open loop/closed loop tuning...

[Hye]

what is the best way to dial my car in via closed loop tuning? I would be using a xcal2 and then just sending the info to my tuner for any corrections (which i know how to do) First off I know that my stft are out of wack, so i want to address this first. Is the best way to dial in the stft to monitor my stft at each rpm level while sitting in neutral in increments of +/- 300 rpm's? What else can/should be monitored via closed loop tuning? Closed loop should always be tuned before open loop correct?

As far as open loop tuning i was always under the impresstion that this has more to do with the actual numbers that the tuner places in the 'tables' in the tune. I usually monitor my open loop via a wideband commander monitoring obviously air/fuel. My open loop's numbers should a/f around 11.2 and my timing at wot is set at 17 degrees.

Driveability in the car is okay, but i'm a perfectionist and i know that it can be improved. at wot the car feels good, but 1/2, 3/4, or 'initially' going wot the car needs improvement, (i believe the stft play a big role here). I'm on the mail order route (which I have no problem with by the way) so if anyone has gone down this same road or has some helpful parameters to datalog via both open and closed loop I would really appreciate it, thanks!

 

[HISSMAN]

Subscribing. I am also interested in knowing what Long and short terms should be at for a great tune, and what they would equal as far as A/F ratio? Say for instance I want to be close to 11.8:1 across the board. What should I look for?

 

[WDW MKR]

You will need to monitor the STFTs at 250-500 RPM increments. Really, you would want to monitor the STFT at each MAF count listed in the transfer table, but that can be a bit tricky. You also need to turn off adaptive learning while tweaking the STFT. If you don't have the SCT PRP, you'll need your tuner to send a separate tune with this turned off.

You take the recorded data and determine how much fuel needs to be added/removed via the MAF transfer table. If your STFT at a certain MAF count (or RPM) is greater than one, you need to multiply the corresponding MAF transfer value by a number less than one to reduce fuel. If the STFT is less than one, you multiply by a number great than one to add fuel. Here is a thread with some decent discussion on the subject.

http://www.modularfords.com/forums/2003-2004-mustang-cobra/stft-discussion-47386.html

 

[Hye]

You will need to monitor the STFTs at 250-500 RPM increments. Really, you would want to monitor the STFT at each MAF count listed in the transfer table, but that can be a bit tricky. You also need to turn off adaptive learning while tweaking the STFT. If you don't have the SCT PRP, you'll need your tuner to send a separate tune with this turned off.

You take the recorded data and determine how much fuel needs to be added/removed via the MAF transfer table. If your STFT at a certain MAF count (or RPM) is greater than one, you need to multiply the corresponding MAF transfer value by a number less than one to reduce fuel. If the STFT is less than one, you multiply by a number great than one to add fuel. Here is a thread with some decent discussion on the subject.

http://www.modularfords.com/forums/2003-2004-mustang-cobra/stft-discussion-47386.html

as always Ike, great info :thumbsup:

1 question about this statement:
you would want to monitor the STFT at each MAF count listed in the transfer table, but that can be a bit tricky

How come it's still tricky if the xcal2 can record both maf counts and stft at the same time? Does the trickiness have more to do with the actual tuner inserting the corresponding numbers into the tables?

I didnt get a chance to reply to your post on the other forum about your terminator up and running, congrats on that..i remember you had a few glitches to hammer out, hope everything's going better!

 

[Hye]

Subscribing. I am also interested in knowing what Long and short terms should be at for a great tune, and what they would equal as far as A/F ratio? Say for instance I want to be close to 11.8:1 across the board. What should I look for?

this is the way I understand it, someone please correct if im wrong

stft has more to due with closed loop tuning, once you are at wot you are now at open loop. stft should not affect air-fuel at wot because once again wot is strictly open loop.

your 11.8 across the board has more to do with your tuner inserting a/f numbers in the tables in your tune at wot (open loop). My understanding is that stft should be close to 0, atleast get them as close as they can to 0. stft are of greater significance than ltft. If your stft is dialed in, your ltft will also be dialed in. Concentrate first on the stft and the ltft will dial themselves in over time (because they are reading correct/accurate stft's.) I hope i'm right on most/all of this, am i Ike?

sure is fun to learn all this!

 

[WDW MKR]

Tuning your STFTs builds your MAF transfer function, from which everything else is based. If you MAF TF is off, it doesn't matter what A/F you command at WOT... it won't be working from the correct base numbers.

