Powertrain Loss

[LIL QIK]

I keep seeing people on this board talk about a 23% powertrain loss....but everything I find on the net says that awd systems have more of a 27%-30% loss. I'm thinking surely that with the builders on this board and the trucks that are making big power....that someone has actually run a real test. Surely someone has engine dynoed their build....and then chassis dynoed there system.

Yes, Yes....I know....it's what is put to the ground that is important.....but I can't help but wonder where this 23% figure is coming from......

I'm planning on doing this very test....but am a ways off of having the build completed.

 

['JustDreamin']

Re: Powertrain Loss

Most all of that is "estimated" loss....

Sadly, there are very few folks who have done what you suggest and compare results.

Even fewer have made comparisons of things like rear-ends and transmissions to know how much power they consume at various power levels. I remember seeing a magazine article comparing rear ends, but about the only thing I can remember about it was that the 12-bolt Chevy was more efficient at putting power to the ground than the 9" Ford. How much more? Can't remember. Any other details? Can't remember them either.

I would expect that an AWD drivetrain does have more loss than a standard RWD setup. There are 2 hypoid type drives, a chain drive, and an automatic transmission, with all of the associated losses in each of those components. 27% to 30% ? Don't know if its a reasonable amount or not.

'JustDreamin'

 

[caci]

Re: Powertrain Loss

I wonder if Powertrain Loss should be expressed as a fixed value, rather than a percentage (i.e. 50hp vs. 23%)?

I can't help but think that for a given engine speed, the PT Loss should be the same for a 250hp output or a 500hp output engine - with identical componets from the flywheel/flexplate to the tires.

I'd be curious to see what the 700hp (engine dyno rated) motor, from a previous thread, is going to put to the ground.

 

[LIL QIK]

Re: Powertrain Loss

I wonder if Powertrain Loss should be expressed as a fixed value, rather than a percentage (i.e. 50hp vs. 23%)?

I can't help but think that for a given engine speed, the PT Loss should be the same for a 250hp output or a 500hp output engine - with identical componets from the flywheel/flexplate to the tires.

I'd be curious to see what the 700hp (engine dyno rated) motor, from a previous thread, is going to put to the ground.

Yeap...I'm actually doing a little research on this very thing.....hoping to come up with an answer that makes total sense....lol

 

[BigAl...]

Re: Powertrain Loss

I wonder if Powertrain Loss should be expressed as a fixed value, rather than a percentage (i.e. 50hp vs. 23%)?

I can't help but think that for a given engine speed, the PT Loss should be the same for a 250hp output or a 500hp output engine - with identical componets from the flywheel/flexplate to the tires.

I'd be curious to see what the 700hp (engine dyno rated) motor, from a previous thread, is going to put to the ground.

I've been preachin this for years.

BigAl...

 

[0260IN3]

Re: Powertrain Loss

We did this test on a 600 hp build (engine dyno test) and in a stock wheel, 700r4, stock t-case Typhoon we lost about 30% to the wheels when all said and done.

The percentage does NOT always stay the same as it has many factors involved. But you can usually count on no less tha 25% and no more than 35% on average.

 

[LIL QIK]

Re: Powertrain Loss

We did this test on a 600 hp build (engine dyno test) and in a stock wheel, 700r4, stock t-case Typhoon we lost about 30% to the wheels when all said and done.

The percentage does NOT always stay the same as it has many factors involved. But you can usually count on no less tha 25% and no more than 35% on average.

Thank You.....that's the kind of stuff I was looking for. I know every situation would be a little different.....but I think that the 30% is a good generalization.

Thanks...

 

['JustDreamin']

Re: Powertrain Loss

I would expect that there is some equation for drivetrain loss.....

I'm expecting that there is some fairly "fixed" losses for certain component (x number of hp for xx device).

And that some of the loss is a percentage of power transmitted.

And that some of the loss may not be a fixed percentage of power loss. For example, front pump power consumption is probably linear in certain pressure ranges, but is probably exponential in other pressure ranges.

What it all boils down to is I don't think you'll find a correct fixed value. Entirely too many variables, including stuff like how the components are set up (like line pressure), not just what components are in the truck (700R4 vs 80E for example).

'JustDreamin'