle and economy and to reduce turbo back pressure caused by the more aggressive profile. The way it tones it down is through pressure differentials that can be changed with cam timing that affect airflow. I had to think a little. Thanks for questioning my post.
Conventional cams are always a trade-off, if you go with higher lift longer duration profile you have low speed drivability issues. Mivec allows the cam timing to be toned down for idle and economy mode, high lift long duration with overlap for spoolup and maximum torque and then they can retard to reduce the overlap caused by the higher lift long duration profile.
Last edited by Mr. Evo IX; Jun 7, 2008 at 11:33 AM.
The factory service manual shows the Intake cams with IVO value of 0-30* and IVC of 80-50*, that is obviously where the 30* total motion is. The bounding limits that MRfred discovered and showed how to alter are set at 0 and 28.8 (min and max). Obviously if the 28.8 even with the bound set higher still wont go above 28.8. You can log the value at -1.2 however once the bounding limit has been altered.
I think its post 99 or something where I put the values in for both the IX and the VIII. It also important to point out that the MIVEC table is crank degrees not cam degrees in case any missed that.
I think its post 99 or something where I put the values in for both the IX and the VIII. It also important to point out that the MIVEC table is crank degrees not cam degrees in case any missed that.
Thanks for all the MIVEC MAP work!
I just wanted to thank all the people that have contributed to this long thread (took me 2 nights to get completely thru it and assimilate everthing). I created a hybrid map for my stock EVO IX by starting with NJ1266's "hybrid" map. I rescaled NJs map to the same scale Shameless Tuning used on his "best" Mivec map (took out 750 and 1,250 rpm and added 4,250 and 7,500 rpm) and then loaded Shameless' values for the 6,500, 7,000 and 7,500 rpm rows into my re-scaled map (I've got good 93 octane gas here in IL, unlike the 91 Cali NJ has).
I flashed the new Mivec table in Saturday nite (along with bumping all the idle timing tables/cells from 5* to 7*, thanks NJ for that tip!) and I can't believe how much better my car runs. ECUFlash rocks!
Mitch
I flashed the new Mivec table in Saturday nite (along with bumping all the idle timing tables/cells from 5* to 7*, thanks NJ for that tip!) and I can't believe how much better my car runs. ECUFlash rocks!
Mitch
Using Evogreen Turbo and HKS 272 mivec cams
Recently I reduced mivec from 28.8* to 24* from load 200 onwards from 3000 rpm. I found the car to run the same boost, same timing but the car ran 0.5 lambda leaner?
Can someone explain what is going on here?
I guess retarding mivec here is making more power/torque?
Would I benefit using 24* from a lower load, for example, from 160 load as opposed to 28.8*?
A bit confused...
Can someone explain what is going on here?
I guess retarding mivec here is making more power/torque?
Would I benefit using 24* from a lower load, for example, from 160 load as opposed to 28.8*?
A bit confused...