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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

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Old 02-04-2007, 12:29 AM   #1
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MAF Bypass?

Lots of info on how to fix these or problems with them...

For those who know about such things..

I'm looking to ditch the stock airfilter location in favor of a different area, but am running into significant issues with the MAF as it is a huge, blocky, chunk of equipment.

How much of this thing can i get rid of before i start screwing up my air mixture and throwing codes? I seriously doubt i can bypass it without messing with my economy and performance, but if someone knows a way, i'd be open to that as well.
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Old 02-04-2007, 12:32 AM   #2
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its a afm not a maf
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Old 02-04-2007, 07:15 AM   #3
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Cant bypass it on a 22r-series. It's critical to airflow calculations.
Want it gone? Gotta do aftermarket EFI: SDS, FAST, Megasquirt.
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Old 02-04-2007, 07:40 AM   #4
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Mass Air Flow sensor=maf why dont you just extend your wires, get rid of the air box and put on a cone filter? i have a custom piping setup to move it next to the intake manifold. from what i see it wouldnt be hard at all just a matter of cutting and connecting the right wires.
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Old 02-04-2007, 08:37 AM   #5
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I have a cone filter already. extending the wires is not a problem. I will just have to find a different way to route the piping than i wanted so that the MAF will fit. Thanks.
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Old 02-04-2007, 08:40 AM   #6
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As seen above, there is no MAF on the 22re.

I think there is some intake temp value for changing where you get air on the 22re.. In terms of flow, it's still got to go through the AFM.. Big pipes, small AFM hole = no difference.
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Old 02-04-2007, 08:46 AM   #7
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It is listed as a MAF in my haynes manual, in the manual at the Toyota dealer where i get my parts, and most folks here refer to it as that.
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Old 02-04-2007, 10:20 AM   #8
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Actually the FSM calls it a VAFM, volume air flow meter, but we usually call it AFM for short. It measures the air flow with a spring loaded flap, estimating the flow by volume.

After about 1996 they went to the MAF, Mass air flow meter. The MAF measures the air flow by a mass. As the air flows across the hot wire it cools down, the computer estimates the flow by how cool the wire gets.

I just saw this week a product that will replace the VAFM or the MAF completely:
/f116/so-you-want-get-more-3-0-huh-105832/
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Old 02-04-2007, 10:30 AM   #9
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I'm not going to say that using that device isn't possible. I will say that every single person I know about that tried to use a piggy back with the stock AFM gave up... The signals out of the toyota AFM are very non-standard. Jeff Mosk has write up on messing with it and some decent data.

If you want to run a speed density system, run megasquirt. Build it yourself for $200 or buy it configured for the toyota for $350. My setup:
http://lakebox.dnsalias.com/photos/1...oenginein3.jpg

No AFM, it's speed density.

That's cheaper than the ECU option that is being disscussed as an option: http://www.mapecu.com/map1.html which is $399...

Also, we're talking about bucks just to get rid of the factory AFM.. On a stock or close to stock (cammed, mild porting) 22RE, it's expensive for a mild theoretical gain....
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Old 02-04-2007, 10:49 AM   #10
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yeah, i've seen those, but its not really what i want. I just wanted to know if there was a way to get rid of the bulky unit so that i could route the air intake anywhere i wanted. Doesn't look to be possible without bucks, and i'm not interested in any performance units. add 10 hp to my 92 hp engine, and i've still only got 102. That and i don't believe it will really make any noticeable difference. Thanks though, thats what i needed to know.
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Old 02-04-2007, 12:26 PM   #11
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Quote:
Originally Posted by dcg9381 View Post
I'm not going to say that using that device isn't possible. I will say that every single person I know about that tried to use a piggy back with the stock AFM gave up... The signals out of the toyota AFM are very non-standard. Jeff Mosk has write up on messing with it and some decent data.

If you want to run a speed density system, run megasquirt. Build it yourself for $200 or buy it configured for the toyota for $350. My setup:
http://lakebox.dnsalias.com/photos/1...oenginein3.jpg

No AFM, it's speed density.

That's cheaper than the ECU option that is being disscussed as an option: http://www.mapecu.com/map1.html which is $399...

