Hey guys Im a nub when it comes to gears. I understand accelerating through your rpm's faster, but thats about it. What do the numbers mean 4.10's 3.73's? Are some better for DD's probley one that will never see a track? Can I install it myself with some jack stands or do i need a Lifter? Long process? Any info is appreciated. Thanks in advance.

I've got an 06 manual gt, daily driver, and i drive it pretty hard on avg.

 

The numbers have to do with the ratio ofdriveshaft rotation to the axles. Thus 4.10 gears are consideredlower gears than the 3.73. Basically the higher the ratio the more rpms required from the engine to obtain a given speed.

Which is better for a daily driver? This really depends on your driving conditions and if you plan on going FI if you aren't already. If you are, then 3.73 is probably plenty and especially if you do a lot of highway driving. If you don't mind a little less gas mileage and aren't going to be spending a lot of time on highways at 70 mph or more for long duration and don't mind the higher rpm on the highway, then the 4.10 will definitely give you more out of the hole power to the ground. If you are FI or plan on it, I am not sure you want to go 4.10 for a DD because of the shear driveability, especially in rain or other bad weather. Just my opinion.

As far as installation... this is not something to do at home unless you are a very good mechanic and understand gear setup, backlash, and have the proper tools. This is definitely worth the money for a pro installation. It is easy to screw up if you do not know what you are doing. I just had 3.73 FRPP gears installed by the local Ford dealer and my installation cost was $487.50 labor. The parts cost me around $260 for the gears and the master bearing kit combination. I plan on going with a Super Charger in the near future or I would have probably gone for the 4.10 gears.

 

Well that's some good insight. I don't have any sc or turbo, can't afford to go that route either. Sounds to me like the 4.10's would be the best for out of the hole which is what I'm looking for. I didn't really take into consideration that the labor charge would be so high. If total price was around $650, would u recommend I just get a CAI/Tuner package instead of changing my gear ratio? Currently I just have the Pypes O/R H from Brenspeed.

 

CAI/Tuner is a good mod, was my first and usually one of the most common first mods.The CAI/Tuner is also a good way to goin conjunction withyour Pypes. Going all the way from where you are to 4.10 would be a noticeable difference too. I am guessing that you are probably running 3.55 currently with the GT Premium.

If you still want to go the gear change route, shop around for a good shop and price combination. You may be able to beat the price for labor since I went to my local dealer for most of my mods.

 

Get the CAI/Tune first. The hand held tuner has the option of changing your gears. If you don't change the gear setting your speed-odometer will be off. Since you have an 06 which already has 3.55's, going to 3.73s will not be worth it. I also have an 06 and I went to 4.10s. Don't let anyone tell you that 4.10s are not great for hwy use. I drive my 70-75 miles per. day round trip. The 4.10s are great on the hwy. Yes, your MPG will drop a little. Mine went from about 27 MPG to 25 MPG, but in town/city your MPGs might actually go up. Overall my MPG has not changed. You will not loose top end performance/accleration with 4.10s. actually it will be better.

 

The purpose of the rear end gear is to multiply engine torque before it gets to your wheels. If you have 3.31s and are making 320 ftlbs of torque, you will have 1,060 ftlbs of torque available at the wheels. If you have 4.10s, with the same engine, you will have 1,312 ftlbs of torque. However, the ratio also shows how fast your engine will be spinning relative to the wheels. With 4.10s, your engine will be spinning faster at a certain vehicle speed than with 3.31s which brings your top speed in each gear down. That is the tradeoff. Gears in your rear end are just like in your transmission. If you are in first gear, you have the best acceleration, but you can't go faster than 40 mph. In 5th gear, you have the worst acceleration, but you can go 150 mph. Hopefully some of that rambling made sense to you.

 

Even with 4.10s, the car has the potential to reach 160+. Yes, with 3.31s and 3.55 the top speed will be greater, but the 4.10s do have better hwy accleration.

 

So if I understand this correctly, from what is said; I line up with someone else and we have an open road ahead of us....

Does that mean I will be shifting earlier and more frequently, since my top mph in each gear will be reduced? If so, will that time it takes me to shift cause a significant loss in acceleration to actually "even out" with my stock gear acceleration. I'm assuming it depends on how fast the person driving can shift. I'm just not sure what kind of gains I can expect from a mod like this.
Mostly looking for 0-80mph

 

Yes, you will be shifting more frequently with 4.10's. If you are good at shifting, the performance increase with the 4.10's will be more than your loss with an extra shift. If you're only going to 80, you might not have an extra shift. I think I can hit 80 in 3rd with my 4.10's, I know I go throught the traps in 4th now while I went through at the top of 3rd with the 3.55's but my times are quicker with the 4.10's

 

Bottom line is that there are trade-offs with either set up. You need to figure out what your goal is, how you will be driving the car most often, and decide if the gear change is worth the money in your situation. Like I said earlier, if you are trying to decide between the CAI/Tune and gears, the CAI/Tune is the better of the choice for the first mod. You can use the tuner for other mods later and as someone else mentioned, the tuner can be used to compensate for the gear change with repsect to the speedometer.

If I were thinking gear change and just trying to decide between the various ratios, strongly consider where your end goal is going to be. Had I not been planning on going with a supercharger at some point, I would have probably gone with 4.10 instead of the 3.73. But my circumstances are such that I do not do much freeway driving above 75 or 80 mph for long durations. Had I gone with 4.10 ratio and then a supercharger, I suspect I would have had more issues with traction control under WOT hole shots which is where I want the advantage on the street. With the 3.73 ratio and WOT out of the hole, I still feel the car fishtail somewhat spinning into second even with the traction control on. I am also running 20" rims which takes away from some of my HP to the wheels so I can only imagine had I been running smaller rims how much stronger out of the hole it may have felt like.

Good luck with what ever your final decision turns out to be.