LLY: Maf tuning

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valleyduramax

Member
Jul 25, 2010
232
4
18
Ottawa ON Canada
I need to retune the maf in my truck and would like to know what the normal flow rate should be from idle up to 2000rpm as I am seing 10 psi of boost at 1800 rpm cruising on highway. I made new intake and maf is much closer to stock turbo now and I assume that since no other changes made, the maf is seeing higher airflow being closer to turbo inlet therefore cooling the maf and requesting more fuel hence more boost. My fuel mileage is a joke right now so need to retune it.

Also what is stock idle rpm?

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S

S Phinney

Active member
Aug 15, 2008
4,011
18
28
Quncy, Fl
Read MAF at idle. It should see 40 gr/sec . At WOT between 400-500. Adjust it using percentages. Let me know if you need help and I will help you.

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chevyburnout1

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
If the intake is still the same diameter then you shouldn't need to change it. Doesn't matter how close to the turbo it is, the same air flow is still moving through the intake regardless what position.
 
Dirtymaxx03

Dirtymaxx03

Active member
Aug 4, 2009
3,110
1
38
Like ^ said. The diameter of the tubing used, dictates the velocity of the air going through it.
 
T

TRUBBS

Member
Jul 6, 2011
461
0
16
not to hijack, but what are you guys running when using 5" intakes?
i think i have mine just maxxed out, but would like to set it up correctly
 
S

S Phinney

Active member
Aug 15, 2008
4,011
18
28
Quncy, Fl
Return it to stock MAF data and read idle MAF readings. Take that reading and compare it to the norm of 40 gr/sec and convert using the percentage method to make it read 40 at idle again.

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S

S Phinney

Active member
Aug 15, 2008
4,011
18
28
Quncy, Fl
Being tuned correctly has a effect on the fueling. Readings under 35 will start to be a little lazy and get was as the readings get smaller. For fueling to occur correctly it needs to be within certain variables. It is easy to fix and well worth fixing. A really dirty air filter can make it drop into the 36 areas. Getting incorrect readings make for poor performance and worse fuel milage. None need to be maxed out to work correctly.

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V

valleyduramax

Member
Jul 25, 2010
232
4
18
Ottawa ON Canada
Just finished adjusting tune. The readings before adjusting was around 53gr/sec now its at 41gr/sec. Im still getting roughly 5 pounds of boost at cruise speed so might havr other adjustments to make as I thought I should only be making like 1 or 2 pounds since its still the stock turbo??

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mike diesel

mike diesel

I'm alright.
Sep 6, 2012
4,005
0
36
SLC, Utah
valleyduramax said:
Just finished adjusting tune. The readings before adjusting was around 53gr/sec now its at 41gr/sec. Im still getting roughly 5 pounds of boost at cruise speed so might havr other adjustments to make as I thought I should only be making like 1 or 2 pounds since its still the stock turbo??

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Click to expand...

How fast are you cruising?
 
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