Question about autotune and PE table

[hpcubed]

It has been suggested that when autotuning, the PE tables values should be all set to 1 (afr=stoich.). Please correct me if I am wrong but this seems to command an AFR of 14.6 when entering PE mode? I don't think that setting the PE values to 1 disables PE mode. It seems more correct (to me) to set the PE enable map to 105kpa and set the PE mode values to something like 12.5 (AFR).

[Black02SS]

I used to do this, but I have since changed. I set my Open Loop AFR table to 14.63 all the way across, leave PE enabled at 15, RPM Delay to 2800, and set it to 12.5 for the entire table.

[GMPX]

There is probably no real need to turn off P.E mode, we are just comparing commanded to actual afterall.

Cheers,
Ross

[VortechC5]

That is good news to me. I am (finally) going to be doing AutoTune to my car. Since it is a boosted application on a stock bottom end I have been concerned that if I accidently hit a little bit of boost I'd nuke a piston with PE disabled. This is especially important since I can see 3 psi of boost at part throttle.



There is probably no real need to turn off P.E mode, we are just comparing commanded to actual afterall.

Cheers,
Ross

[GMPX]

That is good news to me. I am (finally) going to be doing AutoTune to my car. Since it is a boosted application on a stock bottom end I have been concerned that if I accidently hit a little bit of boost I'd nuke a piston with PE disabled. This is especially important since I can see 3 psi of boost at part throttle.

Will you be using one of the 2bar O.S's?.
If yes then you actually don't need to use P.E mode at all!!

Cheers,
Ross

[VortechC5]

Hmm, it looks like I may be running out of excuses not to convert to 2-bar. I don't want to steal hpcubed's thread but I have some questions for you Ross while I have your ear.

I have been thinking that I would AutoTune and go MAFless at the same time with my stock O.S. first. Next I would convert to a custom O.S. and get it working with the same configuration. Finally I would convert to a 2-bar.

Now for the questions:

Does the process detailed above make sense or should I just convert to a custom O.S. and 2-bar now? I currently have the car running near perfect with the stock O.S.

Will MAFless work fine when the car is driven at wide variations in temperature and altitude? I live at an altitude of just over 7000 feet. The car is typically driven at altitudes ranging from about 4000 feet to 11000 feet and at temperatures from about 25 deg. F to about 100 deg. F.

If the answer to the first question is yes then how do I accomplish this while being sure not to go to lean in the process.

Thanks for helping out.


That is good news to me. I am (Will you be using one of the 2bar O.S's?.
If yes then you actually don't need to use P.E mode at all!!

Cheers,
Ross

[lplott]

VortechC5-Mark,

Why go throught the entire process 3 times. I know it would be fun and a learning expreience, but why not go ahead and go MAFLESS, Custom OS, AutoVE all at once. Curious if you have a rationale for wanting to do it that way... As you know, I am planning the same thing but all at once.

I think the hardest thing may be hooking up the LC-1 to replace the NB. And that sounds like it is just a matter of getting the FLASHSCAN and LC-1 connected to the same ground to prevent a floating/differentiated ground.

Did you get my e-mail?

Lonnie

[GMPX]

Will MAFless work fine when the car is driven at wide variations in temperature and altitude? I live at an altitude of just over 7000 feet. The car is typically driven at altitudes ranging from about 4000 feet to 11000 feet and at temperatures from about 25 deg. F to about 100 deg. F.

It's not so much the MAF-less situation, it's the boost that might cause some issues at altitude, it also might not. :?
As a test, as the car is now, can you do a Baro reading at 4000ft and at 7000ft, just to see the difference.
What will occur when you go into boost is the PCM will update the Baro to 105kPa, if you only have a 10kPa difference then this will probably not cause a major problem.
But anyway, I guess what I am saying is the PCM will still adjust for Baro on startup etc, it's when you hit boost it will throw things out but that might not cause any running issues if the difference is small.

Cheers,
Ross

[mistermike]

I'll have to say that switching to the 2 bar O/S was easier than I imagined (worried?) it to be. Some good advice from more experienced people eased the transition. Of course, I'm new to tuning, so I didn't have to unlearn thinking in PE terms. I had previously gone MAFless before I got a WB, and my Ltrims were better after tossing the MAF (with untuned headers) than with it, before I even started to tune.

For 2 bar, my AFR/RPM/MAP table was set up with "stoich" at 1.01 EQ to keep it in open loop for BEN tuning. The boosted VE table, if set up per the tutorial, will be extra fat and safe. It's just a matter of letting BEN bring it down to where it needs to be. The new "copy and fill" feature should be a great help here.

[VortechC5]

I have learned through experience that small incremental changes are a good thing. After reading the Custom OS Tutorial that Blacky made available (written by Ross I think) recently it made it sound fairly easy.

I did get your message and just replied with my stock tune attached. Sorry, it's been a busy couple of days.

Mark


VortechC5-Mark,

Why go throught the entire process 3 times. I know it would be fun and a learning expreience, but why not go ahead and go MAFLESS, Custom OS, AutoVE all at once. Curious if you have a rationale for wanting to do it that way... As you know, I am planning the same thing but all at once.

I think the hardest thing may be hooking up the LC-1 to replace the NB. And that sounds like it is just a matter of getting the FLASHSCAN and LC-1 connected to the same ground to prevent a floating/differentiated ground.

Did you get my e-mail?

Lonnie

[VortechC5]

I'll take some readings this weekend and post the results.

I just Googled for an atmospheric pressure chart and found this:

0 feet 101.33 kPa
4000 feet 87.49kPa
7000 feet 78.19 kPa
10000 feet 69.64 kPa

What do you think?

Are you the Ross that wrote the Custom OS 2/3 Bar document that was recently made available? It is an excellent document.

Mark



It's not so much the MAF-less situation, it's the boost that might cause some issues at altitude, it also might not. :?
As a test, as the car is now, can you do a Baro reading at 4000ft and at 7000ft, just to see the difference.
What will occur when you go into boost is the PCM will update the Baro to 105kPa, if you only have a 10kPa difference then this will probably not cause a major problem.
But anyway, I guess what I am saying is the PCM will still adjust for Baro on startup etc, it's when you hit boost it will throw things out but that might not cause any running issues if the difference is small.
Cheers,
Ross

[GMPX]

Are you the Ross that wrote the Custom OS 2/3 Bar document that was recently made available? It is an excellent document.

Mark

I am the Ross and thank you.

Cheers,
The Ross that wrote the document

[wait4me]

LOL, The quote that will always be remembered by us all.....


"The Ross that wrote the document"

[TAQuickness]

I'll take some readings this weekend and post the results.

I just Googled for an atmospheric pressure chart and found this:

0 feet 101.33 kPa
4000 feet 87.49kPa
7000 feet 78.19 kPa
10000 feet 69.64 kPa

What do you think?



Vortec - You might find these links useful as well:
http://members.aol.com/robogeek/airfuel.htm
http://wahiduddin.net/calc/calc_da_rh.htm

[BowlingSS]

I'll take some readings this weekend and post the results.

I just Googled for an atmospheric pressure chart and found this:

0 feet 101.33 kPa
4000 feet 87.49kPa
7000 feet 78.19 kPa
10000 feet 69.64 kPa

What do you think?



Vortec - You might find these links useful as well:
http://members.aol.com/robogeek/airfuel.htm
http://wahiduddin.net/calc/calc_da_rh.htm

Good stuff....
Bill