MIVEC tuning
Feb 14, 2008 | 12:48 PM
#421
True, thanks for the reminder. I am not gonna go stupid, but I was thinking that it might be worth the experiment since I had it all apart anyway. Then again I am going to S2's, so I will have more lift than I have now with the S1's.
The cam is spending most of its time pulling away from the valves though, its just that little bit while its BTDC that might get me.
The cam is spending most of its time pulling away from the valves though, its just that little bit while its BTDC that might get me.
Feb 15, 2008 | 12:42 AM
#422
Brian, I want to try that map right above your last post (the JB/Radical map) to see if its any difference over my current one. Which cells would you reccomend changing to get the best idle (mine is lumpy right now and almost sounds like it misses) Be much appreciated.
Also JB, I had a question on your Mivec map. Can you explain if its worth it to add the extra 500rpm on the Mivec tables atleast to my setup. Basically take away 750rpm and make it 7500rpm? Atleast in my case since I kept the stock 7600rpm rev limiter because I dont drag race alot, I usually shift at about 7200-7400.
Also JB, I had a question on your Mivec map. Can you explain if its worth it to add the extra 500rpm on the Mivec tables atleast to my setup. Basically take away 750rpm and make it 7500rpm? Atleast in my case since I kept the stock 7600rpm rev limiter because I dont drag race alot, I usually shift at about 7200-7400.
I have seen no gains on the dyno from advancing the Mivec past 6000 rpm. On some Evo's it drops peak hp. I've tried advancing on almost every single Evo 9 that has come through our shop just for shiats and giggles and I come to the same conclusion every time.
Depends on the mods, etc.
On some cosworth equipped Evo 9's I have seen peak HP peak earlier and hold longer up top with advanced Mivec, but not actual peak HP gains.
Depends on the mods, etc.
On some cosworth equipped Evo 9's I have seen peak HP peak earlier and hold longer up top with advanced Mivec, but not actual peak HP gains.
Last edited by dbsears; Feb 15, 2008 at 01:10 AM.
Feb 15, 2008 | 07:47 AM
#423
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Hey JB,
Here is that post with the diagram:
https://www.evolutionm.net/forums/sh...18#post4997318
Its taken from the first few pages of the Evo IX FSM where the MIVEC system is described.
Here is that post with the diagram:
https://www.evolutionm.net/forums/sh...18#post4997318
Its taken from the first few pages of the Evo IX FSM where the MIVEC system is described.
Feb 15, 2008 | 08:54 AM
#425
Derek, the map will extrapolate up to 500 rpm past the last the rpm point so if the last one was 7000 then you are good to 7500. If you are leaving the value at 0 anyway then it doesnt matter. The tune you have should be scaled out to 8k though.
MR- thanks buddy. I figured I would know what to look for when I got it apart but this way I can at least be prepared
MR- thanks buddy. I figured I would know what to look for when I got it apart but this way I can at least be prepared
Jun 4, 2008 | 01:55 PM
#429
Guys, I've compiled what I've been able to learn about mivec and some mivec tuning information that I've learned from experience and others. I may have some things wrong, feel free to correct me if that is the case.
MIVEC essentially enables the engine to have 2 distinct cam profiles and possibly additional profiles between the two.
So what we know about cams is that low lift cams increase low rpm torque (think idle and just off idle) and improve mileage, This is where the retarded economy/idle profile (0's in the map) works best, and probably provides better gas mileage in the cruise areas of the map. I think Jeff is right about too much advance in this area causing the low load hiccup right around 2500rpm.
Now the high performance profile of the stock mivec cam has overlap. That's why if your running on this profile at low rpm you will have poor idle (lopey cam) and lack of torque off of idle, and poor fuel economy, but just after the engine gets moving (towards boost) the higher performance profile with overlap helps spool the turbo (30 in boost areas), as RPM's increase you want the duration but the overlap becomes a bit of a problem due to back pressure so reducing the advance (back to 0 or a low number) as RPM's increase reduces the negative affects of reversion at high rpm (turbo back pressure).
Does anyone have any overun area mivec tuning suggestions? Would increasing overlap on overrun area cause an antilag effect?
References
http://www.youtube.com/watch?v=mgDdbrMh6bo
Visual, Japanese of how MIVEC works.
http://media.mitsubishi-motors.com/p...etail1228.html
"Major features distinguishing the latest model include the adoption of Mitsubishi's proprietary MIVEC*1 variable valve timing technology in the intake system and improvements to the turbocharger that result in higher torque and produce better response for improved engine performance across its full rev range."
