3.73 gears for V6 coupe
10-28-2008, 03:26 PM
#1
Thread Starter
Join Date: Apr 2008
Location: Arizona
Posts: 5
3.73 gears for V6 coupe
This is my first post on a forum of any kind...
Howdy... I am a mechanical retard, so bear with me... I have done some modifications to my '05 coupe which started out as the most base model available. I have since done a fair amount of aesthetic enhancements and I am very pleased with the appearance of this car. I have also done performance enhancements in the nature of JLT CAI, Headers, Ford Racing dual exhaust and the complete Ford Racing handling package and a 91 octane tune with SCT tuner...
I think that covers it. I am now considering switching to a 3.73 rear end and a T-lock differential. I have been told upping the gears will increase 'pick up' off the line... which to me translates to quicker 0-60 and at least a feel of more horsepower/responsiveness... What I am hoping to attain is an off line increase in performance that will at least give the appearance that the car runs as hot as it looks...
My question then is... What is the trade off? I have been told increasing the gears will decrease top speed by requiring more rpm's at higher speed. That it will cause the engine to run at higher rpm's to maintain speeds comparable to before to the change. For example, I run 2200 rpm to maintain 75 mph currently. Does anyone know how significant a change would result in changing up gears?
This is a daily driver... my sole vehicle and I drive as part of my job so I don't want it to be ridiculous off the line and max out at 45 mph... also we all have to take gas prices into consideration and I bought this model partially because of mileage... also I don't want to be running 3000+ rpm to keep up with freeway traffic.
I realize this is a quagmire of questions, but I am frustrated with getting opinions from people that are only interested in selling me something. I appreciate any and all input. Thanks...
Howdy... I am a mechanical retard, so bear with me... I have done some modifications to my '05 coupe which started out as the most base model available. I have since done a fair amount of aesthetic enhancements and I am very pleased with the appearance of this car. I have also done performance enhancements in the nature of JLT CAI, Headers, Ford Racing dual exhaust and the complete Ford Racing handling package and a 91 octane tune with SCT tuner...
I think that covers it. I am now considering switching to a 3.73 rear end and a T-lock differential. I have been told upping the gears will increase 'pick up' off the line... which to me translates to quicker 0-60 and at least a feel of more horsepower/responsiveness... What I am hoping to attain is an off line increase in performance that will at least give the appearance that the car runs as hot as it looks...
My question then is... What is the trade off? I have been told increasing the gears will decrease top speed by requiring more rpm's at higher speed. That it will cause the engine to run at higher rpm's to maintain speeds comparable to before to the change. For example, I run 2200 rpm to maintain 75 mph currently. Does anyone know how significant a change would result in changing up gears?
This is a daily driver... my sole vehicle and I drive as part of my job so I don't want it to be ridiculous off the line and max out at 45 mph... also we all have to take gas prices into consideration and I bought this model partially because of mileage... also I don't want to be running 3000+ rpm to keep up with freeway traffic.
I realize this is a quagmire of questions, but I am frustrated with getting opinions from people that are only interested in selling me something. I appreciate any and all input. Thanks...
10-28-2008, 03:45 PM
#2
5th Gear Member
Join Date: Oct 2006
Location: MO
Posts: 3,234
I have 3.73s installed and have not noticed a significant drop in mpg. RPMs are slightly higher throughout, though, so i'm sure there is some loss.
That said, I have repeatedly been able to achieve as high as 30 mpg when driving between 55 and 60 with the cruise control on. If I drive like a grandma, I can get 27 mpg with some mixed driving. If I drive more realistically (a few WOT runs and defensive driving), I get about 24 mpg with mixed (80% highway 10% city)....so there is room to save money if it's needed.
They do give you a "snappier" (literally) feel off the line, and help keep 5th gear in a usable rpm range. To be honest, they make the car more drivable, and, as a result, are a very good mod for a daily driver.
