PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Do any of these MAF calculators work off of LTFT differences?

Old May 15, 2005 | 05:30 PM
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Question Do any of these MAF calculators work off of LTFT differences?

Do any of these MAF calculators work off of LTFT differences?

Meaning I've used the other MAF calculators based on Dynamic Air but I'm still not where I need to be.

So is there any that will take the percentage the LTFT are away from 0 with in the MAF HZ ranges around each or the points in the MAF table and correct the current MAF table based on that?

Of course the calculations would have to assume VE was 0'd but I'm very close to 0 anyway so should be perfect for my needs.

If there aren’t any calculators that currently do that would someone that knows Excel help me make one based off of the LTFT or STFT variations?

I have no clue how you guys setup the boxes around the MAF points and setup each box to average in all the info with in that range for each of the MAF table points.

Thanks Guys as always!

Last edited by God Forgives I Dont; May 15, 2005 at 05:33 PM. Reason: Typo
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Old May 15, 2005 | 11:52 PM
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TTT? Anyone? Or is everybody just doing it the manual why once you get close using the Maf HZ Vs. Dynamic Air?
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Old May 16, 2005 | 01:56 AM
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Old May 16, 2005 | 07:30 AM
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1. it will never be perfect, airflow measurements are a bitch by nature.
2. you can filter data fairly easy (but it is a rather manual process, excel doesn't lend itself easily to it). i am working on something more automatic, but i'm not done yet (per bin standard deviation based filtering).
3. the best you can do right now is to gather enough points that they mathematically 'drown' the bullshit values. use the historical compounding function of my spreadsheet and you will quickly gather a nice set of data.

other than that, i don't know what you're really asking...
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Old May 16, 2005 | 09:07 AM
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If this is what you mean:

Do the MAF calculator take into account for your trims when figuring out a new MAF curve?

Here's what you should do, shortly after tuning your VE, go take a quick drive, 15-20 min, and let your SD trims learn a bit. That way the airflow representation that will be logged via dynamic airflow will already have the trims taken into account for. The more you drive around and have trims learn, the more accurate your dynamic airflow data will be to build a MAF curve from. Now obviously, we don't need to drive around for hours and hours, since you want to tune the MAF in relatively equal conditions, but this should help.

I hope this is what you were looking for....
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Old May 16, 2005 | 11:17 AM
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the way i do it is to put it in SD, and tune for VE as normal, but at the same time gather data for MAF calibration. this way you do both at the same time, and while it's not perfect, it will get you much closer to your goal after the first time. most cars need 2 sessions like that, some bigger setups need 3.
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Old May 16, 2005 | 03:48 PM
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Yup, that’s pretty much what I wanted to know about the calculators then.

Ok sense the MAF calculators get us close to ideal how are ya'll tweaking out the last little bit that is a little off after you get done with the log / calculate process?

I mean how do you determine that say the stuff around say 6500HZ is off by X percent so you can hand adjust the MAF to get the area's that are giving positive LTFTs still?

I'm getting damn close but I still have certain area's with positive trims with maf on and I just want to get those few area's down into a negative trim.

Thanks for the help! As always ya'll rule!
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Old May 16, 2005 | 03:54 PM
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Originally Posted by God Forgives I Dont
Yup, that’s pretty much what I wanted to know about the calculators then.

Ok sense the MAF calculators get us close to ideal how are ya'll tweaking out the last little bit that is a little off after you get done with the log / calculate process?

I mean how do you determine that say the stuff around say 6500HZ is off by X percent so you can hand adjust the MAF to get the area's that are giving positive LTFTs still?

I'm getting damn close but I still have certain area's with positive trims with maf on and I just want to get those few area's down into a negative trim.

Thanks for the help! As always ya'll rule!
Oh, BTW, if you have slight positive trimming, don't worry about it. It's fine, and actually may help with the gas mileage (probably negligable) from running a tad tad lean.

I've found that almost a 1 to 1 ratio between scaling percentage vs trim value does the trick. just make sure you have a good idea of what MAF Hz range your trimming is occurring in, this will take either a good eye while driving, or some studying of logs! (IE: if you have trims of -10, scale back by 5-10%, 5 being conservative, 10 being overzealous)
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Old May 16, 2005 | 06:25 PM
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Cool thats exactly what I was needing to know!

I'll have to go in and arange the logs so MAF HZ and FT's are beside eachother and then sort by maf HZ.

Thanks again for the info I'm sure it will help me out!
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