4.10s vs 3.73s in a fox

codemonkey

Hungrymonkey's helper monkey
Nov 4, 2004
537
0
16
Wilsonville, OR
I just swapped out the gears in my fox, going from 4.10s to 3.73s. I must say I absolutely love it!

I put 4.10s in my maroon stang, and realized I didn't like them after a while. I bought the white one, which already had them, so I was kind of stuck with them. I decided to give 3.73s a try.

I think my car is faster, because it doesn't run out of steam after 3 seconds in a gear, and my top speed of course is faster. The 4.10s were nice for snappy acceleration, but to be honest, It wasnt worth it to me. Most people bitch about the gas mileage, but that wasn't my primary concern. By the time I get done with the car it wont get good mileage anyway, so screw it. Here are my advantages and disadvantages to both gears, if you are considering either setup:

4.10s Advantages:

Accleration is really nice. You'll beat a honda off the line. The g forces are great, even in a stock 5.0. Makes your car seem more impressive than is, at least on short runs. Shakes people up when you take them for a ride.

Burnouts: being able to stomp it in 2nd, and break loose the tires at 25mph. Kinda neat. (Though most people here can do that with any gears)

Acceration at any speed under 70-80mph is really good.

great for the 1/8th mile.

Disadvantages:

Shifting. You'll be shifting a lot. Going through a parking lot you'll be going through 3 gears. You'll be shifting constantly, the point of killing your arm in the city.

Harder on the drivetrain. If you dont baby the throttle, both accelarating and decelerating, you hammer the drivetrain. If you suddenly let off the pedal, it will shove your rpm pretty high.

Drivetrain problems are amplified A bad u-joint or unbalanced driveline is amplified when it turning 4 times for every axle rotation. Every little vibration is felt much harder.

Your car sounds like a ricer. This is again with the shifting. I can't explain it, but when you are doing 0-2000 rpm hopping through the gears, it just doesnt sound right. Almost ricey. It definitely doesnt sound like a car thats rocking a lot of power.

Highway driving if you plan on doing any highway driving at all in your fox, dont get 4.10s. You'll be at about 2700 rpm at 65mph. It always feels like you have one gear left. I found myself wanting to shift again, and its something I never got used to. With 3.73s, my rpm is about 2100.

1/4 mile not even that great Running the 1/4 mile wasnt even that great, with 4.10s. The 60' was decent, but with my setup, I wasnt able to spend enough time in my peak torque range to really do well. I was going across the line in 5th, and doing around 96mph. There are other conditions involved, but I still think its too high for 1/4 mile even.

Getting beat by a ricer on the freeway. Yeah. When your top speed is 110, and you are afraid to go that speed (see vibrations) its pretty easy for just about anyone to beat you on the freeway. Its kind of embarassing.

Synopsis: I feel 4.10s in a fox are for a limited group of people. If you keep it stock, it will perform better with the gears. And going stoplight to stoplight, its pretty torquey and quick. But its not worth all the other crap, at least to me.

3.73s Advantages:

Smoother acceleration. You know that small "drop off" between gears? Its not nearly as bad with 3.73s, because they are spread out further. Instead of having 5 lull points in a 1/4 mile, you have them in about a 1/2 mile. More consistent feeling.

Better midrange acceleration: from 40 or so up to 100 (not that I'd know, wink wink) the acceleration is great. You can feel it off the line, but once the car is rolling, the accleration is great. If you want to jump it up and pass someone on the freeway, these gears work great. In fact, even over 100 its still acclerating well. It just seems to keep pulling, where the 4.10s were petered out long before.

Driveability: So much better. You feel like you are shifting at the right time.

Cruising: 2100 at 65mph aint that bad. You dont feel wanting to shift in 5th gear.

Longer time spent in the torque range. This feeling is difficult to describe with words, but it doesnt feel like a short jolt of torque then nothing. (My 5.0 is basically stock, so the torque drops off at 4000 or so) it feels like you are spending more time in the torque range during normal driving.

Gas mileage: I dont have any real stats for this, but its pretty obvious.

Disadvantages:

Less Accleration of course. Nothing beats 4.10s for 0-60. I think an identically built mustang could get me in the first city block of a race.

Burnouts: your tires are spinning faster during a 1st or 2nd gear burnie (again, just theory wink wink) so you are doing more damage to the tires. If you are like me, and enjoy the occasional burnout, this probably saves your tires a little bit, having a lower speed.


So, in short, I would say if you want higher gears, 3.73 is the way to go. I can totally see why the folks at blue oval reccomend 3.55s or 3.73s if you are going supercharged or turbo. I couldnt imagine a boosted car with 4.10s being very fun at all.

I would also like to point out that Misha did tell me this, and I chose not to listen to her, when I put in 4.10s the first time. She was right, I was wrong .:hail2:

I also would highly recommend 3.73s for a fox.
 
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Also, Thanks to the Jeffs and Chung for all the work on my car today! Its like a whole new car to me right now, and as always, the work is top notch.

I brought it in because the ujoints were shot, and the driveline was probably out of balance, and I was sick of the 4.10s. At 50mph, it was vibrating so hard I couldnt see out of the mirrors. Now, you could put a cup of water on my dash at 80 and not see a ripple (ok maybe not but you get the point). Smooth as glass. They also did a great job on my exhaust, which was nearly not even on the car.

As always, top notch work from the pros. Well worth the $$$ :nice:
 
AC-PONY said:
Misha, Misha, Misha...it's tough for "GUYS"to think women know anything about cars when they are blonde!!!:D :D :D


...edited :nice:

oh, hey CODEMONKEY once you put some power in your ride, you can stomp on it in 2nd at 30 and haze the tires with 3.08's.
heck with a poweradder you could probably do it in 3rd.

DD
:flag: :nice:
 
It was actually an easier desicion for me.... You don't want anything more than 3:73s with an AOD.

Can I ask what you paid to have your gears changed out? Did you get a new speedo gear? I'm just trying to figure out if I want to spend a day under my car or if the price is reasonable to have someone else spend the day under there.