hi i have an 03 Civic EX with SAFC2 installed. some people told me the ECU will reset the SAFC2 settings after sometime making the adjustment / device useless. just in the case of some other piggybacks which eventually have no effect on our ECU. Claims 2003 - 04 ECU too intelligent for such devices to tap n re-route their signals.

Please advise. thanks.

Is this true guys?

dam that would suck, i have no idea though.

I have a hunch it might be. Someone else here said he could only add fuel up to a point, and then the ecu would correct it. Don't know what year car. I tried adjusting my vafcII up and down, and it's really hard to tell if there's a difference. I guess dyno is the only way to know for sure.

well its true that it does learn, altho it still will be affective for quite some time

just gotta road tune it... its much easier to do with an a/f gauge

I believe the answer might be YES...i.e. Apexi's SV/AFC2 is useless on newer Honda ECUs.

Newer Honda engines i.e. D17A / K20A are controlled by CLOSED LOOP system. The engine uses four wires type of O2 sensor, the speed of feedback control time is quick. O2 sensor of 4wire type has built in heater, which can generate O2 signal immediately after engine start and low exhaust temperature at the time of an idling. It means O2 signal is available at all conditions.

This O2 signal can control fuel finely with realizing engine performance of more power and less fuel. It means automotive ECU becomes very clever. The clever ECU installed to vehicle after 2000 can detect the change of data immediately by Piggyback, Sub-computer (so called after market tuning ECU) which subsequent engine check lamp lighting, a rough idling, and the fuel adjusted by airflow, MAP sensor, additional injector, etc returns to the original A/F ratio immediately being unable to increase an engine output power and other various problems are incurred.

Hope this helps some people who's planning to install a S/VAFC2 in their 03+ model.

It's false, and this has been proven now. Someone dynoed their 03 civic with vafcII, aem intake, and race header. They spent 3+hrs on the dyno. At first the a/f curve was all over the place. When they were done, the ratio was almost a straight line and very close to the ideal value. He gained something like 5whp, so it obviously works. How do you guys think people here are tuning their turbos? People have the e-manage which can basically change everything from a/f to injector cycle to ignition timing with no probs.

Actually its true. The O2 sensor (as mentioned above) does allow the ECU to try and maintain a "setpoint," in our case 14.7 A/F ratio. The only time this doesn't hold true is at WOT, where the ECU jumps to tables, which have hard-programmed A/F ratios.

You can dyno tune the partial throttle area of your car all you want - over time (not immediately, but eventually), the ECU will trim the fuel away because the O2 sensor is reading either more rich or lean (that's what the STFT - short term fuel trim, and LTFT - long term fuel trim, are for)....

Yes it sucks. This is why a lot of the guys at HT convert to either OBDI ECUs or run Hondata or Uberdata......

Well thanks for the info. That means dyno tuning the car with vafcii is completely useless. Wish I would've known before I spent $300 on a cool light box. I actually tried turning up the fuel a little on mine and was like wow this is good stuff, but then a week later I'm wondering what happened? So I turned off the corrections and it felt the same as stock. I guess that's why.

I wonder if resetting your ECU every so often would help. Maybe reset it at every oil change or something.

for real.... damn i about to dyno tune my car with vafc. soo.. it wouldn't work then with our car.

I tuned my turbo 03 with a SAFCII and RSX-S injectors and the SAFCII works great. I pulled a ideal 14.7 A/F when tuning my car

^^ how many hp you get out of it by tuning yours?

Did you go dyno a few weeks later to see if everything went back to stock?

bro you are not alone. couple of my buddies with S/Vafc2 are also facing the same problem. Their 03-04 Civics are reverting back to stock feel after like 1-2 weeks of pleasure. Initially they thought it's getting used to the power but apparently not.

those on e-manage might be lucky should the system able to outsmart the stock ECU. m still testing this product www.obitasia.com and will post my feedback when it's done. stay tune!

Let us know. It's really stupid to pay all that money for vafcii and then have it just to show what rpm you're going. All it is now is an engine monitor. Useless.

Well - the emanage will do the same thing if tuned for partial throttle performance. Even in boost. Which is why I have this installed:

http://www.splitsec.com/products/conditioner.htm

When it sees 1 PSI of boost it sends a stoch signal to the ECU, simulating that everything is OK. This allows you to add more fuel (or take away fuel) without the ECU knowing, and fvcking up the fuel trims. Seems to work nicely!

I guess its all good if your boosted. What if it doesnt see 1psi??
Can you set it up so that it does the same thing without boost??

good question

No - the stand alone ESC1 cannot be adjusted. Apparently, their other fuel computer (which the celica guys use) can though. Its similar to an emanage, and apparently works fairly well!

So how much did that cost, easy to install and is it necessary to run Emanage effectively? i didn't know about this and I am getting an Emanage. Do i need to worry that the Emanage will not work correctly after a week of driving? AAHHHH Gettin scared here!

I'm really not sure how much the stock ECU will effect the A/F ratios without this. If you are running an FMU with boost reference with your emanage you should not have a big issue, because the fuel pressure will increase equally as boost increases. I just installed this to be sure. I bought it off of someone on the newcelica.org forums for $100, the sell for about $200 new.

It installs between the primary O2 sensor and the ECU, and sends a simulated signal to the ECU when it sees boost. Anything less than 1 PSI it sends the actual value of the O2 sensor to the ECU.

So nothing for the NA guys?

i just got off the phone with the guys down at the dyno place and they said that they dyno tuned a 7th gen with vafc2... the guy went back 6 months later and was still at the same tune when he left cause he thought that it also got resetted but it didnt... IDK.. maybe it takes longer than 6 months to reset??

The newer civics may be smarter. I have a 01 so it's like the dinosaur of the 7th gen's. the oldest 7thgen ECU may not be affected? like 01-02? 03+ may be different. I know that newer Subaru's have smart ECM's and u can only go with like UTEC so make modifications.

Oh yeah...OPTO....thanks that sounds like good news. FMU/Emanage combo may not bother th ECU.

bro u got it SPOT ON! a buddy of mine 01 Civic has no problems with the SAFC2. in fact at 3000 rpm you can feel the vtec boost...very apparant.

Any tuning specs with mods?

i also forgot to mention that in my opinion i think there is some truth to this but also false...but see they say the ecu learns from the vafc adjustments and doenst work... my belief and i also agree with Titleist71 is that it does that only on the newer ecu.. 03+... see.. they say after a few weeks or months the ecu resets... i have a friend that has a turboed that got his car tuned and its gonna be well into a year that his car has been tuned... then recently he got his car dynoed again yesterday and i was with him and the settings where pretty much the same... just a 1 point adjustment at the 6000 rpm and he was set again...but he drives an 02 which makes me think that the 01-02 dont learn but the newer ones does

i was just wondering on if the high cam(vtec mode) is rich and the low cam is just a tad bit leaner than the high cam?...or vice versa?.......

The ecu adds alot more fuel when the hi cam turns on. It's not as rich because there's more air as well. Overall, our cars do run rich even with intake/header mods. Most people turn down the fuel with vafcII.