Smoked my first 07 Corvette
07-01-2007, 10:00 PM
#16
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i had a 88 dodge daytona shelby z and i let my girlfriend use the car well she let her dad drive it and he told her it was driver error when i beat his sons 92 toyota mr2 coming from behind entering the hwy mind you LOL well i told him anytime he wanted to drive it i would beat him like i beat his son !!! if you cant drive you loose. however everyone makes mistakes like the 5.0 i raced with the same car he said i missed 2nd gear ah well that will be 50 bucks !!! my dad is like hohn makes sense but doesnt always work
07-01-2007, 10:23 PM
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07-01-2007, 11:04 PM
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Hohn; If it was a plain 400 hp 07' Vette they wiegh 3300 w/ no driver or groceries or golf bags. Was the car an auto or manual? With a manual and 10% drivetrain loss that's 360 hp. Auto would put down less. Calgary is at 3400 feet elevation.Take away another 10% from 400. Now it's 320hp at most! What was the outside temp?
We don't know all the vettes factors.
I can beat the old Z06s, here In Denver..........just barely, and I can annihilate stock SRT-10s, Lightinings, GTOs, EVOs and STis here.
That was a good kill!
We don't know all the vettes factors.
I can beat the old Z06s, here In Denver..........just barely, and I can annihilate stock SRT-10s, Lightinings, GTOs, EVOs and STis here.
That was a good kill!
07-02-2007, 01:29 AM
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I'm not trying to take anything away from this, I'm just trying to put it in perspective.
Is 300hp impressive? In an 18 wheeler? How about in a go-kart?
I'm not trying to take anything away from this guy. Someone could just as easily look at my post and realize how impressive it is that a CTD can even come close to running with a Vette. C'mon-- you got a farm truck with the aero of a barn cruising down the road weigh twice as much as a vette, and you STILL beat him.
I don't think they make idiots big enough to handicap the vette enough to compare to what the CTD has going against it.
As for me not being sensitive to emotions, well I'm sure my wife would agree with you a great deal-- I'm not known for my ability to help others feel good
Justin
Is 300hp impressive? In an 18 wheeler? How about in a go-kart?
I'm not trying to take anything away from this guy. Someone could just as easily look at my post and realize how impressive it is that a CTD can even come close to running with a Vette. C'mon-- you got a farm truck with the aero of a barn cruising down the road weigh twice as much as a vette, and you STILL beat him.
I don't think they make idiots big enough to handicap the vette enough to compare to what the CTD has going against it.
As for me not being sensitive to emotions, well I'm sure my wife would agree with you a great deal-- I'm not known for my ability to help others feel good
Justin
07-02-2007, 08:39 AM
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Now don't get me wrong, I'm not bashing Hohn for his knowledge or explanation. I guess all I'm trying to say is he could have presented it in a better way. If it sounded like I was being ignorant towards Hohn that was not my intention. But back to the topic at hand WAY TO GO MIKE!! Keep racking up. By the way what part of Cow town you live in? I used to live in Somerset/Bridlewood before I moved to the Rock
07-02-2007, 09:45 AM
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The fool driving the 'Vette had no skill. Even a regular, non Z06 should have left you if you were in "tow mode".
The physics don't lie. The vette weighs half of what you do. Your sig says 677hp, and you say you were down over 100hp due to being in "tow mode".
That vette is putting 375 to the rear wheels in most cases. So, let's look at power to weight. Since he weighs half of what you do (almost exactly- you're about 6800#, he's 3400) he only need half the power to break even.
Well, if you are only 577 at the rear wheel instead of 677, then he'd only need 288 hp at his rear wheels to break even with you. Since you say you were down even more power than this, he'd need even less.
Not to mention the aerodynamics of a 'vette versus the CTD. That means he needs even less hp to beat you. At 55mph, the aero isn't such a major factor, but at 80+, it's huge.
So, the numbers don't add up, and the only way to explain this awesome kill is that the other driver was a moron-- pretty common among 'vette owners.
