New Gears - 3:73's and RPM

[riot6]

Can anyone tell me the RPM's I can expect to see at 50 mph, 60 mph, 70 mph and 80 mph. I have a 2002 GT - I do quite a bit of highway driving, long distance in the summer and would like to know the numbers. I see about 1800-2000 rpm at 70-75 mph with stock gears.

Also, has anyone tried the 3:90's yet? Thanks.

 

[Wills Black 98]

get 4.10's instead you wont regret it!

 

[DeadLurker]

I have a 02 GT...I went from 75mph, 2000rpm, 5th gear(stock) to 65mph, 2000rpm, 5th gear(3.73s)

 

[riot6]

I have a 02 GT...I went from 75mph, 2000rpm, 5th gear(stock) to 65mph, 2000rpm, 5th gear(3.73s)

Thanks for the info... so about 500rpm for every 5 miles. I guess I can live with that..... thanks again.

 

[DeadLurker]

Thanks for the info... so about 500rpm for every 5 miles. I guess I can live with that..... thanks again.

Not exactly...lets just put it this way..if you were to get gears and not correct your speedo the faster you went the MORE your speedo would be off.

So for example...at 1,500rpms in 5th gear with 3.27s your probably at 55mph...while with 3.73s your at 50mph..a 5mph difference at 1,500rpms but 10mph difference at 2,000rpm...

understand?

 

[stangman]

Not exactly...lets just put it this way..if you were to get gears and not correct your speedo the faster you went the MORE your speedo would be off.

So for example...at 1,500rpms in 5th gear with 3.27s your probably at 55mph...while with 3.73s your at 50mph..a 5mph difference at 1,500rpms but 10mph difference at 2,000rpm...

understand?

exactly what he said it's actually a percentage that your off, rather than a certain mph

 

[99GHOST]

Can anyone tell me the RPM's I can expect to see at 50 mph, 60 mph, 70 mph and 80 mph. I have a 2002 GT - I do quite a bit of highway driving, long distance in the summer and would like to know the numbers. I see about 1800-2000 rpm at 70-75 mph with stock gears.

Also, has anyone tried the 3:90's yet? Thanks.

Try this link

http://www.allfordmustangs.com/AFM_Tech/Calculators___Decoders/index.shtml

 

[hotrodman]

Try this link

http://www.allfordmustangs.com/AFM_Tech/Calculators___Decoders/index.shtml

ihave 99 cobra has 4.10 rpms as follows at80mph/3000rpms,,at4000rpms/110mph..at 5000rpms/138mph this limits the.top speed.alot but at 75mph/2750rpm.not all bad makes tou obey the speed limit more acuaaly get better gas mileage then the stock 3.27.gears i think because motor not laboring as much..28mpg..with 275/35/zr18s.if i had it to do over a would go with 3.73s..gook luck in your diccisson

 

[Dark Knight GT]

http://www.tchracing.com/tech/gearc...m&givenval=50&givenvaltype=MPH&selectedgear=5


Here is a link to TCH racing and their gear calculator. This should help with determining certain speeds and rpms w/ certain gear ratios.

 

[white99gt]

For every step up from stock.Add 200 rpms for each step up.

3:73's are nice but 4:10s would be better and you really wont see that big of difference in 5th between the two as far as highway driving.

 

[decoy562]

For every step up from stock.Add 200 rpms for each step up.

3:73's are nice but 4:10s would be better and you really wont see that big of difference in 5th between the two as far as highway driving.

I see you're running 3.73's though, is that because you're not N/A anymore?

 

[white99gt]

I see you're running 3.73's though, is that because you're not N/A anymore?

No ive always had 3:73's from day one.

But im changing soon and going up to 4:10's or 4:30's .Not that big of a jump .

 

[Sam98]

Can anyone tell me the RPM's I can expect to see at 50 mph, 60 mph, 70 mph and 80 mph. I have a 2002 GT - I do quite a bit of highway driving, long distance in the summer and would like to know the numbers. I see about 1800-2000 rpm at 70-75 mph with stock gears.

Also, has anyone tried the 3:90's yet? Thanks.

That depends on whether you have a 5-speed or automatic.

For a 5-speed you should see the following in 5th gear with 3.73 gears:

1512 RPM @ 50 mph
1815 RPM @ 60 mph
2117 RPM @ 70 mph
2420 RPM @ 80 mph

These numbers assume an overdrive ratio of 0.62 that the newer transmissions have. The older transmissions have an overdrive ratio of 0.67 and the numbers would be:

1634 RPM @ 50 mph
1961 RPM @ 60 mph
2288 RPM @ 70 mph
2615 RPM @ 80 mph

I don't know what the overdrive ratio is in the automatic, but I'm sure someone else does...