Shift points question

[nizzo]

I looked it up and the sticky for 3.73 gears has all broken links for me, and the sticky for 4.10 gears asks me for a username and passwords and i don't have one (i tried nizzo and my pass of course).

I was wondering if someone could tell me what the shift points are (speeds for each gear) with 3.72 gears.

here are my current shift points approx(i dont push it to the limit lol)

1st: 30-35 at 6k rpm (all will be at this rpm)
2nd: 58-60
3rd: 90 almost exactly
4th: 110-120 (dont usually hit these kind of speeds, maybe 3 times EVER)
5th: No clue lol got the car up at 150 one time, at close to 5500 rpm, had a little left too

If i uploaded a video of the shifting 1-90 that might help, ill try to do that but my buddy is mad shaky on the camera so it may come out bad lol

 

[nizzo]

hmm, everyone talks about how much kick their 3.73s have.

no one has them now?

 

[Stan Weiss]

4.10 rear gear - stock 245-45-17 tires

trans
gear        5750       6000    RPM
3.37       31.8       33.2      MPH
1.99       53.9       56.2
1.33       80.6       84.1
1.00       107.2      111.9
0.67       160        166.9

 

[BlownStangGT]

You shift your car according to how fast you are going......I am confused

 

[bhuff30]

Yup, definately watch the tach instead of the speedo. You'll want to wind 1st out a bit longer than the other gears because the jump to 2nd is steeper.

On another note, it's interesting that I shift my stock 3.27 geared NPI at about the same speeds, but 5000 rpm instead of 6000. 1-2 is around 33mph, 2-3 around 58 and the 3-4 around 110mph.

 

[crazystang25]

well thats with stock 3.27's not 3.73's or 4.10's

 

[nizzo]

You shift your car according to how fast you are going......I am confused

At this Point it time, i do not know what gears are in my car, i bought it with gears but was never told what it had because the dealership was unaware that the car even had gears at all.

I am giving the speeds to see if anyone on here shifts at the same time so they can tell me what gears they have and thus i would know what gears i have.

I had a 2002 mustang gt before this 2001 and the shift times on this car are way different than the 02.

 

[BlownStangGT]

At this Point it time, i do not know what gears are in my car, i bought it with gears but was never told what it had because the dealership was unaware that the car even had gears at all.

I am giving the speeds to see if anyone on here shifts at the same time so they can tell me what gears they have and thus i would know what gears i have.

I had a 2002 mustang gt before this 2001 and the shift times on this car are way different than the 02.

Do you think they are aftermarket such as 4.10 or 3.73 or stock? If stock you can look at the door sticker, if aftermarket you can jack the car up and count the times the tire rotates compared to the driveshaft, I forget the formula, but its on here somewhere

 

[Midnight2V]

Here is the deal, you need to block the front tires, jack up the back end with the car in neutral, and put a couple of jackstands under the car. Once that is done, crawl under and rotate the drive shaft until you complete EXACTLY one turn of the rear wheels. Mark both the wheels and the drive shaft with chalk so you can do it properly. if the driveshaft turns approximately 3 and one quarter turns, you have 3.27 gears, if it turns approximately three and one half, you have 3.55......you get the idea.

There is a reason you MUST do this. You cannot rely on the word of a dealer or the former owner that they calibrated the speedo or actually installed gears. You need to determine this for yourself.

The 1999 and up cars are electrically driven off of engine RPM. In order to calibrate the speedo, you need to use a hand tuner and take into account both your newly established rear gear ratio along with your tire size. if for no other reason do this to avoid the PITA of figuring out in your head how fast you are actually going.

The way your speedo reads right now is set for 3.27 gears, which are stock. This tells me this.......Either you have stock gears and somebody lied to you, or you have aftermarket gears and your speedo has not been recalibrated.

Assuming you have an otherwise stock vehicle, gears alone will not make a crucial difference in shift points so much as the way you launch your car. If this is the case you should shift right about 5600 RPM. Naturally if you have more mods than just the gears, this will change. If you would like you can tell me your mods and maybe I can help you out.

Also, as others have already pointed out you should always shift according to engine RPM, not speedo. Your tach will give your much more precision than your speedo. It is also much safer because in any given speedometer setup, there is an inherent lag that you simply can't get around. It isn't much but it is there.

I hope this helps, if you need any info or opinions, i have plenty of both

 

[nizzo]

Here is the deal, you need to block the front tires, jack up the back end with the car in neutral, and put a couple of jackstands under the car. Once that is done, crawl under and rotate the drive shaft until you complete EXACTLY one turn of the rear wheels. Mark both the wheels and the drive shaft with chalk so you can do it properly. if the driveshaft turns approximately 3 and one quarter turns, you have 3.27 gears, if it turns approximately three and one half, you have 3.55......you get the idea.

There is a reason you MUST do this. You cannot rely on the word of a dealer or the former owner that they calibrated the speedo or actually installed gears. You need to determine this for yourself.

The 1999 and up cars are electrically driven off of engine RPM. In order to calibrate the speedo, you need to use a hand tuner and take into account both your newly established rear gear ratio along with your tire size. if for no other reason do this to avoid the PITA of figuring out in your head how fast you are actually going.

The way your speedo reads right now is set for 3.27 gears, which are stock. This tells me this.......Either you have stock gears and somebody lied to you, or you have aftermarket gears and your speedo has not been recalibrated.

Assuming you have an otherwise stock vehicle, gears alone will not make a crucial difference in shift points so much as the way you launch your car. If this is the case you should shift right about 5600 RPM. Naturally if you have more mods than just the gears, this will change. If you would like you can tell me your mods and maybe I can help you out.

Also, as others have already pointed out you should always shift according to engine RPM, not speedo. Your tach will give your much more precision than your speedo. It is also much safer because in any given speedometer setup, there is an inherent lag that you simply can't get around. It isn't much but it is there.

I hope this helps, if you need any info or opinions, i have plenty of both

Lol i dont have down syndrome guys, i dont shift based on speed The car is a 2001 mustang gt coupe, Mods are flowmaster cat back and MAC O/R X pipe K&N CAI im running 245-45r17 tires on bullit deep dish 17's (obv 17's) my spedometer is between 3 and 4 miles per hour off but the car comes standard with 17" wheels/tires i think the car may have gears in it because my shift points are pretty low and i had a 2002 gt convertable and the shift points aren't at all the same (almost blew the motor first day i had it downshifting to 2nd not knowing 55-58 is 6k rpms in second)

Im almost positive the car has some sort of gears in it, i will jack it up today and scope out whats going on with the rotation to driveshaft turnage.

 

[Stan Weiss]

stock 245-45-17

trans (2nd)
gear           RPM
1.99    5750       6000    Rear 
        53.9       56.2    4.10
        56.6       59.1    3.90
        59.2       61.8    3.73
        62.2       64.9    3.55
        67.5       70.5    3.27

I have some Interactive JavaScript calculator on my web site -- http://users.erols.com/srweiss/index.html#jcalc
Calculate Speed (MPH - Km/H) given RPM, Rear Gear Ratio and Trans Gear Ratio
use 25.68 as tire diameter