3.5" Maf Scaling Table??
3.5" Maf Scaling Table??
I’m hoping some one here can give me a hand or a jump start with the maf scaling tables. I’m going to use a 3.5” maf housing that measures exactly 86mm ID. I measured the stock maf housing and I got 65mm ID. The new maf housing is roughly 31% larger. But from the treads I’ve been reading I think 31% increase to the table will be too much.
Anyone that doesn’t mind sharing there maf scaling tables for a 3.5” maf please post them.
Anyone that doesn’t mind sharing there maf scaling tables for a 3.5” maf please post them.
1) use stock MAF
2) get trims and WOT afr logged
3) swap to 3.5" MAF, start with 1.4 multiplier
4) log trims and WOT AFR adjust scaling and smooth until you trims and WOT AFR match in step 2.
2) get trims and WOT afr logged
3) swap to 3.5" MAF, start with 1.4 multiplier
4) log trims and WOT AFR adjust scaling and smooth until you trims and WOT AFR match in step 2.
It really is that simple, worst case you want to overshoot a bit so it is on the rich side, then work your way back down leaner again to tweak it.
For reference I went with a 1.35 multiplier (35%) and trims are pretty close to what I had. Select the entries you want to change and choose "Multiply Data" under the edit menu and enter in the multiplier you want to use. I like to go to the View menu and do a "view graph" to verify they changed properly, the curve should be pretty much the same as before.
For reference I went with a 1.35 multiplier (35%) and trims are pretty close to what I had. Select the entries you want to change and choose "Multiply Data" under the edit menu and enter in the multiplier you want to use. I like to go to the View menu and do a "view graph" to verify they changed properly, the curve should be pretty much the same as before.
I had a little trouble finding these too, just happen to have them open so I'll share 
evo10base.xml
52680015.xml
I settled on 1.39*stock values after starting at 1.48 (extra safe).
I'd just start at 1.4* just like tephra said. If you do the math, it works out:
area of circle: pi*r*r
inner diameter(stock): 2.8" (r=1.4)
inner diameter(primo): 3.3" (r=1.65)
area (stock) = 1.4*1.4*3.14 = 6.15 sq inches
area (primo) = 1.65*1.65*3.14 = 8.55 sq inches
conversion ratio (primo/stock): 8.55/6.15= 1.39
It is amazing how nicely the car runs on a maf this huge!
evo10base.xml
Code:
<scaling name="MAFVoltScaling" units="units" toexpr="x*5/1024" frexpr="x*1024/5" format="%.3f" min="0" max="5" inc="1" storagetype="uint16" endian="big"/>
<table name="MAF Compensation" category="Fuel" type="2D" scaling="AirFlow16">
<table name="X" type="X Axis" elements="40" scaling="MAFVoltScaling"/>
</table>
<table name="MAF Compensation #2" category="Fuel" type="2D" level="1" scaling="AirFlow16">
<table name="X" type="X Axis" elements="40" scaling="MAFVoltScaling"/>
</table>
<table name="MAF Compensation #3" category="Fuel" type="2D" level="1" scaling="AirFlow16">
<table name="X" type="X Axis" elements="50" scaling="MAFVoltScaling"/>
</table>
Code:
<table name="MAF Compensation" address="5753a">
<table name="X" address="615ea"/>
</table>
<table name="MAF Compensation #2" address="5758a">
<table name="X" address="6163a"/>
</table>
<table name="MAF Compensation #3" address="575da">
<table name="X" address="6168a"/>
</table>
I'd just start at 1.4* just like tephra said. If you do the math, it works out:
area of circle: pi*r*r
inner diameter(stock): 2.8" (r=1.4)
inner diameter(primo): 3.3" (r=1.65)
area (stock) = 1.4*1.4*3.14 = 6.15 sq inches
area (primo) = 1.65*1.65*3.14 = 8.55 sq inches
conversion ratio (primo/stock): 8.55/6.15= 1.39
It is amazing how nicely the car runs on a maf this huge!
I had a little trouble finding these too, just happen to have them open so I'll share
evo10base.xml
52680015.xml
I settled on 1.39*stock values after starting at 1.48 (extra safe).
I'd just start at 1.4* just like tephra said. If you do the math, it works out:
area of circle: pi*r*r
inner diameter(stock): 2.8" (r=1.4)
inner diameter(primo): 3.3" (r=1.65)
area (stock) = 1.4*1.4*3.14 = 6.15 sq inches
area (primo) = 1.65*1.65*3.14 = 8.55 sq inches
conversion ratio (primo/stock): 8.55/6.15= 1.39
It is amazing how nicely the car runs on a maf this huge!
evo10base.xml
Code:
<scaling name="MAFVoltScaling" units="units" toexpr="x*5/1024" frexpr="x*1024/5" format="%.3f" min="0" max="5" inc="1" storagetype="uint16" endian="big"/>
<table name="MAF Compensation" category="Fuel" type="2D" scaling="AirFlow16">
<table name="X" type="X Axis" elements="40" scaling="MAFVoltScaling"/>
</table>
<table name="MAF Compensation #2" category="Fuel" type="2D" level="1" scaling="AirFlow16">
<table name="X" type="X Axis" elements="40" scaling="MAFVoltScaling"/>
</table>
<table name="MAF Compensation #3" category="Fuel" type="2D" level="1" scaling="AirFlow16">
<table name="X" type="X Axis" elements="50" scaling="MAFVoltScaling"/>
</table>
Code:
<table name="MAF Compensation" address="5753a">
<table name="X" address="615ea"/>
</table>
<table name="MAF Compensation #2" address="5758a">
<table name="X" address="6163a"/>
</table>
<table name="MAF Compensation #3" address="575da">
<table name="X" address="6168a"/>
</table>
I'd just start at 1.4* just like tephra said. If you do the math, it works out:
area of circle: pi*r*r
inner diameter(stock): 2.8" (r=1.4)
inner diameter(primo): 3.3" (r=1.65)
area (stock) = 1.4*1.4*3.14 = 6.15 sq inches
area (primo) = 1.65*1.65*3.14 = 8.55 sq inches
conversion ratio (primo/stock): 8.55/6.15= 1.39
It is amazing how nicely the car runs on a maf this huge!
Evolving Member
Joined: Jul 2009
Posts: 226
Likes: 0
From: Moscow, Russia
Guys, I used 1.4 multiplier for 3.5 inch maf, the trims are within 1.5-2%, but there is a big quetion. The car iddles at 0.4 volts, and in the maf scaling table values for 0-1.02 volts are 0-s. So basicaly when we are multiplying those values by 1.4 we are gettion 0 at the end. Does this mean that we are not scaling the MAF in 0-1.02 volts area. Am I missing something ?
Last edited by YaroRS; May 16, 2011 at 03:21 PM.
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Evolving Member
Joined: Jul 2009
Posts: 226
Likes: 0
From: Moscow, Russia
Just for reference it appears that the MAF voltage starts to hit 5v at around 300 ft/sec of flow, which means these are the rough crank HP limits based on pipe velocity:
550 crank HP = Stock MAF
650 crank HP = 3" MAF
900 crank HP = 3.5" MAF
550 crank HP = Stock MAF
650 crank HP = 3" MAF
900 crank HP = 3.5" MAF