Forced Induction Custom FI Setup Questions

Mass Airflow Sensor before or after turbo?

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Old Oct 15, 2005 | 10:52 PM
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ochizon's Avatar
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Default Mass Airflow Sensor before or after turbo?

I have a toyota tacoma, and am thinking about putting the MAF after the turbo. I figure the pro's of doing this will be a more accurate response from the ECU for fuel adjustment, and no issues with Idle with the BOV, but the con's are the possibility of oil from the turbo possibly damaging the sensitive sensor.

Any one with any experience with this type of thing?
Old Oct 15, 2005 | 11:37 PM
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Default Re: Mass Airflow Sensor before or after turbo?

mafs always go before the turbo....
Old Oct 15, 2005 | 11:51 PM
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Default Re: Mass Airflow Sensor before or after turbo?

I have seen setups with the MAF after the turbo, and they work, I am just trying to get info on the pros and cons, as I personally only have experience with the MAF before the turbo.
Old Oct 16, 2005 | 05:39 AM
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Default Re: Mass Airflow Sensor before or after turbo?

we have always put the maf before the turbo
Old Oct 16, 2005 | 09:07 AM
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Default Re: Mass Airflow Sensor before or after turbo?

I have a custom Turbo MR-S and my MAF is after the turbo. It runs good and no problems.
Old Oct 16, 2005 | 11:07 AM
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Default Re: Mass Airflow Sensor before or after turbo?

a MAF is a device that reads the a mount of air flowing
u cant put it before the turbo, it will have to be after the turbo, so the ecu knows the amount of air going TO the engine, and that way being able to compensate according to the volume

before the turbo, it will not know what boost (flow) there is into the engine
Old Oct 16, 2005 | 11:09 AM
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Default Re: Mass Airflow Sensor before or after turbo?

Originally Posted by 4G VTEC
a MAF is a device that reads the a mount of air flowing
u cant put it before the turbo, it will have to be after the turbo, so the ecu knows the amount of air going TO the engine, and that way being able to compensate according to the volume

before the turbo, it will not know what boost (flow) there is into the engine
that makes no sense. so you want to show your ECU how much air you are forcing into the engine? no.

i'm sure that with some setups you can put it afterwards, but put it in pre-turbo
Old Oct 16, 2005 | 11:13 AM
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Default Re: Mass Airflow Sensor before or after turbo?

Originally Posted by 90boostdaccord
Originally Posted by 4G VTEC
a MAF is a device that reads the a mount of air flowing
u cant put it before the turbo, it will have to be after the turbo, so the ecu knows the amount of air going TO the engine, and that way being able to compensate according to the volume

before the turbo, it will not know what boost (flow) there is into the engine
that makes no sense. so you want to show your ECU how much air you are forcing into the engine? no.

i'm sure that with some setups you can put it afterwards, but put it in pre-turbo
taking in consideration that u have an ecu that can adjust for boost... YEA put it after the turbo

if u have a hack , then of course dont


Old Oct 16, 2005 | 11:25 AM
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Default Re: Mass Airflow Sensor before or after turbo?

MAF will read air flow no matter where you put it pre or post turbo as long as you have some sort of engine management to tune it. Most Toyota MAF also reads air temp. and by placing it pre turbo, it'll read uncompressed air temp. which is colder than compressed air so the MAF will be sending wrong temperature readings to the ECU so if you'll be putting it pre turbo, place a separate air temp sensor in your charge piping. As I have said, my MAF is post turbo and its running very well.
Old Oct 16, 2005 | 06:05 PM
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Default Re: Mass Airflow Sensor before or after turbo?

If you put it before the turbo when the blow off valve opens it lets out air that the maf already counted. therefore you will go rich each time you shift. while it should be for a very sort time, it is not optimal. Now I've never hearrd of a maf reading air temp, but if that is true then I guess it would be better after the turbo. I think the best thing to do assuming the maf does not read air temp would be to put it before the turbo and run a reciculating bov system



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