adj mass air flow
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Racer
Joined: Jan 2007
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From: bethlehem PA
adj mass air flow
will an adj MAF help my performance. i have a 357 b/print an balanced. solid cam 239 dur 540 lift. dart iron ported heads. heavly ported stock intake, ported lps runners. 24lbs injectors. do you think i should get bigger injectors. 355 gears 3000 stall
Safety Car
Joined: Jan 2004
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Safety Car
Joined: Apr 2011
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IMO, no.
The adjustable MAF are for the ultimate fine tune for those that have a great deal more money in their engines that you describe. Even then, the bore of the MAF is going to stay the same so the CFM stays the same. It simply alters the data to the ECM for some level of control over the AFR. Not a lot, but it allows you dial-up some richness or lean it out at times. I've worked with adjustables in 280 & 300 Nissan ZXs and they can be very difficult to figure out. Nissan uses a different type of MAF but it does the same thing...measure the air so the ECM can calculate the fuel. Last time I looked an adjustable was running around $500...so its for the most serious of track guys or those that have the data logging equip to see what they're doing and find their way back again..
See the adjustable MAF like this...its a window. The ECM knows the size of that window and what will fit thru there. If you open or close that window the "target" area changes so the ECM does not understand why there is something coming in that should not be able to enter...its out of the normal parameter. The "tune" sets the expected size of the window...go outside that and the ECM freaks out, goes immediately into OL operation or LHM and you loose whatever gains you thought you had...ya gotta get past the ECM and the tune before you need to worry about the <5% values of the MAF adjustment. Since C4s are a "fixed" tune, in a PROM, that has to be physically removed to be reflashed, its just not practical.
If it were OBD-II...so you could set your lap-top in the passenger seat and make some changes as you drive thats another story..but its not.
The adjustable MAF are for the ultimate fine tune for those that have a great deal more money in their engines that you describe. Even then, the bore of the MAF is going to stay the same so the CFM stays the same. It simply alters the data to the ECM for some level of control over the AFR. Not a lot, but it allows you dial-up some richness or lean it out at times. I've worked with adjustables in 280 & 300 Nissan ZXs and they can be very difficult to figure out. Nissan uses a different type of MAF but it does the same thing...measure the air so the ECM can calculate the fuel. Last time I looked an adjustable was running around $500...so its for the most serious of track guys or those that have the data logging equip to see what they're doing and find their way back again..
See the adjustable MAF like this...its a window. The ECM knows the size of that window and what will fit thru there. If you open or close that window the "target" area changes so the ECM does not understand why there is something coming in that should not be able to enter...its out of the normal parameter. The "tune" sets the expected size of the window...go outside that and the ECM freaks out, goes immediately into OL operation or LHM and you loose whatever gains you thought you had...ya gotta get past the ECM and the tune before you need to worry about the <5% values of the MAF adjustment. Since C4s are a "fixed" tune, in a PROM, that has to be physically removed to be reflashed, its just not practical.
If it were OBD-II...so you could set your lap-top in the passenger seat and make some changes as you drive thats another story..but its not.
Last edited by leesvet; Oct 16, 2012 at 08:41 PM.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
Oh, I know ! Those things are for people with all the goodies to adjust everything else... Its a LOT like the adjustable o2 sensor that was being peddled a few yrs ago.
What you do to one thing you must do to everything else. The "tune" has the final say in this...
I remember getting a 300z so screwed up that I just replaced the MAF...it was so sensitive that 1/8th turn of the screw would throw it into chaos...and I never found the original setting again. I wouldn;t mess with one of those now even if Andy Granetelli was there to do the work ! Its one of those things thats great in theory...not in application though.
What you do to one thing you must do to everything else. The "tune" has the final say in this...
I remember getting a 300z so screwed up that I just replaced the MAF...it was so sensitive that 1/8th turn of the screw would throw it into chaos...and I never found the original setting again. I wouldn;t mess with one of those now even if Andy Granetelli was there to do the work ! Its one of those things thats great in theory...not in application though.
Race Director
Joined: Apr 2000
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From: Texas
The need for different injectors is driven by duty cycle. Without knowing the power you produce, the rpms you spin, or the fuel pressure you run it would just be a guess.
