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Sub STI MAF Limit

Practical Reflash Tuning

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Discussion and questions related to the course Practical Reflash Tuning

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Hello everyone, I'm reflashing a 2006 Sub Impreza STI after some upgrades. The car has new intake, bigger turbo, equal length headers, 3" pipes from turbo to bumper with high flow cat. I was rescaling the MAF and I notice that in WOT over 5.800 rpm the AFR is 30% leaner than it should. And at this speed the MAF is in the maximum values. The MAF maximum value is 350 g/s at 4.98v. My question is, can I change the MAF maximum value or do I need new injectors? The engine rev limit is 7k rpm, so I assume that it'll flow much more than 350g/s.

Thanks!

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You have to measure the inside on the old tube intake tube and measure the new intake tube id and update your voltage as well as the maf scaling table to the % needed. You will have to look at what your injector duty cycle and injectors latency is doing if its maxing out you will have to replace them aswell as the fuel lines, rail and fuel pump. The fuel maps in the rom will have to be updated to the injector data that should be providedwith the new injectors. You could allways go speed density? You will need to weld in a iat bung into the intercooler and a i wire wiring kit to run speed density or a combination of both? Hope this helps.

Thanks Al Tyler, the car didn't have the OEM maf housing and I don't know the OEM maf housing ID, is that something you know? I looked everywhere and I couldn't find this information. Thanks

Whats the id size of the intake pipe? mm and inches please? Alao what flashing progam are you using?

0.94

1.523215023

0.98

1.759575974

1.02

2.022199254

1.05

2.297953698

1.09

2.599970469

1.13

2.954511897

1.17

3.348446817

1.21

3.768644064

1.25

4.228234804

1.29

4.740350199

1.33

5.265596759

1.37

5.843367974

1.41

6.499926174

1.48

7.8393049

1.56

9.375651087

1.64

11.08270241

1.72

12.92106536

1.8

15.0220516

1.87

17.30687414

1.95

19.81492646

2.03

22.70378253

2.11

25.92091771

2.19

29.54511897

2.27

33.58951748

2.34

37.98845742

2.42

42.63688947

2.54

50.33175156

2.66

58.99831979

2.77

68.54467601

2.89

79.7061654

3.01

90.04039146

3.12

102.0028819

3.24

114.9764719

3.36

129.1712601

3.48

144.5478532

3.59

161.106251

3.71

178.8333223

3.83

197.8472478

3.95

218.2399455

4.06

240.0902023

4.18

263.4636742

4.3

288.4785416

4.41

315.174198

4.49

333.8073197

4.57

353.3464917

4.61

363.4837503

4.65

373.8442387

4.69

384.4016946

Scaling Based of a 3 inch intake pipe hope this helps.

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