SOHC MAF

[hkssupratt1994]

someone sold me a SOHC MAF,i heard you can use these for an SR20,how do you go about wiring it up?and i heard they cut out on higher boost i plan on going to 14 PSI,i only want to do it if its going to run right.

[hkssupratt1994]

bump

[driftin_sr20det]

It'll be close to maxing out, if not maxed out. When I ran one I tried to keep it around 10psi at the most with a gt28rs.

[burntricer]

is wiring it the same as if you were wiring a stock SR one? like white to white, black to black and black w/white strip to black w/white stripe?

[hkssupratt1994]

i would also like to know if it would run the same as a stock SR MAF

[hkssupratt1994]

im going to get a SOHC MAF connetor and wiring it to reach im pretty sure its the same wires

[IanS]

i would also like to know if it would run the same as a stock SR MAF

yes, they run the same.

[homeslicej2]

....like white to white, black to black and black w/white strip to black w/white stripe?

You are correct on the wiring. However, the SR MAF plug is wider than the SOHC MAF plug so you have to use an SR plug on the SR maf and a SOHC plug on the SOHC maf.

[hkssupratt1994]

i've got a friend thats going to give me a SOHC MAF connector

[homeslicej2]

i've got a friend thats going to give me a SOHC MAF connector

[xpicer]

arent they calibrated differently??

[IanS]

Holly really old thread.

arent they calibrated differently??

No.

[homeslicej2]

I've heard that the SOHC MAF's resolution is a bit off from the S13 SR's MAF, but it must be negligible as people run 230-240whp (the same as you can get with a stock SR MAF) all the time on a SOHC MAF. It's fine. I have a stock SR MAF but originally used my SOHC MAF (still have as back-up) and noticed no difference in performance, fuel efficiency, etc. b/t the two.

Holly really old thread.

[RPS13 DRIFTER]

i have a SOHC MAF and i've never had a problem with it (Knock on wood)

[Rusker]

I know a few people running the SOHC MAF with no issues. It'll work until you upgrade.

[schanne]

I think I replaced the Maf with a DOHC.. What wouyld happen if I did that?Sorry for thread jacking but its old and doesn't matter

[Hijacker]

The car would run a funny Air Fuel mixture. MAFs work by seeing how much voltage is required to keep a heated element a certain temperature. The more air coming through, the more voltage required to keep that element at its proper temperature.

When you hear of someone "maxing" their MAF, they've basically hit the limit of what the MAF can do as far as keeping that element heated.

Z airflow meters work in the same way, but their voltage readouts mean different amounts of air are coming through over the SOHC/SR MAF. IIRC, more air is metered by the Z MAF per signal voltage.

The ECU is used to x-amount of air coming back for z-voltage signal. Now all of sudden it's still seeing z-voltage, but y-amount of air is coming through. The motor's air fuel mixture gets all whacked because the ECU meters out gas based on that voltage signal. IIRC, the motor runs lean to the point that you can't get it to idle for sh1t, let alone actually run. Heck, I think the computer might drop the car into limp mode now that I think about it.

the above is the same for DOHC MAFs as the signal they send back means that a different value of air is actually coming through. The difference isn't as drastic though because the DOHC and SOHC MAFs aren't as different as a SOHC and Z MAF

[Rusker]

Here is more information I dug up about the KAE MAF:

KA24E MAFS compatability

Well, I got sick and tired of my engine not starting easily when it is cold. I have suspected for some time that it is because it is running too rich. The only real thing that I could think of is the MAFS. It has been common knowledge that the KA24DE MAFS is compatable with the SR20DET. I started to question this and here is what I found. These are the VQ maps:KA24E VQ Map 320 320 320 320 320 320 320 320 320 320 320 320 370 450 560 700 880 1090 1350 1640 1970 2340 2760 3220 3720 4270 4860 5490 6180 6910 7680 8510 9380 10300 11280 12300 13370 14500 15690 16930 18230 19590 21030 22530 24100 25760 27510 29340 31280 33330 35500 37800 40240 42840 45620 48580 51740 55140 58770 62690 65535 65535 65535 65535

SR20DET VQ map 246 246 246 246 246 246 246 246 246 246 246 260 297 359 447 561 705 877 1080 1315 1582 1882 2215 2584 2987 3426 3902 4413 4962 5549 6173 6835 7537 8277 9058 9880 10744 11650 12602 13594 14645 15742 16891 18098 19365 20696 22098 23574 25132 26778 28521 30369 32332 34421 36200 38100 40200 42300 44600 47050 49550 52250 55000 57500

For those of you that don't know, the VQ MAP is a multiplication factor for the ECU to determine pulse width for a 14.7 A/F ratio. Each value correlates to a voltage level from the MAFS (each value is .08vdc) and is then multiplied by the "K" value (injector size)and CAS value in an equation to get the TP.

As you can tell from looking at the values, the pulse width throughout the range is always going to be slightly higher with the KA MAFS than with the SR MAFS. This poses many small problems. 1. You are always running rich2. You reach 80% duty cycle lower in the RPM range with the KA24E MAFS3. Beacause your A/F ratio is always a bit higher than needed, you can't extract as much power from the motor.

I can think of one added benefit though: Because there is always a bit more fuel, increasing boost levels is a bit safer, but only in the mid RPM range.

After finding this out I will not be running my motor above 5500RPM until I upgrade my fuel system and engine management.

[schanne]

So my car doesn't hold its idle, sputters and then dies on me. This is probably happening because I'm using a dohc maf right?

edit- i should say " this could be happening because"
Modified by schanne at 2:03 PM 1/31/2008

[Rusker]

I didn't think it would even run on the DOHC MAF. That's your problem.

[schanne]

If this is the damn culprit I'll ...... uhhhhh wait. I will sell the beater car I just purchased for about 2k and get some suspension money!

I only payed 700 for a 99 ford zx2 in perfect condition

[IanS]

Here is more information I dug up about the KAE MAF:

There is only one problem, you think your MAFs causes hard cold starts, when in fact, I have no issues started my car at - 20 degrees, and I have run both the SR, and E MAFs, I noticed no change in idle, starting or AFR between the two. Although I did not run the SR MAFs for more than a few days during the winter to test it for a friend. Your information is useful, but the answer to the OPs question remains the same.

[slow s13]

i dont think those numbers mean the sohc maf is diferent from an sr maf dont forget the ka is not a 2 liter so its guna have different numbers even if the mafs where exactly the same