MAF question...
05-11-2009, 05:23 AM
#1
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MAF question... I've got a fairly large cammed LS1 with stock heads, intake, and tb, stock cubes with bolt ons.
While dyno tuning, it was found that my stock MAF was not reading the correct amount of air and the only good working MAF the shop had was an 85mm Corvette MAF that was descreened.
Well, long story short the MAF ended up splitting in half and now it has a brand new 85mm MAF in its place, screen still intact.
My question is, is that screen taking away a decent amount of airflow from the motor? I was reading on another site that a stock 85mm flows around 850cfm, but a descreened one will flow around 1000cfm. Is this true? Is the difference that significant?
While dyno tuning, it was found that my stock MAF was not reading the correct amount of air and the only good working MAF the shop had was an 85mm Corvette MAF that was descreened.
Well, long story short the MAF ended up splitting in half and now it has a brand new 85mm MAF in its place, screen still intact.
My question is, is that screen taking away a decent amount of airflow from the motor? I was reading on another site that a stock 85mm flows around 850cfm, but a descreened one will flow around 1000cfm. Is this true? Is the difference that significant?
05-11-2009, 06:01 AM
#2
No, the screen does not restrict that much air. It is beneficial in that it directs the air over the heating elements so the MAF can be more accurate. Your engine will never get full use of the MAF frequency range so just leave the screen in where it belongs.
05-12-2009, 08:05 AM
#4
Just to kinda add to this..... is it worth it going with a bigger MAF? I always assumed it was but in the FAQ or some other place I read it wasn't recommended and you'd have issues with going with an aftermarket MAF.
It makes sense to go with a bigger one though if you have cam/heads/90mmintake/90mmlid though right? The stock 78mm MAF would be like a bottleneck wouldn't it? But yet a Fast 90 gets gains on a totally stock LS1.... I'm guessing a new MAF is more trouble than its worth?
It makes sense to go with a bigger one though if you have cam/heads/90mmintake/90mmlid though right? The stock 78mm MAF would be like a bottleneck wouldn't it? But yet a Fast 90 gets gains on a totally stock LS1.... I'm guessing a new MAF is more trouble than its worth?
05-12-2009, 08:22 AM
#5
A bigger MAF is good as long as you actually need it. Turn your key on engine off (KOEO), check the MAP sensor reading. Go do a WOT run, log your MAP sensor. Compare the two, it should be about 3 kPa or less difference between the two readings for a nice free flowing system, if higher, start with a CAI if you don't have one and then move on to the MAF if you are still seeing a restriction.
Tuning a MAF is easy, I would get a GM 85mm if you decide to change it.
Tuning a MAF is easy, I would get a GM 85mm if you decide to change it.