w58 with 3.7

viper92086

New Member
Jan 12, 2006
932
0
0
NJ
hey guys does anyone know how much off my speedo woould be if i got a 3.7 rear diff? i have a w58 trans from my na-t. also those of you with a 3.7, what rpm do you cruise at, say 65mph
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
0
Fullerton,CA
ya in 5th. idk maybe my diff was swapped out and i know my speedo gauge is like 8 mph so was a guess
 

svnmpwr1990

New Member
Feb 9, 2009
47
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0
San Angelo
i have a w58 with 3.73 gears and at 65mph i am at about 2800 rpm although my speedometer is at 59 mph but i noticed that when i roll raced a guy on the highway my speedo said i was going 100 when we started slowing down i only beat him by half a car and he said we were going 125 but i have also heard that in all the mk3 supras the speedo is off by a long shot at those speeds
 

1-2clutch-u

Member
Feb 18, 2006
379
0
16
chi town and ohio
:sarcasm:Gear set: Manually entered values
Gear 1 2 3 4 5 Final
Ratios: 3.285 1.894 1.275 1.000 0.783 3.730

RPM Limit: 6000
RPM @Peak Power: 5500
Tyre Size: 245/50 x 16
Tyre Diameter: 25.65 in
Tyre Circumference: 80.58 in


Gear Mph per 1000 RPM Mph @5500 RPM Mph @6000 RPM
--------------------------------------------------------
1 6.23 34 37
2 10.80 59 65
3 16.05 88 96
4 20.46 113 123
5 26.13 144 157

Mph RPM (in Gears)
-------------------------------------------------
1 2 3 4 5
-------------------------------------------------
5 803 463 312 244 191
10 1606 926 623 489 383
15 2409 1389 935 733 574
20 3211 1852 1246 978 765
25 4014 2314 1558 1222 957
30 4817 2777 1870 1466 1148
35 5620 3240 2181 1711 1340
40 3703 2493 1955 1531
45 4166 2805 2200 1722
50 4629 3116 2444 1914
55 5092 3428 2688 2105
60 5555 3739 2933 2296
65 4051 3177 2488
70 4363 3422 2679
75 4674 3666 2871
80 4986 3910 3062
85 5297 4155 3253
90 5609 4399 3445
95 5921 4644 3636
100 4888 3827
105 5132 4019
110 5377 4210
115 5621 4401
120 5866 4593
125 4784
130 4976
135 5167
140 5358
145 5550
150 5741
155 5932

Gear Change RPM drop (change @5500) RPM drop (change @6000)
-------------------------------------------------------------
1 -> 2 -2329 (to 3171) -2541 (to 3459)
2 -> 3 -1798 (to 3702) -1961 (to 4039)
3 -> 4 -1186 (to 4314) -1294 (to 4706)
4 -> 5 -1194 (to 4306) -1302 (to 4698)
 

viper92086

New Member
Jan 12, 2006
932
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NJ
1-2clutch-u;1266376 said:
i know its hard to read but i cant format it any diffrently unless u want me to email u the file.

email me the file if u can, i'd like to hold onto the spreadsheet. i pmed you my email
 

cjsupra90

previously chris90na-t
Jun 11, 2005
1,029
0
0
48
Lakeland, FL
Everyone here has talked about speed, RPM and gearing.... But not a single person has mentioned tire size and even a small diameter change in tire size can have a noticable effect on true speed.

Just so you know, changing from a 4.30 to a 3.73 rear is a 15% change. So being that you went to a higher ratio, add 15% to your speedos speed to find out what your current speed is... Obviously this is only as accurate as your speedo is...

Below is a Excel spreed sheet program I wrote a while back. Its kinda 2 in 1 so to speak. The first section allows you to pick one particular operating point. The secton section allows you to pic a range. It has both MPH and Kph. Variables in BLUE are changable. RED is your outcome based on your inputs.. Enjoy.....

EDIT: The Trans ratio's that are in the excel spread when you open it are not a Toyota trans so you will need to change them (they are changable)
Here are the ratio's for the V160, R154, and W58
Transmission| V160| R154| W58|
1st Gear|3.827|3.251|3.285
2nd Gear|2.360|1.955|1.894
3rd Gear|1.685|1.310|1.275
4th Gear|1.312|1.00|1.00
5th Gear|1.00|.753|.783
6th Gear|.793|XX|XX
 

Attachments

  • SPEED CALC.xls
    28.5 KB · Views: 5
Last edited:

SupraClaou

Supramania Contributor
Sep 1, 2006
846
4
18
Athens,Greece
cjsupra90;1266929 said:
Everyone here has talked about speed, RPM and gearing.... But not a single person has mentioned tire size and even a small diameter change in tire size can have a noticable effect on true speed.

Just so you know, changing from a 4.30 to a 3.73 rear is a 15% change. So being that you went to a higher ratio, add 15% to your speedos speed to find out what your current speed is... Obviously this is only as accurate as your speedo is...

Below is a Excel spreed sheet program I wrote a while back. Its kinda 2 in 1 so to speak. The first section allows you to pick one particular operating point. The secton section allows you to pic a range. It has both MPH and Kph. Variables in BLUE are changable. RED is your outcome based on your inputs.. Enjoy.....

EDIT: The Trans ratio's that are in the excel spread when you open it are not a Toyota trans so you will need to change them (they are changable)
Here are the ratio's for the V160, R154, and W58
Transmission| V160| R154| W58|
1st Gear|3.827|3.251|3.285
2nd Gear|2.360|1.955|1.894
3rd Gear|1.685|1.310|1.275
4th Gear|1.312|1.00|1.00
5th Gear|1.00|.753|.783
6th Gear|.793|XX|XX

Nice chart! Are these speeds (Mp/h or Km/h) ...car's speedometer numbers
or true gps numbers?
Cause if they are true (gps) numbers,than we are talking about 15-20 km/h
more on the speedometer (gauge) :biglaugh:
 

cjsupra90

previously chris90na-t
Jun 11, 2005
1,029
0
0
48
Lakeland, FL
SupraClaou;1267000 said:
Nice chart! Are these speeds (Mp/h or Km/h) ...car's speedometer numbers
or true gps numbers?
Cause if they are true (gps) numbers,than we are talking about 15-20 km/h
more on the speedometer (gauge) :biglaugh:

Im assuming that you are refering to the actual excel file and not the chart table in the actaul post???

If so, the calculated numbers (and whats shown in the graphs) of the excel file are actual true road speeds +/- probably 1mph (1.6km/h) due to tire pressure and swell because of speed.... If you compare it to a GPS, the numbers might be off while driving due to tire pressure and swell and also due to Tachometer inaccuracy's... If the tach is accurate then the car should be within the above noted +/- 1mph (1.6km/h) of a GPS reading.
 

cjsupra90

previously chris90na-t
Jun 11, 2005
1,029
0
0
48
Lakeland, FL
SupraClaou;1267000 said:
Nice chart! Are these speeds (Mp/h or Km/h) ...car's speedometer numbers
or true gps numbers?
Cause if they are true (gps) numbers,than we are talking about 15-20 km/h
more on the speedometer (gauge) :biglaugh:

Just incase you are refering to the chart in my post, that is just a chart of the trans gear ratio's for the 3 common toyota tranny's. I posted that so anyone who downloads the excel file I attached can insert the accurate gear ratio's cause the ones that are in the file are not for any of those tranny's.