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View Full Version : B4349 ETC Throttle Area Conversion Info


TFZ_Z06
August 30th, 2015, 05:39 PM
For those interested, I created a basic chart of theoretical data for this field:

Here is the formula:
B4349 ETC Throttle Area Conversion (% per Square mm) = 100/(PI * R^2)



Example1 (stock LS6 throttle blade from my intake)
Blade was 70.66mm in diameter, radius = 35.333

Calculated:
100/(3.1415 *35.333^2) = 0.025501

Factory Setting:
Stock factory setting = 0.025497

Example2 (102mm TB)

100/(3.1415*51*51) = 0.01223798101437103696800336511899

Table of Theoretical Data
TB SIZE SQUARE MM (PI*R^2) % PER SQUARE MM
102.00 8171.2825 0.01223798101437100000
101.90 8155.2682 0.01226201239005670000
101.80 8139.2697 0.01228611461989840000
101.70 8123.2868 0.01231028798271240000
101.60 8107.3197 0.01233453275868740000
101.50 8091.3682 0.01235884922939320000
101.40 8075.4325 0.01238323767778870000
101.30 8059.5125 0.01240769838823000000
101.20 8043.6082 0.01243223164647900000
101.10 8027.7196 0.01245683773971150000
101.00 8011.8467 0.01248151695652550000
100.90 7995.9895 0.01250626958695000000
100.80 7980.1480 0.01253109592245330000
100.70 7964.3222 0.01255599625595170000
100.60 7948.5122 0.01258097088181800000
100.50 7932.7178 0.01260602009589030000
100.40 7916.9392 0.01263114419548060000
100.30 7901.1762 0.01265634347938400000
100.20 7885.4290 0.01268161824788710000
100.10 7869.6975 0.01270696880277720000
100.00 7853.9816 0.01273239544735160000
99.90 7838.2815 0.01275789848642600000
99.80 7822.5971 0.01278347822634410000
99.70 7806.9284 0.01280913497498670000
99.60 7791.2754 0.01283486904178120000
99.50 7775.6382 0.01286068073771020000
99.40 7760.0166 0.01288657037532190000
99.30 7744.4107 0.01291253826873880000
99.20 7728.8206 0.01293858473366730000
99.10 7713.2461 0.01296471008740780000
99.00 7697.6874 0.01299091464886400000
98.90 7682.1444 0.01301719873855240000
98.80 7666.6170 0.01304356267861260000
98.70 7651.1054 0.01307000679281680000
98.60 7635.6095 0.01309653140658010000
98.50 7620.1293 0.01312313684697010000
98.40 7604.6648 0.01314982344271720000
98.30 7589.2161 0.01317659152422470000
98.20 7573.7830 0.01320344142357920000
98.10 7558.3656 0.01323037347456060000
98.00 7542.9640 0.01325738801265260000
97.90 7527.5780 0.01328448537505340000
97.80 7512.2078 0.01331166590068580000
97.70 7496.8532 0.01333892993020810000
97.60 7481.5144 0.01336627780602450000
97.50 7466.1913 0.01339370987229620000
97.40 7450.8839 0.01342122647495200000
97.30 7435.5922 0.01344882796169920000
97.20 7420.3162 0.01347651468203480000
97.10 7405.0559 0.01350428698725610000
97.00 7389.8113 0.01353214523047250000
96.90 7374.5824 0.01356008976661600000
96.80 7359.3693 0.01358812095245320000
96.70 7344.1718 0.01361623914659630000
96.60 7328.9901 0.01364444470951430000
96.50 7313.8240 0.01367273800354540000
96.40 7298.6737 0.01370111939290770000
96.30 7283.5391 0.01372958924371160000
96.20 7268.4202 0.01375814792397110000
96.10 7253.3170 0.01378679580361630000
96.00 7238.2295 0.01381553325450470000
95.90 7223.1577 0.01384436065043370000
95.80 7208.1016 0.01387327836715270000
95.70 7193.0612 0.01390228678237520000
95.60 7178.0366 0.01393138627579120000
95.50 7163.0276 0.01396057722907980000
95.40 7148.0343 0.01398986002592150000
95.30 7133.0568 0.01401923505201060000
95.20 7118.0950 0.01404870269506870000
