So I just had to add a new tach to my L60 (AutoMeter) but not sure what I should be seeing. Idle looks right, around 700 RPM, but my first test ride only showed an RPM around 2500 @ 50 mph. I know the ‘spec’ shows 145 hp at 3800 RPM.
I might have a calibration problem but my dip switches are correct for a 6 cyl.
What should be an expected RPM in 3rd, 2 WD at highway speed (55-60 mph)?
Thanks
Dave
RPM Q
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Re: RPM Q
I will post a chart later on with rpm and speed at every gear.
I have a 0-4000 rpm meter on mine, and when you’re in 3rd gear, as a rule of thumb, you double the rpm numbers to get the actual speed.
So 2500 rpm (25x2) do correspond to 50 mph on the speedometer.
Esteban
I have a 0-4000 rpm meter on mine, and when you’re in 3rd gear, as a rule of thumb, you double the rpm numbers to get the actual speed.
So 2500 rpm (25x2) do correspond to 50 mph on the speedometer.
Esteban
Owner of the same Patrol since 1967
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Re: RPM Q
Finally found the numbers for the speed at any rpm that I've done some years ago. The brocures, owners manuals and service manuals, have all varying information.
A 68 Owners Manual has Max. speed at 78 mph. It also mentions 145 HP @ 3800 rpm.
In the Service Manual that we have in the Patrolabilia section (the old Service Manual) there's a drawing of the Rear Axle Assembly showing the diameter of the wheel at 734 to 746 mm (28.9" to 29.37"). I'm using 28.9".
The distance travelled per revolution of the wheel is: (28.9" x 3.1416) = 90.79". This converts to 0.001433 miles per revolution.
Differential ratio is 4.1:1.
So per each revolution of the engine, the wheels travel (0.001433/4.1)= 0.0003496 miles. This is per minute. Per hour will be 60 times that: (0.0003496x60) = 0.020975 miles per hour
So at different rpms of the engine we have the following speeds: 1000 RPM x 0.20975 = 21.0 mph.
RPM ----- MPH
1000 ------ 21.0
1500 ------ 31.5
2000 ------ 41.9
2500 ------ 52.4
3000 ------ 62.9
3500 ------ 73.4
3800 ------ 79.7
So the rule of thumb almost fits. My speedometer has a little error, so sometimes I used the rpms to figure out the speed. And I have compared this with a gps device. Obviously changing to bigger tires can affect the reading, and the speedometer will register lower speeds than the actual ones.
A 68 Owners Manual has Max. speed at 78 mph. It also mentions 145 HP @ 3800 rpm.
In the Service Manual that we have in the Patrolabilia section (the old Service Manual) there's a drawing of the Rear Axle Assembly showing the diameter of the wheel at 734 to 746 mm (28.9" to 29.37"). I'm using 28.9".
The distance travelled per revolution of the wheel is: (28.9" x 3.1416) = 90.79". This converts to 0.001433 miles per revolution.
Differential ratio is 4.1:1.
So per each revolution of the engine, the wheels travel (0.001433/4.1)= 0.0003496 miles. This is per minute. Per hour will be 60 times that: (0.0003496x60) = 0.020975 miles per hour
So at different rpms of the engine we have the following speeds: 1000 RPM x 0.20975 = 21.0 mph.
RPM ----- MPH
1000 ------ 21.0
1500 ------ 31.5
2000 ------ 41.9
2500 ------ 52.4
3000 ------ 62.9
3500 ------ 73.4
3800 ------ 79.7
So the rule of thumb almost fits. My speedometer has a little error, so sometimes I used the rpms to figure out the speed. And I have compared this with a gps device. Obviously changing to bigger tires can affect the reading, and the speedometer will register lower speeds than the actual ones.
Owner of the same Patrol since 1967