Black Jack: Fixing torque steer

View: https://youtu.be/fjpv5aj8EIo?si=Xx6mSmQV8fUz0mfR


The tuning is coming along. It was perfectly smooth at low RPM and was seeing 12.9 at WOT with excellent street manners throughout partial load. Then, without changing a thing, I do one final pull and it runs 13.5, and bucks any lower than about 11-12mph. Still not bad.

Tuning is both awesome and frustrating. I think I just picked up on what it might be. In the vid, the AFR shows in the 16s. Later this evening, in was in the low 15s. I might lean it out intentionally way down low, now.

Overall, the car is acting a lot better. I'm pretty happy overall.

@Willybill32 Funny you mentioned the bucking at low RPM with your E303 cam today. I just kinda sorta cured that. Your response mentioned that you don't jmhave any issue with stalling. What is your idle set to? If it's still ~670 RPM, that's pretty nice. When you set the idle higher, you're building in the buffer you already had on the stock tune.

I get what he means. When the TPS is less than 1.25 V, the computer is trying to make the car idle at the designated RPM. If it doesn't, then it'll try to lower timing and reduce air from the IAC to achieve that idle. Thing is, the tuner can set the voltage at which it leaves idle. So, instead ot the stock 1.25, he can make it 9.98. Then, when you're at all on the throttle, it leaves idle mode and only tries to achieve whatever the standard tables tell it. So, you're tuner's right, but also kinda throwing his hands up.

Swapped back over to my winter wheels & tires (bullets & Cross-Climates). I originally wanted to show the tuning process step-by-step as I went through it, but honestly, the process is not that clean for me. There's a science to it, but there's also a lot of trial-and-error for me. So, I'll try things, and then revert back if I didn't like something about the adjustments in each new tune.

Aside from the tuning & wheel swap, I washed the car and finally vacuumed all of the Soji hair out of the car. It was exhausting. There was at least as much dog hair as carpet, lol.

The stock A9L WOT table:
RPM Timing
16383.75 26.00
5000.00 26.00
3500.00 22.00
2600.00 22.50
2150.00 21.50
1800.00 18.50
1000.00 8.00
0.00 8.00

I took this curve and added 6*. Then, I adjusted the part where it pulls 1/2 degree to align to where I estimate the peak torque plateau ends and torque begins to drop off (4.6k), based on some old dynos. I also bumped the RPM ramp to total timing to 32* @ 5.5k RPM.

Pinging during the test drive showed me that I had gotten too agressive down low. So, I pulled a few degrees back out, and actually ended up less aggressive than the way the stock tune ramps in timing. I'm guessing this issue has something to do with the cam timing difference.

Since this is a daily, I've kept all 3 timing tables active and added 4 degrees across the board. Then, I pulled timing in the same place (higher load from 1-1.8k RPM). And I pulled out any timing adders (when ACT is cold, for example), because I don't want a bad sensor to ever push the motor into detonation.

Now, black jack feels very peppy at part throttle, and runs like a scalded dog at WOT. This is the best I'm gonna be able to do with rough estimates. I may be able to make my own 'dyno code' with the data logs, like I did before on a buddy's car, here.

It's pretty exciting to feel the differences, and I'm excited for feedback on my adjustments from track times/dyno/mpg.

I feel like I'm getting close to the point I can stop tweaking. There is a rough spot in the idle while the car is still cold where it surges, but I might have worked that out, today.

Other than that & some WOT revisions with some way to measure power, I'm pretty much done!