3.90 Gears
4th Gear Member
Joined: Aug 2004
Posts: 1,615
From: Texas
RE: 3.90 Gears
ORIGINAL: mustangman02232
well just goes to show you that even if you work for ford, you still dont know everything
4.10s are fine for autos, they have the shorter .75 5th gear, the t3650s have a .62 5th gear, 4.30s are fine, and yes, for a DD, both will stick you about 3k rpms while driving, however, you must remember, that these are not back in the 70s with the old pushorod OHC V8s, these are SOHC 3Vs that make power north of 4500 rpms, so, you need shorter gears in order for the motor to rev up quicker and take advantage of that power, why ford ever stuck 3.31s in the rear i will never know but i think that there CAFE should be high enough they can sacrifice 2 mpg to put a set of 4.10/4.30s in the rear.
ORIGINAL: StowesStang
Well, just spoke to the old man and he said, "for you, NO!" So it looks like Im back to 3.73s. He told me that I drive my car too much to install those gears. He said its too low of a gear ratio for my "daily driver". He said 3.73 is the lowest he wants to go on my ride. So bottom line, I got shot down!!!! [&:]
Well, just spoke to the old man and he said, "for you, NO!" So it looks like Im back to 3.73s. He told me that I drive my car too much to install those gears. He said its too low of a gear ratio for my "daily driver". He said 3.73 is the lowest he wants to go on my ride. So bottom line, I got shot down!!!! [&:]
4.10s are fine for autos, they have the shorter .75 5th gear, the t3650s have a .62 5th gear, 4.30s are fine, and yes, for a DD, both will stick you about 3k rpms while driving, however, you must remember, that these are not back in the 70s with the old pushorod OHC V8s, these are SOHC 3Vs that make power north of 4500 rpms, so, you need shorter gears in order for the motor to rev up quicker and take advantage of that power, why ford ever stuck 3.31s in the rear i will never know but i think that there CAFE should be high enough they can sacrifice 2 mpg to put a set of 4.10/4.30s in the rear.
3rd Gear Member
Joined: Jul 2006
Posts: 880
From:
RE: 3.90 Gears
3:90 gears(Motive) was my 3rd mod I did over a year ago & I love it!!I can travel at 80mph on HWY trips under 3000RPMs & the pull I get from a light is awesome!Nothing wrong with motives as long as the istaller does it right.Mine had some whine when it first got done & he pulled it back apart & reshimmed it & no more whine!As far as FI goes.3:90s is as steep as you should go!Really 3:73s are better.But Im keeping what Ive got when the Procharger goes on.
ORIGINAL: ALLCHEST
I did a search on this and didn't come up with much.
Why are people not using 3.90 gears? Given the fact that I have 3.55 gears currently, 3.73 wouldn't be enough to spend the money on and some say 4.10 is too much. 3.90 is right in the middle, why aren't people using 3.90???
I did a search on this and didn't come up with much.
Why are people not using 3.90 gears? Given the fact that I have 3.55 gears currently, 3.73 wouldn't be enough to spend the money on and some say 4.10 is too much. 3.90 is right in the middle, why aren't people using 3.90???
Thread Starter
1st Gear Member
Joined: Mar 2007
Posts: 93
From:
RE: 3.90 Gears
ORIGINAL: Norse1974
3:90 gears(Motive) was my 3rd mod I did over a year ago & I love it!!I can travel at 80mph on HWY trips under 3000RPMs & the pull I get from a light is awesome!Nothing wrong with motives as long as the istaller does it right.Mine had some whine when it first got done & he pulled it back apart & reshimmed it & no more whine!As far as FI goes.3:90s is as steep as you should go!Really 3:73s are better.But Im keeping what Ive got when the Procharger goes on.
3:90 gears(Motive) was my 3rd mod I did over a year ago & I love it!!I can travel at 80mph on HWY trips under 3000RPMs & the pull I get from a light is awesome!Nothing wrong with motives as long as the istaller does it right.Mine had some whine when it first got done & he pulled it back apart & reshimmed it & no more whine!As far as FI goes.3:90s is as steep as you should go!Really 3:73s are better.But Im keeping what Ive got when the Procharger goes on.
ORIGINAL: ALLCHEST
I did a search on this and didn't come up with much.
Why are people not using 3.90 gears? Given the fact that I have 3.55 gears currently, 3.73 wouldn't be enough to spend the money on and some say 4.10 is too much. 3.90 is right in the middle, why aren't people using 3.90???
