Real Power Numbers - WHP vs. BHP?

[Kiohtee]

What part of the "removed smart-ass comment" did you not understand.

I posted something, then felt it may be taken the wrong way, so I edited my post and removed it.

Understand?

It shouldn't have been made in the first place. Much less edited out and replaced with 'I've pretty much removed a distasteful remark, but leaving this here just because.' Understand?

Either way, your thread has ventured very much off its original topic because you want to pick a fight with me about the least important parts of my posts. I hope you get the answer you're looking for moving forward.

 

[1 Alibi 2]

From a magazine article, ( 5.0 Mustang & Super Fords, March 2012 )
Ford Engineers discuss the development of the 2013 5.8L GT500 engine.

" By more efficient, we mean the 2.3-liter TVS blower requires less horsepower to drive, and at these higher boost levels it heats the charge air less. These are not inconsequential considerations, either, as SVT says it takes right at 100 hp to drive the 2.3 TVS at its maximum output. That's 100 hp the 5.8 engine must produce but is never seen by the rear tires. In other words, if the 5.8 is rated at 650 flywheel horsepower, its internal parts are producing at least 750 hp just when considering the supercharger drive requirements. That also means the engine is consuming 750 hp worth of gasoline, but that's all part of the fun. "

 

[AustinSN]

They are measuring the HP at the crank with the supercharger on it, so that loss has been absorbed by the engine and it's still making X amount of HP at the crank.

If they have tested and verified the parasitic loss for that particular SC is say 75 HP, then the engine is making the crank HP plus that loss. However without the SC obviously it wouldn't be making that much HP.

One of the reasons exhaust driven turbochargers make more HP per lb of boost is significantly less parasitic HP loss among other factors.

From a magazine article, ( 5.0 Mustang & Super Fords, March 2012 )
Ford Engineers discuss the development of the 2013 5.8L GT500 engine.

" By more efficient, we mean the 2.3-liter TVS blower requires less horsepower to drive, and at these higher boost levels it heats the charge air less. These are not inconsequential considerations, either, as SVT says it takes right at 100 hp to drive the 2.3 TVS at its maximum output. That's 100 hp the 5.8 engine must produce but is never seen by the rear tires. In other words, if the 5.8 is rated at 650 flywheel horsepower, its internal parts are producing at least 750 hp just when considering the supercharger drive requirements. That also means the engine is consuming 750 hp worth of gasoline, but that's all part of the fun. "

^^^ These.

The engine makes 707 after taking into account the loss from the S/C.

 

[jeffh81]

I am pretty sure the 5.0, SS and 392 owners and enthusiasts consider those cars high performance.

Edit: Removed smart-ass comment.

Nope.

 

[Kiohtee]

^^^ These.

The engine makes 707 after taking into account the loss from the S/C.

This car in particular is still underrated using even that method. The least amount of parasitic loss I see an automatic transmission losing, and it probably wouldn't be in a Dodge (as nice as their new 8-speeds are), is like 15%. And that's really pushing it. Probably more like 18-21%. That would leave a 707hp car making 600rwhp on a dyno.

Now you can say the dyno is just a tool and some are happy and this that, but there's still something to be said when the majority of these tools are reporting a similar number, which is 620-630rwhp. I believe the manuals make a little more and those are automatic numbers I'm referencing.

 

[Klay]

This car in particular is still underrated using even that method. The least amount of parasitic loss I see an automatic transmission losing, and it probably wouldn't be in a Dodge (as nice as their new 8-speeds are), is like 15%. And that's really pushing it. Probably more like 18-21%. That would leave a 707hp car making 600rwhp on a dyno.

Now you can say the dyno is just a tool and some are happy and this that, but there's still something to be said when the majority of these tools are reporting a similar number, which is 620-630rwhp. I believe the manuals make a little more and those are automatic numbers I'm referencing.

How would you know that the automatic found in the hellcat is losing 18-21%? You do realize the numbers you used are estimates (and old ones at that).

Modern cars have become more efficient in just about every area, so it would stand to reason that their drivetrains are more efficient as well. Thus, that would mean lower losses of hp/tq. Like was mentioned earlier, engines are more strictly tested now. They can't just underrate it by 100 hp. Not too mention, why would they?

