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Old 04-07-2010, 11:07 PM   #1
bswilmington
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Default perrin big maf scaling??

im about to purchase a perrin big maf intake and was wondering if anyone had the maf scaling for it?
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Old 04-08-2010, 11:21 AM   #2
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Ttt..
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Old 04-08-2010, 01:28 PM   #3
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Default Re: perrin big maf scaling??

77mm (new intake) / 65mm (stock intake) = x

take x and multiply it to stock maf scaling, that should give you a base, then ho from there
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Old 04-08-2010, 05:09 PM   #4
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nice formula and makes sense thanks
ill do this unless someone already has them and is willing to share
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Old 04-14-2010, 04:32 AM   #5
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nope! don't use this! you need to use the SQUARES of each value. so it would be:

(77mm X 77mm) / (65mm X 65mm) = X

then (X) Multiplied by the stock MAF table. and you'll still probably need to scale it, but this might get you in the ballpark. good luck!
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Old 04-14-2010, 10:15 AM   #6
the suicidal eggroll
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Quote:
Originally Posted by Nuke209 View Post
77mm (new intake) / 65mm (stock intake) = x

take x and multiply it to stock maf scaling, that should give you a base, then ho from there
The MAF scaling follows the cross sectional area of the tube, NOT the diameter. The cross sectional area is proportional to the square of the radius (or the square of the diameter, doesn't really matter), as lil'redwagon pointed out.
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Old 04-14-2010, 11:49 AM   #7
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so i use the formula 77squared/65squared = x

do i multiply x to the voltage or g/s?

im guessing the g/s since flow is increased and voltage of sensor should stay the same
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Old 04-14-2010, 11:57 AM   #8
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Right, g/s
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Old 04-14-2010, 01:27 PM   #9
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thank you guys
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Old 05-21-2010, 03:10 PM   #10
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quick question for someone with good knowledge on intake tuning
1) should i raise the maf limit maximun over 300 with big maf?.
2) should i raise engne load limit over 4.0?

neither of these will probaly matter now since i still have vf39 but i should be on 20g by end of year or so.

anything else you guys could think of would be helpful. also i lowered my timing and added fuel to be safe on 1st tune.
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Old 05-21-2010, 08:22 PM   #11
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Originally Posted by bswilmington View Post
1) should i raise the maf limit maximun over 300 with big maf?.
2) should i raise engne load limit over 4.0?

neither of these will probaly matter now since i still have vf39 but i should be on 20g by end of year or so.
You might as well do those anyway, it won't hurt anything
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Old 05-21-2010, 09:15 PM   #12
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what is your suggestion to how much
maf limit 400?? maybe more
load limit?? any ideas?

i just put it on couple hours ago so ive just wrote base tune right now and am scaling maf at this point.
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Old 05-25-2010, 08:15 AM   #13
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Default perrin big maf scaling??

I just ordered one, could you post the scaling when you are don tuning?
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Old 05-25-2010, 05:22 PM   #14
bswilmington
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yeah i can give them to you
ill have to send them to you later tonight when i get home from work

use it at your own risk cause i dont know your car but my correction is very close
below 40 g/s and im still tweaking above 40 g/s but it should be damn close.

my a is around -4% b-d are less than 2%
i dont know how close your af learning are but it may upset your tune if they are very far off

also it is installed with gimmick under manifold intake and i dont know if that will throw you off any
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Old 05-25-2010, 07:34 PM   #15
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autox do you have a wideband and have you ever done maf scaling?
i started with scale on top and then went to scale on bottom
started with
started with
maf volts maf g/s
0.9375 1.7239
0.9766 1.99047
1.0156 2.2851
1.0547 2.60779
1.09375 2.95854
1.1328 3.33735
1.1719 3.77228
1.2109 4.26333
1.25 4.76841
1.28906 5.31558
1.32812 5.91887
1.36719 6.63619
1.42625 7.32366
1.5044 8.76875
1.5825 10.3962
1.66062 12.164
1.73878 14.1282
1.7969 16.2888
1.875 18.6599
1.9531 21.2274
2.03125 24.2017
2.10938 27.611
2.1875 31.3991
2.26562 35.6362
2.34375 40.3643
2.42188 45.4011
2.5391 53.6227
2.65625 62.8965
2.7734 73.1384
2.8906 84.0397
3.0078 95.7968
3.125 108.508
3.2422 122.3
3.3594 137.27
3.4766 153.53
3.59375 171.124
3.7109 189.994
3.8281 210.576
3.9453 233.094
4.0625 258.447
4.1797 285.426
4.2969 313.065
4.4141 341.378
4.4922 360.711
4.5703 381.77
4.6094 392.924
4.6484 404.317
4.6875 415.947
4.7266 427.424
4.7656 439.251
4.8047 451.303
4.8438 463.593
4.8828 476.108
4.9219 488.875

