View Single Post
  #9  
Old 06-27-2021, 08:57 AM
upallnight's Avatar
upallnight upallnight is offline
Member
 
Join Date: Aug 2012
Location: Cook County
Posts: 7,280
upallnight is on a distinguished road
Quote:
Originally Posted by RocketyMan View Post
"A rule of thumb on a MAF's air flow rate at 500 rpm is 1 gram per second per liter of engine displacement."

This rule of thumb only works for an engine that has relatively no load on it, e.g. no A/C on and no heavy electrics (like cooling fan). So since you have a 3.0L engine, that means at 1000 rpms, you should be seeing about 6 g/s of air being reported by the MAF. This is the easiest to do with just the throttle. Then you can check it by then rev'ing slowly to 1500 rpms, 2000 rpms and record what readings you are getting. This should follow a linear fashion, so you can also interpolate data if you are running at say 700 rpms or something in between.

Obviously there will be pumping losses and and friction involved, so more likely than not the mass flow rate is going to be slightly higher.

Make sense?
Only to a Rocket Scientist. So why not just answer his question about which MAF is reporting the correct airflow? The old Siemens or the new VDO?

So just from your explanation, the new VDO is not correct since a BMW M54 idles around 700 rpm so 7.8 g/s is Waaaaay too much.
__________________
2006 Infiniti G35
2001 BMW 3.0I E53 X5 Build date 08/2000 SOLD
Lotus Europa 1970 Destroyed by fire
Lotus Europa 1970 S2 Renault Powered
Lotus Type 52 1970 Twincam Webers Powered
PORSCHE 911 Targa 1982 The Garage Queen
Audi Avant donated to Kars for Kids
BMW 525IT Sold
Audi 4000CS Quattro Sold
Jensen Healey Lotus Powered Sold
Opel 1900 Sold
Triumph Spitfire 1971 Sold
Triumph Spitfire 1968 Sold
Plymouth "Cuda" 340 Six pack SOLD
Reply With Quote

Sponsored Links