Well I've been browsing the forums for a few days, and after seeing Barmabob's gearing charts, I was inspired to dig up a similar one I had for the Suburu WRX. I had also seen a sampler power chart from Ford on our new 2.0L ecoboost, and realized I could do a little more detailed power comparison between these two cars.
I've been interested in buying a new car within the next year, and while previously I was leaning heavily to WRX, after I heard of this new Focus ST I have been waffling back and forth and eating up as much info on the fast Ford as I can find. There are so many +/-'s to each car - I just HAD to know how the performance would stack up. Well one thing led to another, adding in car weight, driver weight, drivetrain losses, air resistance... FWD grip... and well here you go.
DISCLAIMER: The tables and graphs produced in this chart are not all calculated with official numbers and are intended only for serious armchair racing.
EDIT: Does anyone know how to embed pictures in a thread? It would probably help with the readability of this lengthy post... I have removed some of the WRX charts. Album here
GEARING
ST Gearing Table (gearing info from http://fordstnation.com/attachments...nfo-recieved-dealership-13_focusst_jobaid.pdf):
ST Gearing Chart:
Generated Force in Gear
I then decided to throw in the torque figures into the gearing ratios to figure how much force was being generated at the wheels of each vehicle. You always see people forever arguing the torque vs. horsepower argument to no end. Well, they're all wrong. FORCE at the wheel is what really matters, right?
ST Force @ Speed Table (via Ford press release @ http://media.ford.com/images/10031/13FocusST_Overboost_infographic.jpg)
ST Force @ Speed, in gear Chart:
Acceleration at Speed
Now the real measure of which car is faster is the force generated divided by weight, also known as acceleration. After adding driver weight, drivetrain losses for the ST (estimated optimistically at 10%), I also wanted to take into account air resistance, which becomes a huge factor at higher speeds. I used the published coefficients of drag and used a reference area of the (track width + wheel width) x (car height - ground clearance). In each chart you can see I have highlighted the speeds that you'd ideally be in for each gear for maximum power.
ST Acceleration Chart:
Comparison Chart
And now for the penultimate acceleration chart. Note I have blended each gear into each other to show a smooth acceleration profile up to top speed. The points used are those highlighted in the previous graphs. I have also added in a traction limit line for the FWD Focus, which I will explain after:
Take it as you will. The top speeds match up pretty well with reality. The ST shows to have decent power over the WRX in all gears, but it's all unusable until you hit 50 mph somewhere in the upper range of 2nd gear. And that traction limit is actually pretty optimistic, unfortunately. So in a drag race, a WRX with a perfect launch should absolutely demolish the ST, and the ST will take some time catching up from behind as you head to 100.
Explanation of FWD Traction Limit
Derivation of the Focus traction limit was based on some various data from the ST geometry, 2010 Focus static stability factor (to find the CG height), and an estimated 60/40 weight distribution (this is not released yet, but I figure it's fairly common for FWD cars).
Focus ST CG and weight distribution data:
Weight distribution at different accelerations, as determined by the coefficient of friction on the tires. Note that the brown area is an optimistic dry friction for summer tires, while the blue area is what you might expect with wet tires.
I've been interested in buying a new car within the next year, and while previously I was leaning heavily to WRX, after I heard of this new Focus ST I have been waffling back and forth and eating up as much info on the fast Ford as I can find. There are so many +/-'s to each car - I just HAD to know how the performance would stack up. Well one thing led to another, adding in car weight, driver weight, drivetrain losses, air resistance... FWD grip... and well here you go.
DISCLAIMER: The tables and graphs produced in this chart are not all calculated with official numbers and are intended only for serious armchair racing.
EDIT: Does anyone know how to embed pictures in a thread? It would probably help with the readability of this lengthy post... I have removed some of the WRX charts. Album here
GEARING
ST Gearing Table (gearing info from http://fordstnation.com/attachments...nfo-recieved-dealership-13_focusst_jobaid.pdf):

ST Gearing Chart:

Generated Force in Gear
I then decided to throw in the torque figures into the gearing ratios to figure how much force was being generated at the wheels of each vehicle. You always see people forever arguing the torque vs. horsepower argument to no end. Well, they're all wrong. FORCE at the wheel is what really matters, right?
ST Force @ Speed Table (via Ford press release @ http://media.ford.com/images/10031/13FocusST_Overboost_infographic.jpg)

ST Force @ Speed, in gear Chart:

Acceleration at Speed
Now the real measure of which car is faster is the force generated divided by weight, also known as acceleration. After adding driver weight, drivetrain losses for the ST (estimated optimistically at 10%), I also wanted to take into account air resistance, which becomes a huge factor at higher speeds. I used the published coefficients of drag and used a reference area of the (track width + wheel width) x (car height - ground clearance). In each chart you can see I have highlighted the speeds that you'd ideally be in for each gear for maximum power.
ST Acceleration Chart:

Comparison Chart
And now for the penultimate acceleration chart. Note I have blended each gear into each other to show a smooth acceleration profile up to top speed. The points used are those highlighted in the previous graphs. I have also added in a traction limit line for the FWD Focus, which I will explain after:

Take it as you will. The top speeds match up pretty well with reality. The ST shows to have decent power over the WRX in all gears, but it's all unusable until you hit 50 mph somewhere in the upper range of 2nd gear. And that traction limit is actually pretty optimistic, unfortunately. So in a drag race, a WRX with a perfect launch should absolutely demolish the ST, and the ST will take some time catching up from behind as you head to 100.
Explanation of FWD Traction Limit
Derivation of the Focus traction limit was based on some various data from the ST geometry, 2010 Focus static stability factor (to find the CG height), and an estimated 60/40 weight distribution (this is not released yet, but I figure it's fairly common for FWD cars).
Focus ST CG and weight distribution data:

Weight distribution at different accelerations, as determined by the coefficient of friction on the tires. Note that the brown area is an optimistic dry friction for summer tires, while the blue area is what you might expect with wet tires.
