Dyno'd
Legacy TMS Member
Joined: January 25, 2010
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From: Massachusetts
The major problem is that the "affordable" dynos don't measure torque directly, but rather infer it from acceleration of a rotating assembly . . . . . The point the article makes is that the most reasonable measure of real world performance is actual real wheel horsepower, without the correction factors.
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V6 Member
Joined: September 15, 2004
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A buddy of mine contacted Dynojet about this same discussion regarding with what gear the measurement is done. Looks to me like we could expect to see a higher HP number if this was done in the 1:1 gear. This is what Kevin Lockliear at Dynojet had to say:
"Typically, you will see the highest numbers in the 1:1 or closest to 1:1 ratio gear. This is because no additional power is being exhausted to accelerate the inertia of the drivetrain. In 2nd gear, let’s say, because the gearing allows the car to accelerate more quickly, more HP will be used to accelerate the inertia of the drivetrain than in 1:1. See my graph below. This example was a 1996 Pontiac Trans Am WS6, all gear run. Ignore the small shift spikes at the beginning of each gear as that’s an inertia spike (where letting the clutch out abruptly against an engine with higher RPM than matching the next gear at that speed causes a brief quick acceleration of the drums).
As you can see, the HP was the highest in the 1:1 gear, and lower in other gears. From what I have experienced, the further you get from 1:1, the lower the power getting to the wheels and drum surface will be, as more is used to accelerate the inertia of the drivetrain, overcome frictional losses in meshing gears, side loading bearings, etc."
"Typically, you will see the highest numbers in the 1:1 or closest to 1:1 ratio gear. This is because no additional power is being exhausted to accelerate the inertia of the drivetrain. In 2nd gear, let’s say, because the gearing allows the car to accelerate more quickly, more HP will be used to accelerate the inertia of the drivetrain than in 1:1. See my graph below. This example was a 1996 Pontiac Trans Am WS6, all gear run. Ignore the small shift spikes at the beginning of each gear as that’s an inertia spike (where letting the clutch out abruptly against an engine with higher RPM than matching the next gear at that speed causes a brief quick acceleration of the drums).
As you can see, the HP was the highest in the 1:1 gear, and lower in other gears. From what I have experienced, the further you get from 1:1, the lower the power getting to the wheels and drum surface will be, as more is used to accelerate the inertia of the drivetrain, overcome frictional losses in meshing gears, side loading bearings, etc."
Power = work/time How fast can you use your available torque.
GT Member
Joined: January 10, 2010
Posts: 146
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From: huntley, il
A buddy of mine contacted Dynojet about this same discussion regarding with what gear the measurement is done. Looks to me like we could expect to see a higher HP number if this was done in the 1:1 gear. This is what Kevin Lockliear at Dynojet had to say:
"Typically, you will see the highest numbers in the 1:1 or closest to 1:1 ratio gear. This is because no additional power is being exhausted to accelerate the inertia of the drivetrain. In 2nd gear, let’s say, because the gearing allows the car to accelerate more quickly, more HP will be used to accelerate the inertia of the drivetrain than in 1:1. See my graph below. This example was a 1996 Pontiac Trans Am WS6, all gear run. Ignore the small shift spikes at the beginning of each gear as that’s an inertia spike (where letting the clutch out abruptly against an engine with higher RPM than matching the next gear at that speed causes a brief quick acceleration of the drums).
As you can see, the HP was the highest in the 1:1 gear, and lower in other gears. From what I have experienced, the further you get from 1:1, the lower the power getting to the wheels and drum surface will be, as more is used to accelerate the inertia of the drivetrain, overcome frictional losses in meshing gears, side loading bearings, etc."
"Typically, you will see the highest numbers in the 1:1 or closest to 1:1 ratio gear. This is because no additional power is being exhausted to accelerate the inertia of the drivetrain. In 2nd gear, let’s say, because the gearing allows the car to accelerate more quickly, more HP will be used to accelerate the inertia of the drivetrain than in 1:1. See my graph below. This example was a 1996 Pontiac Trans Am WS6, all gear run. Ignore the small shift spikes at the beginning of each gear as that’s an inertia spike (where letting the clutch out abruptly against an engine with higher RPM than matching the next gear at that speed causes a brief quick acceleration of the drums).
