Is anyone NOT satified with their 4.10 gears?

I had 4.10's on mine. Awesome acceleration. Saying that, terrible gas mileage. 16 hwy. If I took the the car to work, it burn 1/2 tank of gas a day. If I had to do it all over again, I would have put 3.73's in.

again, 2v does not =4v, were talking 4v motors here, people.

yes, but ur formula's off.

if 4.10 = 3.73 then 4.30 would not = 4.10

it'd be:

2V-----4V
4.10=3.90
4.30=4.10

my bad ,not an exact science, just a general rule. 3.90's were never available until motive came out with them for the 8.8 years behind which I keep forgetting, so that was always the next gear used in the comparison.

Stock in the '01 Cobra is 3.27's. I calculate 3.73's to be a 15% increase in RPM and 4.10's to be a 25% increase. I don't think you'd see a whole lot of difference in highway mileage between 4.10's and 3.73's. If you got a 10% increase, that would only be 17.6 MPG. Here's the RPM's at 70 MPH in 5th gear with a Tremec 3650 for a transmission:

3.27's - 1920
3.73's - 2208
4.10's - 2450

Gears don't effect emissions.

+1

I don't know about that. If you have a higher RPM, each piston goes up and down many more times per mile. Each time it comes up on the exhaust stroke, it pushes out a volume (cubic inch displacement) of burned exhaust gases.

If your gas mileage goes down, you're obviously burning more gasoline each mile you travel and creating more exhaust.

You're not changing the efficiency of the engine but you are increasing the volume of exhaust you're putting out.

The smog tests are done at certain speeds. Usually in 2nd gear in a certain RPM range. All the tester would have to do is shift in into 3rd gear.

With the 4.30s in a Cobra, it is taking the engine less effort to get the car moving..this being said, your gas mileage is most affected by your foot on the floor due to the enormous acceleration boost from the gears. Most of the guys that have 2v are going to say 4.10. I had 4.10s in my 04 GT, but that is just not enough gear for a 4v engine. 4.30s are perfect for Cobras and Machs. If you see a huge gas mileage difference, it is your fault, not the gears.

What you really need to do is ride in one with both gears... 2 different Cobras that is. 4.10 in a 2v is gonna feel most like 4.30s in a 4v. If you get 4.10s in 3 mos of getting used to them, you will be looking for a set of 4.30s.

So what you're saying is gears don't affect the emissions test. That's true. The pollutants are measured by percentage of exhaust but if you're a tree huggin' activist, you care about the total volume being pushed into the atmosphere killing the Pandas and Spotted Owls....

...in which case it's possible they'd make a law against it but I've been searching and can't find it anywhere.

I love the results of my 4.10 gears when im really on the gas, but to be completely honest when I am cruising around everyday it's mildly irritating. I like to shift at low RPM's (2,000) and it takes forever to get moving. That's my only complaint, but hey you can't have everything, I just wanted you to know the truth.

I appreciate the honesty.

Dave,

I dont mean to beat an old horse to death bc I've already posted on this. However, this thread is getting really long. Taking advice from people with 2v's is like comparing apples to oranges. Your car is not going to respond anywhere similar to all the peoples cars in here with 2v's and 4.10's.

+1

Cobra (4V) = 4.10's

GT (2V) = 3.90's