Gernby

I've been tuning with my FlashPro for a few weeks now, and am really surprised by the challenge of part throttle tuning. Hondata didn't have a calibration for my intake (PWJDM), so I started with their calibration for a stock "tuned" car.

The full throttle tuning wound up being really easy, and I was able to get a very smooth AF Corr value. However, when I looked at my STFT and LTFT graphs at part throttle, they were all over the place. I had assumed that the harmonics of the CAI (resonant humps) would impact the AF values at all load levels, so my fuel map looked like this:



Then as I spent probably 100 hours trying to perfect the part throttle tune, I wound up with the fuel map below. It seems that unless the throttle plate is 90-100% open, the resonance of the CAI really has no impact at all.



After all that time and effort, I then opened up Hondata's CAI tunes to see what they looked like. To my surprise, they looked very much like my 1st attempt (1st picture). Did Hondata make the same poor assumption that I did?

Gernby

Here is an overlay of the low speed fuel map compared to the stock equivalent.

macr88

So the jump in fuel between 3 and 4 thousand rpm is needed for your intake because of resonance. Someone needs to make an intake that adjusts so the resonance happens at all rpm's
Part throttle tuning is very time consuming and I have yet to do it.

EliteTuning

Part throttle tuning shouldn't take more than 2 hours in an s2k if you know how to do it right. Nonetheless, ok job

Gernby

I can see how it would be a much quicker process if you already knew what to do, but learning is never a quick process. That's been the most enjoyable part of this! I really didn't gain as much power as I was expecting from fuel or ignition tuning since it seems that the '08 is tuned MUCH more agressively than my '02 was. I gained a lot of power on my '02 from simply leaning out my fuel by as much as 15% in some areas.

What is a realistic goal for a "good enough" part throttle tune? I realize that I would never be able to achieve a tune that would result with long and short term fuel trims that are always zero, but what is good enough? My LTFT has stayed at zero for several driving cycles, and my STFT during steady state accelleration at 10%, 13%, 15% etc. throttle is staying between +/-3%, and FlashPro Manager is recommending 0% change for those areas. Is that good enough?

93turbo16

Honestly if you are using a stock o2 sensor still, you don't have to make it absolutely perfect.

Just tune it within a reasonable margin to your taget A/F ratio and get on with your life.

Realistically I would like to see the car under a steady state throttle between +/- 10 percent. On my personal car I have the max/min trims set very small, so it can only adjust +/- 4% so it can only apply a small adjustment. That may seem useless but it is just enough to help out with temp changes, etc.

Gernby

93turbo16,

There's a lot about what you said that doesn't make sense to me. I wasn't aware that you can turn off an O2 sensor, so I've just been adjusting the fuel tables so that the STFT values while accellerating at steady state in closed loop stay low. Basically, I didn't know how or why I needed to disable closed loop.

The second thing that was confusing was when you said that you have the max/min trims set very small. I didn't know you could set max/min trims. I thought those were just whatever the ECU decides in real time to achieve the target AFR while in closed loop.

93turbo16

I definitely did contradict myself in the second sentence. I don't tune with the stock o2 sensor, I always tune with an aftermarket wideband and then put the stock sensor back in afterwards.

With that being said, I will say that it does not look like you can still use the primary o2 sensor and tune the car in open loop. As it seems this disables the sensor all together.

On some of the older softwares you could still disable closed loop but keep the o2 sensor heater enabled and you could still get readings from a stock O2 sensor. But this is not the case here.

What I was talking about with the Min/Max trims is located in the closed loop section of the software.



It sets a min and max range that the ecu is allowed to correct the fuel while in closed loop.

By settings these ranges tighter together you will get much less fluctuation in the readings.

If you zeroed out the min/max trim it would be comparable to putting the car in open loop, as it would not allow the ecu to add or subtract fuel from the car via the o2 sensor reading.

Sorry for any confusion.

Gernby

What would be the reason to limit the min / max STFT range for closed loop? That seems liike it would just prevent the ECU from protecting the engine if something went wrong (clogged injector, bad gas, etc.). Is there a performance benefit to limit them (assuming the fuel table is properly tuned)?

As I type this, I'm developing theories about how it could improve performance since I have noticed that there are occasional "blips" in the AFR and STFT's that could just be sensor errors.

thesilverbullet

you can force open loop with the MAP WOT table for both part and WOT throttle tuning.

i wish hondata would give an option to change the closed loop a/f target..