Thread: Screen removal on MAF below intake on NA 3.2 M112
View Single Post
  #40 (permalink)  
Old 10-12-2011, 06:57 PM
onehundred80's Avatar
onehundred80
onehundred80 is offline
Senior Member
Join Date: Apr 2006
Location: Ontario
Age: 84
Posts: 25,374
Received 544 Likes on 460 Posts
Default Re: Screen removal on MAF below intake on NA 3.2 M112
Originally Posted by LantanaTX
If you have it, I would use the V8 MAF in the 74mm housing. Here's why: It is a MASS AIR FLOW METER. It works by keeing an electrode at a contant temperature. More air cooling it requires more current to heat it. The sensor is also calibrated to the diameter of the housing. A larger housing means more air (MASS AIR) is passing through. Is this starting to make sense?? No need for a tune. Our cars run a open loop fuel management system and can adjust to differences. Just an FYI, when I got my V8 running, my V8 MAF was bad so I put the V6 one into the V8 housing and ran that until the new one arrived. It seemed to drive just fine.
I could be wrong in my opinion on this, the 74mm TB has an increase in area of about 20% over the 68mm TB. The difference in the 3.2 liter engine and the 5.5 liter say is about 70%. Hence at any given rpm the need for air in the 5.5 liter engine is 70% greater.

The air passing the sensor will be travelling faster in the 5.5 liter engine and any cooling will thus be greater. Using a sensor for a 5.5 liter MAF in the 3.2 liter MAF will let the sensor stay warmer as less air travels over it.
I would think that the 3.2 liter sensor will adapt better than the 5.5 liter sensor.

I had no idea at all how the sensor worked, but if what you say is correct and I have no reason to doubt you, the use of the sensor for the larger engine does not seem correct to me.

I'm using the 3.2 sensor in the 74mm MAF with no problems that I can see.

A smaller V8 would have less difference naturally. It would even out with a 4 liter V8 approx.
 
Reply Like