LOL, I took my car to the track with the stock clutch and just rolled off the line like I was at a stop light and ran a similar time. 13.4 @ 117 on pump baby!

 

Also the stock maf is at about 28 in.H20 pressure drop at about 1060 KG/HR that's about 1750HZ and jumps to 65 in. H20 at 1905 KG/HR so If you are getting readings higher than that, you have a serious bottle neck.

I'll post up the actual data later today.

 

Actually that makes sense, since the stock turbo and the stock "Setup" would typically never see over 1900hz, in fact even with really high boost levels when my car had the stock MAF and stock Turbo, it never went over 2000hz..

 

With a "White Rabbit" I'm seeing readings as high as 2100 Hz at 21 psi and 7500 RPM. As soon as I get a new intake welded up I'll do a few back to back pulls with and without the MAF and see if the road dyno shows any differences.

-Paul

 

Here's the actual data from yesterday.

sorry it's all compressed but I don't know how to correctly post it.






Professional Mass Air Systems
720 terminal Rd.
Lansing, MI 48906
517-327-3900

*** 37pt FLOW TEST FOR MASS AIR FLOW METER ***

DATE: 15 Oct 2006 TIME: 18:16:38 BARO: 29.147 TEMP: 60.3 HUM: 33%
Air Density: 1.1835 kg/m3
Ser No: 06C02590 Calibration: KARMAN 10
evo8 test stock airbox 2500kghr

ACTUAL AVG. PRESSURE
FLOW 90 SAMPS. SIGMA DROP Calc % %
KG./Hr. KHZ KHZ In. H2O KGH ERROR NOISE

2497.34 3.090 .140 66.520 5.38 -40.04 3.00
2563.54 3.130 .127 67.742 5.41 -39.01 2.71
2214.13 3.098 .163 66.923 5.39 -45.16 3.49
1905.57 3.023 .137 65.145 5.35 -52.48 2.97
1671.91 2.749 .134 55.514 5.19 -59.81 2.97
1432.06 2.454 .084 46.800 5.02 -69.83 1.93
1232.77 2.110 .066 36.118 4.82 -81.12 1.58
1053.60 1.753 .053 26.722 4.61 -94.91 1.32
898.37 1.434 .042 18.759 4.43 -99.51 1.08
766.16 1.197 .034 13.827 4.29 -99.44 .92
654.41 1.019 .028 10.251 4.19 -99.36 .77
559.14 .873 .024 7.528 4.10 -99.27 .68
479.17 .746 .022 5.637 4.03 -99.16 .63
409.57 .645 .017 4.209 3.97 -99.03 .51
352.23 .558 .013 3.175 3.92 -98.89 .38
300.38 .484 .011 2.362 3.88 -98.71 .32
258.76 .419 .011 1.800 3.84 -98.51 .33
222.19 .366 .008 1.352 3.81 -98.28 .26
188.91 .314 .007 1.016 3.78 -98.00 .22
162.33 .274 .007 .791 3.76 -97.68 .23
140.40 .240 .007 .600 3.74 -97.34 .20
120.40 .206 .006 .467 3.72 -96.91 .19
101.90 .177 .007 .351 3.70 -96.37 .21
87.18 .156 .007 .266 3.69 -95.77 .21
75.21 .135 .004 .202 3.68 -95.11 .14
64.91 .117 .004 .169 3.67 -94.35 .11
56.53 .102 .002 .143 3.66 -93.53 .07
50.84 .092 .002 .131 3.65 -92.81 .06
44.55 .082 .002 .118 3.65 -91.81 .05
38.99 .072 .001 .097 3.64 -90.66 .04
33.29 .062 .001 .095 3.64 -89.08 .04
26.74 .051 .001 .077 3.63 -86.42 .04
21.41 .041 .001 .070 3.62 -83.07 .03
15.12 .030 .001 .062 3.62 -76.08 .02
12.26 .024 0.000 .067 3.62 -70.50 .02
9.42 .019 0.000 .049 3.61 -61.67 .01
0.00 4.615 5.340 0.000 6.26 0.00 0.00

 

awdgsx91 that looks like fantastic data, but I can't make out what all the columns are.

I can see 7 columns but I'm not sure on the labelling, can you run me across from left to right with the data item and unit for each one please?

 

actual flow KG/HR <2497.34> ----- avarage 90 samples KHZ <3.090> ------ pressure drop in.h20 <66.52> ----- calculated kgh <5.38> (calc. flow based on equasion i used and freq. sample form the maf) (n/A for this one) -------- %error <-40.04> (difference between what the maf read and what the equasion says it should be) --------- noise <3.00%>(the spikes in hz, the variance between the 90 samples taken)

 

*** 37pt FLOW TEST FOR MASS AIR FLOW METER ***

DATE: 16 Oct 2006 TIME: 13:46:10 BARO: 29.181 TEMP: 61.1 HUM: 42%
Air Density: 1.1824 kg/m3
Ser No: 06C02592 Calibration: EVO8 560

