Ford is lying. The new 5.0 V8 makes more than 412hp
03-24-2010, 10:00 PM
#1
Thread Starter
Join Date: Mar 2010
Location: Ontario
Posts: 16
Ford is lying. The new 5.0 V8 makes more than 412hp
03-24-2010, 11:27 PM
#4
2nd Gear Member
Join Date: Dec 2009
Location: Nevada
Posts: 336
As one of the commenters pointed out, they dyno'd the car in fourth, not fifth. Fourth gear in the new trans is 1.32, fifth is 1.1. They probably assumed the ratios were similar to the old T56/T6060.
I'm still betting on 360-370 at the wheels.
I'm still betting on 360-370 at the wheels.
03-25-2010, 07:35 AM
#6
5th Gear Member
Join Date: Jun 2007
Location: Decatur AL USA
Posts: 2,176
Running a 1.32 gear instead of 1.00:1 will lower the horsepower not raise it. Just like running 4.10 rear instead of 3.55.
That said I believe the new engine may be underated. Her is why.
412 bhp @ 65000 rpm is roughly 333 lb-ft of torque and 94% VE.
The lead powertrain engineer stated the engine made in excess of 100% VE through 6500 rpm.
100% VE would be roughly 355 lb-ft @ 6500 rpm or 439 bhp. So I would expect about 386 rwhp @ 6500 rpm on a Dynojet (12% loss).
So it seems to me that either the 100% VE or the 412 bhp @ 6500 rpm would have to bee incorrect..
Disclaimer: The above is an oversimplification but you get the idea of why Im suspicious that something is up.
That said I believe the new engine may be underated. Her is why.
412 bhp @ 65000 rpm is roughly 333 lb-ft of torque and 94% VE.
The lead powertrain engineer stated the engine made in excess of 100% VE through 6500 rpm.
100% VE would be roughly 355 lb-ft @ 6500 rpm or 439 bhp. So I would expect about 386 rwhp @ 6500 rpm on a Dynojet (12% loss).
So it seems to me that either the 100% VE or the 412 bhp @ 6500 rpm would have to bee incorrect..
Disclaimer: The above is an oversimplification but you get the idea of why Im suspicious that something is up.
Last edited by Gene K; 03-25-2010 at 08:28 AM.
03-25-2010, 09:16 AM
#8
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Join Date: Jun 2009
Location: Orange County, CA
Posts: 1,162
rrocket says:
I'm right....because in this case it's a Dynojet. On a Dynojet, it uses a mathematical equation based on the known weight of the rollers and acceleration of said rollers. If you use a gear that accelerates faster (in this case 4th gear instead of 5th gear) the rollers will spin up quicker (accelerate) and skew the numbers in a positive way. The opposite would happen if you used 6th gear (.65:1)...you'd have lower numbers.
On other dynoes, like Dynapack and Mustang, they are less sensitive to gearing as they use a different method of calculating the HP. But the Dynojet is VERY sensitive and you must use a 1:1 ratio (or as close as possible) so as not to skew numbers.
Inside Line and Mr. Kavanagh dropped the ball on this one. Shame.
I'm right....because in this case it's a Dynojet. On a Dynojet, it uses a mathematical equation based on the known weight of the rollers and acceleration of said rollers. If you use a gear that accelerates faster (in this case 4th gear instead of 5th gear) the rollers will spin up quicker (accelerate) and skew the numbers in a positive way. The opposite would happen if you used 6th gear (.65:1)...you'd have lower numbers.
On other dynoes, like Dynapack and Mustang, they are less sensitive to gearing as they use a different method of calculating the HP. But the Dynojet is VERY sensitive and you must use a 1:1 ratio (or as close as possible) so as not to skew numbers.
Inside Line and Mr. Kavanagh dropped the ball on this one. Shame.
03-25-2010, 09:34 AM
#9
1st Gear Member
Join Date: Jan 2010
Location: WI
Posts: 77
Jason Kavanagh replied to comment from rrocket
10:14 PM, 03/24/10
The Dynojet itself doesn't care what gear the car's in. Remember, there's a final drive gear reduction after the transmission, which further alters the wheelspeed - engine speed relationship beyond what the transmission does, so there's nothing magical about 1:1.
In fact, dynoing in a gear that's 1:1 usually results in a hair less (yes, less) driveline loss as its a more (the most) efficient ratio in the gearbox. That's why a lot of dyno operators like the 1:1 ratio. Plus, when using an inertia dyno like a Dynojet, higher gear ratios have a lower rate of acceleration, so less power is soaked up in accelerating the rotating masses, which further props the numbers up.
Higher gears do tend to result in higher tire losses since the wheelspeed is higher... at this point all you're doing is trading off one loss mechanism for another. Generally, though, what I've seen come out in the wash is that on an inertia dyno, higher gears will result in higher numbers than lower gears.
Furthermore, higher gears also load the engine for a longer duration, requiring more cooldown, plus put more heat stress on driven tires. As the dyno operator, I don't like either of those things.
Last edited by Slickvic_; 03-25-2010 at 09:46 AM.
03-25-2010, 09:49 AM
#10
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Location: Decatur AL USA
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