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[Foowee]

Anyone that has used a real flow bench, how well do you think this one works?

Flow Bench Build

Cylinder Head Flow Test

[d112crzy]

Probably useless to compare the numbers it produces to any real flow bench. Just like dyno's, flowbench results will vary from bench to bench. What matters is consistency. As long as you have your own benchmark to go by then you're good.

[PhilStubbs]

I was curious about this too. I have been considering building one lately. I read about using for MAF sensors to measure flow. I'm sure the data would be useless except to compare to your own testing.

It would be useful to see gains and keep all of the ports the same though

[nock]

make yourself a peedo tube and get a manometer it will be more accurate, and think about getting something like 6-8 vacuums to get real numbers. i think hotrod magazine had a few articles about this.

the one we made used an 80 gallon air compressor tank with a release valve and a 4 inch pipe going to the cylinder, i really wished we finished it because the math said it would pull harder then all but the biggest benches and still use a small three stage pump.

also HVAC guys have a meter for balancing duct flow, (looks like a DMM with an antenna) they are fairly accurate and read CFM directly they can also read air temp and air speed. maybe you could find one on CL.

[kgx]

I was curious about this too. I have been considering building one lately. I read about using for MAF sensors to measure flow. I'm sure the data would be useless except to compare to your own testing.

It would be useful to see gains and keep all of the ports the same though

the data wouldn't be useless if you had the transfer function for the MAF sensors. i'm pretty sure there is data out there published for the bosch 0-5v sensors as well as the frequency sensors. in fact, i know i've seen the data for the GM 3" MAF.

