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Modifiying Stock MAF's!

Old 07-29-2008, 01:47 PM
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Default Modifiying Stock MAF's!

So who has done it and has words of advice.
Anything from moving to a different tube, changing the MAF tables, adding a resistor to the signal wire, a voltage clamp... I am in the process of trying all of these and want to see what others have done!
Working with a bosch MAF off a 95 5series bmw.
It maxes out at like 10psi around 4.5k and pulls all my timing so my AFRs shoot to nines and I lose a ton of power.
I need some more ideas to mess with this MAF lads. Anyone resistor or clamp successfully?
Would that make my last column of values under load/voltage just be used for the entire range of 10-25psi from 4-7k? :1
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Old 07-29-2008, 09:50 PM
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Default Re: Modifiying Stock MAF's!

I have moved dual mafs from the skyline gtr from the stock size tube to a 3" tube. At 500whp they read 4.3vdc and better than stock driveability with some tuning. I didn't touch the transfer (vq table in nissanese) table at all. I fired up the car with no changes to start with, then changed the k-value by the percentage needed to achieve a 14.7:1 afr after the engine was warm.

I have also dropped voltage via a resistor. Retuned as per above.

I have also bypassed the maf by installing another pipe with a filter behind the maf. This achieves the same thing as a larger tube without having to touch the stock maf. I knew by how much I wanted to increase the size so the bypass was made the same size as the larger injectors were over stock. I then retuned the spark table and did a bit of fine tuning on the main fuel table.

I much prefer bypassing as it circumvents failsafe's such as min maf voltage and lowers the restriction the maf element presents to the inlet passage.






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Old 07-29-2008, 10:19 PM
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Default Re: Modifiying Stock MAF's!

larger maf body for maf sensors (separate from body) basically cut the flow it sees down.

if it's one unit like older cars liked to use, then i dunno. resistor or maf hack ftw
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Old 07-30-2008, 02:16 AM
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Default Re: Modifiying Stock MAF's!

You might be better off just running a decent MAF out of the gate. Get one of the 3.5" GM/Hitachi units, run a freq-volt converter if your ECU is expecting a 5/12 volt hotwire unit, tweak MAF table to suit.
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Old 07-30-2008, 10:59 AM
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Default Re: Modifiying Stock MAF's!

there is an 803 porsche hfm that with my current tuning capabilities would be plug and play but costs ~250$ new
I am trying to make 100% sure that I am beyond working with the stocker before I upgrade, thats the easy way out.
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Old 07-30-2008, 11:43 AM
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Default Re: Modifiying Stock MAF's!

Contact Hitchhikkr about a better priceon that MAF, if you have to go that route.
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Old 07-30-2008, 12:21 PM
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Default Re: Modifiying Stock MAF's!

Originally Posted by Joseph Davis
Contact Hitchhikkr about a better priceon that MAF, if you have to go that route.
No need because....

Originally Posted by ichbinsobose
there is an 803 porsche hfm that with my current tuning capabilities would be plug and play but costs ~250$ new
Those MAF are notorious for failure. Anything so much as a K&N filter will send them to their death. You will be bringing on more problems than you solve.

Am I wrong in thinking that you can use the MAF translator or the PROversion? It has a function to convert to a GM style map sensor, or run the 3"-3.5" gm MAF sensors. $400 bux doesnt sound too bad. I know they work well on dsms and supras, couldnt be too far off on bosch system.
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Old 07-30-2008, 05:26 PM
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Default Re: Modifiying Stock MAF's!

You can build a freq-voltage converter for under $10. If you can tweak your MAF tables in the ECU no need for the whole MAF-T package.
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Old 07-30-2008, 05:45 PM
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Default Re: Modifiying Stock MAF's!

Originally Posted by Joseph Davis
You can build a freq-voltage converter for under $10. If you can tweak your MAF tables in the ECU no need for the whole MAF-T package.
OIC, good to know.
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Old 07-30-2008, 06:12 PM
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Default Re: Modifiying Stock MAF's!

Originally Posted by Hitchhikkr
OIC, good to know.
http://www.national.com/ds/LM/LM2907.pdf

Common logic 2907/2917 does the trick. I have a couple somewhere in a bin as I was going to help Pokey do a poor man's MAF-T on his Eclipse before he got angry with the thing and beat all it's windows out with a crowbar.
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