Is it worth it...3.55 to 3.73?

[Dragon]

I currently have 3.55 gear ratio (manual trans) and am thinking of going to 3.73. Some say it will wake up my car, but a number of others say I will not notice any difference at all. I wanted to see if anyone made this change and get opinions.

I am not really looking to drag race so I don't need the 4.10 ratio. I just don't want to get smoked by Infinities or BMW 3 series.

Also, I do not have any immediate plans for FI. I will be getting a CAI and tune soon.

 

[kleistang]

3.90s ?

 

[JimmyD]

Without a doubt, especially since you're manual, go to 4.10's

Going from 3.55 to 3.73, you probably won't notice much. Hell, I'm an auto, I went from 3.31 to 3.73 and ddin't notice a hell of alot, some difference, but not night and day difference.

 

[Steedman07]

NO DIFF...get the 4:10's...i love mine

 

[kleistang]

i had 4.10 installed in my last stang and it made a hell of a diff. and mine was auto.

 

[ixtlan]

The best way to make this decision is to get your CAI and tune first.
Then once you have that all setup look into gears.
When your Tune and CAI are setup you need to look into your torque curve. This can be done by the seat of the pants if you wish (Although I am sure to be beat up by that statement).
You need to watch your RPMs where the real power comes on.
In other words where does the car come alive at?
Stop lugging.
Wake up.
Really start jumpin.
However you want to describe it...
Once you know that RPM that is where you want to decide on your gear ratio.
The question to ask yourself is:
What ratio will get me to that RPM off the line.
With an auto trans the torque converter plays a large roll in that (Stall speed).
Here is a good calculator for that (Requires Excel):
http://www.xmission.com/~ixtlan/RPM_vs_Speed.xls


But remember it is a trade off.
Give at the top to get at the bottom.
I went 4.10's because I wanted the bottom, and my tune was pretty much setup around the bottom end too.
I also run an Auto trans.
My shift points around town also placed my 4th to OD shift about 40 mph with normal throttle after I raised my shift points 7mph at that point. So basically I dont use OD in normal around town driving.
It shifts into OD too early for my taste so I just turn it off.
I also lost 1 mpg (No biggie to me) as an average for town driving.

 

[94tbird]

forget 3.90s as they are motive gears and they blow. go 4.10s to wake the car up. 3.73's arent enough to justify the cost or install labor

 

[Hitman]

forget 3.90s as they are motive gears and they blow. go 4.10s to wake the car up. 3.73's arent enough to justify the cost or install labor

+10

 

[PolkThug]

I noticed a big difference going from 3.55 to 3.73 (manual trans), but maybe I'm just sensitive.

 

[Steedman07]

The best way to make this decision is to get your CAI and tune first.
Then once you have that all setup look into gears.
When your Tune and CAI are setup you need to look into your torque curve. This can be done by the seat of the pants if you wish (Although I am sure to be beat up by that statement).
You need to watch your RPMs where the real power comes on.
In other words where does the car come alive at?
Stop lugging.
Wake up.
Really start jumpin.
However you want to describe it...
Once you know that RPM that is where you want to decide on your gear ratio.
The question to ask yourself is:
What ratio will get me to that RPM off the line.
With an auto trans the torque converter plays a large roll in that (Stall speed).
Here is a good calculator for that (Requires Excel):
http://www.xmission.com/~ixtlan/RPM_vs_Speed.xls


But remember it is a trade off.
Give at the top to get at the bottom.
I went 4.10's because I wanted the bottom, and my tune was pretty much setup around the bottom end too.
I also run an Auto trans.
My shift points around town also placed my 4th to OD shift about 40 mph with normal throttle after I raised my shift points 7mph at that point. So basically I dont use OD in normal around town driving.
It shifts into OD too early for my taste so I just turn it off.
I also lost 1 mpg (No biggie to me) as an average for town driving.

hmm....I actually gained top-end speed going with 4:10's vs. 3.31's..as long as the boost doesnt fall off too much shifting into OD...