edit: here it is. sorry for the horseshit formatting:
MAF Type 6.0L truck 5.3L truck Truck ZL1 02 01 Z06 98 Fbody 99-00 Fbody 02 Fbody
freq Hz flow gm/s flow gm/s flow gm/s flow gm/s flow gm/s flow gm/s flow gm/s
750 0 0.14 0.2 0.39 0 0 0.39
800 0 0.2 0.27 0.41 0 0 0.41
850 0 0.27 0.34 0.44 0 0 0.44
900 0 0.34 0.41 0.46 0 0 0.46
950 0 0.41 0.49 0.48 0 0 0.48
1000 0 0.49 0.58 0.5 0 0 0.5
1050 0 0.58 0.66 0.52 0 0 0.52
1100 0 0.66 0.73 0.54 0 0 0.54
1150 0 0.73 0.81 0.56 0 0 0.56
1200 0 0.81 0.89 0.58 0 0 0.58
1250 0 0.89 0.97 0.6 0 0 0.6
1300 0 0.97 1.05 0.62 0 0 0.62
1350 0 1.05 1.13 0.64 0 0 0.64
1400 0 1.13 1.21 0.66 0 0 0.66
1450 0 1.21 1.29 0.68 0 0 0.68
1500 1.59 1.29 1.59 1.48 2.32 2.32 2.32
1625 1.88 1.59 1.88 1.8 2.7 2.7 2.7
1750 2.2 1.88 2.2 2.13 3.15 3.15 3.15
1875 2.58 2.2 2.58 2.49 3.65 3.65 3.65
2000 2.99 2.58 2.99 2.89 4.16 4.16 4.16
2125 3.45 2.99 3.45 3.33 4.73 4.73 4.73
2250 3.95 3.45 3.95 3.8 5.36 5.36 5.36
2375 4.5 3.95 4.5 4.34 6.05 6.05 6.05
2500 5.1 4.5 5.1 4.91 6.8 6.8 6.8
2625 5.76 5.1 5.76 5.54 7.64 7.64 7.64
2750 6.46 5.76 6.46 6.22 8.53 8.53 8.53
2875 7.23 6.46 7.23 6.95 9.47 9.47 9.47
3000 8.06 7.23 8.06 7.73 10.43 10.43 10.43
3125 8.95 8.06 8.95 8.56 11.45 11.45 11.45
3250 9.9 8.95 9.9 9.45 12.56 12.56 12.56
3375 10.9 9.9 10.91 10.38 13.78 13.78 13.78
3500 12 10.91 11.98 11.38 15.09 15.09 15.09
3625 13.1 11.98 13.14 12.45 16.49 16.49 16.49
3750 14.4 13.14 14.39 13.6 17.98 17.98 17.98
3875 15.7 14.39 15.74 14.85 19.58 19.58 19.58
4000 17.2 15.74 17.19 16.21 21.26 21.26 21.26
4125 18.7 17.19 18.74 17.7 23.03 23.03 23.03
4250 20.4 18.74 20.39 19.32 24.91 24.91 24.91
4375 22.1 20.39 22.14 21.02 26.88 26.88 26.88
4500 24 22.14 23.99 22.77 28.95 28.95 28.95
4625 26 23.99 25.95 24.54 31.13 31.13 31.13
4750 28 25.95 27.99 26.43 33.4 33.4 33.4
4875 30.1 27.99 30.14 28.41 35.78 35.78 35.78
5000 32.4 30.14 32.38 30.49 38.28 38.28 38.28
5125 34.7 32.38 34.71 32.66 40.93 40.93 40.93
5250 37.2 34.71 37.16 34.95 43.73 43.73 43.73
5375 39.7 37.16 39.73 37.36 46.69 46.69 46.69
5500 42.5 39.73 42.5 39.9 49.8 49.8 49.8
5625 45.4 42.5 45.41 42.62 53.07 53.07 53.07
5750 48.5 45.41 48.47 45.48 56.51 56.51 56.51
5875 51.7 48.47 51.67 48.5 60.11 60.11 60.11
6000 55 51.67 55.02 51.66 63.88 63.88 63.88
6125 58.5 55.02 58.48 54.98 67.8 67.8 67.8
6250 62.1 58.48 62.1 58.44 71.9 71.9 71.9
6375 65.9 62.1 65.86 62.05 76.16 76.16 76.16
6500 69.8 65.86 69.77 65.82 80.58 80.58 80.58
6625 73.8 69.77 73.82 69.73 85.16 85.16 85.16
6750 78.06 73.82 78.06 73.8 89.91 89.91 89.91
6875 82.48 78.06 82.48 78.03 94.83 94.83 94.83
7000 87.07 82.48 87.07 82.4 99.93 99.93 99.93
7125 91.82 87.07 91.82 86.94 105.2 105.2 105.2
7250 96.74 91.82 96.74 91.63 110.65 110.65 110.65
7375 101.8 96.74 101.82 96.49 116.28 116.28 116.28
7500 107.1 101.82 107.08 101.51 122.12 122.12 122.12
7625 112.5 107.08 112.48 106.71 128.15 128.15 128.15
7750 118.1 112.48 118.07 112.09 134.38 134.38 134.38
7875 123.8 118.07 123.83 117.63 140.87 140.87 140.87
8000 129.8 123.83 129.76 123.35 147.59 147.59 147.59
8125 135.9 129.76 135.87 129.24 154.53 154.53 154.53
8250 142 135.87 142.17 135.3 161.72 161.72 161.72
8375 148.6 142.17 148.61 141.53 169.15 169.15 169.15
8500 155.3 148.61 155.26 147.87 176.82 176.82 176.82
8625 162.1 155.26 162.11 154.41 184.73 184.73 184.73
8750 169.2 162.11 169.17 161.15 192.82 192.82 192.82
8875 176.4 169.17 176.44 168.08 201.15 201.15 201.15
9000 183.9 176.44 183.94 175.22 209.74 209.74 209.74
9125 191.7 183.94 191.72 182.58 218.61 218.61 218.61
9250 199.8 191.72 199.8 190.23 227.77 227.77 227.77
9375 208.1 199.8 208.06 198.21 237.26 237.26 237.26
9500 216.6 208.06 216.62 206.34 247.08 247.08 247.08
9625 225.4 216.62 225.44 214.8 257.27 257.27 257.27
9750 234.5 225.44 234.52 223.52 267.86 267.86 267.86
9875 243.9 234.52 243.89 232.52 278.88 278.88 278.88
10000 253.5 243.89 253.45 241.83 290.34 290.34 290.34
10125 263.2 253.45 263.21 251.34 302.31 302.31 302.31
10250 273.2 263.21 273.23 261.13 314.81 314.81 314.81
10375 283.6 273.23 283.55 271.19 327.88 327.88 327.88
10500 294.2 283.55 294.15 281.53 341.56 341.56 341.56
10625 305.1 294.15 305.06 292.15 355.91 355.91 355.91
10750 316.3 305.06 316.32 303.05 370.95 370.95 370.95
10875 327.9 316.32 327.93 314.25 386.76 386.76 386.76
11000 339.9 327.93 339.92 325.73 403.36 403.36 403.36
11125 352.32 339.92 352.32 337.51 420.83 420.83 420.83
11250 365.16 352.32 365.16 349.59 439.2 439.2 439.2
11375 378.47 365.16 378.47 361.96 439.2 439.2 439.2
11500 392.3 378.47 392.3 374.64 439.2 439.2 439.2
11625 406.7 392.3 406.7 387.63 439.2 439.2 439.2
11750 421.7 406.7 421.7 400.92 439.2 439.2 439.2
11875 437.34 421.7 437.34 414.53 439.2 439.2 439.2
12000 453.69 437.34 453.69 428.46 439.2 439.2 439.2