At these power levels, insurance is already going to be more expensive. It wouldn't drastically change from 707 hp to 780 hp. When there is competition, it makes sense to advertise a higher number, not lower if it truly makes that power level.

 

[gimmie11s]

Maybe so. I don't personally. I have always defaulted to the bread and butter portion of a offering when hearing "high performance." Either way, that's not what this conversation is even about. As for the removed comment, debate maturely without making it personal or being an ass. Stop letting your feelings and inability to post a meme interfere with your ability to conversate.

Spelling police hat on:

It's worth noting "conversate" is a nonstandard word. "Converse" is the word you were looking for.



.

 

[Kiohtee]

How would you know that the automatic found in the hellcat is losing 18-21%? You do realize the numbers you used are estimates (and old ones at that).

Modern cars have become more efficient in just about every area, so it would stand to reason that their drivetrains are more efficient as well. Thus, that would mean lower losses of hp/tq. Like was mentioned earlier, engines are more strictly tested now. They can't just underrate it by 100 hp. Not too mention, why would they?

At these power levels, insurance is already going to be more expensive. It wouldn't drastically change from 707 hp to 780 hp. When there is competition, it makes sense to advertise a higher number, not lower if it truly makes that power level.

As advanced and efficient as modern automatic transmissions are, I don't believe they're only seeing 10-12% loss yet. There's still way more components to them than manuals who still see a 12-15% parasitic loss.

Spelling police hat on:

It's worth noting "conversate" is a nonstandard word. "Converse" is the word you were looking for.



.

Add another to the list I won't conversate with.

 

[MFE]

FWIW, the correct way to calculate the gross from the net or the crank from the wheels is not to add the lost amount straight back to the net, it's divide the net by the balance of the loss.

Sticking with 12% (which is awfully low IMO)

500 crank
12% loss
= 440 wheel

Going back the other way:
440 x 1.12 = 493 = wrong

440/0.88 = 500 = correct

 

[Black02GT]

http://www.superstreetonline.com/how-to/engine/modp-1005-drivetrain-power-loss/

Pretty good read regarding driveline loss.

 

[Zemedici]

FWIW, the correct way to calculate the gross from the net or the crank from the wheels is not to add the lost amount straight back to the net, it's divide by the net by the balance of the loss.

Sticking with 12% (which is awfully low IMO)

500 crank
12% loss
= 440 wheel

Going back the other way:
440 x 1.12% = 493 = wrong

440/0.88% = 500 = correct

Preach.

 

[03cobra#694]

You guys can argue about what tampon to use. I myself like...

 

[L8APEX]

I remember when 'ol O John Coletti was said to have found the world's most efficient drivetrain by magazine editors testing the '00 Cobra R, as it put down the 385hp it was rated at to the wheels.


The sentimental purist misses that SVT...
"Performance, substance, exclusivity, and value."
But the system they have now makes awesome machines that Ford also makes money on.

Sent from my Note8

 

[ON D BIT]

Just a few years ago the amg auto tranny was losing 18-20%. There's no way they are close to 40% more efficient today with most likely the same tranny.

The man gearbox has gotten more efficient with technology and engineering like the rear mounted transmission thats mounted just in front of the drive axle. Even with that most are still seeing 10-12% loss in wheel power.

 

[Deceptive]

You guys can argue about what tampon to use. I myself like...

A fresh, new paper towel roll?


Sent from my iPhone using Tapatalk

 

[SolarYellow]

In response to the previous post, one of the Fiat Chrysler insiders has stated the Hellcats all make more than 707hp, at all areas of the country and elevations. 707 seemed like a catchy number to rate it vs. "735" .......to marketing at least.

727 would have been my pick.

This topic has me surprised after learning just how much hp it takes to run the sc's.

 

[98 svt]

Are you really so new to cars that you've never heard of underrating? This goes back to even LS1s, Terminators, etc. No telling how far back it actually really goes (before my time, 1992).

Goes back to the 60s

 

[4a7191a]

My head hurts after reading this.
Need a drink now