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Paddy X350



Member Since: 15 Nov 2023
Location: Wexford
Posts: 34

Ireland 2008 Range Rover Vogue TDV8 Stornoway Grey
Normal rpm for 3.6TDV8 at 70mph?

I'm just getting used to my new to me L322.
As the title says, what rpm would you usually see in a 3.6TDV8 at 70mph on the motorway? All the best
Chris

Post #699845 9th Sep 2024 6:48pm
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RRPhil



Member Since: 22 Aug 2011
Location: Blackburn, Lancashire
Posts: 968

United Kingdom 

Tyre rolling radius (255/55 R19 or 255/50 R20) = 378mm nominally

Final drive ratio = 3.54:1

Transfer box ratio (high range) = 1.0000

6th gear ratio = 0.6911

Therefore, assuming the torque converter lock-up clutch is fully engaged (which it should be) the engine speed at 70mph =

((70*1760*3*12*25.4/60)/(2*PI*378))*3.54*1.0000*0.6911 = 1934rpm

Bear in mind that the speedo will read 3-5% fast.

Phil

Post #699853 10th Sep 2024 12:59am
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Merchy



Member Since: 14 Feb 2021
Location: North Wales
Posts: 1192

United Kingdom 2006 Range Rover Vogue Td6 Zermatt Silver

Reading Paddy X350's post, I thought easy peasy, I will note my RPM at said speed later today and report back, as off the top of my head I have no idea Whistle
THEN I read RRPhil's reply Bow down and despite being a marine engineer I now feel like the village idiot Thud Big Cry

Post #699861 10th Sep 2024 8:04am
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Paddy X350



Member Since: 15 Nov 2023
Location: Wexford
Posts: 34

Ireland 2008 Range Rover Vogue TDV8 Stornoway Grey

Thanks Phil,
Was expecting someone to just have an idea from driving, but of course it can be worked out if you have the skill and knowledge!!
I'm pretty much on the button there, a bit less than 2000rpm at 70
Thought this was a bit high, but I'm used to driving a modern diesel with a 9 speed box... All the best
Chris

Post #699862 10th Sep 2024 8:08am
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JayGee



Member Since: 27 Jul 2021
Location: London
Posts: 3235

United Kingdom 2012 Range Rover Vogue 4.4 V8 Orkney Grey

That does seem uneccessarily high for a big torquey V8. On the later 8 speed 4.4 it's around 1400rpm which likley accounts for the better economy and is a very civilised way to progress at speed. 2012 TDV8 Vogue (L322)

Post #699864 10th Sep 2024 8:34am
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RRPhil



Member Since: 22 Aug 2011
Location: Blackburn, Lancashire
Posts: 968

United Kingdom 

Completely agree. Although the top gear ratio is similar for the 6-speed and the 8-speed (0.691 & 0.667 respectively), the increased ratio spread of the 8-speed (7.05 compared with 6.04) allowed Land Rover to use a much taller axle ratio (2.76:1) in the 4.4 TDV8, producing a top gear ratio of 48mph/1000rpm compared with the 3.6 TDV8 6-speed’s 36mph/1000rpm.

Phil

Post #699868 10th Sep 2024 9:46am
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