AFM Removal Tutorial.
#1
Boost Pope
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AFM Removal Tutorial.
Since I first mentioned that I’d removed the AFM on my '92 back in December I’ve gotten a few p-mails asking about the setup, and I’ve promised those folks that a writeup is coming. My apologies for the delay, insert generic excuse here.
At any rate, it's finally done. I've been running with the AFM removed for about a month now, and it's going quite well. I've given this its own web page due to the graphics-intensive nature. You can find it here:
http://miatajoe.50megs.com/index.html
Perhaps this will finally earn me the coveted Sticky Thread for which I have longed O' these many months. (Hint to moderators )
Edit: Geocities sucks. Site moved to new host.
UPDATE: musanovic has now done a version of this for the NB (which may work with the 1.8 NA) here: http://www.rpaperformance.com/miatamaf.html
At any rate, it's finally done. I've been running with the AFM removed for about a month now, and it's going quite well. I've given this its own web page due to the graphics-intensive nature. You can find it here:
http://miatajoe.50megs.com/index.html
Perhaps this will finally earn me the coveted Sticky Thread for which I have longed O' these many months. (Hint to moderators )
Edit: Geocities sucks. Site moved to new host.
UPDATE: musanovic has now done a version of this for the NB (which may work with the 1.8 NA) here: http://www.rpaperformance.com/miatamaf.html
Last edited by Joe Perez; 05-02-2010 at 11:39 AM.
#8
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you boner! :gay:
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#9
Boost Pope
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Ok, sorry about all that. I've temporarily moved the site to a new host:
http://miatajoe.50megs.com/index.html
Tonight I'll try to migrate it to a permanent server. Damn Geocities...
http://miatajoe.50megs.com/index.html
Tonight I'll try to migrate it to a permanent server. Damn Geocities...
#10
hey joe I made a mirror, if you want I can leave it there forever or until you find a home for it.
http://jazz.sdsc.edu/miata/afm%20index.html
http://jazz.sdsc.edu/miata/afm%20index.html
#13
Boost Pope
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More importantly however, the airflow vs. MAP/RPM characteristics for the 1.8 are going to be a lot different. Not only is the engine larger, but it has different cam profiles, a different head design, etc. I suspect that you'd actually need different maps for the different 1.8 head styles- one for the '94 to '97, one for the 99+, one for the variable intake cam...
However, if anybody has a 1.8 Miata they'd care to loan me for a few weeks, I'd be happy to generate the data for it.
#14
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What are your driving impressions?
I have not really noticed any serious change in driveability, which I consider to be a good thing. One benefit is that I'm now able to run my BOV direct to atmosphere, through a K&N filter of course.
My biggest gripe with the AFM was that after I'd installed by BOV the fuel pump relay would click off and on a few times every time I shifted due to the flapper banging back and forth. It did this even after I plumbed it for recirculated, which puzzled the hell out of me. Fortunately this didn't cause any serious problems, but being toggled every single time I shift can't be good for the relay contacts. Switching a big DC load like the fuel pump causes relay contacts to degrade, which is the typical cause of failure for these devices.
#16
Hello Joe,
great write up!!
2 points:
1: whats the reason why the 2 bar sensor dont work correct?
From the data, it should deliver same results.
2: The hotwire 1,8 Airflow Meter ( is ít still a AFM?)
dont restrict the inlet that much and need not a lot space.
I remember, with the Ultimate its easy? possible to use a 1,8 AFM
on a 1,6 system with 1,6 ECU. Is that correct?
Falk
great write up!!
2 points:
1: whats the reason why the 2 bar sensor dont work correct?
From the data, it should deliver same results.
2: The hotwire 1,8 Airflow Meter ( is ít still a AFM?)
dont restrict the inlet that much and need not a lot space.
I remember, with the Ultimate its easy? possible to use a 1,8 AFM
on a 1,6 system with 1,6 ECU. Is that correct?
Falk
#17
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Secondly, the EMU software limits you to dealing with a voltage range from 0.5 to 4.5 volts, which is what the Greddy sensor produces. The 2-bar MAP sensor operates from 0 to 5 volts, so it's off the scale at very high vacuum and at very high boost.
2: The hotwire 1,8 Airflow Meter ( is ít still a AFM?)
dont restrict the inlet that much and need not a lot space.
dont restrict the inlet that much and need not a lot space.
I remember, with the Ultimate its easy? possible to use a 1,8 AFM
on a 1,6 system with 1,6 ECU. Is that correct?
on a 1,6 system with 1,6 ECU. Is that correct?
You could do it via the same method- namely connecting it to the AFM input and selecting AFM(v) in the Airflow Map, but since you couldn't log both sensors back-to-back that way I'm not sure how you'd generate the basemap.
It might also be possible to use the Analog Input-Output wires for this and just do a 1-d map, but again, I'm not sure how you'd do the initial logging without some external equipment. I can't seem to enable Analog Input on the logger screen.
#18
I got a chance to log Joe's AF Output map against my RX-7 AFM. Looks really close.
The dyno also showed about 1 pound of boost improvement. The only thing I can attribute that too is the change of AFM to the rx-7 and larger filter. Can't wait to get rid of the AFM completely.
Log file attached
The dyno also showed about 1 pound of boost improvement. The only thing I can attribute that too is the change of AFM to the rx-7 and larger filter. Can't wait to get rid of the AFM completely.
Log file attached
#19
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Seem to have my initial "issues" cleared up. I guess my car pulls a little less vac at idle than yours?
I set the first column to 650 rpm and raised the voltage output in the -12.3, -10.1, and -8 cells in that column... Seems to be running well, pretty nice idle, and right now I'm running 0 injector in that area, but I may end up running a little correction due to my big 550s.