Folks,

I was wondering how many RPMs my 2.5L/Automatic Ranger is at for 55, 60, and 65 mph. I'm not sure if they offered the tach for the 4 cyl automatics, but figured that some packages had it. Can anyone oblige?? As noted in my signature, I have 4.10 gearing. My transmission is the 4 speed auto with OD.

Thanks,

Kevin

 

There is a program called GearCalc that is a free download. It will give you rpm's at different speeds based on trans. gear ratios, rear axle ratio and tire size. I have found it to be a very useful program to have.

Also, if you go to the FTE tool bar and click on "Articles/Specs" and select "Automotive Calculators" in drop down menu, I think you will find something there also.

 

Thanks MI66. I'll give it a look.

Kev

 

Thanks MI66 - that did the trick!!!

Kevin

 

Who needs a program?
If you know the basic stuff, like axle ratio, final drive (OD X axle ratio) and tire diameter, it's quite simple:
(MPH) X (Final drive) X 336 / (tire OD) = RPM

 

Rogue,

Maybe so, but the program quickly calculates expanded data for all the gears for 5 MPH increments over the calculated topspeed for the vehicle.

Regards,

Kevin

Data for my 2000 Ford Ranger -
Gear Mph per 1000 RPM Mph @5000 RPM Mph @5000 RPM
--------------------------------------------------------
1 7.79 39 39
2 13.09 65 65
3 19.24 96 96
4 25.66 128 128
Mph RPM (in Gears)
----------------------------------------
1 2 3 4
----------------------------------------
5 642 382 260 195
10 1284 764 520 390
15 1925 1146 779 585
20 2567 1528 1039 779
25 3209 1910 1299 974
30 3851 2292 1559 1169
35 4493 2674 1819 1364
40 3056 2079 1559
45 3438 2338 1754
50 3820 2598 1949
55 4202 2858 2144
60 4583 3118 2338
65 4965 3378 2533
70 3638 2728
75 3897 2923
80 4157 3118
85 4417 3313
90 4677 3508
95 4937 3703
100 3897
105 4092
110 4287
115 4482
120 4677
125 4872
Gear Change RPM drop (change @5000) RPM drop (change @5000)
-------------------------------------------------------------
1 -> 2 -2024 (to 2976) -2024 (to 2976)
2 -> 3 -1599 (to 3401) -1599 (to 3401)
3 -> 4 -1250 (to 3750) -1250 (to 3750)

 

Glad to heard that Gear Calc did what you wanted.

 

Yes, thank you. I suppose that it could be validated for accuracy using Wulff's formula, but I'll assume it to be fine. It's interesting to play around with different tire/rearend ratios to see if a wheel/ tire size reduction/increase will hurt or improve your fuel economy.

Kevin