95.10 7103.1488 0.01407826334485650000
95.00 7088.2184 0.01410791739318730000
94.90 7073.3037 0.01413766523393990000
94.80 7058.4047 0.01416750726307160000
94.70 7043.5214 0.01419744387863140000
94.60 7028.6538 0.01422747548077310000
94.50 7013.8019 0.01425760247176900000
94.40 6998.9658 0.01428782525602320000
94.30 6984.1453 0.01431814424008520000
94.20 6969.3406 0.01434855983266340000
94.10 6954.5515 0.01437907244463910000
94.00 6939.7782 0.01440968248908050000
93.90 6925.0205 0.01444039038125610000
93.80 6910.2786 0.01447119653864950000
93.70 6895.5524 0.01450210138097300000
93.60 6880.8419 0.01453310533018240000
93.50 6866.1471 0.01456420881049100000
93.40 6851.4680 0.01459541224838430000
93.30 6836.8046 0.01462671607263450000
93.20 6822.1569 0.01465812071431540000
93.10 6807.5250 0.01468962660681720000
93.00 6792.9087 0.01472123418586140000
92.90 6778.3082 0.01475294388951570000
92.80 6763.7233 0.01478475615820950000
92.70 6749.1542 0.01481667143474910000
92.60 6734.6008 0.01484869016433290000
92.50 6720.0630 0.01488081279456710000
92.40 6705.5410 0.01491303977548150000
92.30 6691.0347 0.01494537155954480000
92.20 6676.5441 0.01497780860168110000
92.10 6662.0692 0.01501035135928520000
92.00 6647.6101 0.01504300029223940000
91.90 6633.1666 0.01507575586292930000
91.80 6618.7388 0.01510861853626030000
91.70 6604.3268 0.01514158877967420000
91.60 6589.9304 0.01517466706316560000
91.50 6575.5498 0.01520785385929880000
91.40 6561.1848 0.01524114964322480000
91.30 6546.8356 0.01527455489269810000
91.20 6532.5021 0.01530807008809380000
91.10 6518.1843 0.01534169571242500000
91.00 6503.8822 0.01537543225136030000
90.90 6489.5958 0.01540928019324110000
90.80 6475.3251 0.01544324002909940000
90.70 6461.0701 0.01547731225267570000
90.60 6446.8309 0.01551149736043670000
90.50 6432.6073 0.01554579585159360000
90.40 6418.3995 0.01558020822812020000
90.30 6404.2073 0.01561473499477130000
90.20 6390.0309 0.01564937665910130000
90.10 6375.8701 0.01568413373148280000
90.00 6361.7251 0.01571900672512520000
89.90 6347.5958 0.01575399615609410000
89.80 6333.4822 0.01578910254332990000
89.70 6319.3843 0.01582432640866730000
89.60 6305.3021 0.01585966827685480000
89.50 6291.2356 0.01589512867557370000
89.40 6277.1849 0.01593070813545860000
89.30 6263.1498 0.01596640719011680000
89.20 6249.1304 0.01600222637614800000
89.10 6235.1268 0.01603816623316520000
89.00 6221.1389 0.01607422730381440000
88.90 6207.1666 0.01611041013379550000
88.80 6193.2101 0.01614671527188260000
88.70 6179.2693 0.01618314326994510000
88.60 6165.3442 0.01621969468296830000
88.50 6151.4348 0.01625637006907520000
88.40 6137.5411 0.01629316998954700000
88.30 6123.6631 0.01633009500884510000
88.20 6109.8008 0.01636714569463260000
88.10 6095.9542 0.01640432261779630000
88.00 6082.1234 0.01644162635246820000
87.90 6068.3082 0.01647905747604820000
87.80 6054.5088 0.01651661656922620000
87.70 6040.7250 0.01655430421600460000
87.60 6026.9570 0.01659212100372100000
87.50 6013.2047 0.01663006752307120000
87.40 5999.4681 0.01666814436813220000
87.30 5985.7472 0.01670635213638560000
87.20 5972.0420 0.01674469142874050000
87.10 5958.3525 0.01678316284955780000
87.00 5944.6787 0.01682176700667380000
86.90 5931.0206 0.01686050451142390000
86.80 5917.3783 0.01689937597866720000
86.70 5903.7516 0.01693838202681080000
86.60 5890.1407 0.01697752327783410000