The reason I said it is tricky to datalog at particular MAF counts is that they are harder to keep steady than RPM, making it easier to lose your frame of reference. You may be looking a MAF counts thinking the engine is screaming, only to look at RPM and see it at 2500. When you go to look back at MAF counts, your foot has moved and the numbers are different. It helps if you can display RPM and MAF counts right on top of each other. I think this is possible with my Raptor, but I'm not sure about using the XCal2 display screen.

 

[WDW MKR]

I didnt get a chance to reply to your post on the other forum about your terminator up and running, congrats on that..i remember you had a few glitches to hammer out, hope everything's going better!

Thanks. There have been more than a few glitches, but that's all part of the fun! I'm currently working to get the tune lined out and the engine break-in taken care of.

 

[Hye]

Tuning your STFTs builds your MAF transfer function, from which everything else is based. If you MAF TF is off, it doesn't matter what A/F you command at WOT... it won't be working from the correct base numbers.

The reason I said it is tricky to datalog at particular MAF counts is that they are harder to keep steady than RPM, making it easier to lose your frame of reference. You may be looking a MAF counts thinking the engine is screaming, only to look at RPM and see it at 2500. When you go to look back at MAF counts, your foot has moved and the numbers are different. It helps if you can display RPM and MAF counts right on top of each other. I think this is possible with my Raptor, but I'm not sure about using the XCal2 display screen.

okay that makes sense to me. Yikes, I better check and make sure that the Xcal2 has a display screen with those features. Thanks again for the info! ttyl

 

[Venimus]

It is waaaayyyy easier to tune your MAF transfer function if you datalog your AD counts vs. STFT numbers. Then, get it into Excel (file/open/file type=txt/csv) and then you can create a mini database and perform simple sorting and filtering to see all the different spots along the AD counts spectrum and their associated STFT figures. If you need some help with the basic Excel functions to sort and filter I would be happy to help you out. Makes it much easier than trying to spot what the numbers are on a small screen as they are flashing and changing.

 

[WDW MKR]

It is waaaayyyy easier to tune your MAF transfer function if you datalog your AD counts vs. STFT numbers. Then, get it into Excel (file/open/file type=txt/csv) and then you can create a mini database and perform simple sorting and filtering to see all the different spots along the AD counts spectrum and their associated STFT figures. If you need some help with the basic Excel functions to sort and filter I would be happy to help you out. Makes it much easier than trying to spot what the numbers are on a small screen as they are flashing and changing.

True. I'm using a Raptor, which makes it much easier. This method would definitely be of benefit to those using an XCal2 for datalogging.

Also, keep in mind that this is only for idle and part throttle tuning. The MAF transfer needs to be correct before adjusting anything like idle and commanded A/F. Once the idle and part throttle MAF curve is set, you can move onto the WOT tuning. The WOT MAF transfer adjustments are made based on actual A/F vs. commanded A/F.

 

[Hye]

forgive my newbiness what are AD counts? Good info there

 

[LargeOrangeFont]

These damn fords are alot different than the imports I have been tuning

WDW MKR - great info, and I have an unrelated question:

Does the SCT PRP allow you to change the open loop \ closed loop crossover point?

Thanks,

Ashley

 

[WDW MKR]

These damn fords are alot different than the imports I have been tuning

WDW MKR - great info, and I have an unrelated question:

Does the SCT PRP allow you to change the open loop \ closed loop crossover point?

Thanks,

Ashley

The SCT PRP allows you to change everything except for a few scalers that can only be viewed by dealers. Basically, it gives you the power to tune everything of relevance. The transition you speak of is based on different things like throttle position, time running, ECT, etc. You can adjust all of them.

 

[LargeOrangeFont]

The SCT PRP allows you to change everything except for a few scalers that can only be viewed by dealers. Basically, it gives you the power to tune everything of relevance. The transition you speak of is based on different things like throttle position, time running, ECT, etc. You can adjust all of them.

That is great news. I'll be jumping into the fold in a week or so.

On a forced induction car I really don't like the idea of building boost while in closed loop. It is an invitation for disaster, and something I have disliked from day 1.

 

[BlackSabbath]

Great info here.

 

[Tommy98016]

Great info here.

+ 1 :read:

 

[Hye]

AD counts, anyone?

 

[Venimus]

AD counts is just another way to view the volts from MAF meter. To convert volts to AD counts multiply volts by 205. To convert AD counts to volts, multiply AD counts by .00488. Maximum volts the EEC can read is 5.0 and maximum AD counts is 1023