- Joined
- Sep 28, 2002
- Messages
- 39,799
Quote:
If we take my example again, no way is the engine doing the 80 miles in 90 minutes generating the same, bi-products and junk that the engine going 15 miles in 90 minutes is.
If it consumed the same amount of fuel (one distinctive qualifier we have here) ..yes, they are. They'll both transition through the same fuel enrichment curve and will experience the same "90% of all wear occurs at startup" for about 20 minutes.
Quote:
The combustion bi-products are not linear across all operating conditions, there are certainly good operating and bad operating conditions.
Assuming you have a functional engine management system, you'll cycle in and out of closed loop in both modes. Maybe if you're in OHIO or some place where you can actually cruise you might get a fraction better fuel trimming. Your fuel maps should be adapted to what you're doing at the time you're doing it.
Quote:
Yes the oil is hot, and up to temps, however an engine that idles is putting a lot more contaminants into the oil than one that is being run under optimum conditions. That is the point I'm making here.
Only if viewed on a per mile basis. In this case, the odometer is very blind to engine usage.
I'd say that if you had two identical cars doing this with OLM's, the fuel processed would be about the same. The miles ...would be miles apart.
There will naturally be exceptions ..meteor showers, incidentals and a laundry list of POTENTIAL influences that effect either vehicle ..but this is a basic engineering concept that's pretty much immutable. That's the fundamental lifespan of an engine, the amount of fuel that it processes and turns into work.
Quote:
My point in this discussion is this, getting that oil out twice a year, is better than once a year.
As a general rule, sure. If you're going to do exceptional drain intervals, you need an exceptional oil. Not all oils are meant to go that far.
If we take my example again, no way is the engine doing the 80 miles in 90 minutes generating the same, bi-products and junk that the engine going 15 miles in 90 minutes is.
If it consumed the same amount of fuel (one distinctive qualifier we have here) ..yes, they are. They'll both transition through the same fuel enrichment curve and will experience the same "90% of all wear occurs at startup" for about 20 minutes.
Quote:
The combustion bi-products are not linear across all operating conditions, there are certainly good operating and bad operating conditions.
Assuming you have a functional engine management system, you'll cycle in and out of closed loop in both modes. Maybe if you're in OHIO or some place where you can actually cruise you might get a fraction better fuel trimming. Your fuel maps should be adapted to what you're doing at the time you're doing it.
Quote:
Yes the oil is hot, and up to temps, however an engine that idles is putting a lot more contaminants into the oil than one that is being run under optimum conditions. That is the point I'm making here.
Only if viewed on a per mile basis. In this case, the odometer is very blind to engine usage.
I'd say that if you had two identical cars doing this with OLM's, the fuel processed would be about the same. The miles ...would be miles apart.
There will naturally be exceptions ..meteor showers, incidentals and a laundry list of POTENTIAL influences that effect either vehicle ..but this is a basic engineering concept that's pretty much immutable. That's the fundamental lifespan of an engine, the amount of fuel that it processes and turns into work.
Quote:
My point in this discussion is this, getting that oil out twice a year, is better than once a year.
As a general rule, sure. If you're going to do exceptional drain intervals, you need an exceptional oil. Not all oils are meant to go that far.
