carnot

I need some help adjusting the TC parameters to get a more smooth control action. A good example of how the system is responding is in the attached datalog (zipped) at about the 7:58 time through 8:01. I am targeting a 6% slip with the dial selection but the TC seems to oscillate and I can feel it while driving as being kinda jerky.

Also, I have noticed a tremendous amount of overboost in 1st gear. I have a 5psi spring in my wastegate but as you can see in the datalog I will often hit 15psi+ in first. I assume this is happening because the timing is being retarded by the TC. Any advice on how to prevent this?

ls joker

i didnt open the files. But did you make sure your quick spool isnt set to 15psi or anywhere near that.

carnot

I have quick spool disabled. The over boost in 1st gear only happens when TC is enabled so I think it's caused by retarded timing. RPM is increasing so fast in 1st that I think it over boosts before the wastegate can even respond (<0.7sec).

motoxxxman

I refuse to download zip files from the internet. Can you post the actual raw files?

How is your boost by gear set up for first gear?

carnot

Unfortunately honda-tech.com will not allow the uploading of the hondata type file extensions so that is why I put them in *.zip folders. My BBG is setup for 0% duty in 1st gear which if I turn TC off will generate about 5psi. I've done some more playing with the TC parameters and have come to the conclusion that I'm going to have to use both the ignition retard and rev limit functions in order to prevent this overboost situation. I initially wanted to use only ignition retard for traction control because it is smoother than rev limits but I guess with a boosted application this is not possible.

Are you running traction control on your prelude?

carnot

You can access the hondata files here in a post I made on the Hondata forum. Thanks for any help you can offer.

https://www.hondata.com/forum/viewto...p?f=41&t=22736

motoxxxman

No, The chassis I currently use didn't come with ABS. Plus I don't drag race it often enough to really need it. I just adjust my boost by gear depending on which tire and surface I'm on to raise or lower peak torque, and hold as flat of a torque curve as possible.

For your first gear overboost issue, the cause is a form of "glitch" in the coding. Notice you have negative compensation values for air temps below 80*F. In first gear, 0% is the starting point. And if air temp is below 80*F, the ecu subtracts the proper percentage from zero, which is a negative number. The problem is that the ecu sees negative EBC DC values as positive values below 100%. IE you have -5% @50*F. 100 - 5 = 95. So in first gear, if air temp is 50*F, the ecu is outputting 95% DC to the solenoid.
The "fix" for this is to make sure all values in the duty cycle table are higher than your minimum compensation values. IE, you have -7% for the 20*F air temp comp. So enter 7% or 8% across the board for 1st gear. 8% DC will do next to nothing for raising boost pressure above spring pressure, so it shouldn't negatively impact anything.

As for your traction control issues, from what I can gather it seems you actually need to do some more tuning and testing before messing with the TC settings too much. In order for the TC to work properly and smoothly, you need to have a torque output in each gear that is as linear as possible, and as close as possible to the actual limit of traction. To do this, you would need to get on a dyno and raise/lower the boost curve throughout the rpm range until you achieve a nearly flat torque curve across the entire rpm range you plan to use while racing. Then road test with TC shut off, and do the best you can to determine what power output is right around the limit of traction for each gear, then back on the dyno to dial it in to right around that torque level for each gear.

The reason you're likely getting so much oscillation with your TC is because you're probably making WAY too much power for your level of traction, and/or have a peaky torque curve.

motoxxxman

This is my current boost table I'm using with a stock b20a5 engine and performance street tires. In 3rd 4th and 5th gear, it's a dead flat 250ft/lb torque curve from 4500-7200. Lower for lower rpm so I don't lug the motor, and obviously lower in 2nd and 1st gears. I don't know the tq output in 2nd, but its flat enough tq output that the tires spin at all rpms if the tires are cold, and hook at all rps if the tires are warm.
I have a 6psi spring installed, and run the solenoid at 46hz

motoxxxman

This is a dyno chart from a couple months ago with slightly lower boost than what I run now from the above boost control settings, and before I got it completely dialed out. In this one, notice how I have a very flat torque curve from 5k-7300, 225tq to 235tq to 231tq. Purple is the boost curve. My current setup is very mid-range oriented physically due to the stock cams and smaller class turbo, so I need to jack the boost in top end to keep tq flat.

carnot

Wow, how'd you learn about this "glitch"? I wonder if Hondata knows about it and plans to fix it. I'll fix my BBG table as you suggest and see if that fixes the issue, thanks! I've recently gotten the TC to work MUCH better by reducing the amount of retard that happens as a function of slip and also went one notch higher on the dial so the target slip is now 8% as opposed to 6%. Seems to be really hooking nicely now.

motoxxxman

I learned by having the same issue as you, when I had zeros in the DC table. Through some trial and error I did the math and figured it out. Hondata does know about it, not sure what they'll ever do about it though. Since the ecu can't interpret negative numbers, the only thing hondata could do is add a line in the coding to never allow DC to go below zero even if comps tell it to. Maybe I'll try giving them another boot to work on this