GEAR RATIO CHANGE???
#1
01-07-2007, 08:52 PM
Join Date: Dec 2006
Location:
Posts: 667
Likes: 0
Received 0 Likes
on
0 Posts
GEAR RATIO CHANGE???
This is for a friend of mine,In an 03 CTD where can he find the parts to go from a 4:10 to a 3:54 or 3:73 , and whats the deal on getting the speedometer in sync and how will this effect the antilock system. They bought the truck new and use it mainly for non pulling hwy use.It is a 6spd. Any help will be appeciated.
#2
01-07-2007, 09:22 PM
Join Date: Dec 2006
Location: Ft. Meade, MD
Posts: 420
Likes: 0
Received 0 Likes
on
0 Posts
RE: GEAR RATIO CHANGE???
I would highly advise against swapping gears just to get better mileage. It is very expensive proposition if you can't do the work yourself. If your considering doing it yourself, you will need some expensive special tools as well as the parts.
I have 4.10 gears and can get 19 mpg highway. I think if you do the calculations, you'll find that 3.73 gears will only drop your cruise speed about 200 rpm. There was some good advice in an earlier post (quoted below).
From an earlier post:
I have 4.10 gears and can get 19 mpg highway. I think if you do the calculations, you'll find that 3.73 gears will only drop your cruise speed about 200 rpm. There was some good advice in an earlier post (quoted below).
From an earlier post:
Here's the deal if you are even considering a gear swap to get better MPG.......
Swapping gears for MPG is like ordering a Diet Coke with a king size Double Whopper meal, it'll never pay off.
Figure this (double it for a 4x4)
Gear set: $150 - 200
Install Kit: $100 - 200, depending on the level of kit you get
Labor: $300 - 600 per axle, unless you know how to do it yourself. Little hint, this IS NOT a beginner job. You need a few special tools to do it right and you can screw it up real easy.
So, for a 2wd truck, you would be looking at $550 - 1000 dollars to do a gear swap. That's a lot of fuel to recoup. Double that for a 4wd.
Best bets to getting some mileage
1 - Lose the un-needed weight. All that crap in the toolbox that you NEVER use. Get rid of it.
2 - Run your tires at the max inflation that still gives you good wear.
3 - Change your air / fuel filters. Not necessarilly to a high flow air filter, as this means more air. More air = more fuel.
4 - Drive like you have an egg under your foot.
5 - Try to keep the engine in the meat of the torque curve at highway speeds. Above 2K and your making a good amount of boost. Boost = Air = Fuel = Poopy MPG.
< Message edited by cumminalong -- 1/5/2007 9:59:35 AM >
Swapping gears for MPG is like ordering a Diet Coke with a king size Double Whopper meal, it'll never pay off.
Figure this (double it for a 4x4)
Gear set: $150 - 200
Install Kit: $100 - 200, depending on the level of kit you get
Labor: $300 - 600 per axle, unless you know how to do it yourself. Little hint, this IS NOT a beginner job. You need a few special tools to do it right and you can screw it up real easy.
So, for a 2wd truck, you would be looking at $550 - 1000 dollars to do a gear swap. That's a lot of fuel to recoup. Double that for a 4wd.
Best bets to getting some mileage
1 - Lose the un-needed weight. All that crap in the toolbox that you NEVER use. Get rid of it.
2 - Run your tires at the max inflation that still gives you good wear.
3 - Change your air / fuel filters. Not necessarilly to a high flow air filter, as this means more air. More air = more fuel.
4 - Drive like you have an egg under your foot.
5 - Try to keep the engine in the meat of the torque curve at highway speeds. Above 2K and your making a good amount of boost. Boost = Air = Fuel = Poopy MPG.
< Message edited by cumminalong -- 1/5/2007 9:59:35 AM >
#3
01-07-2007, 09:33 PM
Join Date: Dec 2006
Location:
Posts: 667
Likes: 0
Received 0 Likes
on
0 Posts
#4
01-07-2007, 09:48 PM
Join Date: Jul 2006
Location: Swollen Beaver, OR
Posts: 2,800
Likes: 0
Received 0 Likes
on
0 Posts
RE: GEAR RATIO CHANGE???
ORIGINAL: sabersix
I would highly advise against swapping gears just to get better mileage. It is very expensive proposition if you can't do the work yourself. If your considering doing it yourself, you will need some expensive special tools as well as the parts.
I have 4.10 gears and can get 19 mpg highway. I think if you do the calculations, you'll find that 3.73 gears will only drop your cruise speed about 200 rpm. There was some good advice in an earlier post (quoted below).
I would highly advise against swapping gears just to get better mileage. It is very expensive proposition if you can't do the work yourself. If your considering doing it yourself, you will need some expensive special tools as well as the parts.
I have 4.10 gears and can get 19 mpg highway. I think if you do the calculations, you'll find that 3.73 gears will only drop your cruise speed about 200 rpm. There was some good advice in an earlier post (quoted below).
Normally a single step up or downin gears isn't worth the expense. Each step will only net you about 200 - 250 rpms either way.
The only reason you should be swapping gears is to regain lost performance from a tire size change or if you see your towing needs changing pretty drastically. Even then, if you are not going at least 2 gear sizes, it's not worth it.
Before he decides to swap gears, I'd have him look at one of the econo boxes that drop the power level. Would be a lot cheaper than a gear swap.
If you are gonna do a gear swap, I can not stress enough to get someone that has been doing it for years. It's one thing to swap gears in one of your toys (like my Samurai) that you won't even put enough miles on to destoy the gears anyways, but it's a whole different story when it's your DD. You have no idea how scary it is to hear this howl start up at highway speed and then have your rear gears disintegrate and lock up the wheels. Not fun.
BTW, changing the gear size will not affect your speedo. It reads off of the ring gear and is directly related to tire speed. What will affect your speedo is a tire size change, as you have effectively changed the number of rotations that it takes to cover 1 mile.