Also, we're talking about bucks just to get rid of the factory AFM.. On a stock or close to stock (cammed, mild porting) 22RE, it's expensive for a mild theoretical gain....
You're probably right. I think it's one of those good news/bad news things. The good news is you can adjust the a/f ratio for max performace and get rid of that AFM restriction. The bad news is you have to make a complete fuel map for the complete rpm and pressure range from scratch, not an easy task at all for an inexperienced tuner.
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Old 02-04-2007, 02:58 PM   #12
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thanks guys. I'm not interested in screwing with all that. I'll make the stock junk work. I appreciate the info though, those sites and threads were quite informative.
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Old 02-05-2007, 08:07 PM   #13
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Cool

Quote:
Originally Posted by mt_goat View Post
You're probably right. I think it's one of those good news/bad news things. The good news is you can adjust the a/f ratio for max performace and get rid of that AFM restriction. The bad news is you have to make a complete fuel map for the complete rpm and pressure range from scratch, not an easy task at all for an inexperienced tuner.

Yes god forbid the AFM is restrictive...

/f116/why-yall-dont-need-ditch-your-afm-aka-why-toyota-right-106225/
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Old 02-06-2007, 05:03 AM   #14
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Interesting, so where do you think the restrictions are? Valves?
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Old 02-06-2007, 05:59 AM   #15
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That post was quoting a TURBO motor, not an NA motor, so it's really not a valid comparison, as the turbo is stuffing air into that motor vs pulling via vacuum.

The question is how much air can you flow past a given surface area at vacuum..
We're 146 CI, flowing (theory) about 250 cfm at 6000 RPM.
Figure out how large a TB is required to flow ~250cfm... Honestly, since the 22R doesn't produce power at 6k, we'll come in under that number.
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Old 02-06-2007, 03:33 PM   #16
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That's a perfectly valid post.That post was concerning the larger Denso vane flap AFM loosing 3whp & less than a ft-lb of torque after having 373 horsepower worth of air SUCKED THROUGH THE AFM.......
What? You think your tiny engine pulling 1/3 the amount of air through your smaller AFM is going to respond any differently?
Build a manometer for & check it yourself if you want... Just recognize that it takes 27.68 inches of water to equal just 1 psi.



Your math is incorrect for what you need to flow. You've stopped short & not finished your math.
A 22r-e would only injest 160CFM of air @ 5000rpm, and I'd have to see a dyno of a 22r-e that ran 6000rpm to tell you that number. But 6000rpm would fall under 140CFM.
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Old 02-06-2007, 03:39 PM   #17
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Quote:
Originally Posted by Toysrme View Post
That's a perfectly valid post.That post was concerning the larger Denso vane flap AFM loosing 3whp & less than a ft-lb of torque after having 373 horsepower worth of air SUCKED THROUGH THE AFM.......
What? You think your tiny engine pulling 1/3 the amount of air through your smaller AFM is going to respond any differently?

BTW, we can't view the post.. Requires registration. Does the post say anything about the size of the denso AFM on that motor?
The question is: Where is the restriction in the 22re? My guess is there isn't one until you start porting the head.. Can we agree on that?


pulling 1/3 the amount

The 22RE is pulling.. One could say that a turbo motor is pushing or you could say that it pulls a lot harder based on the pressure differential. The turbo motor has a much more sigificant pressure differential. For a fixed hole size, the amount of air that goes through it is going to have something to do with the pressure or vacuum behind. More pressure = more air flow through the same hole.

I don't think my math is wrong but it was scaled from some numbers from larger displacement motors. Consider it to be a theoretical maxium (100 VE).. Definitely on the high side, I don't disagree. Most webers are rated around 200-260 cfm, if I recall correctly. I do believe the stock 22RE head generally flows like crap, maybe in the 140? Bench flow numbers on my head are over 200 cfm @ 425.

So again, what's the size of the AFM and at what flow point does it start restricting airflow?
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Old 02-06-2007, 08:17 PM   #18
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I think the key here is to note that nothings sucks.

Pressure pushes.

With the pressure drop of a VAFM on a N/A engine you can never reach 100%VE.

A turbocharger can push air into the engine to create boost til the wastegate opens with very little change in regards to atmosphere

A very good example of this is how much atmospheric pressure (altitude) affects power output on a N/A engine as compared to a Turbocharged engine
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Old 02-06-2007, 09:40 PM   #19
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Quote:
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It is listed as a MAF in my haynes manual, in the manual at the Toyota dealer where i get my parts, and most folks here refer to it as that.
Just those "not in the know", we have basically 3 systems, a AFM, MAF and a MAP systems. Thet are all different. (air flow meter, mass air flow and manifold absolute pressure)
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Old 07-06-2011, 09:35 AM   #20
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how bout bypassing the afm on a 3vze?
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Old 07-06-2011, 09:35 AM
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