"Coast and Burn" only works if you shut down the engine completely during the coast part. Burn, turn on engine accelerate to coasting speed, shutdown coast down to a slow speed and do it again.DOES NOT WORK FOR STREET CARS only ultra light (under 70lbs vehicle wheight) .5-1hp bubble cars.

 

OP, using the Ectune datalogger heres a screen shot of my motor under idle conditions and while throttling down in gear (foot off the gas) for comparison.


Below is my engine under idle conditions. Notice in the display box circled in green is the Engine speed at 841(RPM), Throttle posistion 0% (TPS), Injector Duty Cycle 2%. Vehicle speed and gear is circled in green in the box to the top right.


Below is my engine while throttling down/coasting with my foot off the gas. Notice in the display box circled in green is the Engine speed at 3130(RPM), Throttle posistion 0% (TPS), Injector Duty Cycle 0% due to the Fuel Cut activation (notice the green light FCut in the Outputs box in the display panel). Vehicle speed and gear can be referenced in the box to the top right.

 

Ok, maybe it's not combustion, but it is still a power cycle, with air being compressed at about the rate of 10:1. The compressed air is still going to push the piston back down.

 

I are confused. I thought you meant under engine braking, which some refer to as coasting.

 

ha, post funny!

 

Load makes a far bigger difference on fuel consumption than rpms. A civic si spinning 4500 on the freeway going 80 mph on cruise control can still get 35 mpg, because it doesn't take much fuel to maintain speed as opposed to accelerating which burns a lot of fuel. The same car, constantly going from 60 to 70 mph and back down, will get high 20s.

 

The only way there is 0 fuel consumption is if ign. is turned off, nuff said. 94

 

When you coast in gear without touching the gas the injectors will turn off. If you have a wideband on your car it will lean all the way out as there is no fuel.

 

or the tank is empty?
you are wrong, BTW, nuff said

 

not really, because the engine is attempting to compress the other two cylinders (on a four banger) what makes the cylinders move is pure inertia.
some of you people (and i don't mean you, ben) need to go back to school.

 

Just learned something new.

 

So suffice it to say that rolling resistance and friction ar the only positive forces that slow the vehicle down during engine braking? What about gravity pulling the pistons down on intake and power strokes?

 

Oh, few.

No, because it would be countered by the exhaust and compression strokes. Perhaps on a Boxer engine though

Aerodynamics also play a large key.