you'd probably need a MAP sensor for each runner to determine flow at specific pressure. you could just datalog the voltages through something like a JAW. i did that last night while trying to calibrate some MAP sensors to match a denso sensor. datalog, open the csv file in excel and plot the voltage curves to see how they match up.

now that i think about it, that would be a good method to get the data necessary to build a MAF translator to ditch the flappy door AFM on the MR2 and replace it with something that sucks a lot less.

[jdmhatchracer94]

there wesite site says it is a manometer just like they use in hvac systems i got a duddy that does that I will see if he has one I wanna build this. what the hell is inside the tubes? just ports? looks like i could build it alotcheaper if i knew all the parts

[HiProfile]

I was curious about this too. I have been considering building one lately. I read about using for MAF sensors to measure flow. I'm sure the data would be useless except to compare to your own testing.

I was thinking about doing the same...at some point. My idea was to put a MAF between the head and suction, then have another port between the MAF and suction as a bypass thing. Use a MAP sensor & bypass to attain the same vacuum, then the MAF will give you an idea of how much mass (not cfm's) is flowing through the head at that vacuum level. You could probably set it up with the MAF before the head too, but again pressure doesn't matter since it's measuring mass (volume & density).

If you use a hot-wire MAF, it will be fairly consistant concerning changing temps & even atmospheric pressure changes. Actually it might be better in some ways, since it's air mass that creates power, not raw cfm's. Hot-wire MAF's usually output voltage instead of frequency, but require a steady stream of air. You'd just need a fairly long tube between the MAF & head and/or the straightening vane/grid that some cars have before the MAF. FYI I'd use my Innovate SSI-4 to datalog MAF & MAP voltages.


It should show consistency between ports and other heads you use on it, but as mentioned, useless for compairing numbers to other flow benches. You'd have to compare stock heads to even try that.

[PhilStubbs]

It wouldn't be too hard to borrow a bunch of stock heads to get a nice set of base numbers for yourself. I think I'm going to do this in the very near future. I have 3-4 different stock honda heads laying around. Sounds like a fun afternoon of learning

[Joseph Davis]

A vacuum cleaner isn't going to maintain a specified vacuum across all heads, ports, valve openings.

I'd use a procharger or roots blower run by a 5+ hp inductor motor with a VFD.  You'd have to adjust for pressure every time you made a significant flow change, unless you farmed that off to a microcontroller.


Nothing wrong with using a MAF, just get a flow straightener and make sure entry and exit for the MAF is well spaced with no bends to fuck measurements at different flows.

[PhilStubbs]

Getting expensive adding a procharger to the material list. I wonder if an Eaton m62 would flow enough. Those are usually pretty cheap on eBay.

[92CXyD]

Getting expensive adding a procharger to the material list. I wonder if an Eaton m62 would flow enough. Those are usually pretty cheap on eBay.

I see the M90s running cheaper in jy off of GM and Ford s/c cars.

[Joseph Davis]

Getting expensive adding a procharger to the material list.

Wait until you see what their owners sell them for in a fit of disgust.

[PhilStubbs]

I have done some searching for them before when the thought of sticking one on my M3 crossed my mind but they were pricey. I also looked at m90's for my m3 and when I was lookig they were more than m62's. It's been a couple/few years though.