MEGAsquirt A place to collectively sort out this megasquirt gizmo

megasquirt and boost

Old 07-19-2010, 09:11 AM
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Default megasquirt and boost

While using a megasquirt and having a turbo setup I expect that the map sensor also acts as boost sensor and relays that info to the ecu for boost

Now since I plan to use a MAF sensor will I need to isntall another map sensor in it as well so it can see boost\psi the turbo is pushing for boost control?

Any information is appericated

Thanks
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Old 07-19-2010, 09:14 AM
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you have a AFM that you will remove since the MS has a MAP sensor.
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Old 07-19-2010, 09:20 AM
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I plan to add a hot wire MAF afterwards
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Old 07-19-2010, 09:36 AM
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Why?
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Old 07-19-2010, 09:56 AM
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good luck. sounds like a lot of wasted effort for absolutely nothing to gain but insanity.
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Old 07-19-2010, 01:04 PM
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Originally Posted by lordrigamus
Why?
decided to go this way because I like how it works ( suppose to work ) compared to a map setup with reguardes to reading airflow.
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Old 07-19-2010, 01:06 PM
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so what ECU is going to read the MAF signal and do something with it?
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Old 07-19-2010, 01:10 PM
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Originally Posted by Braineack
so what ECU is going to read the MAF signal and do something with it?
Megasquirt 1
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Old 07-19-2010, 01:38 PM
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Are you not aware of the restriction the MAF poses? What kind of MAF do you plan on using anyway? 94+ miata MAF?

I wanted nothing but to get rid of this. You can buy mine if you like, now that I'm no longer using it lol
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Old 07-19-2010, 01:40 PM
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I'm aware

Ka24de maf
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Old 07-19-2010, 02:15 PM
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The standard MegaSquirt MAP sensor can read from near absolute vacuum to near 21 psi of boost.
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Old 07-19-2010, 02:43 PM
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Techsalvager, good luck with the project. From a pragmatic standpoint, you're not going to get much love from the folks around here with regard to running a MAF sensor in anything other than certain very strictly regulated race classes.

While it's true that MAF is a slightly less ambiguous predictor of load in situations where VE is highly variable (such as with variable cam advance), from a practical standpoint, the vast majority of us just haven't had an issue with it. And relative to a stock Miata MAF, speed-density is certainly advantageous as the MAF sensor (as well as the VAF sensor) simply don't have enough headroom to deal with anything approaching a doubling of airflow.


In your original post, you asked about installing "another map sensor in it as well", and I'm a little puzzled here. The MS comes with precisely one MAP sensor built-in, and that is exactly the number of MAP sensors required for operation. You can optionally add a second one to do realtime barometric correction, which would be handy for a car which will be running the Targa Newfoundland, but isn't generally necessary otherwise.
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Old 07-19-2010, 03:09 PM
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Originally Posted by Techsalvager
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MegaSquirt-I does not have the ability to blend MAF and MAP load sensing. This is available if you go with the latest alpha MS2/Extra, or with MS3. I would only recommend trying blended MAF and MAP if you really know what you're doing at this point; it's not well documented at all.
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Old 07-19-2010, 04:44 PM
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Originally Posted by Joe Perez
Techsalvager, good luck with the project. From a pragmatic standpoint, you're not going to get much love from the folks around here with regard to running a MAF sensor in anything other than certain very strictly regulated race classes.

While it's true that MAF is a slightly less ambiguous predictor of load in situations where VE is highly variable (such as with variable cam advance), from a practical standpoint, the vast majority of us just haven't had an issue with it. And relative to a stock Miata MAF, speed-density is certainly advantageous as the MAF sensor (as well as the VAF sensor) simply don't have enough headroom to deal with anything approaching a doubling of airflow.


In your original post, you asked about installing "another map sensor in it as well", and I'm a little puzzled here. The MS comes with precisely one MAP sensor built-in, and that is exactly the number of MAP sensors required for operation. You can optionally add a second one to do realtime barometric correction, which would be handy for a car which will be running the Targa Newfoundland, but isn't generally necessary otherwise.
If your airflow is doubling of course you will have to get a MAF rated for higher flows.

yes I didn't realize I couldn't do maf\map blend if I could, I believe I would of needed a 2nd map sensor to use as a boost sensor.

I bought a very old board that I'm putting together, MS1 PCB v1.01 and stim from the author of megatunix.
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Old 07-19-2010, 04:58 PM
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Originally Posted by Techsalvager
If your airflow is doubling of course you will have to get a MAF rated for higher flows.
Yup. I was just highlighting one of the many reason why most of us chose to run in speed-density mode. Throwing away the MAF sensor and running MAP-only is cheaper than buying and plumbing in a larger MAF sensor, in addition to being simpler (from a wiring and configuration standpoint) and arguably better from a "restrictions in the flow path" standpoint.


yes I didn't realize I couldn't do maf\map blend if I could, I believe I would of needed a 2nd map sensor to use as a boost sensor.
Nope. As Matt said, you won't be using any MAP at all with an MS1 in AFM mode (which I would argue is a sub-optimal arrangement), and with an MS2/3 running in Hybrid mode, you would use the one MAP sensor that comes standard with every MS package.


I bought a very old board that I'm putting together, MS1 PCB v1.01
Wow. Ok, I think we're done here.
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Old 07-19-2010, 05:04 PM
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Originally Posted by Joe Perez

Nope. As Matt said, you won't be using any MAP at all with an MS1 in AFM mode (which I would argue is a sub-optimal arrangement), and with an MS2/3 running in Hybrid mode, you would use the one MAP sensor that comes standard with every MS package.
you would use one map sensor for barometric as in all it sees is the open air and not plumed into the engine, so you would need a 2nd for boost, thats where I got two from.
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Old 07-19-2010, 05:52 PM
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Originally Posted by Techsalvager
you would use one map sensor for barometric as in all it sees is the open air and not plumed into the engine, so you would need a 2nd for boost, thats where I got two from.
Yes, but unless your going to see dramatic elevation changes, you only need one standard map sensor.
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Old 07-19-2010, 05:53 PM
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i run two:

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Old 07-19-2010, 05:58 PM
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Don't think MS2 or 3 can support 2 map sensors AND a MAF besides wouldn't the MAF perform the baro correction for you?
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Old 07-19-2010, 05:59 PM
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yeah there's not much docs on anything but alpha-n or speed density. but i know you need ms-II to run MAF/MAP.
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