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Author Topic: Ev14 w/ 90MM MAF - Need base map help.  (Read 20764 times)
DonSupreme
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« on: July 28, 2011, 07:57:04 AM »

Hey guys,

I have been lurking on this forum for quite sometime, but tried to avoid going this route. A las, I have come to the point where I feel it might behoove me to learn from the knowledge you guys have gained and so freely shared.

My car currently runs ev14 52lb injectors @ 4 bar, 90mm MAF. I see the base stage 3 tune circulating on this forum is for 60lbers with a smaller MAF.

I figured by now someone would have probably started work on migrating to a 90mm/52lb setup. I would really appreciate if you could share your map with me, so that I can have a base to start with.

Otherwise, any solid suggestions for converting from the nyet base would be helpful.

Thanks.
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infinkc
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« Reply #1 on: July 28, 2011, 08:44:50 AM »

if you currently have a tune with the 52lbs and 90mm, just read out the bin and post it up, from there you can learn how to modify and code certain sensors out.
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NOTORIOUS VR
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« Reply #2 on: July 28, 2011, 09:05:20 AM »

I'm pretty sure in his tune everything is moved around... so it's not of too much use.
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Matt Danger
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« Reply #3 on: July 28, 2011, 09:16:54 AM »

Welcome! You can read and post your tune. I'm not sure we'll be able to make much sense of it, but we can try. You'll probably end up starting from scratch like I did, it's easier in the end.

Read this to get started and familiar with the tools/software you'll need:

http://www.nefariousmotorsports.com/wiki/index.php/Getting_Started

Then read Nye's tuning wiki article to familiarize yourself.

http://s4wiki.com/wiki/Tuning

Start with a stock M box file.

MAF scaling:

I have an 83mm RS4 MAF housing and originally attempted to scale the stock MLHFM MAP by calculating a correction factor:

73mm (stock MAF housing) / 83 (RS4 housing) = 0.8795

I then multiplied all of MLHFM by 0.8795. This worked ok, but my AFR would vary between gears.

So I redid the MLHFM by scaling from Tony@Nefmoto's 85mm MAF housing file. Copy Tony's MLHFM then calculate the correction:

85mm (stock MAF housing) / 83 (RS4 housing) = 1.024

Then multiply the whole table by a correction. This seemed to work better for me. You will calculate using 90 instead of 83, obviously. Try either of these routes and see how they work for you. I still have a stock KFKHFM MAF correction table.

Injector scaling:

You will want to get the datasheet for your injectors, if possible. You will need to edit KRKTE and maybe TVUB.

There is a calculation for KRKTE although a few of us have kind of just been estimating it and altering the value based on LTFTs. My gasoline 60lb Deka @ 3 bar KRKTE was 0.101, for reference.

My 1000cc EV14s came with a datasheet. I used the dead time specs for TVUB. When I had 60lb Dekas I used a stock TVUB.
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nyet
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« Reply #4 on: July 28, 2011, 10:49:19 AM »

MAF scaling:

I have an 83mm RS4 MAF housing and originally attempted to scale the stock MLHFM MAP by calculating a correction factor:

73mm (stock MAF housing) / 83 (RS4 housing) = 0.8795

I then multiplied all of MLHFM by 0.8795. This worked ok, but my AFR would vary between gears.

So I redid the MLHFM by scaling from Tony@Nefmoto's 85mm MAF housing file. Copy Tony's MLHFM then calculate the correction:

85mm (stock MAF housing) / 83 (RS4 housing) = 1.024


I think your scaling math is wrong Smiley

1) you want to scale UP for a larger maf
2) you have to scale by the area, not the diameter

so, technically, it is (85*85)/(73*73) = 1.355
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phila_dot
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« Reply #5 on: July 28, 2011, 11:46:20 AM »

MAF scaling:

I have an 83mm RS4 MAF housing and originally attempted to scale the stock MLHFM MAP by calculating a correction factor:

73mm (stock MAF housing) / 83 (RS4 housing) = 0.8795

I then multiplied all of MLHFM by 0.8795. This worked ok, but my AFR would vary between gears.

So I redid the MLHFM by scaling from Tony@Nefmoto's 85mm MAF housing file. Copy Tony's MLHFM then calculate the correction:

85mm (stock MAF housing) / 83 (RS4 housing) = 1.024


I think your scaling math is wrong Smiley

1) you want to scale UP for a larger maf
2) you have to scale by the area, not the diameter

so, technically, it is (85*85)/(73*73) = 1.355

Isn't the area of a circle pi(radius squared)?
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nyet
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« Reply #6 on: July 28, 2011, 12:41:40 PM »

yes, but pi/pi is 1 Smiley
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nyet
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« Reply #7 on: July 28, 2011, 12:45:15 PM »

to be clear, if r=d/2:

pi(D0/2)^2/pi(D1/2)^2 = (pi/4)/(pi/4) * (D0^2/D1^2) = (D0^2/D1^2)

make sense?
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Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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« Reply #8 on: July 28, 2011, 01:45:39 PM »

For the example given, from 73mm to 85mm:

3.14(42.5*42.5) = 5671.625
3.14(36.5*36.5) = 4183.265

5671.625 / 4183.265 = 1.355

Got it.
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gremlin
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« Reply #9 on: July 28, 2011, 03:22:33 PM »

I think recalibrating MAF for new tube can't be as simple as multiply by any constant value.
Regargless how this constant was estimated.
And this was many times confirmed by live experiments.
As example compare MLHFM curves for Bosch S4 MAF and 1.8T 150ps ME7.5 400BB (4B0906018AL or similar)
Both MAF using the SAME insert-sensor and differs only in tube diameter.
What about this?


   
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nyet
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« Reply #10 on: July 29, 2011, 01:14:21 AM »

Yes. Its a terrible approximation... but without a flow bench, there is no other way to calibrate it.
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Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
judeisnotobscure
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« Reply #11 on: August 04, 2011, 12:13:48 PM »

For the example given, from 73mm to 85mm:

3.14(42.5*42.5) = 5671.625
3.14(36.5*36.5) = 4183.265

5671.625 / 4183.265 = 1.355

Got it.

I've tried it both ways and gotten better results with your first method, similar to tony's stage 3 base file, and then tweaking kfkhfm.
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nyet
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« Reply #12 on: August 04, 2011, 12:31:58 PM »

I've tried it both ways and gotten better results with your first method

The "first" method isn't really a method. Its totally wrong. It is equivalent to an unscaled MAF file (albeit less unscaled than totally unscaled)

Quote
and then tweaking kfkhfm

you mean after tweaking KRKTE Smiley
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Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
judeisnotobscure
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« Reply #13 on: August 04, 2011, 02:09:28 PM »

I've tried it both ways and gotten better results with your first method

The "first" method isn't really a method. Its totally wrong. It is equivalent to an unscaled MAF file (albeit less unscaled than totally unscaled)

Quote
and then tweaking kfkhfm

you mean after tweaking KRKTE Smiley

tweaking both actually.  and i know it's not correct, but i was getting way higher numbers than I should have on the top end... so i massaged the top and bottom of mlhfm and then used kfkhfm to fine tune along with krkte
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nyet
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« Reply #14 on: August 04, 2011, 02:23:16 PM »

I was getting way higher numbers than I should have on the top end

Out of curiosity, how high? Until recently, I have been running an unscaled MAF file (with an 85mm MAF) and im in the process of scaling it.
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Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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