Since I have a 2001 Lude (OBD II) wont me getting a VAFC be pointless ? I mean since the ECU will adjust everything back?

 

First of all, u can still control vtec engagement with the vafc, and also, i thought that "obdII detuning ur mods" was after a longer period of time with mods like an intake, and people would just reset their ecu regularly to counteract this. Please correct me if im wrong, but vafc would still have its benefits

 

This little ditty resets your ecu everytime you turn off your car. You dont lose your radio presets though. http://www.ntpog.org/mods/fifth-afc/ecu.shtml
Spare me the thank you.

 

Yeah I know I can still Control the Vtec engagement but what about the Air/Fuel .

 

Yes vafc does that for every 500 rpms you can set how much fuel the car is taking in.

 

You shouldn't have any trouble putting a V-AFC in your Prelude as long as:
1. It's installed correctly
2. It's properly tuned on a Dyno

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vet_girl &raquo;</TD></TR><TR><TD CLASS="quote">First of all, u can still control vtec engagement with the vafc, and also, i thought that "obdII detuning ur mods" was after a longer period of time with mods like an intake, and people would just reset their ecu regularly to counteract this. Please correct me if im wrong, but vafc would still have its benefits</TD></TR></TABLE>

yeah long term fuel trim aka the learning curve. the the workaround, obd1 conversion or just pull the fuse every week which means you have to reset your radio presets

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by luda01 &raquo;</TD></TR><TR><TD CLASS="quote">Since I have a 2001 Lude (OBD II) wont me getting a VAFC be pointless ? I mean since the ECU will adjust everything back? </TD></TR></TABLE>
The stock ecu will NOT "adjust everything back" if you only make changes that affect open loop (high load, WOT).

The OBDII "workaround" is WORTHLESS. Resetting the ecu is "WORTHLESS". Long Term Fuel Trim recalibrates after a reset in about 20 minutes of driving. The base fuel maps are VERY rich, so all you are doing on a reset is causing the car to run VERY rich for the first 20 minutes, until LTFT recalibrates and subtracts out all the unnecessary fuel.

 

i was under the assumption that the base map was corrected by the short term fuel trim after a reset and after a given amount of time in days the long term fuel trim had enough to start doing adjustments.

 

OBD II does NOT change your fuel map or VAFC settings as long as you tune for full throttle only.

I will explane more when I get home

 

ok, have time to explain more now:

What OBD II does is try to keep your air to fuel ratio (A/F) at 14.7 under normal driving conditions. 14.7 is the best ratio for emmitions and fuel consumption. The way it does this is it monitors your primary O2 sensor and if it’s not at 14.7 it will trim the fuel level until its reached 14.7. Thus if your car is running at 13 A/F it will adjust the fuel map until it’s back at 14.7.

It however does NOT try to keep A/F at 14.7 when at full throttle!! Under full throttle the ECU ignores the reading from the primary O2 sensor and does NOTHING to try to trim the fuel. In fact hondas are set in stock form to run rather rich under full throttle and not at 14.7.

Knowing this we can tune the VAFC in such a way that it will not be “detuned” by the ECU. Don’t set the VAFC to do anything under part throttle because that will though off what the ECU is trying to do. What’s the point of trying to get anything other than 14.7 at part throttle anyway?? If you want more power just push the throttle down more! You can set the Apexi VAFC to only adjust fuel at 90% or more throttle. This will give you max power at full throttle and the ECU will not try to “detune” it.

Basically let your ECU do the A/F tuning for part throttle (it does a good job of that), and you do the tuning under full throttle via VAFC.