86.50 5876.5454 0.01701680035731410000
86.40 5862.9659 0.01705621389445000000
86.30 5849.4020 0.01709576452208850000
86.20 5835.8539 0.01713545287674940000
86.10 5822.3215 0.01717527959865070000
86.00 5808.8048 0.01721524533173520000
85.90 5795.3038 0.01725535072369580000
85.80 5781.8185 0.01729559642600200000
85.70 5768.3490 0.01733598309392670000
85.60 5754.8951 0.01737651138657220000
85.50 5741.4569 0.01741718196689760000
85.40 5728.0345 0.01745799550174590000
85.30 5714.6277 0.01749895266187110000
85.20 5701.2367 0.01754005412196560000
85.10 5687.8614 0.01758130056068870000
85.00 5674.5017 0.01762269266069390000
84.90 5661.1578 0.01766423110865740000
84.80 5647.8296 0.01770591659530660000
84.70 5634.5171 0.01774774981544880000
84.60 5621.2203 0.01778973146800030000
84.50 5607.9392 0.01783186225601530000
84.40 5594.6739 0.01787414288671540000
84.30 5581.4242 0.01791657407151960000
84.20 5568.1902 0.01795915652607370000
84.10 5554.9720 0.01800189097028100000
84.00 5541.7694 0.01804477812833240000
83.90 5528.5826 0.01808781872873710000
83.80 5515.4115 0.01813101350435360000
83.70 5502.2561 0.01817436319242120000
83.60 5489.1163 0.01821786853459070000
83.50 5475.9923 0.01826153027695690000
83.40 5462.8840 0.01830534917009030000
83.30 5449.7915 0.01834932596906900000
83.20 5436.7146 0.01839346143351180000
83.10 5423.6534 0.01843775632761090000
83.00 5410.6079 0.01848221142016450000
82.90 5397.5782 0.01852682748461060000
82.80 5384.5641 0.01857160529906080000
82.70 5371.5658 0.01861654564633360000
82.60 5358.5832 0.01866164931398920000
82.50 5345.6162 0.01870691709436370000
82.40 5332.6650 0.01875234978460400000
82.30 5319.7295 0.01879794818670290000
82.20 5306.8097 0.01884371310753440000
82.10 5293.9056 0.01888964535888960000
82.00 5281.0173 0.01893574575751230000
81.90 5268.1446 0.01898201512513590000
81.80 5255.2876 0.01902845428851940000
81.70 5242.4463 0.01907506407948490000
81.60 5229.6208 0.01912184533495420000
81.50 5216.8110 0.01916879889698710000
81.40 5204.0168 0.01921592561281880000
81.30 5191.2384 0.01926322633489810000
81.20 5178.4757 0.01931070192092630000
81.10 5165.7287 0.01935835323389590000
81.00 5152.9974 0.01940618114212960000
80.90 5140.2818 0.01945418651932030000
80.80 5127.5819 0.01950237024457050000
80.70 5114.8977 0.01955073320243290000
80.60 5102.2292 0.01959927628295110000
80.50 5089.5764 0.01964800038170020000
80.40 5076.9394 0.01969690639982800000
80.30 5064.3180 0.01974599524409750000
80.20 5051.7124 0.01979526782692770000
80.10 5039.1225 0.01984472506643730000
80.00 5026.5482 0.01989436788648630000
79.90 5013.9897 0.01994419721671990000
79.80 5001.4469 0.01999421399261190000
79.70 4988.9198 0.02004441915550820000
79.60 4976.4084 0.02009481365267170000
79.50 4963.9127 0.02014539843732640000
79.40 4951.4328 0.02019617446870300000
79.30 4938.9685 0.02024714271208380000
79.20 4926.5199 0.02029830413884940000
79.10 4914.0871 0.02034965972652390000
79.00 4901.6699 0.02040121045882260000
78.90 4889.2685 0.02045295732569860000
78.80 4876.8828 0.02050490132339020000
78.70 4864.5128 0.02055704345446930000
78.60 4852.1584 0.02060938472788950000
78.50 4839.8198 0.02066192615903480000
78.40 4827.4969 0.02071466876976910000
78.30 4815.1897 0.02076761358848580000
78.20 4802.8983 0.02082076165015790000
78.10 4790.6225 0.02087411399638860000
78.00 4778.3624 0.02092767167546220000
