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Guest Message by DevFuse
 

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hotwire or flapper?


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11 replies to this topic

#1 archemitis

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Posted 27 August 2003 - 12:41 AM

which mpfi system is better, hotwire, or the flapper air flow sensor? im going to turbo a na mpfi motor, and need to know what computer system would be the best. and what years they came on.

#2 Hondasucks

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Posted 27 August 2003 - 12:53 AM

All the SPFI's I have seen, are hot-wire. My 87 Turbo is VAF (Vane Air Flow, i.e., flapper), my 86 XT Non-turbo was also VAF. I dunno if the later ones were Hot-Wire or not...

#3 GLCraig

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Posted 27 August 2003 - 01:54 AM

There were hotwire turbos the first year was probably 88, these also used the crankangle distributor. You might run into trouble is you take parts form a fulltime 4wd turbo with an automatic. I'm not sure if the TCU for the 4EAT ties into the ECU, like they do with legacys.

#4 calebz

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Posted 27 August 2003 - 08:45 AM

Thats interesting.. I have had some questions about hotwire versus vane.. my 87 is a hotwire, but I see one post above that says their 87 is a vane type, and skips 87 is also vane type.. but my 87 is hotwire.. weird

#5 XSNRG

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Posted 27 August 2003 - 09:05 AM

I was under the impression that '85/'86 was the early style and '87/later the newer style? '86/'87 could depend on early/late?

#6 archemitis

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Posted 27 August 2003 - 03:04 PM

well, i just pulled an ea82 mpfi out of the junkyard today. its an 85 xt. i got the wiring, the computer, the long block, and the maf sensor. looked like a flapper to me. would this be a good one to turbo? are the older ones the same, turbo, or na? like is this computer just waiting to see boost?

#7 Skip

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Posted 27 August 2003 - 04:29 PM

The hot wire MAF came out in 87.

Caleb mine is a hot wire.

The 85 was a vane style ie flapper door MAF

Arguments Pro Con
Hot wire
Pro -
less restriction to the flow of air
more accurate in all temps
With it you get a crank angle dist. as Craig says, which is more accurate for firing fuel and controls ig. timing.
Quicker responce to air flow changes

Con-
not "tuneable"
with it you get the ECU controled over boost fuel cut
bit more fragile than vane

Vane style
Pro -
Has a tuneable spring loaded vane, less spring tension = richer mix
Has a over boost switch which can be easily unplugged

Con -
Moving mechanical parts
Some restriction to the air flow (has to push the flapper open)
Standard distrib. with vacuum advance diaph.on side.

Hope this helps, if I missed anything or errored, please chime in

#8 archemitis

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Posted 27 August 2003 - 05:40 PM

does that go for na and turbo? thanks skip!

#9 Skip

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Posted 27 August 2003 - 05:52 PM

yes the basics are the same but the ECU's may be different.
Sorry I have no info on the NA systems.

#10 archemitis

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Posted 27 August 2003 - 06:08 PM

im sure it will work ok... we'll see:banana:

#11 archemitis

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Posted 28 August 2003 - 06:29 PM

so is there a cfm that will max out the movement of the flapper?do i have to put a checkball on the vaccum advance hose, so i dont boost the disty?

#12 Hondasucks

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Posted 28 August 2003 - 11:54 PM

Went out and looked at my car, cuz my curiosity was up. I do not have a vac. advance on my dizzy, and my MAF LOOKS like a Hot-Wire type, but it has a plug in the side, adn if you take the plug out, there is a screw behind it that looks like an adjustment screw of some kind. Do I have some weird system??




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