Quote:
Originally Posted by DRW
I also tested fuel consumption in neutral at various rpms. It was suprising and enlightening. At idle it uses .35gph, 1k rpm uses .45gph, 2k rpm uses .84gph, and 2.5k uses 1.16gph. When driving on the freeway at steady speed at 55mph the engine is turning 2k rpm and uses about 1.6gph. Half of the fuel is used just to turn the engine! It makes me want to push in the clutch and coast for a while.
I haven't thought about testing driveline drag, I also wonder how much it uses?
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I'm surprised that half the fuel is used to turn the engine (however, I suppose that as you are maintaining a steady speed, it makes it worse). That makes me even less likely to cruise at steady speeds unless I need to!. I have recently started driving at just below the point where the engine enriches (about 1/3 throttle on my turbo car), and then cut the engine when possible for downhills (even slight gradients where I can go from 40mph to 20mph, but cover 1 mile doing so).
I'm thinking the driveline drag will show the effect of the oil and the bearings in the transmission (also the wheel bearings, CV joints, etc). I assume that when driving, there will be increased resistance as there is more 'load' on the gearbox. I'm not sure how much the resistance would go up however.
The advantage of transmission testing is that you could test the transmission for 5 minutes, after a 10 minute warmup drive in summer. Then change the oil to a supposedly better one, and then test it again for 5 minutes - and see what the difference is!. You could subtract the GPH of the idling engine to see the effect on the transmission.
Edit - Mods - you could move this to the 'discussion' thread if you want, so we keep this thread for stats etc from now on
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