77.90 4766.1181 0.02098143574239570000
77.80 4753.8894 0.02103540725899110000
77.70 4741.6765 0.02108958729388710000
77.60 4729.4792 0.02114397692261260000
77.50 4717.2977 0.02119857722763980000
77.40 4705.1319 0.02125338929843820000
77.30 4692.9818 0.02130841423152880000
77.20 4680.8474 0.02136365313053900000
77.10 4668.7287 0.02141910710625810000
77.00 4656.6257 0.02147477727669280000
76.90 4644.5384 0.02153066476712390000
76.80 4632.4669 0.02158677071016300000
76.70 4620.4110 0.02164309624580970000
76.60 4608.3708 0.02169964252151000000
76.50 4596.3464 0.02175641069221440000
76.40 4584.3377 0.02181340192043660000
76.30 4572.3446 0.02187061737631360000
76.20 4560.3673 0.02192805823766570000
76.10 4548.4057 0.02198572569005640000
76.00 4536.4598 0.02204362092685450000
75.90 4524.5296 0.02210174514929520000
75.80 4512.6151 0.02216009956654280000
75.70 4500.7163 0.02221868539575350000
75.60 4488.8332 0.02227750386213840000
75.50 4476.9659 0.02233655619902830000
75.40 4465.1142 0.02239584364793800000
75.30 4453.2783 0.02245536745863140000
75.20 4441.4580 0.02251512888918750000
75.10 4429.6535 0.02257512920606720000
75.00 4417.8647 0.02263536968417970000
74.90 4406.0916 0.02269585160695100000
74.80 4394.3341 0.02275657626639150000
74.70 4382.5924 0.02281754496316560000
74.60 4370.8664 0.02287875900666130000
74.50 4359.1562 0.02294021971505990000
74.40 4347.4616 0.02300192841540770000
74.30 4335.7827 0.02306388644368720000
74.20 4324.1195 0.02312609514488980000
74.10 4312.4721 0.02318855587308810000
74.00 4300.8403 0.02325126999151040000
73.90 4289.2243 0.02331423887261440000
73.80 4277.6240 0.02337746389816300000
73.70 4266.0394 0.02344094645929920000
73.60 4254.4704 0.02350468795662340000
73.50 4242.9172 0.02356868980027040000
73.40 4231.3797 0.02363295340998720000
73.30 4219.8579 0.02369748021521200000
73.20 4208.3519 0.02376227165515370000
73.10 4196.8615 0.02382732917887170000
73.00 4185.3868 0.02389265424535760000
72.90 4173.9279 0.02395824832361650000
72.80 4162.4846 0.02402411289274970000
72.70 4151.0571 0.02409024944203830000
72.60 4139.6452 0.02415665947102700000
72.50 4128.2491 0.02422334448960960000
72.40 4116.8687 0.02429030601811420000
72.30 4105.5040 0.02435754558739050000
72.20 4094.1550 0.02442506473889670000
72.10 4082.8217 0.02449286502478840000
72.00 4071.5041 0.02456094800800740000
71.90 4060.2022 0.02462931526237190000
71.80 4048.9160 0.02469796837266750000
71.70 4037.6456 0.02476690893473900000
71.60 4026.3908 0.02483613855558310000
71.50 4015.1518 0.02490565885344220000
71.40 4003.9284 0.02497547145789890000
71.30 3992.7208 0.02504557800997110000
71.20 3981.5289 0.02511598016220920000
71.10 3970.3526 0.02518667957879300000
71.00 3959.1921 0.02525767793562980000
70.90 3948.0473 0.02532897692045450000
70.80 3936.9182 0.02540057823292910000
70.70 3925.8049 0.02547248358474460000
70.60 3914.7072 0.02554469469972270000
70.50 3903.6252 0.02561721331391980000
70.40 3892.5590 0.02569004117573080000
70.30 3881.5084 0.02576318004599470000
70.20 3870.4736 0.02583663169810100000
70.10 3859.4544 0.02591039791809740000
70.00 3848.4510 0.02598448050479790000
Highlander
August 31st, 2015, 12:35 AM
You are missing something in that formula... and it doesn't always work well that way.
TFZ_Z06
August 31st, 2015, 12:59 AM
You are missing something in that formula... and it doesn't always work well that way.

