MAF question to S/C guys
10-30-2002, 06:36 PM
#1
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MAF question to S/C guys
I have a question regarding MAF readings. What is the highest MAF reading you S/C guys have?
Mine is about 87% with 9.3 psi boost. So at 11 or 12 psi it should be pretty close to 90%+.
Is there any way to upgrade a MAF to increase airflow? I am thinking that if I get a larger MAF body with the same element, more air will flow for the same reading (in volts), this would make the car run lean. I could either use the S-AFC or get larger injectors (or a combination of both) to balance this out. What do you think?
Or is this even an issue?
Mine is about 87% with 9.3 psi boost. So at 11 or 12 psi it should be pretty close to 90%+.
Is there any way to upgrade a MAF to increase airflow? I am thinking that if I get a larger MAF body with the same element, more air will flow for the same reading (in volts), this would make the car run lean. I could either use the S-AFC or get larger injectors (or a combination of both) to balance this out. What do you think?
Or is this even an issue?
10-30-2002, 06:56 PM
#2
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Re: MAF question to S/C guys
With the right ECU configuration you can run pretty much any MAF as far as I know. However, you've got a 97+ so it could be a problem for you. I'm not sure of any MAF sensors that are compatable with our ECU's, and if they are, I'm pretty sure someone would have posted about them. I think MardiGras was messing around with one a while back.
10-31-2002, 06:23 AM
#4
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Originally posted by Chebosto
using my S-AFC, the reading from the AFL measurement, peak was 86.8 % with 9.5 psi.
using my S-AFC, the reading from the AFL measurement, peak was 86.8 % with 9.5 psi.
Thanks dude! That is almost exactlt what I get. At least I know it's right.
10-31-2002, 06:57 AM
#5
Whoooah..
Where are you reading this MAF PERCENT?
My OBD scanner gives a lbs./min value for the MAF reading, so how does the AFC know what 100% is?
Unless it's learns/remembers your maximum value and considers that to be 100%, which just means it could be increased with more boost.
My OBD scanner gives a lbs./min value for the MAF reading, so how does the AFC know what 100% is?
Unless it's learns/remembers your maximum value and considers that to be 100%, which just means it could be increased with more boost.
10-31-2002, 07:24 AM
#6
the AFL% is what i get off my Super AFC.
obviously if it was 100%, your engine would be super efficent and there would be absolutely no obstructions in your air flow path into the engine.
NA, my max air flow was around 58%
once i got the S/C, it's been peaked at 87%
i have been able to get 9x.x%, but if you do, then you know something was wrong, i was able to get that reading when one of the hoses near that piping leading from the TB to the MAF popped off, and once when my belt skipped when i was racing.
obviously if it was 100%, your engine would be super efficent and there would be absolutely no obstructions in your air flow path into the engine.
NA, my max air flow was around 58%
once i got the S/C, it's been peaked at 87%
i have been able to get 9x.x%, but if you do, then you know something was wrong, i was able to get that reading when one of the hoses near that piping leading from the TB to the MAF popped off, and once when my belt skipped when i was racing.
10-31-2002, 07:35 AM
#7
...
Originally posted by Chebosto
the AFL% is what i get off my Super AFC.
obviously if it was 100%, your engine would be super efficent and there would be absolutely no obstructions in your air flow path into the engine.
the AFL% is what i get off my Super AFC.
obviously if it was 100%, your engine would be super efficent and there would be absolutely no obstructions in your air flow path into the engine.
I guess it's not obvious to me
, but what does 100% have to do with being efficient? It just means your flowing 100% or more of the air that the meter can measure, right? It's a voltage or resistance vs. air flow through the meter value, right?
NA, my max air flow was around 58%
once i got the S/C, it's been peaked at 87%
i have been able to get 9x.x%, but if you do, then you know something was wrong, i was able to get that reading when one of the hoses near that piping leading from the TB to the MAF popped off, and once when my belt skipped when i was racing.
once i got the S/C, it's been peaked at 87%
i have been able to get 9x.x%, but if you do, then you know something was wrong, i was able to get that reading when one of the hoses near that piping leading from the TB to the MAF popped off, and once when my belt skipped when i was racing.
10-31-2002, 09:16 AM
#8
Re: ...
100% is impossible. you cant possibly hit 100% air flow mass into the engine. efficent would mean Zero loss right?
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
Originally posted by IceY2K1
AFL% = Air flow measured through the MAF right?
I guess it's not obvious to me, but what does 100% have to do with being efficient? It just means your flowing 100% or more of the air that the meter can measure, right? It's a voltage or resistance vs. air flow through the meter value, right?
What size pulley are you running that gives you 87%?
AFL% = Air flow measured through the MAF right?
I guess it's not obvious to me
, but what does 100% have to do with being efficient? It just means your flowing 100% or more of the air that the meter can measure, right? It's a voltage or resistance vs. air flow through the meter value, right?What size pulley are you running that gives you 87%?
10-31-2002, 09:45 AM
#9
Re: Re: ...
Originally posted by Chebosto
100% is impossible. you cant possibly hit 100% air flow mass into the engine. efficent would mean Zero loss right?
