To clear up the MAFS placement issue..
08-06-2003, 05:51 PM
#1
To clear up the MAFS placement issue..
Looks as though on 95-97 4th generation maxima's there are Fuel Pump Control Modules (FPCM) on the car, but 98-99 4th gen and 00-03 5th gen there are no FPCM's (ie why I currently have a CEL for a FPCM on the 97 5-spd ecu on my 98).
Therefore, you have to place the MAFS near the throttle body (pressurized side) on a 95-97 because the FPCM will cutoff fuel pressure as you release throttle no matter what. However, on a 98-99 4th gen and 00-03 5th gen, there is no FPCM which would lead me to believe you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings.
Point being, 98 and 99 4th gens are the same as 5th gens when it comes to MAFS placement (nearest to the intake and away from pressurization as possible).
These are the things you learn when you build your own turbo kit and talk to some informative people.
By the way, early thanks to ramius83 on all his help, what a great guy.
Therefore, you have to place the MAFS near the throttle body (pressurized side) on a 95-97 because the FPCM will cutoff fuel pressure as you release throttle no matter what. However, on a 98-99 4th gen and 00-03 5th gen, there is no FPCM which would lead me to believe you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings.
Point being, 98 and 99 4th gens are the same as 5th gens when it comes to MAFS placement (nearest to the intake and away from pressurization as possible).
These are the things you learn when you build your own turbo kit and talk to some informative people.
By the way, early thanks to ramius83 on all his help, what a great guy.
08-06-2003, 08:10 PM
#4
Originally posted by Confused
96 fsm says for cali emmissions only... you sure about that?
96 fsm says for cali emmissions only... you sure about that?
if it is about fpcm's on all 96's, then there may be a clause regarding fed-spec cars.. i am unaware of any turbo'd fed-spec cars, or am aware and didn't know they were fed-spec.
08-06-2003, 09:57 PM
#6
Originally posted by bags533
why have you not called me?
why have you not called me?
i think we are going to go with the standard supercharger setup and place my MAFS next to the throttle body and just assume that it will work the same as 97 and below and that 5th gen MAFS are just really weak.
*crossing the fingers*
08-07-2003, 04:57 AM
#7
i think you understand what I was saying but this is what I am looking at..
http://www.confusedmax.com/howto/fpcm.jpg
I'm not trying to correct you but since I'm going to be relocating a z maf to the non pressurized side, I thought its worth a look
http://www.confusedmax.com/howto/fpcm.jpg
I'm not trying to correct you but since I'm going to be relocating a z maf to the non pressurized side, I thought its worth a look
08-07-2003, 08:53 AM
#8
Originally posted by thebigsadler
because i am jealous of your turbo maybe.. and i dont have a number or anything.
i think we are going to go with the standard supercharger setup and place my MAFS next to the throttle body and just assume that it will work the same as 97 and below and that 5th gen MAFS are just really weak.
*crossing the fingers*
because i am jealous of your turbo maybe.. and i dont have a number or anything.
i think we are going to go with the standard supercharger setup and place my MAFS next to the throttle body and just assume that it will work the same as 97 and below and that 5th gen MAFS are just really weak.
*crossing the fingers*
I would do it that way until you go above 10 PSI. Then maybe look at changing to a Z maf and tehn moving it just as confused said
And check your PM's
08-07-2003, 10:44 AM
#9
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Re: To clear up the MAFS placement issue..
I think I disagree with you on this. My MAF is on the intake side (non-pressurized). Mine is a 1997. We have done exactly the same on '96 through 2001 without any issues. Also I am not sure I understand what you mean by
"... you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings ..."
The MAF measures airflow and not pressure. It will measure the amount of air that flows through it. Personally, I prefer having the MAF at the intake for several reasons one of which is because of the fact that the MAF measures airflow using a thermistor which is temperature dependent. I would rather measure cold air intake temp than air that is heated up by the turbo. People will argue that you should measure actual air intake temp. If you do this, you must have the temp sensor in a similar location to the MAF to measure actual air temp otherwise the MAF element thinks less air is flowing in (thermistor in the MAF doesn't cool down as much when hot air flows over it) This being the case, the computer will deliver less fuel ... bad! If you have the MAF in the boost pipe, you need the temp sensor there also so be wary of boost leaks!
"... you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings ..."
The MAF measures airflow and not pressure. It will measure the amount of air that flows through it. Personally, I prefer having the MAF at the intake for several reasons one of which is because of the fact that the MAF measures airflow using a thermistor which is temperature dependent. I would rather measure cold air intake temp than air that is heated up by the turbo. People will argue that you should measure actual air intake temp. If you do this, you must have the temp sensor in a similar location to the MAF to measure actual air temp otherwise the MAF element thinks less air is flowing in (thermistor in the MAF doesn't cool down as much when hot air flows over it) This being the case, the computer will deliver less fuel ... bad! If you have the MAF in the boost pipe, you need the temp sensor there also so be wary of boost leaks!
Originally posted by thebigsadler
Looks as though on 95-97 4th generation maxima's there are Fuel Pump Control Modules (FPCM) on the car, but 98-99 4th gen and 00-03 5th gen there are no FPCM's (ie why I currently have a CEL for a FPCM on the 97 5-spd ecu on my 98).
