so svt, why bother with a 3.73

[1shetan]

So I am reading about the svt package and thought great.........a 3.73 that should improve acceleration.

Then I looked at the rear tire specs and the tire is an inch larger in diameter. The combination seems to keep the rpms quite similar to the 3.55 base car.

 

So why not have used a wider tire with the same diameter as the 3.55 car for better traction, and allowed you the option of improved acceleration if you order the svt 3.73.

 

In other words why make all the tire and gear changes and have it stay the same? am I thinking it all out wrong or is there a benefit?

[kahmann]

I'd say that they really wanted to add that bigger wheel to the package and realized that by doing so, they needed to make a gear swap, in order to meet (or slightly exceed) the launch of the base model.

[1shetan]

then correct me if I am wrong, the svt pp is a suspension upgrade and different wheels and tires? plus some cosmetic items?

[03reptile]

then correct me if I am wrong, the svt pp is a suspension upgrade and different wheels and tires? plus some cosmetic items?

 

 

You are definitely right. I didn't order it on my upcoming 2011.

[AlloyDropTop]

I can't get my '08 with 3.31's to hook-up under 30mph, so I am not sure what the point is anyway.....

[LuckySnake]

I can't get my '08 with 3.31's to hook-up under 30mph, so I am not sure what the point is anyway.....

 

With 3.73's the overall gearing is better, more fun to drive and easier on the drive train, 5th and 6th become usable gears. Gearing "3.31" that could push your car well over 200 mph on paper is useless because of the amount of hp required to push a brick through the air at those speeds.

Better tires would help you more than 3.08s or 3.31. Bottom line is we all have different opinions and it's easy enough to put what ever gear you want within reason. I had the 3.31, then 4.11s, now 3.73's and think it's just right.

[1shetan]

Lucky,

 

you are correct.......except I feel like the svt package is a bit misleading they advertise the 3.73 as part of it, but with the taller tire you are still overall like the 3.55...................I do agree with you that if the tires were left with the same diameter and they added the 3.73 it would make the acceleration incredible (cheaper than adding horsepower)

[AlloyDropTop]

With 3.73's the overall gearing is better, more fun to drive and easier on the drive train, 5th and 6th become usable gears. Gearing "3.31" that could push your car well over 200 mph on paper is useless because of the amount of hp required to push a brick through the air at those speeds.

Better tires would help you more than 3.08s or 3.31. Bottom line is we all have different opinions and it's easy enough to put what ever gear you want within reason. I had the 3.31, then 4.11s, now 3.73's and think it's just right.

 

 

I agree with what you are saying, but can you get traction under 30MPH in first or second gear? I can't, so 3.73 would make it even worse, due to the torque multiplication. I would only change the rear end gear if I was either going to put slicks on it, or some seriously higher traction tires, than the stock F1's.

[vinstang]

I agree with what you are saying, but can you get traction under 30MPH in first or second gear? I can't, so 3.73 would make it even worse, due to the torque multiplication. I would only change the rear end gear if I was either going to put slicks on it, or some seriously higher traction tires, than the stock F1's.

 

I thought the tires of the SVT PP where different then the Stock car and had more traction?

[1shetan]

I thought the tires of the SVT PP where different then the Stock car and had more traction?

 

 

they are, custom just for the svt, but they are an inch in diameter taller therefore negating the 3.73 to 3.55 performance.....

they are nicer tires....

[moabman]

The size of the wheel is not the important thing here, it is the circumference of the tire-wheel combo. For example, it is possible that a low profile tire on a larger wheel might be a higher ratio than a tall tire on a smaller wheel. I don't know what the final gear ratio effect of the new tire wheel combo is but it might not totally "negate" the 3.55 to 3.73 ratio change.

 

Even if it did "negate" the change, there are other handling benefits of having a larger wheel that results in the same final drive ratio.

 

Remember, it is a package designed to work together.

