2011 MDX VTEC ENGAGEMENT

Modded11MDX
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Modded11MDX »

Linszter, Thanks for making it a little bit clearer as to how and when Vtec kicks in. Now I understand the rpm part but as you said the Mbar also plays a role. What number can I set Mbar at to guarantee Vtec will kick in using only the rpm requirements? I am not sure if the number has to be super high or super low.
Linszter
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Linszter »

Modded11MDX wrote:Linszter, Thanks for making it a little bit clearer as to how and when Vtec kicks in. Now I understand the rpm part but as you said the Mbar also plays a role. What number can I set Mbar at to guarantee Vtec will kick in using only the rpm requirements? I am not sure if the number has to be super high or super low.
In normal case the vtec kicks in at higher rpm on low load, and lower rpm on high load. If you set the mbar higher than what you can reach it will always open at the lower rpm settings.
Settings is depends on your engine but here is an example:
You can set the lower engage rpm to 3000 like you want (disengage always below that so thats 2800 for example), higher rpm to 5500 (disengage like 5300).
In the Vtec window you need to set rpm from 3000 to like 7000. If you set mbar to 850 at 3-4-5000 rpm, that means Vtec only kicks in at that rpm range at almost full throttle or higher acceleration (using the lower engagement). If you don't reach 850mbar (low load, cruising ...etc) the Vtec will only switch at 5500rpm. I hope this makes it's clear.
Modded11MDX
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Modded11MDX »

Thanks Linszter for your help and explanation :D

Right now I am using the 1 and only performance tune available for the MDX which is Tune 1. Mbar I haven't modified at all and it is set to 4311 under all rpms from 1000 to 5000.
I changed the Vtec settings to Lower engage 3200, lower disengage 3000, Upper engage 3200, upper disengage 3000, Engage speed 6, Disengage speed 1.

As of right now, does this mean Vtec will kick in at 3200 rpms from 1 gear all the way to 6th or because the Mbar graph only goes to 5000 rpm, will Vtec turn off at 5000 rpm? What would be a mbar number that would guarantee Vtec would kick in under any load at 3200 rpms? Thanks!
Linszter
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Linszter »

Modded11MDX wrote:Thanks Linszter for your help and explanation :D

Right now I am using the 1 and only performance tune available for the MDX which is Tune 1. Mbar I haven't modified at all and it is set to 4311 under all rpms from 1000 to 5000.
I changed the Vtec settings to Lower engage 3200, lower disengage 3000, Upper engage 3200, upper disengage 3000, Engage speed 6, Disengage speed 1.

As of right now, does this mean Vtec will kick in at 3200 rpms from 1 gear all the way to 6th or because the Mbar graph only goes to 5000 rpm, will Vtec turn off at 5000 rpm? What would be a mbar number that would guarantee Vtec would kick in under any load at 3200 rpms? Thanks!
Vtec will always kicks in at 3200 at any load and turns off when goes under 3000.
Modded11MDX
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Modded11MDX »

Linszter wrote: Vtec will always kicks in at 3200 at any load and turns off when goes under 3000.
Thanks for your all your help Linszter!! I'm gonna mess around with when the Vtec kicks in and it sounds pretty good when it does through my Borla mufflers. Now I just have to figure out why I keep getting the P0171 and P0174 codes that shuts off my SH-AWD. Funny thing is, it only happens after the car has been driven for a few miles then parked for less than 2 hours and restarted. The check emissions comes on within a minute of starting after being parked then the SH-AWD light goes on right after. All Air fuel and O2 sensors are brand new Bosch, air fuel is wide band, new plugs, valves adjusted, new egr, pcv, 4" intake with new MAF, did smoke test and no leaks. Was happening before I changed all the parts so nothing has changed. Gonna have to test fuel pressure next then injector flow rates.
KTuner
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Re: 2011 MDX VTEC ENGAGEMENT

Post by KTuner »

Likely the 4" intake if it changes the MAF housing size and you haven't recalibrated the MAF curve for it.
Modded11MDX
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Modded11MDX »

KTuner wrote:Likely the 4" intake if it changes the MAF housing size and you haven't recalibrated the MAF curve for it.
I think you are correct that the larger than stock intake is causing problems, prior to this I tried a generic ebay 3" pipe but that gave me running rich codes and I couldn't find a 3.5" pipe with the correct MAF fitting so I went with 4" using a 4" to 3.5" reducer to fit the stock rubber flex tube that goes to the throttle body. I wish I knew how to adjust MAF settings but as you already know, I don't have the skill or understanding of how do that. It's frustrating that I can fabricate, rebuild an engine, differential, do brake jobs and alignment but cannot comprehend how to adjust the sensor settings. I'm not afraid to experiment with new flash settings with some guidance but I cannot afford the MDX to be out of commission because it is not legal in Hawaii to put my 5 year old daughter's car seat in my Porsche Cayman.
KTuner
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Re: 2011 MDX VTEC ENGAGEMENT

Post by KTuner »

There's plenty of information out there about adjust MAF settings, which could be useful here. Or you can work with a tuner via e-tune to correct it. I'd suggest Derek at Innovative Motorworks.
Modded11MDX
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Re: 2011 MDX VTEC ENGAGEMENT

Post by Modded11MDX »

Ok thanks, I will search on how to adjust the MAF settings and will contact Innovative Motorworks if I cannot figure something out.
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