As far as I understand it, the stock ecu looks for a target AFR during part throttle. Would the advantage to tuning part throttle be that the EMS look for a target AFR more suitable to making power vs the stock ecu target AFR?

If I had a shop tune my setup with either VAFC (WOT only) or Greddy Emanage, would a wideband be good to have?

thanks

my2000

 

The stock ecu runs pretty lean from what I've seen so you aren't going to make much power by leaning it out. Your going to make your power with advanced ignition timing. The Greddy emanage is the better out of the two and would allow you to advance ignition timing. A wideband is a must when tuning a car so I would invest in one unless your tuner has one that they can use while tuning (which they should).

Edit- just read that you have a my2000. You will gain a good chunk of power in the higher RPMs. The stock WOT map runs rich so you can lean it out and make some power.

 

With the ems + wideband, you can set AFR map and feedback to whatever you want for each (load level and rpm) partial throttle and wot. it'll compensate for imperfections on your fuel map depending on how it is setup and pin it to the end result afrs programmed.

The stock ecu in closed loop pins partial throttle to like 14.7afr because that all the narrowband primary sensor can see. This is why vafc doesn't work in partial throttle on stock ecu because ecu is pinning at 14.7 no matter what the vafc is trying to trick it to do. Stock ecu goes into open loop around 60% throttle and stops pinning the afrs. Around 60% throttle you are pretty much near 0 vacuum aka full load anyway at the top of the fuel map.

The ems is a very powerful tuning solution for our car and I highly recommend one.

Example my series 2 is programmed to be in closed loop at all times to deal with temperature compensation etc. At idle and very low cruising loads I could be at 15.5afr thus saving gas compared to stock. Wot is pinned to 13.2afr (I found on dyno testing that my car that between 13 to 13.2afr is where it puts most whp). Moderate loads quickly ramps up from 14.7 afr to the 13.2

Sent from my T-Mobile G2 using Tapatalk

 

If you have very basic bolt-ons, then the OEM ECU will do a good job keeping AFR's in line in closed loop. However, if you have bolt-ons that cause significant changes to AFR due to resonance, then the ECU won't react quickly enough in closed loop to maintain a good / safe AFR. However, if you get a good part throttle tune, the ECU won't need to rely on the O2 sensor to constantly make significant adjustments via short / long term fuel trims.

Contrary to popular belief, a VAFC can be used for part throttle tuning. It can't be used to change the part throttle AFR, but it can certainly be used to reduce short term fuel trims caused by bolt-ons.

 

x2

Seems like I'm always quoting and agreeing with you.