DIY tuning

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Sbrach

Corporal
Platinum Vendor
Oct 2, 2017
224
Thanks for the update and glad you’re feeling better. Going to the ER is never fun.

I know you were working hard on tuning. Have you finalized your approach or are you still working on tables, etc? If you’re pretty much finalized could you please share a little bit with what your preferred approach is? I’m still on commanded wastegate and based on your logs whatever you are doing seems to be working better.

Also, Is the flywheel a 100% fix or are you still seeing random phantom misfires? Sorry , I know you’re busy but just trying to kill two birds with one stone.

The flywheel is next for me, but I’m only willing to do it if the tuning is there too.
Flywheel and PI fixed all misfires 100%

On cars with commanded WG available I still use it with some changes to the I tables. Turbine power WG control adds P and D but not to WGDC. Only to the turbine power calculation. It still only applies I Control to the actual WGDC. I increase the max allowable I value.

Increasing the fuel scalar limits (lowering the lower limit) allows more PI and resolves the limits on fuel flow/fuel quantity/injection time. I sent the tables I use to MHD. Hopefully they add it like they did with the HPFP tables I sent.

The car runs mint with PI and S55 flywheel. I highly recommend.
 

houtan

Corporal
Nov 2, 2017
184
Flywheel and PI fixed all misfires 100%

On cars with commanded WG available I still use it with some changes to the I tables. Turbine power WG control adds P and D but not to WGDC. Only to the turbine power calculation. It still only applies I Control to the actual WGDC. I increase the max allowable I value.

Increasing the fuel scalar limits (lowering the lower limit) allows more PI and resolves the limits on fuel flow/fuel quantity/injection time. I sent the tables I use to MHD. Hopefully they add it like they did with the HPFP tables I sent.

The car runs mint with PI and S55 flywheel. I highly recommend.
Thanks Steve.

I had a chance to look at the WGDC I Factor table (I cant remember if that is the exact name but I believe it is the table you are referring to) and couldn't make sense of the x-axis or the values in the table. When you say you increase the max allowable value, do you mean you increased all the values in the table? Are the changes something you can share? Totally understand if you can't.

For the fuel scalar limits, what issue did lowering the lower limit fix? Were you still getting misfires because of the reduction of fuel needed from the DI side and lowering the lower limit allowed a smaller amount of fuel from the DI side to be acceptable? Trying to get PI to work using gas was always a challenge for the people I know, so they all switched to methanol. This is awesome you have it working 100%. I hope MHD releases the tables soon as well.
 

Sbrach

Corporal
Platinum Vendor
Oct 2, 2017
224
The scalar has a low/high value that is allowable. Lowering the low limit allows turning up PI and lowering the scalar which has the effect of turning down DI. This allows you to run more PI, reduce demand on HPFP, and avoids limits on injection window/fuel quantity.

The i table you are referring to is not what I meant. There are additional min/max limits on how much wgdc the I portion of PID can add. It is pretty low stock - -10% across the rev range and +10 decreasing to +4% from 3000-6000rpm. I increase the max so it can add more and I increase the min so it can pull more out post shift.
 

cookiesowns

Lurker
Nov 13, 2017
24
The scalar has a low/high value that is allowable. Lowering the low limit allows turning up PI and lowering the scalar which has the effect of turning down DI. This allows you to run more PI, reduce demand on HPFP, and avoids limits on injection window/fuel quantity.

The i table you are referring to is not what I meant. There are additional min/max limits on how much wgdc the I portion of PID can add. It is pretty low stock - -10% across the rev range and +10 decreasing to +4% from 3000-6000rpm. I increase the max so it can add more and I increase the min so it can pull more out post shift.
Would you be able to share the table for this? Do you happen to know if it's available on N55 F series? If not I'll have to dig through my files and see if I can find it documented somewhere...
 

Weehe

Specialist
May 21, 2019
72
Been lurking for a while now, but really want to self tune flash only. Was the xdf ever released? The one on github is pretty old so figured there was an updated one.
 

Stokes

Corporal
Jan 26, 2018
142
Houston, TX
I'm looking for help with PID tuning. I put a PS2 in and my approach was to reuse a lot of the factory table values and x/y values, except where it makes sense like scaling out the Compressor Table to 443 g/s. I was able to achieve a fairly smooth boost curve with PID zeroed out just by bumping up the compressor table where the factory values started dropping (lower right). I've been struggling with PID as I don't know what to look at to tweak it. Is there a custom parameter I should be logging?

Any pointers for
1. what to focus on when putting a PS2 in
2. how to go about tuning PID?

I've been experimenting for 2 months now. Lots of fuel and tires gone.
 

houtan

Corporal
Nov 2, 2017
184
I'm looking for help with PID tuning. I put a PS2 in and my approach was to reuse a lot of the factory table values and x/y values, except where it makes sense like scaling out the Compressor Table to 443 g/s. I was able to achieve a fairly smooth boost curve with PID zeroed out just by bumping up the compressor table where the factory values started dropping (lower right). I've been struggling with PID as I don't know what to look at to tweak it. Is there a custom parameter I should be logging?

Any pointers for
1. what to focus on when putting a PS2 in
2. how to go about tuning PID?

I've been experimenting for 2 months now. Lots of fuel and tires gone.
Are you open to tuning via commanded WGDC instead? That’s how my car is tuned, runs great.
 

houtan

Corporal
Nov 2, 2017
184
Houtan, you should try the compressor characteristic. You'll only have I factor working in your PID with commanded. Once you get the hang of the stock setup, its not bad.
Honestly, I would love to. It’s just I have no clue where to start so if someone would help me a little then I would be able to learn from there. I am guessing @Stokes is in the same boat.

I recently got the M4 fly wheel installed so now I am starting to turn up the boost. Of course I’m using commanded WGDC because it’s familiar and I can quickly make tweaks to dial the boost in. Would be a great time to try compressor characteristic.
 
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Stokes

Corporal
Jan 26, 2018
142
Houston, TX
Now, to be honest, I started learning about tuning on the stock turbo and it is now melted. Circuit of the Americas all day with the turbo hitting target in gears 5, 6, and 7. Stock doesn't like to go 18 psi at redline for long periods of time. lol. 1st through 4th did well holding 16 trending down to 14 at redline. I was a noob.

Anyone willing to share how to specify custom addresses to log in MHD? If I could log P error, that'd be helpful.
 

Stokes

Corporal
Jan 26, 2018
142
Houston, TX
PS2. Right now I have boost at 20 PSI above 4500 and timing ramps up to 11°. AFR Is around 12.2 in the upper average. is around 12.2 in the upper average. Logs look good.
fuel pump? port injection? meth?
I want to stay 93 with 3 gal of Ethanol (E20 ish) . Which means 19 psi and 9 ish timing max. I'm early N55 with the late N54 HPFP.
Also, I'm road track / Autocross oriented, so straight line tuning doesn't excite me. Meaning, temps will be a concern and available fuel in large quantities.
 

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