EuroAccord13's Re-Tune....(NOW WITH VIDEO ON FIRST POST)

[EuroAccord13]

This morning, I took MUGEN88 down to my tuner to have his UR UD Pulleys installed (For those of you considering this modification, TAKE NOTE, IT'S NOT AN EASY JOB) as well as His FULLY SIK Apexi NEO... This is another story for him to tell...

While his car was being operated on, I took the opportunity to put my hand up to have my car retuned.....

1 Hour later...

The results as follows...

126Kws @ Wheels on a nice sunny 25 Degree day!

Couldn't push anymore than 126KWs but midrange improved heaps.. If the car had gone on, the heat would have killed the Kws....






VIDEO!!!

Pardon the quality... For some reason when it's uploaded to Photobucket and becomes a swf file.. The quality level becomes bad and jerky.....

http://www.youtube.com/watch?v=ytqvkl964xo

[aaronng]

Nice numbers!
Does the Euro ECU's optimising function end up confusing and messing with the VAFC's tuning? Do you require frequent retunes?

[yfin]

Good work Nick - so what has changed on your car since the last tune? And did Mugen88 get his a/f controller tuned?

[TypeG]

what's mod u got b4 and after to have 14kw more beside retune?

[euro77]

well done Nick!

what's mod u got b4 and after to have 14kw more beside retune?

He got rid of the 18" chromies!!!!! LOL

hehehe... he got the header

[tron07]

I take it that the 140kw Euro specifications is at the crank then??

[yfin]

Nice numbers!
Does the Euro ECU's optimising function end up confusing and messing with the VAFC's tuning? Do you require frequent retunes?

The tune settings are stored in the VAFC so you shouldn't need retunes. The real issue I think is how long can the car achieve those numbers without the ECU adjusting a/f accordingly. Let us know if you see a drop off Nick.

[aaronng]

I take it that the 140kw Euro specifications is at the crank then??

Yes, all specifications from manufacturers are at the crank/fly.

[aaronng]

The tune settings are stored in the VAFC so you shouldn't need retunes. The real issue I think is how long can the car achieve those numbers without the ECU adjusting a/f accordingly. Let us know if you see a drop off Nick.

Yup, that's what I meant. The ECU's optimised A/F ratio is no longer optimised for the VAFCii.

[yfin]

Yup, that's what I meant. The ECU's optimised A/F ratio is no longer optimised for the VAFCii.

edit... did a look around for more info on the net. Seems like varied opinion on the VAFC for modern ECUs. Is what this chap saying about the s2000 manifold Air Pressure Sensor the same for the CL9 (vs mass airflow sensor)? I don't know the difference between these sensors. If Nick's dyno figure stays the same after a few weeks then there is the answer..

http://www.s2ki.com/forums/index.php?showtopic=390966

"Depending on who you talk to, VAFC's are useless. We have a manifold Air Pressure Sensor (not a Mass Airflow Sensor). So when the VAFC adjusts the air/fuel ratio, the ECU notices that the intake manifold pressure is higher, and corrects. The only way I think the VAFC will work is with an engine management unit (like AEM) that can be programmed to not correct for the pressure difference.

This is from what I have gathered. In order to gain any real gains, the ECU will need to be reset every so often, so the ECU will have to "learn" all over again about the MAP sensor readings.

Let me know what you find out....I have been looking into this as well (because the earlier AP1's run REALLY rich up top).

John "

and

"There was a thread on here, I will see if I can find it, that had a dyno sheet RIGHT after install (amazing gains). Then there was one 2 weeks later, after the ECU adapted.......and there was barely any gain anywhere (a little at the top, but not much)."

[aaronng]

edit... did a look around for more info on the net. Seems like varied opinion on the VAFC for modern ECUs. Is what this chap saying about the s2000 manifold Air Pressure Sensor the same for the CL9 (vs mass airflow sensor)? I don't know the difference between these sensors. If Nick's dyno figure stays the same after a few weeks then there is the answer..

http://www.s2ki.com/forums/index.php?showtopic=390966

"Depending on who you talk to, VAFC's are useless. We have a manifold Air Pressure Sensor (not a Mass Airflow Sensor). So when the VAFC adjusts the air/fuel ratio, the ECU notices that the intake manifold pressure is higher, and corrects. The only way I think the VAFC will work is with an engine management unit (like AEM) that can be programmed to not correct for the pressure difference.

This is from what I have gathered. In order to gain any real gains, the ECU will need to be reset every so often, so the ECU will have to "learn" all over again about the MAP sensor readings.

Let me know what you find out....I have been looking into this as well (because the earlier AP1's run REALLY rich up top).

John "

and

"There was a thread on here, I will see if I can find it, that had a dyno sheet RIGHT after install (amazing gains). Then there was one 2 weeks later, after the ECU adapted.......and there was barely any gain anywhere (a little at the top, but not much)."

He's a little confused. It is not a matter of MAF vs MAP. Even B series runs MAP, and VAFC works fine on them.

The issue is that VAFC is an interceptor. It gets readings from sensors and outputs a different optimised value to the ECU so that the ECU makes changes that gives you more power.

So:
Signal1 + VAFC modification1 = Input1.
Input1 + ECU = Optimised A/F ratio

Once you tune the VAFC to perfection, all is fine and dandy. Until while you are driving and the ECU continues to optimise your A/F ratio. Then what you get is:

Signal1 + VAFC modification1 = Input1
Input1 + ECU (reoptimised) = Unoptimised A/F ratio

So even if the VAFC is doing what you programmed it to, the ECU with its constantly optimising algorithm just further messes with the input signal, leading to an A/F ratio that not the same as when you dyno tuned.

The ECU also has Open-loop and Closed-loop modes. Closed-loop is used when there are smaller throttle opening and when in lowcam. I think that closed-loop operation with VAFC is not affected by the optimisation. But open-loop is. And open-loop is what matters when you are doing full throttle acceleration runs.

BTW, I noticed in one of the threads linked in that s2ki thread, they posted up VAFC settings. I'm pretty shocked by the poor resolution of the VAFC:

LVT
1000 = 0
2000 = 0
3100 = -5
3600 = -4
4000 = -6
4500 = -10
5500 = -11
5900 = -11

HVT
5500 = -4
5900 = -4
6100 = 0
6500 = -4
7400 = -3
7800 = -5
8400 = -10
9000 = -9

[aaronng]

AEM just announced a new piggyback at SEMA 2006. Instead of intercepting inputs and leaving a chance for the ECU to reoptimise, this AEM Fuel & Ignition Controller (FIC) intercepts OUTPUTS! So this might work with the Euro's ECU.

http://vtec.net/articles/view-article?article_id=631542