message for frank&beans re diff. works
Thread Starter
|
Member
Joined: Sep 1999
Posts: 25
Likes: 0
From: philippines
message for frank&beans re diff. works
I read a lot of topics about you changing to a 4.10 from the stock 3.55...much say i am very impressed with the power you described...i have a 1999 f150 4X2 auto tranny 4.2V6 supercab with 235/70/16 and 3.31 rear and 8.8 rear...have a jet module and i just remove the true trac due to a couple bolts being broken..i am thinking of going with a 3.73 or even 4.10 and changing my tires to 265/70/16 or even 265/75/16..my question is..
1. did u see the shop perform the change of gears?
2. can ur rig easily do 80 or even 90mph? what do u think your top speed could be??
3. if u do your own change for the diff?,is it hard to remove the pinion gear?
the reason is i can easily remove the ring gear and the housing but i have never even change or remove the pinion gear..my rig easily does 100mph on the freeway here in the philippines...anyway 150's speedometer only goes to 100mph only !!
thanks for your advise...and what is your RPM at 65mph??
1. did u see the shop perform the change of gears?
2. can ur rig easily do 80 or even 90mph? what do u think your top speed could be??
3. if u do your own change for the diff?,is it hard to remove the pinion gear?
the reason is i can easily remove the ring gear and the housing but i have never even change or remove the pinion gear..my rig easily does 100mph on the freeway here in the philippines...anyway 150's speedometer only goes to 100mph only !!
thanks for your advise...and what is your RPM at 65mph??
Member
Joined: Feb 1999
Posts: 85
Likes: 0
From: Beamsville, Ontario, Canada
I just posted most of this in another spot, but it answers many of your questions.
Try a set of 4.11's.(or 4.10's...same thing, almost) The ratio will DEFINATELY wake your truck up outta the hole. If you do lots of hiway miles, your gas mileage will suffer a little. You can figure out your new RPM's at 60 miles an hour by determining the circumference of your tire, and dividing it into 5280 feet( a mile). You travel one mile per minute at 60mph, so RPM is easy to figure out.
Let's use my truck as an example: My tire (a little tall) is 94.5 inches in circumference = 7.875 feet
You can get your circumference by measuring the tire's diameter and multiplying by "PI"(3.1415927)
Therefore, 5280 ft divide by 7.875 = 670.47619 tire revolutions per minute. Now, multiply that by your gear ratio:
(mine's 3.08)2065 RPM
a 4.11 = 2756 RPM
a 3.73 = 2500 RPM
a 3.55 = 2380 RPM
Don't forget, your overdrive actually drives less than one to one.. (4R100 O/D is 1:1 in third, and .71:1 in fourth) I'm not sure what the slushbox automatic is, but it's probably close to this.I just don't have that number
off hand
(3.08)2065 x .71 = 1466 RPM
(4.11)2756 x .71 = 1957 RPM
(3.73)2500 x .71 = 1775 RPM
(3.55)2380 x .71 = 1690 RPM
The numbers will show higher RPM's for stock tires or lower profile rubber.
The next trouble you'll have is the speedo will be outta whack, but look that up on the message board as well, lotsa guys have overcome this problem, too. I think ya just gotta order a chip from Mike Troyer (superchips ditributor), & tell him
your new ratio. They reprogram the chip.
So, with the overdrive, and 17" tires, the 4.11 rear end is not so bad, and you'll LOVE the difference. I have 4.11's for my '66 Mustang coupe, and have driven long distance trips up north, and got used to it. Car tires are much smaller, and at 60mph, I spin 3500 RPM.
------------------
'97 S/C XLS black/silver 157" WB, 4.6/auto, 3:08, home made custom stainless tube grille, terminator muffler, phantom sweep wiper switch(factory installed), a few billet aluminum goodies (the list grows), airbox mods, TPS tuned
email: bazils@hotmail.com
http://content.communities.msn.com/bazilspix/PhotoAlbum
Try a set of 4.11's.(or 4.10's...same thing, almost) The ratio will DEFINATELY wake your truck up outta the hole. If you do lots of hiway miles, your gas mileage will suffer a little. You can figure out your new RPM's at 60 miles an hour by determining the circumference of your tire, and dividing it into 5280 feet( a mile). You travel one mile per minute at 60mph, so RPM is easy to figure out.
Let's use my truck as an example: My tire (a little tall) is 94.5 inches in circumference = 7.875 feet
You can get your circumference by measuring the tire's diameter and multiplying by "PI"(3.1415927)
Therefore, 5280 ft divide by 7.875 = 670.47619 tire revolutions per minute. Now, multiply that by your gear ratio:
(mine's 3.08)2065 RPM
a 4.11 = 2756 RPM
a 3.73 = 2500 RPM
a 3.55 = 2380 RPM
Don't forget, your overdrive actually drives less than one to one.. (4R100 O/D is 1:1 in third, and .71:1 in fourth) I'm not sure what the slushbox automatic is, but it's probably close to this.I just don't have that number
off hand
(3.08)2065 x .71 = 1466 RPM
(4.11)2756 x .71 = 1957 RPM
(3.73)2500 x .71 = 1775 RPM
(3.55)2380 x .71 = 1690 RPM
The numbers will show higher RPM's for stock tires or lower profile rubber.
The next trouble you'll have is the speedo will be outta whack, but look that up on the message board as well, lotsa guys have overcome this problem, too. I think ya just gotta order a chip from Mike Troyer (superchips ditributor), & tell him
your new ratio. They reprogram the chip.
So, with the overdrive, and 17" tires, the 4.11 rear end is not so bad, and you'll LOVE the difference. I have 4.11's for my '66 Mustang coupe, and have driven long distance trips up north, and got used to it. Car tires are much smaller, and at 60mph, I spin 3500 RPM.
------------------
'97 S/C XLS black/silver 157" WB, 4.6/auto, 3:08, home made custom stainless tube grille, terminator muffler, phantom sweep wiper switch(factory installed), a few billet aluminum goodies (the list grows), airbox mods, TPS tuned
email: bazils@hotmail.com
http://content.communities.msn.com/bazilspix/PhotoAlbum
