ScanGauge Questions for a VW Diesel.

[Crazyrabbit]

Miles per hour divided by gallons per hour = miles per gallon in my book. Miles per hour is pretty easy, gallons per hour is more difficult especially if you can't get a place to measure it upstream of the injector spill return. A lot of Diesels dump the spill back to the tank to keep the fuel temp low. It sure would be nice to get a real time measurement. I don't know what cruise speed will optimize the mileage on my '81 Rabbit Diesel, but it sure seems like it is about 55 mph, maybe quite a bit higher when drafting.

Air flow is neither here nor there. Not sure why anyone would even try to measure it on a Diesel, unless it was for trend monitoring, like: Is the turbo performance what it used to be?

[tasdrouille]

Originally Posted by Crazyrabbit

Air flow is neither here nor there. Not sure why anyone would even try to measure it on a Diesel, unless it was for trend monitoring, like: Is the turbo performance what it used to be?

They wanted the engine not to smoke under any circumstances, and keep the EGT low. If you don't monitor airflow and you have a gunked up intake from crankcase vent oil and egr soot, you'll get smoke out the back under high load and high EGT.

[rmay635703]

Originally Posted by tasdrouille

They wanted the engine not to smoke under any circumstances, and keep the EGT low. If you don't monitor airflow and you have a gunked up intake from crankcase vent oil and egr soot, you'll get smoke out the back under high load and high EGT.

In terms of a fuel economy gauge its still a moot point though, unless of coarse you are bumping against the limit on your throttle which a good ecomodder doesn't do anyway.

[Imatech]

Good records will always show you where you going wrong.