JH
The physics don't lie. The vette weighs half of what you do. Your sig says 677hp, and you say you were down over 100hp due to being in "tow mode".
That vette is putting 375 to the rear wheels in most cases. So, let's look at power to weight. Since he weighs half of what you do (almost exactly- you're about 6800#, he's 3400) he only need half the power to break even.
Well, if you are only 577 at the rear wheel instead of 677, then he'd only need 288 hp at his rear wheels to break even with you. Since you say you were down even more power than this, he'd need even less.
Not to mention the aerodynamics of a 'vette versus the CTD. That means he needs even less hp to beat you. At 55mph, the aero isn't such a major factor, but at 80+, it's huge.
So, the numbers don't add up, and the only way to explain this awesome kill is that the other driver was a moron-- pretty common among 'vette owners.
JH
Good points, but don't forget about torque. Also, if his turbo is spooled with all the torque a CTD puts out, he might get a pretty good jump on him. I see plenty of v-8 street cars get spanked at the drag strip. This is feasable.
07-02-2007, 12:18 PM
#22
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Awesome kill Mike ! That guy was probably cursing you out....or his car...lol
I read an article the other day about the '07 ZO6...505hp/470tq out of a 7.0L....wow...still best bang for the buck I think in the world of sports cars.
I read an article the other day about the '07 ZO6...505hp/470tq out of a 7.0L....wow...still best bang for the buck I think in the world of sports cars.
07-02-2007, 05:06 PM
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Ok, I know you are contemplating them anyway......
Here is how I see it: Gassers have the same tq or a little less than hp. CTD's have double tq over what their hp # is give or take.
Torque is what gets you moving. HP maintains and gives you mph.
I think you may be able to out accelerate a high hp sportscar, but he's gonna out mile per hour you and maybe catch you on the top end. I've seen it many times at the drag strip. Sports cars are a compromise of hp, light weight and handling for a total driving experience. A highly modified CTD isn't going to hang in the "S" turns with a Corvette, but many have enough power to out run a stock sportscar or muscle car in a straight line. Now if he's highly modified, it's probably not going to happen. I understand the physics, but at the track I've seen things that seem to defy physics......even in my old 6 speed
.
OK, now your turn Hohn. I'm interested to see your #'s crunched. One caveat......sometimes the numbers lie.....ask a statistician or the marketers....
Here is how I see it: Gassers have the same tq or a little less than hp. CTD's have double tq over what their hp # is give or take.
Torque is what gets you moving. HP maintains and gives you mph.
I think you may be able to out accelerate a high hp sportscar, but he's gonna out mile per hour you and maybe catch you on the top end. I've seen it many times at the drag strip. Sports cars are a compromise of hp, light weight and handling for a total driving experience. A highly modified CTD isn't going to hang in the "S" turns with a Corvette, but many have enough power to out run a stock sportscar or muscle car in a straight line. Now if he's highly modified, it's probably not going to happen. I understand the physics, but at the track I've seen things that seem to defy physics......even in my old 6 speed
.OK, now your turn Hohn. I'm interested to see your #'s crunched. One caveat......sometimes the numbers lie.....ask a statistician or the marketers....
07-02-2007, 05:29 PM
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Congrads on the kill but, I think you beat the driver not the car. I'm pretty knowlegdable about vette's, f-bodies and most vechiles that come with an LSX motors and that 07 came with an underrated LS2 (400 hp) motor at the very least which I have seen with nothing done to it put down 385rwhp on a dyno. Which could turn low to mid 12's around 112'ish. Good kill anyways
On a side note I find this alittle bit more funny than others because I was gonna buy an 06-07 vette a few months ago but knew I wouldn't leave it alone so I bought 98 12valve which I thought I would leave alone but find myself on here looking for info on how to modify it
On a side note I find this alittle bit more funny than others because I was gonna buy an 06-07 vette a few months ago but knew I wouldn't leave it alone so I bought 98 12valve which I thought I would leave alone but find myself on here looking for info on how to modify it
07-02-2007, 07:11 PM
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Gee, you guys know just how to bait me into posting a windbag post with lots of numbers that makes no sense and contradicts itself--don't you?