 

[MikeVistaBlue06]

Without a doubt, especially since you're manual, go to 4.10's

Agree.

Going from 3.55 to 3.73, you probably won't notice much. Hell, I'm an auto, I went from 3.31 to 3.73 and ddin't notice a hell of alot, some difference, but not night and day difference.

I went from 3.31 to 3.73 with my auto tranny and noticed a helluva difference.

BTW 4.10s in a manual transmission setup gives the same final drive ratio as 3.73s do in an automatic. Final drive ratio = high gear ratio x back end ratio.

Do not get the 3.90's. They are from Motive and they whine like hell based on everything I have read about them. Be sure to get FRPP gears from Ford as well.

All said: 4.10s for you are perfect.

Search gears as well for numerous discussions on this and the math.

Hope this helps.

Mike

 

[ixtlan]

hmm....I actually gained top-end speed going with 4:10's vs. 3.31's..as long as the boost doesnt fall off too much shifting into OD...

I am N/A though.
Big difference there.
And when I say Top I mean Redline.
Lower gears will mean less mph at Redline.

 

[gmantheman]

I also agree with the majority of the people- get 4.10s. I have 4.10s and I do lot of hwy driving. I drive approx 70 miles per. day on the hwy. Before you get gears, get a hand held tuner. You will need the tuner to adjust your speed odometer after you install the gears.

 

[chad05gt]

At least go 4.10's

 

[don_w]

Don't fear the gear!!! Another big +1 on 4.10s.

 

[GRAYPNY]

I had 4:10's with my manual trans and due to a poor install the gears failed after 10,000 miles. I put the stock 3:55's back in and really don't miss the 4:10's that much. It was fun but not being a drag racer I think I prefer the 3:55's. Tune and CIA is a better bang for the buck IMO~

 

[USCav19D]

I am N/A though.
Big difference there.
And when I say Top I mean Redline.
Lower gears will mean less mph at Redline.

If you ain't Cav, you ain't shit.

That being said, I'd say go with the 4.10s. A friend of mine has an 07 GT with 4.10 gears, and there's a big difference between that and my Bullitt.

The twin screw under the hood doesn't hurt either.

 

[ixtlan]

If you ain't Cav, you ain't shit.

That being said, I'd say go with the 4.10s. A friend of mine has an 07 GT with 4.10 gears, and there's a big difference between that and my Bullitt.

The twin screw under the hood doesn't hurt either.

Charge Hard!!!!

 

[Dragon]

Thanks for all the replies. I think that I will forget about the 3.73 gears and go with the CAI and tune first.

I will see how that goes and consider the 4.10. Just a little suspicious that those gears will make by car rev like crazy on the freeway.

 

[ixtlan]

Thanks for all the replies. I think that I will forget about the 3.73 gears and go with the CAI and tune first.

I will see how that goes and consider the 4.10. Just a little suspicious that those gears will make by car rev like crazy on the freeway.

Not so bad in OD. This with Stock Tires and 4.10 gears :
RPM 1ST 2ND 3RD 4TH OD
Auto Trans
2500 15.31 21.53 32.01 49.30 69.44
2600 15.92 22.39 33.29 51.27 72.21
2700 16.54 23.25 34.57 53.24 74.99
2800 17.15 24.11 35.85 55.22 77.77
2900 17.76 24.97 37.14 57.19 80.55
3000 18.37 25.83 38.42 59.16 83.32

Manual Trans
2000 11.67 19.72 29.88 39.44 58.43
2100 12.25 20.71 31.37 41.41 61.35
2200 12.84 21.69 32.87 43.38 64.27
2300 13.42 22.68 34.36 45.36 67.19
2400 14.00 23.66 35.85 47.33 70.12
2500 14.59 24.65 37.35 49.30 73.04
2600 15.17 25.64 38.84 51.27 75.96
2700 15.75 26.62 40.34 53.24 78.88
2800 16.34 27.61 41.83 55.22 81.80
2900 16.92 28.59 43.32 57.19 84.72


Damn only had to edit like 10 times.