EVO8 STOCK AIRBOX


actual flow---sample---sigma---p.drop--calc. flow--%-------------%
KG./Hr.--------KHZ--------KHZ----In. H2O----KGH-----ERROR-----NOISE

2062.20 =2.892 = 1.171 = 69.239 = 1677.50 = -18.66 = 53.86
2139.24 = =3.156 = .143 = 69.999 = 1810.52 = -15.37 = 7.31
1854.91 = 3.107= .145 = 67.598 = 1786.34 = -3.70 = 7.62
1636.58 = 2.751= .119 = 55.660 = 1601.83 = -2.12 = 7.87
1395.63 = 2.431= .076 = 45.580 = 1419.06 = 1.68= 6.25
1199.32 = 2.055= .064 = 34.572 = 1202.53 = .27 = 5.88
1024.41= 1.694= .048= 24.890 = 1025.99 = .15 =4.42
871.95 = 1.383 = .037 = 17.551 = 870.85 = -.13 = 4.54
741.39 = 1.165 = .031 = 12.840 = 746.27= .66 =4.97
635.92 = .997 = .021 = 9.568 = 641.97 = .95 = 4.20
543.47 = .852 = .022 = 7.067 = 547.84 = .80 = 5.26
464.32 = .733 = .021= 5.275 = 468.48 = .90 = 5.96
398.71 = .634 = .015= 3.958 = 402.46 = .94 = 5.18
340.48 = .549 = .012= 2.983 = 344.64 = 1.22 = 4.67
293.06 = .475 = .011= 2.266 = 295.16 = .71 = 4.88
250.42 = .411 = .009= 1.740 = 252.39 = .79 = 4.50
215.08 = .359 = .007= 1.348 = 217.78 = 1.25 = 4.44
184.99 = .309 = .007= 1.055 = 185.44= .24 = 4.84
156.77 = .266 = .005= .805 = 157.31 = .34 = 4.40
135.46 = .232 = .005= .638 = 135.75 = .21 = 5.11
117.53 = .201 = .006= .510 = 116.51 = -.87 = 6.05
100.02 = .175 = .005= .413 = 100.07 = .05 = 6.18
85.11= .152 = .005 = .334 = 86.00 = 1.04 =7.58
72.49= .132 = .006 = .278 = 73.94 = 2.00 = 10.06
62.01= .112 = .003 = .231 = 62.27 = .41 =5.11
55.47= .100 = .002 = .213 = 55.48 = .01 =4.85
47.36= .086 = .002 = .184 = 47.16 = -.42 =4.63
42.69= .078 = .002 = .171 = 42.40 = -.68 = 5.30
37.14= .068 = .001 = .159 = 36.84 = -.81 = 4.44
31.63= .059 = .001 = .156 = 31.56 = -.21 = 4.85
27.76= .052 = .001 = .155 = 27.82 = .20 = 5.43
22.21= .042 = .001 = .147 = 22.19 = -.08 = 4.35
17.54= .034 = .001 = .150 = 17.51 = -.16 = 5.18



These are the results from today using the equation i posted for jack yesterday.

 

Thanks. Shows the non-linearity after 3100 Hz well.

30 inH20 pres drop (is this including the snorkel and lid?) at a typical max flow for the stock turbo fits with barometer readings from the MAF sensor I've seen with the airbox lid on.

 

yes, this is with the complete airbox.

It also looks like the stock maf is done around 2700 hz. That's when the - error numbers start, probably losing count.

 

That is 60 lb/min though Quite impressive it goes that far, although the pressure drop of 2PSI wouldn't be amusing, although in my on-car testing the snorkel and/or lid are the source of half of the drop at 40 lb/min sort of airflows.

 

...

 

So, at 2700hz, where would that be reached on a set up like mine? Roughly what psi of boost and rpm on a 2.3 with a 35R?

 

I made an interesting observation today in ECUFlash.. I may be way off, but I was playing with the scaling settings and decided to make one for MAFHz (x/6.29 & 6.29*x, uInt16, little endian, it suffers from a slight rounding error though)

When I did this, I noticed that the g/s values started to correlate in the with MAFHz I have seen on the roms (Maf scaling and MAF Smoothing tables) Although I'm not completely sure this is even correct, the values in the left column for HZ, seem to correlate real closely..

Does anyone have any data on a rough g/s vs MAF HZ that they can post? Even if its inferrential data from logs off the ECU. The reason I'm asking is I think it makes that missing link on how to work with troublesome maf anomolies directly with the ECU.

I also think the 6.29 value is derived from the MAF Size in some way, and therefore altering the size obviously will alter the MAF value vs digital raw value.

 

I completely forgot to mention.. I got this number from the MafHz calculation in the loggers... But what is interesting....

the last cell on the column's value is 16384, which conveniently converts to 2604.77 which appears to be the highest value that the stock MAF may accurately read at...

Makes you say Hmmmmm.. Eh?

The Stock MAF size is set to 357.5 g/s according to ECUFlash, although I can't put my finger on it, there is definitely a relationship to this value and the 6.29 scale value used to convert the raw MAF value in the ECU Logs to Hz.