Strange 03GT Gears?

[highvolts]

Hello Everyone,

A friend and I were comparing RPM vs. Speed. I have a 03GT 5Speed and he has a 99GT Automatic. It was mainly to see how each of our exhaust drones sounded. Anyways, he said he is at 3000RPM at 80 MPH with 4.10s, I'm at 2500 RPM at 70MPH with Stock gears. So… I came across West Coast Fords's "Engine, Gear, & Tire calculator ". I plugged in my numbers of 2500 RPM, 75MPH, T45/TR3650 - 5th, 245/45/17. The lil calculator comes up and says I have 3.80 Rear End Gears. What the heck is going on!? I've never changed the gears or tires.

Thanks in advance! Engine, Gear, & Tire calculator

 

[stangman]

did you buy yours new or used??????

 

[highvolts]

did you buy yours new or used??????

Brand Spanking New, 250 Miles on it when I got it.

 

[moreause]

i got a 2002 and i'm running 120 kph or 74,4 mph at 2000 rpm.
and that is with 3.27.
one thing i know is my fifth gear is 0.62 but if you try all those program it end with 0.68. I ask around but i didn't know how come. For what i know at the beginning gt was 0.68 and mach were 0.62.

to get 2500 rmp at 75 i should have 4.1

and i dont know if there a difference between the us and canada who know's ???

if your still not sure then take some real value in each speed
at a fixed rpm
exemple for me
3- 3500 rpm for 100kph
4- 2680 rpm for 100kph
5- 2000 rpm for 100kph

 

[moreause]

hi it's still me but i check on the tremec site and it exist a 3650 with a fifth with 0.74 if i put it in my excel software it give me around 78 mph with 3.27
not that far off.

better check with multiple speed. to make sure how off this sofware is off

i tried the software and i end up with 3.08 differential daw!!!

 

[highvolts]

I put my g-tech pro comp meter in and did a run with that.. I got stockers.. 3.27 exactally after I do some calculations.. i dunno what was wrong with my first numbers... o well .. Thanks guys!

 

[03redfiregt]

thats definetly not right because i'm running about 2000 at 70 with my 3:55s. So something is off.

 

[FallenPhoenix]

according to that, my truck has about 4.50 gears in the rear. I had to pick the tranny closest to mine but it was pretty close.

 

[JOHNS01GT]

Something is definately up, because my 4.10's in fifth are running at about 2500, a little higher.