Focus ST Dyno Numbers

[TiStick]

Originally Posted by swansong

If we assume a 15% drivetrain loss, here are estimated crank numbers:

Average HP: 227.04 x 1.18 = 267.1 HP
Average TQ: 276.316 x 1.18 = 325.1 ft/lbs



If you're asking why Ford underrates the numbers, I'm guessing because the advertised numbers are minimums guaranteed, while manufacturing tolerances and tune variances allow certain (most) cars to be above that.

It goes like this,
If you buy an ST, and it dyno's above the numbers, you think "Thanks Ford, you made my ST awesome!"
If you buy an ST, and it dyno's below the numbers, you think "Screw you Ford, you lied to me!"
So when Ford underrates the numbers, you get more happy customers.

Kinda the opposite of the 2008 STi fiasco. Subaru is still feeling the shame of that one, plus the owners took a huge hit on resale.

[streetxracerx102]

Originally Posted by swansong

It goes like this,
If you buy an ST, and it dyno's above the numbers, you think "Thanks Ford, you made my ST awesome!"
If you buy an ST, and it dyno's below the numbers, you think "Screw you Ford, you lied to me!"
So when Ford underrates the numbers, you get more happy customers.

Exactly

[Outlaw5.0]

Comparing engine Dyno to chassis Dyno is impossible without knowing the actual drivetrain losses. Maybe the loss is less than 15-18%?. The 2013 GT500 is a good example of reduced losses. Lets not leave out dyno accuracy. If believing the ST makes 267 horsepower or what ever makes you happy, then so be it.

[swansong]

Originally Posted by Outlaw5.0

Comparing engine Dyno to chassis Dyno is impossible without knowing the actual drivetrain losses. Maybe the loss is less than 15-18%?. The 2013 GT500 is a good example of reduced losses. Lets not leave out dyno accuracy. If believing the ST makes 267 horsepower or what ever makes you happy, then so be it.

Right, we can't know exactly how these real world numbers compare to the crank numbers, because of the uncertainty in drivetrain losses. Dyno accuracy and peculiarities are mitigated by the sampling of many different dyno's and averaging the results out. Of course we only have a small sample to deal with, but it's a start. So, even if we assume a 10% loss, the numbers still look good:

Average HP: 227.04 x 1.11 = 252.27 HP
Average TQ: 276.316 x 1.11 = 307.02 ft/lbs

It certainly seems as though the torque number is being underrated. By quite a bit.

(Aside: hopefully we all realize why I'm multiplying the whp/wtq by 1.11 instead of 1.10 for a 10% loss, and 1.18 instead of 1.15 for a 15% loss. Can explain if necessary.)

[lscrx]

Originally Posted by swansong

Right, we can't know exactly how these real world numbers compare to the crank numbers, because of the uncertainty in drivetrain losses. Dyno accuracy and peculiarities are mitigated by the sampling of many different dyno's and averaging the results out. Of course we only have a small sample to deal with, but it's a start. So, even if we assume a 10% loss, the numbers still look good:

Average HP: 227.04 x 1.11 = 252.27 HP
Average TQ: 276.316 x 1.11 = 307.02 ft/lbs

It certainly seems as though the torque number is being underrated. By quite a bit.

(Aside: hopefully we all realize why I'm multiplying the whp/wtq by 1.11 instead of 1.10 for a 10% loss, and 1.18 instead of 1.15 for a 15% loss. Can explain if necessary.)

The non-ST's are making almost as much torque to the wheels as Ford rates them at the crank. IIRC the stock torque rating is 146, and people (with the 5 speed) are dyno'ing at 140+ to the wheels.

Posted via FF Mobile

[streetxracerx102]

Added another Cobb chart and updated the averages. Cobb did a run after 1000 miles to see if there was any change from a "break-in" tune.

[- Thed -]

Those are some pretty damn impressive numbers!!! A black ST2 is definitely on my short list for a new car.

[jamminsvt]

Originally Posted by Outlaw5.0

Comparing engine Dyno to chassis Dyno is impossible without knowing the actual drivetrain losses. Maybe the loss is less than 15-18%?. The 2013 GT500 is a good example of reduced losses. Lets not leave out dyno accuracy. If believing the ST makes 267 horsepower or what ever makes you happy, then so be it.

That's more believable than Hyundai's claim of 274 for their 2.0 turbo.

[FLYLOW]

Originally Posted by jamminsvt

That's more believable than Hyundai's claim of 274 for their 2.0 turbo.

so hyundai "claims" (according to you) 274hp at the crank... yet a stock 2013 2.0T dynos ~240-242whp thats a give or take 12% hp to whp difference...

i believe that...

[streetxracerx102]

In response to those saying they would rather have more horsepower, and less torque, here is a decent article I found explaining the difference between the two. The peak horsepower really means very little if you don't have enough torque to take advantage of the power.

Notice that although Engine B has more peak horsepower, Engine A has more power at speeds up to 5500 rpm. What's more, it has significantly more power in the 1500-4000 rpm range (highlighted area), the range of engine speeds in which you'd typically operate a car.

Now let's look at the torque curves of the two engines:

We see that Engine A puts out much greater torque, especially over the typical engine speed range, indicating that under normal conditions Engine A will give you much more “oomph” than Engine B. Peak numbers are nice to brag about but often don't mean much, since few people operate their engines at peak conditions (which would generally be full throttle) in a typical day.

http://www.straightdope.com/columns/...wer-and-torque