new differential
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Joined: Apr 2006
Posts: 52
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From: Fairfield Connecticut
new differential
I just finished putting in the new transmission in my car. Its a tremec transmission from the keisler auto to manual conversion kit and i want to put in a higher geared differential (i have a 3.08 right now) to really make the car unwind. I was thinking about putting in a 4.11 but a friend told me that 3.55 would do just fine and that the only difference is the 4.11 gets worse gas mileage. I am just wondering what you guy think i should put in.
This isn't going to be a car i commute in, its just a car i drive around town so gas mileage doesn't really bother me, but what i want is a decent top speed so that i can cruise on the high way but really jump off the line.
This isn't going to be a car i commute in, its just a car i drive around town so gas mileage doesn't really bother me, but what i want is a decent top speed so that i can cruise on the high way but really jump off the line.
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
go to their web site and look at the mph calc they have. it should give you an idea of where your curise rpms will be. 3.73 gears would be a great choice. if you have any kind of power, much more gear than that and traction will become an issue on the street.
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
I have a 73 and you are doing the same mods I just finished. This winter I converted from a TH400 to a Keisler 5-speed and I *just* finished the break-in period on the new rear diff where I went from the 3.08 to a 3.55. I have not had a chance to really test it since I have been taking it easy but I can definitely tell a difference while still being very drivable with my 383.
By the way, if you are looking for a reasonably priced unit from a good vendor, check out Ikerds. Jasper (where I got my motor from) recommended them and I had a great experience. In fact, I just got my core charge back this week.
Shane
By the way, if you are looking for a reasonably priced unit from a good vendor, check out Ikerds. Jasper (where I got my motor from) recommended them and I had a great experience. In fact, I just got my core charge back this week.
Shane
Melting Slicks
Joined: Dec 2005
Posts: 2,441
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Put in a 4.11 and you'll be shifting just after your rear tires clear the white line at the intersection that signifies where to stop. Most folks agree you want a total gear ratio reduction in first of not much higher than 10:1 or much less than 9:1.
Multiply the first gear ratio with the rear ratio and you'll get the total ratio.
With a 4.11 if you've got the TKO600 the total ratio would be 11.7:1, the 500 would yield 13.4:1
Multiply the first gear ratio with the rear ratio and you'll get the total ratio.
With a 4.11 if you've got the TKO600 the total ratio would be 11.7:1, the 500 would yield 13.4:1
Last edited by shafrs3; Jun 24, 2007 at 06:50 PM.
Melting Slicks
Joined: May 2005
Posts: 2,826
Likes: 3
From: Tennessee
Which TKO did you buy, the 500 or 600?
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Which TKO did you buy, the 500 or 600?
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
RIchard would never steer anyone wrong.
Melting Slicks
Joined: Oct 2001
Posts: 2,065
Likes: 1,395
From: Halifax, Nova Scotia, Canada
Which TKO did you buy, the 500 or 600?
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
If you bought the TKO-500, I wouldn't go any lower than a 3.55. If you run a 3.73, 4.11 etc... with the 500, your first gear will be useless as in granny gear useless.
If you went with the 600, then a 3.73 or 4.11 will be a great gear. For reference, I have a T-45 in my mustang(same gear ratios as the TKO-500) and am running a 3.55. 1st gear is awesome as are my cruising rpm's
Richard
I purchased a 600 (Keisler) last year and with my 3.70, this is a perfect combination.
A 500 with 3.70 would be too much first gear.
I really enjoy the 5-speed !!!!!!!!!
Barry
Melting Slicks
Joined: Apr 1999
Posts: 3,264
Likes: 3
From: Toms River NJ
I did my own Tremec TKO swap long before these companies sold the conversion kits... and its probable the second best mod ive ever done behind the ZZ4... In any case I can say that the 3.55 gears in my car are great with the Tremec 3.27:1 first gear... pulls so nice and you dont have to shift out right away!.. and then with the 5th gear I can do 80 @ 2500... So you get killer accelleration and decent gas mileage!
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Melting Slicks
Joined: May 2005
Posts: 2,826
Likes: 3
From: Tennessee
I did my own Tremec TKO swap long before these companies sold the conversion kits... and its probable the second best mod ive ever done behind the ZZ4... In any case I can say that the 3.55 gears in my car are great with the Tremec 3.27:1 first gear... pulls so nice and you dont have to shift out right away!.. and then with the 5th gear I can do 80 @ 2500... So you get killer accelleration and decent gas mileage!
Technically, my T45 has a 3.38 1st gear and it is still great with a 3.55.
From another personal experience, I had a Fox-body mustang and I did put the TKO-500 in it, I also ran 3.73's. 1st gear was useless except for burning the tires to the rim. I had to shift inside of 30 feet of taking off. For the "normal" person it would be over way too quick. Tried to break the tranny for 2 years straight and couldn't and I was putting a ton of power thru it.
Richard