Fuel burn at wide open throttle

[MadBill]

VE doesn't relate directly to power or torque for a diesel, just to airflow vs. displacement and RPM

[andyf]

0.50 BSFC is the rule of thumb but modern engines should be much better than that. Most of the big block Mopar engines that I test these days are around 0.400 BSFC at torque peak. I'm sure the NASCAR boys are somewhere in the 0.3's

[Truckedup]

0.50 BSFC is the rule of thumb but modern engines should be much better than that. Most of the big block Mopar engines that I test these days are around 0.400 BSFC at torque peak. I'm sure the NASCAR boys are somewhere in the 0.3's

From what I understand, fuel use at torque peak is less than at maximum power..

[David Redszus]

0.50 BSFC is the rule of thumb but modern engines should be much better than that. Most of the big block Mopar engines that I test these days are around 0.400 BSFC at torque peak. I'm sure the NASCAR boys are somewhere in the 0.3's

From what I understand, fuel use at torque peak is less than at maximum power..

That depends on whether we measure on a per stroke or time basis.

[David Redszus]

Whenever horsepower numbers are used, the engine rpm must accompany the power numbers.

Considering a 5.0L (305cuin) engine producing 400 hp, would need an engine speed of 5500 rpm and would produce 13.0 bar BMEP.

A 4.0L (244 cuin) engine producing 13.0 bar BMEP would need 6900 rpm to make 400 hp.

The smaller engine would have to run faster to make the same power as the larger engine.

The 5.0L engine, running at 5500 rpm, would use 160.0 lbs/hr of fuel.
The 4.0L engine, running at 6900 rpm, would use 161.5 lbs/hr of fuel.

Much depends on the fuel used. In the above examples, I used a fuel with a fuel stoich value of 14.7, a SpG of.745, and a Lambda of 1.0. Fuel can only burn at a Lambda of 1.0. Using less fuel will reduce power. But more fuel may be necessary to reach a Lambda of 1.0. Excess fuel will not burn and will be carbonized or spit out the exhaust.

Not all contributing variables have been considered for simplification purposes.

[randy331]

Here's a dyno sheet that may be of some help seeing fuel consumption vs RPM-power-BSFC #s etc.

Sunoco says the fuel used has specific gravity of .734

The HPCF was 1.061 on that pull.

Randy

EMC run 4.jpg