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
07-02-2007, 07:30 PM
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Gee, you guys know just how to bait me into posting a windbag post with lots of numbers that makes no sense and contradicts itself--don't you?
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
07-02-2007, 09:17 PM
#28
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Gee, you guys know just how to bait me into posting a windbag post with lots of numbers that makes no sense and contradicts itself--don't you?
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
Seriously, I'd hoped to avoid going down the "hp vs tq" path as that horse is in the glue factory.
Vette specs: 400hp @ 6000 rpm, 400 lb-ft @4400 rpm, weight 3179#
Truck specs: 577hp @ 2700rpm, ~1200lb-ft @2000rpm weight 6800#
More relevant specs, tire revs per mile:
Corvette: 285/35/ZR19: 775 revs per mile
Truck: 265/75R16: 655 revs per mile
We don't know which tranny the Vette had. We'll assume it was the 6-speed auto, since it's the slowest for acceleration. Ratios in the gears for this trans are 4.02, 2.36, 1.53, 1.15, 0.85, 0.67—Diff ratio is 2.56
Let’s assume the truck is an auto trans. You’ll notice I’m making every assumption favoring the truck—the truck has small stock size tires, the Vette has the slowest tranny, etc etc.
(All specs from Chevy site:http://www.chevrolet.com/corvette/specifications/ )
So we have two vehicles side by side at 50mph. The vette’s driveshaft is spinning 1653 rpm, based on the tire size and diff ratio. The truck’s driveshaft is spinning at 1938 rpm, based on 265 size tires and a 3.55 diff ratio.
The rpm in each gear at 50mph looks like this:
RPM
Gear truck Vette
1 4748 6645
2 2810 3901
3 1938 2529
4 1337 1900
5 1405
6 1107
Obviously, the truck can’t downshift to 1st or 2nd, so you go to 3rd. In this gear, the truck is putting about 1200lb-ft to the driveshaft, and doing the math for the tq at the wheels, you get about 4260 lb-ft to a 31” tire, hence 1670 lb of force, accounting for the 31” diameter of the tires. All these numbers just to get to this key value: 1670lb of force to accelerate a 6800lb truck.
The ‘Vette can downshift from loafing at 1100 rpm in 6th all the way to 2nd gear at 3900rpm. The engine is making about 380 lb-ft here, giving us about 896 lb-ft to the driveshaft, and 2296 lb-ft to a 27” tire. Dividing out the leverage of the 27” tire, we get 1020 lb of force at the wheels to move a 3180 lb Corvette.
Let’s compare the force applied using F=MA. Solving for A, we get A=F/M. For the Truck, we get A=1670/6800= .245Gs
For the Vette, we get A= 1020/3180=.32 Gs
So, instantly, the Vette accelerates harder-- .32 vs .245 Gs. This doesn’t account for the much heavier wheels and tires of the truck, the much worse aero factors, etc. In other words, even when we stack assumptions in favor of the truck, it still loses.
The faster you go, the worse it gets for the truck, as aero becomes a huge factor. The Vette doesn’ t have to upshift to 3rd gear until 83mph! When it DOES shift, it will experience a reduction in driving tq of 24.8%
The truck has to upshift to OD at 72mph (2800 rpm), and when it does, it will experience a reduction in drive tq of 31%. (going from 1:1 in 3rd to .69 OD)
So the Vette starts out accelerating harder, and won’t have to upshift until 83 mph, while the truck has to upshift at 72mph, and after they each shift, the Vette gets an even bigger advantage.
If we run the numbers quickly for 50mph, we see that the CTD would have to put down 1583lb-ft at 1938 rpm just to break even with the Vette (this is 584 hp, btw). This means that even “non-tow” mode you’d still probably lose, or ought to.
The fact that you won either makes this an awesome kill, or makes me wonder if they guy knew there was a race on.
Man, I hope I didn't keep you from getting anything important done today by egging you on.......
07-02-2007, 09:48 PM
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