I did a search on this and didn't come up with much.
Why are people not using 3.90 gears? Given the fact that I have 3.55 gears currently, 3.73 wouldn't be enough to spend the money on and some say 4.10 is too much. 3.90 is right in the middle, why aren't people using 3.90???
Thread Starter
1st Gear Member
Joined: Mar 2007
Posts: 93
From:
RE: 3.90 Gears
ORIGINAL: Norse1974
Im using a Diablo Predator.It has the ability to set for ANY gear.Scott Beer is my Tuner.He designed the canned tunes for the S197s that Diablo uses!
Im using a Diablo Predator.It has the ability to set for ANY gear.Scott Beer is my Tuner.He designed the canned tunes for the S197s that Diablo uses!
Thanks for clearing this up.
3rd Gear Member
Joined: Jul 2006
Posts: 880
From:
RE: 3.90 Gears
Not everyone here knows what they are talking about.But thats the beauty of the internet!Everyone can say things & sound really knowledgable & if they get caught then they can act like it never happened.This is one of the better forums though.But if you really need info call Brenspeed or any other mustang specialty shop to get the down low!
Joined: May 2007
Posts: 1
RE: 3.90 Gears
Guys,
Nothing wrong with motives........we run them in our race cars w/no issues at all. Some of these cars are making in excess of 1500 HP, using 8.8" rears. Also, as stated before, Motive GearIS the manufacturer of the FRPP (motorsport) gears. Hope this helps!
Nothing wrong with motives........we run them in our race cars w/no issues at all. Some of these cars are making in excess of 1500 HP, using 8.8" rears. Also, as stated before, Motive GearIS the manufacturer of the FRPP (motorsport) gears. Hope this helps!
3rd Gear Member
Joined: May 2006
Posts: 700
From:
RE: 3.90 Gears
ORIGINAL: StowesStang
No, no, no! lol What my husband is telling me, is specifically for me! lol He has installed many 4.10s in mustangs,different year models,but for my stang he is saying NO! lol Basically, he does not see a need for me to have a set that low, based on how I drive itand the main use of my ride. Just wanted to set the record straight on that one! lol
ORIGINAL: mustangman02232
well just goes to show you that even if you work for ford, you still dont know everything
4.10s are fine for autos, they have the shorter .75 5th gear, the t3650s have a .62 5th gear, 4.30s are fine, and yes, for a DD, both will stick you about 3k rpms while driving, however, you must remember, that these are not back in the 70s with the old pushorod OHC V8s, these are SOHC 3Vs that make power north of 4500 rpms, so, you need shorter gears in order for the motor to rev up quicker and take advantage of that power, why ford ever stuck 3.31s in the rear i will never know but i think that there CAFE should be high enough they can sacrifice 2 mpg to put a set of 4.10/4.30s in the rear.
ORIGINAL: StowesStang
Well, just spoke to the old man and he said, "for you, NO!" So it looks like Im back to 3.73s. He told me that I drive my car too much to install those gears. He said its too low of a gear ratio for my "daily driver". He said 3.73 is the lowest he wants to go on my ride. So bottom line, I got shot down!!!! [&:]
Well, just spoke to the old man and he said, "for you, NO!" So it looks like Im back to 3.73s. He told me that I drive my car too much to install those gears. He said its too low of a gear ratio for my "daily driver". He said 3.73 is the lowest he wants to go on my ride. So bottom line, I got shot down!!!! [&:]
4.10s are fine for autos, they have the shorter .75 5th gear, the t3650s have a .62 5th gear, 4.30s are fine, and yes, for a DD, both will stick you about 3k rpms while driving, however, you must remember, that these are not back in the 70s with the old pushorod OHC V8s, these are SOHC 3Vs that make power north of 4500 rpms, so, you need shorter gears in order for the motor to rev up quicker and take advantage of that power, why ford ever stuck 3.31s in the rear i will never know but i think that there CAFE should be high enough they can sacrifice 2 mpg to put a set of 4.10/4.30s in the rear.
Going from 3.55 to 3.73 is only going to increase your RPM by...let's see...4.8%, right? I can't see that doing much. If the performance benefit is so small, then perhaps you're better off just getting better gas mileage?
Now, if you started at 3.31's and went to 3.73's, that would certainly make some sense to me.