As you can see, the HP was the highest in the 1:1 gear, and lower in other gears. From what I have experienced, the further you get from 1:1, the lower the power getting to the wheels and drum surface will be, as more is used to accelerate the inertia of the drivetrain, overcome frictional losses in meshing gears, side loading bearings, etc."
Tasca Super Boss 429 Member
Joined: November 14, 2007
Posts: 3,651
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From: Pacific NW USA
Oh my, this is getting rather silly. Let's not make too much noise about this dyno pull. Dyno's are tuning tools, no more.
Want to know how much power is really getting to the ground? Take an '11 GT to the dragstrip and let's see what it'll run. With 412 flywheel hp and weighing 3600 lbs (closer to 3800 lbs with a driver), that equates to 112 mph trap speeds in the 1/4 mile. If it really makes 395 rwhp, then it'll run 114 mph through the traps. The proof is all in the timeslips when they start happening.
Want to know how much power is really getting to the ground? Take an '11 GT to the dragstrip and let's see what it'll run. With 412 flywheel hp and weighing 3600 lbs (closer to 3800 lbs with a driver), that equates to 112 mph trap speeds in the 1/4 mile. If it really makes 395 rwhp, then it'll run 114 mph through the traps. The proof is all in the timeslips when they start happening.
Cobra Member
Joined: November 30, 2009
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From: South
Doesn't mesh with my dynosheets or anyone elses. I really wish Insideline would clear it up, or someone else would throw one on the dyno. Are we now to believe the car would put out 410 in 5th? Are we to believe the engine is actually worth 475 crank HP, and Ford is just "underrating it" to 412?
I pulled my two sheets from the G8 out, 331 in 3rd, 301 in 4th. Dynojet 248c.
I'll be on a 224xLC with my Mustang in a week, I'll have them run it in 3rd which is close to the ratio of the GT's 4th.
I pulled my two sheets from the G8 out, 331 in 3rd, 301 in 4th. Dynojet 248c.
I'll be on a 224xLC with my Mustang in a week, I'll have them run it in 3rd which is close to the ratio of the GT's 4th.
Bullitt Member
Joined: September 8, 2009
Posts: 350
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From: San Antonio, TX
Actually eci they have already tested these, the real problem with the 750 HP variant is that at that point (9500 RPM) torque has been sacrificed to the point that it no longer exists. That's right. Zero torque. Can't have it all.
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Member
Joined: February 28, 2008
Posts: 37
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From: Greeley, CO
Ford may well have gone conservative on the power ratings so that they can put up new numbers against whatever new numbers the bowtie boys put out in response.
Also, remember that most of the 03-04 terminator cars dyno'd stronger than what their official power ratings would have suggested they would.
Also, remember that most of the 03-04 terminator cars dyno'd stronger than what their official power ratings would have suggested they would.
I'll say if these engines really are this underrated when they start getting into public hands, and there aren't huge HP fluctuations between cars, I might just have to purchase one sooner then I wanted.. ugh!!
Last edited by Jeffs08GT; Mar 25, 2010 at 06:17 PM.
Cobra R Member
Joined: September 21, 2004
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Heck my 03 Cobra dynoed 390rwhp bone stock and 415rwhp with just exhaust. I have high hopes for the 5.0
I'll say if these engines really are this underrated when they start getting into public hands, and there aren't huge HP fluctuations between cars, I might just have to purchase one sooner then I wanted.. ugh!!
I'll say if these engines really are this underrated when they start getting into public hands, and there aren't huge HP fluctuations between cars, I might just have to purchase one sooner then I wanted.. ugh!!
Shelby GT350 Member
Joined: September 11, 2006
Posts: 2,349
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From: Cumming, GA
It's just very bizarre that Ford would UNDER rate the GT considering their primary competition is the Camaro SS and they would want to beat it in HP ratings. Heck ... they made sure to beat the V6 Camaro by 1 HP just to say they did.