MAF vs transmission pressures, someone please help!

[oakleafresin]

Why would an 85mm maf sensor and a stock maf sensor not be measuring the same lb/min, in the exact same conditions??

I have a scan of my car with an 85mm maf sensor measuring 1.2lb/min at 3200hz
I have a scan of my friends car with a stock sensor measuring .70lb/min at 2500hz

The more than 30% different value than stock is causing havoc with my pcs line pressure.

My car is using a stock maf table from a 2003 silverado and the friends car is just a stock 97-98 maf table. Regardless, why doesn't my maf table have a .7 (or even .8!) in the 3200hz cell??? I'm sure the car would not like to run with 30+% less fuel if I changed the value there..........

[Russ K]

Because your flowing a lot more air to hit 3200 hz with a 85 mm Maf vs 2500 hz with the stock 78 mm Maf.

Russ Kemp

[oakleafresin]

Because your flowing a lot more air to hit 3200 hz with a 85 mm Maf vs 2500 hz with the stock 78 mm Maf.

Russ Kemp

Right, I get that, but why wouldn't two cars, given the exact same setup (but different mafs) flow the same "lb/hr" regardless of the hz they are measuring?

[Russ K]

Right, I get that, but why wouldn't two cars, given the exact same setup (but different mafs) flow the same "lb/hr" regardless of the hz they are measuring?

Because the car with the larger Maf needs more air (lb/hr) flowing through it to hit the same HZ as the car with the smaller Maf.

Russ Kemp

[oakleafresin]

Because the car with the larger Maf needs more air (lb/hr) flowing through it to hit the same HZ as the car with the smaller Maf.

Russ Kemp

Russ, sorry to confuse lol. Here's the deal. I know another person with an LS6 maf like myself. At idle, his maf shows 2.6k hz. My car shows about 3.1k hz. Same exact MAF sensors! I have my idle set to 800, so I commanded 700 like his car. It still read about 3,000hz, as well as ran like complete shit idling that low.

I have about 6 inches of tubing behind the MAF and the filter is connected directly to the other side of it. Would that cause a high reading like that not having any tubing in front of the maf? Really at a loss as to why two very similar cars are apparently flowing very different amounts of air at idle....

PS I have an XP cam, while he just has rockers. That's really the only major difference between the cars.