Your info is good & I'd thought I'd give a little more detailed engineering insight into this, if anyones interested or cares!
For top speed, you need a small C/D & small frontal area, to give you a low product of drag co-efficient * frontal area, and lightweight & high horsepower (to give you a good HP/WT ratio). Also, the height of the vehicle above the road surface contributes quite a bit to the drag equation, as the more flow you send under the rough underbody rather than around out it really screws the aero/drag up.
As far as drag racing times, traction, gearing & torque off the line contributes to low 60' times, which are almost impossible to regain as the velocity increases & the required HP becomes a cube function w/ velocity.
Also, the number & speed of gear changes & a bunch of other stuff are the driving factors for good ET's.
Torque gives you acceleration & HP/RPM give you top end, in general.
You also need the proper gearing and these factors are what gives a vehicle a high top speed & can also contribute to better fuel mileage. By the way, HP is a fictious number & can not be directly measured. It is calculated from the engine torque & rpm.
As far as the CX-7, there are some significant issues w/ a large frontal area & grill opening causing large amounts of drag/turbulence, which is also made worse by the rear hatch design, which generates large amounts of unsteady turbulent flow at the rear of the vehicle where the flow detaches and creates a large unsteady turbulent low pressure area (That's why the rear hatch gets so damn dirty).
A little more wind tunnel time & even some of the Mazda accessories, front splitter (more downforce/more drag, but will probably help divert more flow around the vehicle which is better than under it, where there's all kind of junk to disrupt the air flow) & maybe even the optional rear spoiler, which appears to redirect the flow down across the rear window & will help keep the flow attached longer for less drag. Also, properly designed side skirts would also help immensely over the cheap black plastic stuff on their now.An easy way to confirm this would be to see if any one who has installed these components can comment on the fuel economy.
Also, owning a few high horsepower turbo toys, I can tell you that boost is the killer of fuel economy. My 94 RX7 (~470 RWP), 95 ECLIPSE GSX (~390 RWP) & 2005 IMPREZA STI (~430 RWP) can get as low as 6 MPG during a track event & up in the mid 20's if I drive it like a granny.
The CX-7's turbo is small to reduce turbo lag & that coupled with a small inefficient top mount intercooler raises intake temperatures, so the ECM is programmed on the rich side to account for lower cylinder oxygen content to keep the A/F ratios on the rich side & make the engine last (look at how fast the rear tail pipes get black), but makes it practically impossible to stay out of boost, especially around town when you're always accelerating/decelerating. The 2008 change to be able to use 89 octane only makes this worse, as the knock sensor detects more knock (made worse w/ high intake temps) & starts pulling ignition timing to prevent it. So basically, Mazda can say you can use 89 octane, but you get worse performance & fuel economy, which kind of contradicts the whole Zoom-Zoom thing!
But like you summarized, weight is the killer of all aspects of performance, from fuel economy, performance, handling,braking, etc. That's why F1 teams spend millions to shave a few grams & gain a few thousandths of a second per lap.
A kilo of fuel, in general, reduces an F1 cars lap time by around 0.10 seconds.
For top speed, you need a small C/D & small frontal area, to give you a low product of drag co-efficient * frontal area, and lightweight & high horsepower (to give you a good HP/WT ratio). Also, the height of the vehicle above the road surface contributes quite a bit to the drag equation, as the more flow you send under the rough underbody rather than around out it really screws the aero/drag up.
As far as drag racing times, traction, gearing & torque off the line contributes to low 60' times, which are almost impossible to regain as the velocity increases & the required HP becomes a cube function w/ velocity.
Also, the number & speed of gear changes & a bunch of other stuff are the driving factors for good ET's.
Torque gives you acceleration & HP/RPM give you top end, in general.
You also need the proper gearing and these factors are what gives a vehicle a high top speed & can also contribute to better fuel mileage. By the way, HP is a fictious number & can not be directly measured. It is calculated from the engine torque & rpm.
As far as the CX-7, there are some significant issues w/ a large frontal area & grill opening causing large amounts of drag/turbulence, which is also made worse by the rear hatch design, which generates large amounts of unsteady turbulent flow at the rear of the vehicle where the flow detaches and creates a large unsteady turbulent low pressure area (That's why the rear hatch gets so damn dirty).
A little more wind tunnel time & even some of the Mazda accessories, front splitter (more downforce/more drag, but will probably help divert more flow around the vehicle which is better than under it, where there's all kind of junk to disrupt the air flow) & maybe even the optional rear spoiler, which appears to redirect the flow down across the rear window & will help keep the flow attached longer for less drag. Also, properly designed side skirts would also help immensely over the cheap black plastic stuff on their now.An easy way to confirm this would be to see if any one who has installed these components can comment on the fuel economy.
Also, owning a few high horsepower turbo toys, I can tell you that boost is the killer of fuel economy. My 94 RX7 (~470 RWP), 95 ECLIPSE GSX (~390 RWP) & 2005 IMPREZA STI (~430 RWP) can get as low as 6 MPG during a track event & up in the mid 20's if I drive it like a granny.
The CX-7's turbo is small to reduce turbo lag & that coupled with a small inefficient top mount intercooler raises intake temperatures, so the ECM is programmed on the rich side to account for lower cylinder oxygen content to keep the A/F ratios on the rich side & make the engine last (look at how fast the rear tail pipes get black), but makes it practically impossible to stay out of boost, especially around town when you're always accelerating/decelerating. The 2008 change to be able to use 89 octane only makes this worse, as the knock sensor detects more knock (made worse w/ high intake temps) & starts pulling ignition timing to prevent it. So basically, Mazda can say you can use 89 octane, but you get worse performance & fuel economy, which kind of contradicts the whole Zoom-Zoom thing!
But like you summarized, weight is the killer of all aspects of performance, from fuel economy, performance, handling,braking, etc. That's why F1 teams spend millions to shave a few grams & gain a few thousandths of a second per lap.
A kilo of fuel, in general, reduces an F1 cars lap time by around 0.10 seconds.