then went with
final
maf volts maf g/s
0.9375 1.7239
0.9766 1.99047
1.0156 2.2851
1.0547 2.60779
1.09375 2.95854
1.1328 3.33735
1.1719 3.77228
1.2109 4.26333
1.25 4.76841
1.28906 5.31558
1.32812 5.91887
1.36719 6.63619
1.42625 7.32366
1.5044 8.76875
1.5825 10.3962
1.66062 12.164
1.73878 14.1282
1.7969 16.2888
1.875 18.6599
1.9531 21.2274
2.03125 24.2017
2.10938 27.611
2.1875 31.3991
2.26562 35.6362
2.34375 40.3643
2.42188 45.4011
2.5391 48.658
2.65625 54.81
2.7734 64.026
2.8906 75.636
3.0078 86.22
3.125 99.459
3.2422 113.67
3.3594 127.143
3.4766 145.377
3.59375 153.108
3.7109 165.591
3.8281 184.122
3.9453 205.281
4.0625 232.605
4.1797 256.887
4.2969 281.763
4.4141 307.242
4.4922 324.639
4.5703 343.593
4.6094 353.628
4.6484 363.888
4.6875 374.355
4.7266 384.678
4.7656 395.325
4.8047 406.17
4.8438 417.231
4.8828 428.499
4.9219 439.992

here is screen shot of learning view
Code:
CAL ID:A2ZJE11J
Description: 06 USDM Impreza STi MT
ECU ID:4312594006

IAM    1.0000

A/F Learning #1:
0 - <5.60    5.60 - <10.00    10.00 - <40.00    40.00+
-3.70        -3.30            -0.90             -0.50 

FLKC Table      0 - <0.90    0.90 - <1.20    1.20 - <1.50    1.50 - <1.90    1.90+
0 - <2400       0.00         0.00            0.00            0.00            0.00 
2400 - <3000    0.00         0.00            0.00            0.00            0.00 
3000 - <3600    0.00         0.00            0.00            0.00            0.00 
3600 - <4200    0.00         0.00            0.00            0.00            0.00 
4200 - <5000    0.00         0.00            0.00            0.00            0.00 
5000 - <5800    0.00         0.00            0.00            0.00            0.00 
5800+           0.00         0.00            0.00            0.00            0.00
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Old 05-25-2010, 09:57 PM   #16
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Quote:
Originally Posted by bswilmington View Post
autox do you have a wideband and have you ever done maf scaling?
Did you tune that with the stock injectors or bigger?
if so, which injectors
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Old 05-26-2010, 12:56 AM   #17
bswilmington
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stock injectors but i do have size set to 513

another thing is its tuned with meth so top end fuel may be off some if somebody else uses it. i would only use this scaling if you have a wideband to make sure wot fueling is correct
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Old 05-27-2010, 02:12 PM   #18
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Default perrin big maf scaling??

Thank for the info, I have a wideband and will add fuel, take away timing. I just wanted a starting point.
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Old 05-27-2010, 02:15 PM   #19
bswilmington
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thats good to hear

the 1st maf scaling was a little rich to me, around 10.5:1 but i think my meth was on, so that maybe closer to what you need.
i got the second one by multipling everything above 40 g/s by 90% which made it almost dead on for me.
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Old 09-10-2012, 03:41 PM   #20
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i know this is an old thread but i have a perrin cai and im going to get it tuned in a day or 2. but what we need to save time and to help out is cai maf scaling's. i have looked but have not seen anything online or on this forum. if anyone has something for an 08+ wrx that would help a tone.
this is what i have
08 wrx
perrin cai
3" cat less turbo back
1.5 tune currently
stock td04 turbo
stock tmic

any help would be great.
thanks
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