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4 inch MAF
#1605684
06/08/2017 21:26
06/08/2017 21:26
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Laipy
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Laipy
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Hello guys, I wanna make a 4 inch side intake, and I was wondering if the maf sensor will work without a honeycomb in front of it, or it will affect the idle? The car will be mapped after that to suit the bigger housing. Has anyone done this mode? Any advices?
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Re: 4 inch MAF
[Re: ]
#1605685
06/08/2017 21:33
06/08/2017 21:33
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Joined: Dec 2007
Posts: 2,252 Windsor/ Reading
knight7660
Competition Level
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Competition Level
Joined: Dec 2007
Posts: 2,252
Windsor/ Reading
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FC Performance have a 4 inch MAF conversion so drop him a PM mate
LE53 (452BHp & 389ftlb's with Quaife) Wine red VIS FOOFY Audi RS4 B7
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Re: 4 inch MAF
[Re: ]
#1605908
10/08/2017 22:18
10/08/2017 22:18
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Laipy
Unregistered
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Laipy
Unregistered
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Re: 4 inch MAF
[Re: ]
#1605944
11/08/2017 17:10
11/08/2017 17:10
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Joined: Feb 2006
Posts: 220 Czech republic
Honza
Making a profit
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Making a profit
Joined: Feb 2006
Posts: 220
Czech republic
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honeycomb before sensor has function - it make the airflow more even (velocity profile) across the pipe diameter, so you have more precise data from sensor... without it you get the data somehow distorted based on the shape of current velocity profile.. but it will somehow work.
20 years with yellow 2.0 16v NA 22 years with black SEDICIVALVOLE
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Re: 4 inch MAF
[Re: ]
#1610430
24/10/2017 16:01
24/10/2017 16:01
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Laipy
Unregistered
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Laipy
Unregistered
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Standard maf size is 76mm and it maxes out at around 400hp. If you increase the size of the housing you need to remap the ecu.
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Re: 4 inch MAF
[Re: ]
#1610433
24/10/2017 19:23
24/10/2017 19:23
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PhoB
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PhoB
Unregistered
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I tried to solve bigger MAF properly rescaled in bosch ecu. But this 2.10.4 ecu has some limiter and when new maf reads higher hex value than maximum value from oem calibration curve, its throw MAF DTC error. I bandaid it by disable this DTC message, but still have problems with stability around idle(very big injectors, ethanol fuel...) Only way without DTC error is to not touch scale curve, just roughtly adjust maf axis to suit real condition. But still will be weird condition for example decel fuel cut will not be engaged correctly, ect. So i decided to convert to "normal" standalone ecu.
Btw stock maf maxes at cca 300bhp and my tested 3.5" housing(bmw OEM maf housing incl. honey mesh) maxes at cca 400bhp. Confirmed by measuring, not repeating info from internet;)
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Re: 4 inch MAF
[Re: ]
#1610449
24/10/2017 22:58
24/10/2017 22:58
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Joined: Feb 2008
Posts: 1,725 London
kj16v
My life on the forum
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My life on the forum
Joined: Feb 2008
Posts: 1,725
London
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I tried to solve bigger MAF properly rescaled in bosch ecu. But this 2.10.4 ecu has some limiter and when new maf reads higher hex value than maximum value from oem calibration curve, its throw MAF DTC error...
...Btw stock maf maxes at cca 300bhp and my tested 3.5" housing(bmw OEM maf housing incl. honey mesh) maxes at cca 400bhp. Confirmed by measuring, not repeating info from internet;) You can definitely get 400 bhp with the stock MAF and housing. I've done this myself. Also there are two 10x1 MAF limit tables, one at CE3F and one at CE55. These allow you to raise the MAF limit - or you can just disable that nonsense by filling them with 255s
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Re: 4 inch MAF
[Re: kj16v]
#1610480
25/10/2017 11:04
25/10/2017 11:04
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PhoB
Unregistered
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PhoB
Unregistered
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You can definitely get 400 bhp with the stock MAF and housing. I've done this myself. Also there are two 10x1 MAF limit tables, one at CE3F and one at CE55. These allow you to raise the MAF limit - or you can just disable that nonsense by filling them with 255s Im not talk about physical restriction, i was about voltage signal to ecu. I done 400bhp on stock maf also, but there is start to be lack of resolution for multiple boost levels or parthrottle accel at high rpm. Two limiters tables, and others limiters i try to find not have influence on problem i noted, i think its must be somewhere some single value limiter of max kg/h value (MLMAX called in newer motronics) or something like that. I tested, last value on stock MAF curve is 1C95 hex at 5volt, which calculate is cca 914kg/h, i rescaled curve for 3.5" housing to read up to 1250kg/h at 5volt and every time maf signal passed 1C95 (which was in my curve little after 4volt) i recieved MAF error (incl.Injector light on dash). If you have different experience let us know.
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