What ambient temperature do Internal combustion...

[dailydriver]

Originally Posted By: 4wheeldog
The best economy in my experience occurs at the highest ambient temperature. Best power, at a much lower temperature. So....It all depends on what you consider "Most efficient"....Best power, or best fuel economy?


Yes, there IS a reason that drag racers want their oil very hot, and their coolant/water almost cold, AND set their best times in very cool, dry, high barometric pressure, low density altitude conditions, as long as traction does not suffer too much in the cold ambients.

 

[userfriendly]

It took 4 pages for someone to mention low density altitude conditions. Replace altitude with high temperature ambient conditions. Less aerodynamic drag in hot weather should yield the best fuel economy.

 

[Jetronic]

but in gasser you might end up with the ignition advance being pulled.

 

[userfriendly]

Not with EcoTec3 according to GM authority.

 

[Snoman002]

Since I log the data my ECU is reporting obsessively, I had to take a look at the data.

Ambient temp of between 33 and 50, maximum oil temp observed was 209, minimum observed 199, over the course of a 3 hour drive. From March of this year.

Ambient temp of between 88 and 109, maximum oil temp observed was 210, minimum oil temp observed was 167, over the course of a 1 hour drive. This was from August of this year. Note, the minimum temp was at the highest ambient temp, I assume this was from the car heating up when turned off and stopped.

If anybody wants to dig through the data I have 100 MB of logs you can tear through.

for the record, the car is a G8 with an 8 quart sump.

 

[splinter]

Originally Posted By: Snoman002
...over the course of a 3 hour drive...If anybody wants to dig through the data I have 100 MB of logs you can tear through...


Actually that sounds quite 'normal' to me. Of course you're welcome to post those logs, too.

 

[BrocLuno]

Originally Posted By: riggaz
There's no such thing as winter fuel or economy drop according to BITOG, you must be mistaken.

There certainly are winter blends mandated by the regulators. In this case you are dead wrong ...

Fuel/Air ratios and atmospheric corrections for "density/altitude" are well know in the performance arena. The hotter it gets, the "higher" you go for altitude equivalency when jetting for current conditions.

That's why a lot of drag cars run well at night. The track is warm enough to be sticky from daytime heat, but the air is cooling and the motors pick up (and more than make up for the small rise in air resistance...).

Humidity also has a large factor to play. Cool dense air with moderately high humidity will make a lot of engines do their best

 

[riggaz]

Ever heard of sarcasm?