Stock Dyno Numbers

[OldSalt]

I recently read an article (more than one in fact) about the new 2011 Mustang 5.0 having been dynoed and it was found to have 397 HP at the rear wheels which would typically equate to approximately 440 - 448 hp at the crank when you take into consideration the industry standard 11-13% drive train losses. Now Ford rates the engine at 412HP and many are saying that they underrated the power (for many reasons) and I was wondering if that same tactic might have been applied to the 3.5 Ecoboost. Has anyone seen dyno specs of a production factory standard SHO they could share? Not being up on all the details but I seem to recall a very ambiguous statement being made during the introduction of the Police interceptor about the output being "in excess of 365hp"which at the time struck me as a funny statement since typically they provide a specific rating. Now I’m thinking that maybe they have also underrated the 3.5 and could add another 10 hp or so as they deem it necessary. I would be interested to hear others opinion on this subject especially if you have data to provide.

 

[SHO U UP]

I recently read an article (more than one in fact) about the new 2011 Mustang 5.0 having been dynoed and it was found to have 397 HP at the rear wheels which would typically equate to approximately 440 - 448 hp at the crank when you take into consideration the industry standard 11-13% drive train losses. Now Ford rates the engine at 412HP and many are saying that they underrated the power (for many reasons) and I was wondering if that same tactic might have been applied to the 3.5 Ecoboost. Has anyone seen dyno specs of a production factory standard SHO they could share? Not being up on all the details but I seem to recall a very ambiguous statement being made during the introduction of the Police interceptor about the output being "in excess of 365hp"which at the time struck me as a funny statement since typically they provide a specific rating. Now I’m thinking that maybe they have also underrated the 3.5 and could add another 10 hp or so as they deem it necessary. I would be interested to hear others opinion on this subject especially if you have data to provide.

There is more of a loss than the 10-13% for sure. IIRC, it was like 260-ish to the wheels. The AWD zaps a lot of power as can be expected though.

 

[OldSalt]

Without a doubt the AWD system will use more of the available power, the 11 - 13% is the accepted std loss for a RWD vehicle such as the Mustang, which is what I was referring too. Does anyone know the std for our SHO style AWD system, is it 20%, I don't know and I'm just throwing a number out there to start the discussion, and what do others think is Ford being conservative with the performance numbers of the 3.5 ecoboost.

 

[SuperHO]

wow...

[youtube]<object width="640" height="385"><param name="movie" value="http://www.youtube.com/v/XykNKojmhkY&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/XykNKojmhkY&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object>[/youtube]

so much for 365hp...

 

[RonPorter]

Without a doubt the AWD system will use more of the available power, the 11 - 13% is the accepted std loss for a RWD vehicle such as the Mustang, which is what I was referring too. Does anyone know the std for our SHO style AWD system, is it 20%, I don't know and I'm just throwing a number out there to start the discussion, and what do others think is Ford being conservative with the performance numbers of the 3.5 ecoboost.

The loss # for MTX SHOs has been 18%, and 22% for the ATX. And engines like the N-S Chrysler cars with FWD was around 26%.

I suspect the AWD SHO would be around 25% or so.

 

[RonPorter]

wow...


so much for 365hp...

If I use my 25% loss guesstimate, 292 at the wheels is 389 to the crank.

 

[PonySHO]

I seem to recall seeing some dyno numbers on a stock SHO on here somewhere a few months ago. I don't remember the exact numbers at the wheels, but I do remember calculating a 25% power loss from the AWD using the claimed 365hp.

 

[hawkeye18]

What? I'd say that with the mushy 6-speed and AWD, it loses 20% in the drivetrain. So 293hp = 366.25. So I'd say that's pretty spot-on.

FWIW, the GT with the MT will only lose about 10-12% due to the more efficient manual and more efficient solid axle (half shafts soak up power). So that puts the power somewhere between 436 and 446. It is kinda sad that the mustang's engine gets more at the wheels than the SHO gets at the crank. It's the main reason I just couldn't justify buying a SHO.