The t-lok has it's own advantages, one of which is way better traction off the line. A negative property (although I like it) to the t-lok is that it will be easier to fishtail if you give the car too much gas on slippery and dry surfaces while in a turn; however, a locking differential gives you more predictable handling in turns in general.
You will not be running at 3000 rpm... unless you keep it in 4th and are going 65 mph or so... which is what I do on this stretch of twisty road in Bourbon Mo on occasion...
That said, I have repeatedly been able to achieve as high as 30 mpg when driving between 55 and 60 with the cruise control on. If I drive like a grandma, I can get 27 mpg with some mixed driving. If I drive more realistically (a few WOT runs and defensive driving), I get about 24 mpg with mixed (80% highway 10% city)....so there is room to save money if it's needed.
They do give you a "snappier" (literally) feel off the line, and help keep 5th gear in a usable rpm range. To be honest, they make the car more drivable, and, as a result, are a very good mod for a daily driver.
The t-lok has it's own advantages, one of which is way better traction off the line. A negative property (although I like it) to the t-lok is that it will be easier to fishtail if you give the car too much gas on slippery and dry surfaces while in a turn; however, a locking differential gives you more predictable handling in turns in general.
You will not be running at 3000 rpm... unless you keep it in 4th and are going 65 mph or so... which is what I do on this stretch of twisty road in Bourbon Mo on occasion...
10-28-2008, 04:41 PM
#3
2nd Gear Member
Join Date: Apr 2008
Posts: 213
That's weird I was just looking at my rpm gauge on the way home and I was like I wonder what it used to be at. It was at 2500 rpm's when doing 70mph. As for gas I feel like I have a hole in the gas tank ever since I bought my gears. It's not that the gears made me loose too many mpg but you tend to drive the car a little harder after the install .
.
10-29-2008, 01:57 AM
#5
Thread Starter
Join Date: Apr 2008
Location: Arizona
Posts: 5
Thanks... for the input thus far. I am thinking at this point that the T-lock is perhaps overkill for what I want. This being said... concensus appears that the first choice in product line would be to stick with FRP items...
Any input pro or con, or suggestions for alternatives is appreciated.
Any input pro or con, or suggestions for alternatives is appreciated.
10-29-2008, 02:18 AM
#6
2nd Gear Member
Join Date: Apr 2008
Posts: 213
Thanks... for the input thus far. I am thinking at this point that the T-lock is perhaps overkill for what I want. This being said... concensus appears that the first choice in product line would be to stick with FRP items...
Any input pro or con, or suggestions for alternatives is appreciated.
Any input pro or con, or suggestions for alternatives is appreciated.
10-29-2008, 08:12 AM
#7
2nd Gear Member
Join Date: Sep 2008
Location: Boston, MA
Posts: 498
level01 - I have had 3.73 gearing since about a month ago.. you will LOVE IT!
When I'm doing 60mph in 5th, the engine is @ 2000 rpm; 80 mph = 2750 rpm. So don't worry, it's nothing that will bug you on the highway.. the REAL PLUS is the acceleration! I found the performance increase to be more remarkable than when I added the CAI/tune/exhaust.
Our 4.0 V6 engine is in the "powerband" from the upper 2000's to 5500 rpm, so these gears effectively put the engine in the "sweet spot" for maximum acceleration . Each gear feels perfect once you switch to 3.73 gearing ; you no longer feel "bogged down".
Personally, I chose to swap out my 7.5" axle for the 8.8" GT with 3.73 gearing because I wanted the t-loc to get max traction and stop making those wimpy 1-tire burnouts! Not to mention I got a great deal on the axle (newtakeoff.com) which made it about the same price as adding the gears & t-loc to the 7.5". Also, consider all the people who have gears changed and then have problems with them "whining"... The GT axle saved me those headaches and now I have a brand-new beefy axle that I can feel confident will handle any future power upgrades I add to the car!
Oh and YES, my gas milage dropped about 10% due to the higher rpms AND the fact that I can't stop putting my BOOT into the accelerator... TOO much FUN! And as someone previously posted.. "If you're concerned about mpg, you should have bought a Prius... not a MUSTANG!"