Therefore, you have to place the MAFS near the throttle body (pressurized side) on a 95-97 because the FPCM will cutoff fuel pressure as you release throttle no matter what. However, on a 98-99 4th gen and 00-03 5th gen, there is no FPCM which would lead me to believe you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings.
Point being, 98 and 99 4th gens are the same as 5th gens when it comes to MAFS placement (nearest to the intake and away from pressurization as possible).
These are the things you learn when you build your own turbo kit and talk to some informative people.
By the way, early thanks to ramius83 on all his help, what a great guy.
Looks as though on 95-97 4th generation maxima's there are Fuel Pump Control Modules (FPCM) on the car, but 98-99 4th gen and 00-03 5th gen there are no FPCM's (ie why I currently have a CEL for a FPCM on the 97 5-spd ecu on my 98).
Therefore, you have to place the MAFS near the throttle body (pressurized side) on a 95-97 because the FPCM will cutoff fuel pressure as you release throttle no matter what. However, on a 98-99 4th gen and 00-03 5th gen, there is no FPCM which would lead me to believe you need to place the MAFS on the non-pressurized side (near the intake) because if not it will have pressure and incorrect readings.
Point being, 98 and 99 4th gens are the same as 5th gens when it comes to MAFS placement (nearest to the intake and away from pressurization as possible).
These are the things you learn when you build your own turbo kit and talk to some informative people.
By the way, early thanks to ramius83 on all his help, what a great guy.
08-07-2003, 11:36 AM
#10
Re: Re: To clear up the MAFS placement issue..
So if the mafs is relocated to the intake side of the blower, the intake air temp sensor should also be relocated so that the mafs is referenced to the correct air temperature. Makes sense.
Just curious, does the 5th gen Stillen SC kit require relocation of the iats as well as the mafs?
Just curious, does the 5th gen Stillen SC kit require relocation of the iats as well as the mafs?
08-07-2003, 09:51 PM
#11
Re: Re: To clear up the MAFS placement issue..
Originally posted by turbo97SE
I think I disagree with you on this. My MAF is on the intake side (non-pressurized). Mine is a 1997. We have done exactly the same on '96 through 2001 without any issues. Also I am not sure I understand what you mean by
The MAF measures airflow and not pressure. It will measure the amount of air that flows through it. Personally, I prefer having the MAF at the intake for several reasons one of which is because of the fact that the MAF measures airflow using a thermistor which is temperature dependent. I would rather measure cold air intake temp than air that is heated up by the turbo. People will argue that you should measure actual air intake temp. If you do this, you must have the temp sensor in a similar location to the MAF to measure actual air temp otherwise the MAF element thinks less air is flowing in (thermistor in the MAF doesn't cool down as much when hot air flows over it) This being the case, the computer will deliver less fuel ... bad! If you have the MAF in the boost pipe, you need the temp sensor there also so be wary of boost leaks!
I think I disagree with you on this. My MAF is on the intake side (non-pressurized). Mine is a 1997. We have done exactly the same on '96 through 2001 without any issues. Also I am not sure I understand what you mean by
The MAF measures airflow and not pressure. It will measure the amount of air that flows through it. Personally, I prefer having the MAF at the intake for several reasons one of which is because of the fact that the MAF measures airflow using a thermistor which is temperature dependent. I would rather measure cold air intake temp than air that is heated up by the turbo. People will argue that you should measure actual air intake temp. If you do this, you must have the temp sensor in a similar location to the MAF to measure actual air temp otherwise the MAF element thinks less air is flowing in (thermistor in the MAF doesn't cool down as much when hot air flows over it) This being the case, the computer will deliver less fuel ... bad! If you have the MAF in the boost pipe, you need the temp sensor there also so be wary of boost leaks!
still got me a little perplexed brett..
08-07-2003, 10:23 PM
#12
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Re: Re: Re: To clear up the MAFS placement issue..
Yes I stand corrected on the IAT sensor. The thermistor is indeed only for diagnostic purposes. This is a little unusual. It only highlights the importance of having the MAF at the intake side before the turbo. If the MAF is in the boost pipe, the turbo gets hotter and hotter the harder you run. The hotter the air gets passing through the MAF, the less the MAF thinks is actually flowing through it. If the IAT did compensate for air temp, then this would be less of an issue, but since it is pretty useless we are out of luck here. The only saving grace might be if you put the MAF close to the TB and you are intercooled, hopefully the air would be cooled sufficiently not to make such a difference.
I have been very interested in how well the MAF placed close to the TB would work ... maybe I'll try it one of these days!
I have been very interested in how well the MAF placed close to the TB would work ... maybe I'll try it one of these days!
Originally posted by thebigsadler
that thermostir is worthless, i thought this had been proven before that it is more for diagnostic than for checking any air temp or air flow.. it doesnt measure anything really, its more of a self check to make sure the mafs still reads air flow, not any temp or amount of air flow itself.
still got me a little perplexed brett..
that thermostir is worthless, i thought this had been proven before that it is more for diagnostic than for checking any air temp or air flow.. it doesnt measure anything really, its more of a self check to make sure the mafs still reads air flow, not any temp or amount of air flow itself.
still got me a little perplexed brett..
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