 

In reality, the improvement of the lap times is the real proof of the effectiveness of the package. I'm sure that as these cars get out to the public, we will see many of these comparisons that will either confirm the SVT teams claims or they won't. With the SVT teams track record, I'm betting that the additional testing will confirm their claim of improved lap times.

[1shetan]

Very true Moabman,

 

The math we used here is ................285-35-20...................tire diameter ............28"....................with a 3.73

285-35-19.......................................................27"................................3.55

both seem to create the same or close rpms at 65 mph. Usually a taller rear gear would allow the engine to run at higher rpms and aids acceleration.

just think what it would be like if the rear was changed to a 285-30-20 at 27" of diameter.........2-300 rpms more, faster pick up and go especially in the taller gears.

This was my assumption when i read the specs on the svt package, but I dont think the rear gear in this case is as advantageous as others think. Just my .02.

[2sharpie]

I was debating to put 3.73's on my '10 also. But I know the issues with traction and our tires that should be Vette-like (325's standard please!!) Then, since it was warm yesterday, I had a little fun sliding in 1st, chirping in 2nd and 3rd. I couldn't wipe the grin off my face..........so maybe 3.73's would be more fun, if that's even possible!!

[BigDan]

 

 

In other words why make all the tire and gear changes and have it stay the same? am I thinking it all out wrong or is there a benefit?

 

 

Answer: Because the car would of been slower in acceleration if they would of left the 3.55's with the 20's. Supersnakes have 3.73's and 20's for the same reason. 20's require 3.73's on these car's to keep them in useable power band, especially in 5th and 6th.

[AlChernosky]

The calculated engine RPMs between the 3.55 gears with 285-35R19 inch tires and the 3.73 gears with 285-35R20 inch tires is essentially the same.

 

Theoretical advantage to the 3.73's

 

Engine RPMs at 70 miles per hour

2011 GT500 Tremec TR6060 six speed

 

Gear

RPM's 3.55 w/19”

RPMs 3.73 w/20”

 

2nd

5537

5609

 

3rd

4044

4096

 

4th

3110

3151

 

5th

2302

2332

 

6th

1555

1575

[sportscars]

What you all may be over looking is the impact on Corporate Average Fuel Economy (CAFE) and gas guzzler tax.

 

Ford knows that people want these gears for racing. They also know that few people are going to track their cars with the stock tires. Since most people who race are going to change the tires anyway, they can put taller tires on and in essance keep the same RPM thereby keeping the car off the Gas Guzzler rolls.

 

Saves the customer money and saves Ford's CAFE rating.

 

JMO

[6.1hemi]

What you all may be over looking is the impact on Corporate Average Fuel Economy (CAFE) and gas guzzler tax.

 

Ford knows that people want these gears for racing. They also know that few people are going to track their cars with the stock tires. Since most people who race are going to change the tires anyway, they can put taller tires on and in essance keep the same RPM thereby keeping the car off the Gas Guzzler rolls.

 

Saves the customer money and saves Ford's CAFE rating.

 

JMO

 

 

+1

[TX STIG]

If Ford was serious about setting new track times, they would have done it with 18" wheels. However, aesthetics play a big part in this, and therefore a 20" comes into play with gearing to offset the taller tire.

 

I almost went the 18" route, but knew I wouldn't have this car on the track much so I went with 20's. My 315/35-20's have a tire height of 28.6" and with my 4.10 gears this will give me an 'effective' gear ratio of a 3.83. This is almost perfect as I found the 3.55's to be a little sluggish when off the boost.

 

If I had kept my stock 3.55's in place, and went with 315/35-20's, my 'effective' gear ratio would have turned into a 3.31.

[1shetan]

all you have to do when you get the car is to switch to 285-30-20, that will give you true 3.73 gears......................(maybe they make a 305-30-20)

[TX STIG]

all you have to do when you get the car is to switch to 285-30-20, that will give you true 3.73 gears......................(maybe they make a 305-30-20)

 

 

It will also give you almost no sidewall.