When I'm doing 60mph in 5th, the engine is @ 2000 rpm; 80 mph = 2750 rpm. So don't worry, it's nothing that will bug you on the highway.. the REAL PLUS is the acceleration! I found the performance increase to be more remarkable than when I added the CAI/tune/exhaust.
Our 4.0 V6 engine is in the "powerband" from the upper 2000's to 5500 rpm, so these gears effectively put the engine in the "sweet spot" for maximum acceleration . Each gear feels perfect once you switch to 3.73 gearing ; you no longer feel "bogged down".
Personally, I chose to swap out my 7.5" axle for the 8.8" GT with 3.73 gearing because I wanted the t-loc to get max traction and stop making those wimpy 1-tire burnouts! Not to mention I got a great deal on the axle (newtakeoff.com) which made it about the same price as adding the gears & t-loc to the 7.5". Also, consider all the people who have gears changed and then have problems with them "whining"... The GT axle saved me those headaches and now I have a brand-new beefy axle that I can feel confident will handle any future power upgrades I add to the car!
Oh and YES, my gas milage dropped about 10% due to the higher rpms AND the fact that I can't stop putting my BOOT into the accelerator... TOO much FUN! And as someone previously posted.. "If you're concerned about mpg, you should have bought a Prius... not a MUSTANG!"
Last edited by iROK24/7; 10-29-2008 at 08:14 AM.
10-29-2008, 08:18 AM
#8
Site Moderator of Fury!
Join Date: Aug 2007
Location: Houston, TX
Posts: 5,104
You should most definitely get a t-lok. Those of you that don't have one, and say you don't need one, need to seriously reconsider. A t-lok is not just for racing, it is to provide traction to both rear tires. That means in the snow, rain, and dry pavement. Not only does it help you get better traction, and be safer, but it also doesn't make you look like a dolt when you do a 1 wheel peel.
As far as the 3.73's, they are a nice fit for our cars, it will give you a great jump off the line. And they have minimal impact on fuel economy and rpm's on the highway. I frpp 3.73's and a t-lok and I use it as my daily driver.
As far as the 3.73's, they are a nice fit for our cars, it will give you a great jump off the line. And they have minimal impact on fuel economy and rpm's on the highway. I frpp 3.73's and a t-lok and I use it as my daily driver.
10-29-2008, 09:16 AM
#9
5th Gear Member
Join Date: Oct 2006
Location: MO
Posts: 3,234
Not getting a t-lok now will probably end up costing you more money in the future.. you will definitely lose traction more easily without it (and wish that you bought one).. and rotating your tires will be interesting when you have only one tire that is significantly worn compared to the others; having two evenly worn rears to swap with evenly worn fronts is always the best scenario.
10-29-2008, 11:00 AM
#10
2nd Gear Member
Join Date: Jul 2006
Location:
Posts: 371
New Take Off 8.8" Axle w/ Gears
This is what I did. Actually just finished with the install yesterday. I'll have plenty of pictures later on need to resize/host them. But when you consider the separate costs of gears, t-lok, and Steelership install charges... buying the GT takeoff rear end is better.
There is really only a dozen or so bolts to take out, basic hand tools is all that is required (though pneumatic tools can make job faster/easier), and you get to enjoy the time spent with your precious.
Overall time spent is only 3-4 hours. Plus it goes by faster when you have plenty of Octoberfest.
This is what I did. Actually just finished with the install yesterday. I'll have plenty of pictures later on need to resize/host them. But when you consider the separate costs of gears, t-lok, and Steelership install charges... buying the GT takeoff rear end is better.
There is really only a dozen or so bolts to take out, basic hand tools is all that is required (though pneumatic tools can make job faster/easier), and you get to enjoy the time spent with your precious.
Overall time spent is only 3-4 hours. Plus it goes by faster when you have plenty of Octoberfest.