"For Evolution IX the 4G63 engine gains Mitsubishi's MIVEC variable valve timing technology that improves top-end output as well as fuel efficiency. MIVEC technology allows GSR to return 10.0 km/l in the Japanese 10-15 mode driving cycle, equivalent to a three percent improvement in mileage. "
http://auto.howstuffworks.com/camshaft.htm
and
http://auto.howstuffworks.com/camshaft2.htm
MIVEC essentially enables the engine to have 2 distinct cam profiles and possibly additional profiles between the two.
So what we know about cams is that low lift cams increase low rpm torque (think idle and just off idle) and improve mileage, This is where the retarded economy/idle profile (0's in the map) works best, and probably provides better gas mileage in the cruise areas of the map. I think Jeff is right about too much advance in this area causing the low load hiccup right around 2500rpm.
Now the high performance profile of the stock mivec cam has overlap. That's why if your running on this profile at low rpm you will have poor idle (lopey cam) and lack of torque off of idle, and poor fuel economy, but just after the engine gets moving (towards boost) the higher performance profile with overlap helps spool the turbo (30 in boost areas), as RPM's increase you want the duration but the overlap becomes a bit of a problem due to back pressure so reducing the advance (back to 0 or a low number) as RPM's increase reduces the negative affects of reversion at high rpm (turbo back pressure).
Does anyone have any overun area mivec tuning suggestions? Would increasing overlap on overrun area cause an antilag effect?
References
http://www.youtube.com/watch?v=mgDdbrMh6bo
Visual, Japanese of how MIVEC works.
http://media.mitsubishi-motors.com/p...etail1228.html
"Major features distinguishing the latest model include the adoption of Mitsubishi's proprietary MIVEC*1 variable valve timing technology in the intake system and improvements to the turbocharger that result in higher torque and produce better response for improved engine performance across its full rev range."
"For Evolution IX the 4G63 engine gains Mitsubishi's MIVEC variable valve timing technology that improves top-end output as well as fuel efficiency. MIVEC technology allows GSR to return 10.0 km/l in the Japanese 10-15 mode driving cycle, equivalent to a three percent improvement in mileage. "
http://auto.howstuffworks.com/camshaft.htm
and
http://auto.howstuffworks.com/camshaft2.htm
Last edited by Mr. Evo IX; Jun 6, 2008 at 08:49 PM. Reason: added references
Jun 4, 2008 | 09:29 PM
#431
What I have discovered, is that with more Mivec advance, you hold more boost till redline, AFR's will be stabilized, and knock will be decreased. I have a Cosworth cammed evo w/ supporting mods. Pushing 24.6 peak psi, and redline at 21psi. w/ a EBC.
Jun 5, 2008 | 06:04 AM
#433
Guys, I've compiled what I've been able to learn about mivec and some mivec tuning information that I've learned from experience and others. I may have some things wrong, feel free to correct me if that is the case.
MIVEC essentially enables the engine to have 2 distinct cam profiles and possibly additional profiles between the two.
So what we know about cams is that low lift cams increase low rpm torque (think idle and just off idle) and improve mileage, This is where the low lift economy/idle profile (0's in the map) works best, and probably provided better gas mileage in the cruise areas of the map (14s in the stock map). I think Jeff is right about too much advance in this area causing the low load hiccup right around 2500rpm.
Now the high performance profile of the stock mivec cam has overlap. That's why if your running on this profile at low rpm you will have poor idle (lopey cam) and lack of torque off of idle, and poor fuel economy, but just after the engine gets moving (towards boost) the higher performance profile with overlap helps spool the turbo (30 in boost areas), as RPM's increase you want the high lift long duration but the overlap becomes a bit of a problem so reducing the advance (back to 0 or a low number) as RPM's increase reduces the negative affects of overscavaging at high rpm (pushing boost out the exhaust valve).
Does anyone have any overun area mivec tuning suggestions? Would increasing overlap on overrun area cause an antilag effect?
References
http://www.youtube.com/watch?v=mgDdbrMh6bo
Visual, Japanese of how MIVEC works.
http://media.mitsubishi-motors.com/p...etail1228.html
"Major features distinguishing the latest model include the adoption of Mitsubishi's proprietary MIVEC*1 variable valve timing technology in the intake system and improvements to the turbocharger that result in higher torque and produce better response for improved engine performance across its full rev range."
"For Evolution IX the 4G63 engine gains Mitsubishi's MIVEC variable valve timing technology that improves top-end output as well as fuel efficiency. MIVEC technology allows GSR to return 10.0 km/l in the Japanese 10-15 mode driving cycle, equivalent to a three percent improvement in mileage. "
http://auto.howstuffworks.com/camshaft.htm
and
http://auto.howstuffworks.com/camshaft2.htm
MIVEC essentially enables the engine to have 2 distinct cam profiles and possibly additional profiles between the two.