 

[RonPorter]

What? I'd say that with the mushy 6-speed and AWD, it loses 20% in the drivetrain. So 293hp = 366.25. So I'd say that's pretty spot-on.

20% is too low when MTX FWD cars are near that. From the TC through the tranny, the 90-degree power changes and CV shafts, 25% is being generous.

 

[hawkeye18]

20% is too low when MTX FWD cars are near that. From the TC through the tranny, the 90-degree power changes and CV shafts, 25% is being generous.

Ok, so assume that 25% is generous... would 28% sound better? Do you really want a car that loses damn near a third of its power through the driveline? That is utterly ridiculous.

But then again, a 25% loss means 378hp and a 28% loss means 406hp. Frankly, I think that's a little more than even what ford would overrate an engine to be. yes, it's only 40hp but that's 15% under-rated... and then there is the psychological effect of crossing that 400hp barrier. I think 25% might be a little more rational. Still... losing a quarter of your power... damn.

 

[drivinhard]

who cares what theoretical hp number is at the crank, all that matters is what's at the wheels, that's all you got to work with

 

[PonySHO]

OK guys, I found the dyno I was referring to, it was on You Tube.

http://www.youtube.com/watch?v=JNigmGSvu3k&feature=player_embedded#

The raw data yields a 25.0% power loss and with WCF it's 27.0%.

 

[hawkeye18]

What's WCF?

 

[PonySHO]

What's WCF?

I believe it's weather correction factor. A dyno needs to be corrected for altitude, temperature, barometric pressure and relative humidity in order to level the playing field. Then again, dyno numbers differ from brand to brand of dyno manufacturers also.

 

[RonPorter]

who cares what theoretical hp number is at the crank, all that matters is what's at the wheels, that's all you got to work with

Yep.

The percentage loss can vary for a number of reasons. Tires, tranny fluid, tight joints, etc, etc.

If the percentages were absolute, how would people spend all the time they waste bench racing about crank HP??

 

[tardboy21]

Never worked with an AWD dyno, does it run in full 50/50 and not biased to the front?

 

[drivinhard]

how would people spend all the time they waste bench racing about crank HP??

nothing like a good argument on a number that's impossible to come up with, that doesn't even matter anyway

peak crank numbers are like hp/L numbers, great for an engine on a stand in a dyno cell, but meaningless when bolted into a car.

I have seen 11hp/10 ft/lbs peak from 5w30 oil vs 15w50 and 42 lb 17" wheels/tires vs 48 lb 18" wheels/tires. Surely that's as cool as a set of $1100 headers

 

[Toolman]

I have seen 11hp/10 ft/lbs peak from 5w30 oil vs 15w50 and 42 lb 17" wheels/tires vs 48 lb 18" wheels/tires. Surely that's as cool as a set of $1100 headers

11hp from headers blows. But if they sounded REEEEAAAALLY good, then maybe $1100 would not be so bad!

Oh, and to carry the argument further, who cares what hp you are measuring at the wheels. All the REALLY matters is how fast those wheels move the car that is attached to them.

 

[SuperHO]

I dunno...it's like with the old Terminator Cobras. Back when they were released, Ford was saying something stupid like 390hp, but guys were seeing box stock numbers of 425+. I'm beginning to wonder about the 365hp number myself, since, let's face it...physics can't be broken. Methinks it takes more than 350ft-lbs of torque to move 4400+/- down the 1/4 in 13.5 seconds....

 

[OldSalt]

Well, I started this thread having a suspicion that the numbers Ford published were on the low side, my thinking, based on the AWD configuration, weight, and demonstrated performance the motor has to be putting out 380HP and 375LB/FT of torque. That’s just a SWAG and I don’t intend to try to justify that number but it’s a gut feeling. One of the Youtube videos shows 299.9 hp at the wheels and if the 27% loss from the AT/AWD setup is true then that would equate to 380 HP at the crank and to me that’s not that unreasonable, and would easily allow Ford to “upgrade” the power rating in their new Police Interceptor to 375 just like they magically upgraded to 365 from 355 for the SHO. Don’t shoot me guys, it’s just MHO.