I was just wondering if there was an equation or percentage to find out how much a certain HP at the wheels is at the crank?? Like if the drivetrain is a 15% power lossage.

I realize that it is different for each engine and transmission, but what about a 98 4.6L auto? Mike, you might know this since you have dyno numbers...

thanks,

Rick

 

Hi Rick,

As I've said no less than hundreds of times here, there is NOT one set % figure that people can use for automatics, or for manuals, to calculate/determine driveline losses, or to "equate" flywheel to rear wheel power levels, etc.

There is only 1 way to correctly calculate driveline losses, and that is by doing a proper drag-down test on a good chassis dyno. Period.

Use the search feature and you'll be able to access everything I've already written on this here, I've discussed this *many* times, too many to count, and with many exact numbers, etc. All of that is easy to find via the F-150 Online search engine.

Read that material, and you will find all the info you're looking for.

Some examples using 2WD F-150's at STOCK power levels:

On a 4.2 V6 automatic F-150, the driveline losses are a whopping 31.70%, and with a manual, it's a tad over 17%.

Take a 4.6 automatic F-150, and the driveline loss is 28.14%, same truck with a manual would be 15.16%.

Take a 5.4 (non-Lightning) F-150, which only comes in an automatic, and the driveline losses are 25.0% with the 4R70W automatic, and 26.54% with the 4R100 automatic. But if you *could* get a 5-spd. manual in a 5.4 F-150, the driveline loss would be about 13.46%.

Take a 1999 or 2000 Lightning, all of which use the 4R100-HD automatic transmission, and the driveline loss is 19.17%. However, take a 2001-2003 Lightning, and the driveline loss is 18.16%.

Driveline losses on 4R70W automatic-based 2WD drivelines in these F-150's averages 65 HP at stock power levels.

Driveline losses on 4R100-HD automatic-based 2WD drivelines in these F-150's averages 69 HP at stock power levels.

Driveline losses in any manual-tranny F-150 run anywhere from 32-36 HP at stock power levels, on a 2WD platform.

Add 4WD, and you pick up another 4-7 HP in driveline losses.

And we haven't even begun to talk at all about GM's 4L60-E automatics, or their 4L80-E automatics, or the newer Allison 5-speed automatics, or the automatics in a Ford Taurus, etc. All of which have significantly different driveline loss HP numbers and percentage figures from what I've exampled here in these Fords.

All of that HP & % data I've listed above for these F-150's comes from years & years of dyno testing *many* F-150's, Lightnings, etc. Because we have done so much of that, yes, we **approximate** a rough percentage for the driveline losses for just about any F-150 configuration, but that still doesn't change the basic fact that you just cannot use any set percentage for either manual or automatic transmission vehicles to determine driveline losses, or to equate flywheel to rear wheel power levels, etc. You have to do the drag-down tests to see what the power losses for each different vehicle platform actually are, to get to a final percentage figure for *that* vehicle.

Happy reading!