So what we know about cams is that low lift cams increase low rpm torque (think idle and just off idle) and improve mileage, This is where the low lift economy/idle profile (0's in the map) works best, and probably provided better gas mileage in the cruise areas of the map (14s in the stock map). I think Jeff is right about too much advance in this area causing the low load hiccup right around 2500rpm.
Now the high performance profile of the stock mivec cam has overlap. That's why if your running on this profile at low rpm you will have poor idle (lopey cam) and lack of torque off of idle, and poor fuel economy, but just after the engine gets moving (towards boost) the higher performance profile with overlap helps spool the turbo (30 in boost areas), as RPM's increase you want the high lift long duration but the overlap becomes a bit of a problem so reducing the advance (back to 0 or a low number) as RPM's increase reduces the negative affects of overscavaging at high rpm (pushing boost out the exhaust valve).
Does anyone have any overun area mivec tuning suggestions? Would increasing overlap on overrun area cause an antilag effect?
References
http://www.youtube.com/watch?v=mgDdbrMh6bo
Visual, Japanese of how MIVEC works.
http://media.mitsubishi-motors.com/p...etail1228.html
"Major features distinguishing the latest model include the adoption of Mitsubishi's proprietary MIVEC*1 variable valve timing technology in the intake system and improvements to the turbocharger that result in higher torque and produce better response for improved engine performance across its full rev range."
"For Evolution IX the 4G63 engine gains Mitsubishi's MIVEC variable valve timing technology that improves top-end output as well as fuel efficiency. MIVEC technology allows GSR to return 10.0 km/l in the Japanese 10-15 mode driving cycle, equivalent to a three percent improvement in mileage. "
http://auto.howstuffworks.com/camshaft.htm
and
http://auto.howstuffworks.com/camshaft2.htm
EVO MIVEC does not "kick in". it as a gradual proccess throughout the RPM range depending on load/RPM and who-knows-what. If there were just two different cam profiles, there would just be a 0 for off and a 1 for on in the tables.
Last edited by Mojo Rising; Jun 5, 2008 at 06:06 AM.
Jun 5, 2008 | 04:15 PM
#434
Mojo Rising, Actually I'm not familiar with the engine in the demonstation video, some references are just generic cam information. A lot of people dont understand how MIVEC works or why it works the way it does or what you should do with it. This information is very relevant. Especially with rising fuel costs in the US. There is a reason why Mitsu calls all of their MIVEC implementations the same thing .
Notice my post doesnt say 2 different sized lobes.. its says "two distinct cam profiles and possibly additional profiles between the two". That is to say when the MIVEC map is on 0 the cams are in their lowend torque/economy profile and when the intake cam is advanced to 24 or 30 on the map the cams are in their performance profile high lift, long duration, some overlap. Inspite of the implementation being completely different it's actually alot like VTEC or any other variable valve timing system it just achives the different profiles a different way. They still serve the same purpose and knowing what the purpose is will help people to optimize the cam timing for performance or economy or both!
One of the questions that I have concerning the Mivec map is why is it stepped using specific values 0,4,8,14,24. Do you think these are specific profiles that Mitsubishi engineered into the camshafts? Also why is the Mivec map not smoothed (may support previous question/theory)?
. Notice my post doesnt say 2 different sized lobes.. its says "two distinct cam profiles and possibly additional profiles between the two". That is to say when the MIVEC map is on 0 the cams are in their lowend torque/economy profile and when the intake cam is advanced to 24 or 30 on the map the cams are in their performance profile high lift, long duration, some overlap. Inspite of the implementation being completely different it's actually alot like VTEC or any other variable valve timing system it just achives the different profiles a different way. They still serve the same purpose and knowing what the purpose is will help people to optimize the cam timing for performance or economy or both!
One of the questions that I have concerning the Mivec map is why is it stepped using specific values 0,4,8,14,24. Do you think these are specific profiles that Mitsubishi engineered into the camshafts? Also why is the Mivec map not smoothed (may support previous question/theory)?
Last edited by Mr. Evo IX; Jun 7, 2008 at 11:47 AM.
Jun 5, 2008 | 05:21 PM
#435
Performance cams generally have more lift / duration and move the power band upwards. Most cams designed for turbo applications actually reduce or eliminate overlap as turbo back pressure at high rpms cause reversion (exhaust gases pushing back into the cylinders due to exhaust back pressure) - This is the reason why it works best to retard MIVEC as rpms increase.
Last edited by Mr. Evo IX; Jun 5, 2008 at 05:25 PM.