There are a lot of things people do to their tunes that don't work well. Keep working with it and you'll get it.
Note, the obvious part above, it says THEORETICAL data.
Highlander
August 31st, 2015, 01:04 AM
No,

YOU need to keep working on it. As you can see not even your 78mm calculation matches what is in the calibration. Good Luck!
TFZ_Z06
August 31st, 2015, 01:58 AM
No,

YOU need to keep working on it. As you can see not even your 78mm calculation matches what is in the calibration. Good Luck!

The 78 is not really 78mm. See my first post. Your a smart guy. Appreciate if you try to enhance the conversation. Negative comments don't help much.
Have a great day!
monkeywrenched
September 1st, 2015, 03:39 AM
So you are saying that the original calculation is off, and by changing this it helps?
TFZ_Z06
September 1st, 2015, 03:24 PM
So you are saying that the original calculation is off, and by changing this it helps?

No, I never said the calculation was off. In fact, I think its right on. However, if you go from a "78mm" to a "90mm", then yes it would in theory be off. Obviously, the pcm uses that field somewhere in its airflow calculations.

I derived the formula by measuring the actual diameter of the throttle blade. Based on the units listed in EFI Live's software, "% PER SQUARE MM" and the area of a circle, the equation is the result. Its just straight forward math.

As far as tuning goes, I have seen some that never change this field and others have random numbers they use that they claim is the magic number. I plan to look at other airflow params for relations to this one.
monkeywrenched
September 2nd, 2015, 02:47 AM
But if the maf calculates airflow then it assumes it knows the amount of air going into the chamber and any difference would be viewed as unmetered air so this would change its calc on what it thinks it's suppose to have. I think, but if that's right wouldn't the test b to change the throttle body itself and calculate it and see if a maf code is set.
joecar
September 2nd, 2015, 02:58 AM
But if the maf calculates airflow then it assumes it knows the amount of air going into the chamber and any difference would be viewed as unmetered air so this would change its calc on what it thinks it's suppose to have. I think, but if that's right wouldn't the test b to change the throttle body itself and calculate it and see if a maf code is set.PCM needs to know the area of the throttle plate/bore so it knows how to manipulate/predict ETC.
monkeywrenched
September 2nd, 2015, 02:59 AM
Ahhh I get it