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
100% is impossible. you cant possibly hit 100% air flow mass into the engine. efficent would mean Zero loss right?
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
10-31-2002, 09:57 AM
#10
Re: Re: ...
Originally posted by Chebosto
100% is impossible. you cant possibly hit 100% air flow mass into the engine. efficent would mean Zero loss right?
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
100% is impossible. you cant possibly hit 100% air flow mass into the engine. efficent would mean Zero loss right?
i'm on a 3.25
i'm pretty sure keving used to see 89 % or higher.
I'll do some
10-31-2002, 10:06 AM
#11
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Join Date: Jul 2001
Posts: 7,530
I am not boosted so I dont remember if this was done or just discussed before but at one point I read some threads talking about using the Q45 MAF sensor. Anyone remember these or have any idea if it was setup different to allow better gains? If not I will search for the threads in the meantime.
SuDZ
SuDZ
10-31-2002, 10:37 AM
#12
Originally posted by SuDZ
I am not boosted so I dont remember if this was done or just discussed before but at one point I read some threads talking about using the Q45 MAF sensor. Anyone remember these or have any idea if it was setup different to allow better gains? If not I will search for the threads in the meantime.
SuDZ
I am not boosted so I dont remember if this was done or just discussed before but at one point I read some threads talking about using the Q45 MAF sensor. Anyone remember these or have any idea if it was setup different to allow better gains? If not I will search for the threads in the meantime.
SuDZ
10-31-2002, 11:03 AM
#13
The question remains about what does 100% air flow mean.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
And yes, a SCed or TCed engine can achieve greater than 100% volumetric efficiency, that's how they work. A NA engine will never achieve 100% volumetric efficiency, though.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
And yes, a SCed or TCed engine can achieve greater than 100% volumetric efficiency, that's how they work. A NA engine will never achieve 100% volumetric efficiency, though.
10-31-2002, 11:20 AM
#14
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Join Date: Aug 2000
Posts: 2,807
You are correct. The MAF on the se-r and U11 maxima/Z31 is know to top out around 260-270hp.
Originally posted by Stephen Max
The question remains about what does 100% air flow mean.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
The question remains about what does 100% air flow mean.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
10-31-2002, 11:21 AM
#15
...
Originally posted by Stephen Max
The question remains about what does 100% air flow mean.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
And yes, a SCed or TCed engine can achieve greater than 100% volumetric efficiency, that's how they work. A NA engine will never achieve 100% volumetric efficiency, though.
The question remains about what does 100% air flow mean.
I think that what the % number is comparing is the MAF sensor output signal compared to the maximum possible signal, and is not really saying anything about the volumetric efficiency of the engine, except maybe indirectly. Certainly, if a SC or TC can shove more air through the MAF sensor than it is calibrated for, then the MAF sensor will register 100%. I may be completely wrong here, however.
And yes, a SCed or TCed engine can achieve greater than 100% volumetric efficiency, that's how they work. A NA engine will never achieve 100% volumetric efficiency, though.
What I figure happens is that the Apexi S-AFC records the maximum voltage it ever sees and uses this value as a "100%" boundry, then it just simply calculates the percentage(AFL%) from what % the current voltage is compared to that recorded MAX. Then if that limit is exceeded it stores that value as 100% and the saga continues.
The Apexi S-AFC is nothing more than a somewhat smart voltmeter that can store the peak value, measure the current value, and divide the two. Nothing more really.
An OBD scanner shows actual lbs./min measurements that I can put into Excel and graph to see more of what is going on at certain RPMs, Loads, speeds, etc., which is more useful IMO. However, it requires lugging around a laptop to store anything.
10-31-2002, 11:23 AM
#16
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Join Date: Aug 2000
Posts: 2,807
Re: MAF question to S/C guys
IF you are getting close to topping it out, then yes you need to upgrade. Otherwise going over 95-100% = spare parts. The ECU won't be able to map a fuel curve once the maf is over its limit and for nissan's it is generally 5.0v. Now I think the Z32 MAF might be able to support more than the 4th gen MAF, however I can't confirm that. Either way the engine could benefit at that power level with a bigger maf. I say get bigger injectors and a MAF then go from there. That way you leave more room to expand. Assuming you don't blow a HG or throw a rod first 
.
.
Originally posted by turbo97SE
I have a question regarding MAF readings. What is the highest MAF reading you S/C guys have?
Mine is about 87% with 9.3 psi boost. So at 11 or 12 psi it should be pretty close to 90%+.
Is there any way to upgrade a MAF to increase airflow? I am thinking that if I get a larger MAF body with the same element, more air will flow for the same reading (in volts), this would make the car run lean. I could either use the S-AFC or get larger injectors (or a combination of both) to balance this out. What do you think?
Or is this even an issue?
I have a question regarding MAF readings. What is the highest MAF reading you S/C guys have?
Mine is about 87% with 9.3 psi boost. So at 11 or 12 psi it should be pretty close to 90%+.
Is there any way to upgrade a MAF to increase airflow? I am thinking that if I get a larger MAF body with the same element, more air will flow for the same reading (in volts), this would make the car run lean. I could either use the S-AFC or get larger injectors (or a combination of both) to balance this out. What do you think?
Or is this even an issue?
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