Air flow meter

Discussions relating to Turbochargers, Superchargers, Induction, Engine Mods, Exhaust Mods, and other items specifically to make your MX5 or Roadster put out more power.

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WideOpenThrottle
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Air flow meter

Post by WideOpenThrottle » Mon Jul 19, 2010 8:11 pm

Can i mount my AFM in a vertical position and not suffer any problems?
I need to do it this way & have it in front of the radiator as i dont have room elsewhere.
Would rain affect the electrical connector?
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brownie
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Post by brownie » Mon Jul 19, 2010 9:44 pm

Must be placed Horizontal as possible,I had a custy with a KE30 Corolla S/W with B6 motor and box !!,I was done nicely but ran like a bag of sh*t ,Idle up and down all over the show,Had the sparky who wired it stuff,Silly bugger had the AFM just sitting in the engine bay with a pod filter on it facing down,i looked under the bonnet got him to start the car ,Lifted the AFM to where it should be ,Ran perfect,Tilt in down ,Ran like sh*t,
The flap in them does not have a huge amount of tension on it so will move when not sitting flat.
Can't give the exact reason why but it ran good when he mounted the AFM the way it was supposed to be.

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Airflow meter

Post by Nearly too late » Mon Jul 19, 2010 10:15 pm

The early 1600 uses a vane type AFM, this must be mounted flat as the weight of the vane effects the movement of said vane if mount vertical which sends the wrong information too the computer.
Not sure what the later 1600 and 1800 use this may be a mass airflow meter which may be mount vertical as it does not have a vane.
I would make sure that the electrical connection was well sealed against moisture even if was only to prevent corrosion of the terminals.

brownie
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Post by brownie » Mon Jul 19, 2010 11:05 pm

Your way of saying it sounds flasher than mine,We agree though ,Right ? :)

WideOpenThrottle
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Post by WideOpenThrottle » Tue Jul 20, 2010 8:26 am

Thanks guys-in the back of my mind i had a feeling that they must stay horizontal.Just have to see if there's room for a horizontal mount otherwise its chucked out for a later model AFM or link! :D
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air fow meter

Post by Nearly too late » Tue Jul 20, 2010 4:16 pm

We are on the same wave length Brownie.

sprsta
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Post by sprsta » Thu Jul 22, 2010 6:46 pm

yeah chuck it and get yourself a link
itll be turbo right?

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Post by WideOpenThrottle » Thu Jul 22, 2010 9:02 pm

sprsta wrote:yeah chuck it and get yourself a link
itll be turbo right?
Yup turbo'd
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WideOpenThrottle
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Post by WideOpenThrottle » Sun Aug 22, 2010 8:26 am

Well i have relocated my AFM to a horizontal position between the IC & the TB.It now still idles fine but has an enourmously worse hesitation under throttle.I was wondering it might be restrictive so does any one know if i can plug & play my 323 AFM to the MX connector as it has a bigger flow capacity?

Its specs are D B660 13 210 197100-3270.
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Post by sprsta » Sun Aug 22, 2010 10:32 am

a non turbo fc rx7 one fits

Keith Jones
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Post by Keith Jones » Sun Aug 22, 2010 10:58 am

A restrictive AFM isn't likely to cause a hesitation under acceleration, it'll limit top end revs (which is where the RX7 AFM is better).
I'm not sure that putting the AFM between the TC and IC is a good idea.
The turbo flow output will lag the inlet airflow. So you have effectively got a closed loop system where the sensor (AFM), which is controlling the fuel flow, is on the output side of the loop rather than the input. This means that the signal to the injectors to increase fuel flow is not responding quick enough to the increase in throttle opening, hence the hesitation.

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Post by Nearly too late » Sun Aug 22, 2010 12:21 pm

As Keith said the air flow meter should go before the turbo for the reasons he has pointed out.

jif
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Air flow meter

Post by jif » Sun Aug 22, 2010 2:47 pm

www.miata.net/solo/airflowmtr.html


Also, my previous turbo setup had some hesitation like you described as well ... I read that running it rich helps (that and IRTBs), but wasn't interested in that ! :)

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WideOpenThrottle
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Post by WideOpenThrottle » Sun Aug 22, 2010 7:21 pm

Thanks for the help to all so far :D .
I would like to try the 323AFM but as yet unable to find a wiring diag.
I am now on to my third experimental stage of induction configuration so hopefully will have some success before i leave for Europe so my posts might be quiet for a month soon! and you can all take a well earned rest from my naggin!
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Post by sprsta » Sun Aug 22, 2010 7:36 pm

ever changed your leads and plugs?
thats a common cause of hesitation

SLYDIT
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Post by SLYDIT » Wed Aug 25, 2010 9:03 pm

WIDEOPEN:
Can you please post what engine management and injectors you are using and any other fuel and ignition system mods so i can get an idea of whats going on....thanks.
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

WideOpenThrottle
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Post by WideOpenThrottle » Thu Aug 26, 2010 4:46 am

SLYDIT wrote:WIDEOPEN:
Can you please post what engine management and injectors you are using and any other fuel and ignition system mods so i can get an idea of whats going on....thanks.
Hi slydit - done nothing yet so will catch up with you in a month after my trip to sort what i do next

Cheers WOT :D
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Post by SLYDIT » Sat Aug 28, 2010 12:22 am

Hi slydit - done nothing yet so will catch up with you in a month after my trip to sort what i do next

Cheers WOT :D
Hmmm well there's you r answer. you can't expect to put a turbo on the car without any sort of fuel system mods or you will blow up your engine in about 10 seconds.
For starters :
OPTION #1
i would be looking at some 330cc injectors from a 1800GTX 323 or even some 270cc ones from a RB20DET skyline. Also add an O2 clamp for the issues yyou are describing.

OPTION #2
buy a rising rate fuel pressure regulator from begi/flyin miata to get your fuelling sorted and an o2 clamp.
then i'd be knocking the igniton back to 8 degrees and use ONLY 98 octane gas.

any more than that and you should be purchasing a megasquirt ecu or emanage blue unit
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

sprsta
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Post by sprsta » Fri Sep 03, 2010 7:36 am


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