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Suppliers/Dealers or anyone selling with a commercial view in mind CANNOT post here unless responding to a specific request of a member in a "wanted" post.
Suppliers include people "breaking for spares" on a regular basis, when purchasing spares members should ask a supplier what they contribute to the running of the forum particularly if contacted by a Private Message
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Water and gearing
06 Jan 2024 21:44 #253318
by lightning
Replied by lightning on topic Water and gearing
lf you're needing to drive through that depth of water it might be worth considering something with a higher rated maximum wading depth, such as a Defender
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07 Jan 2024 00:22 #253321
by Busta
Replied by Busta on topic Water and gearing
Torque is irrelevant, it's power that does work and at 2,500rpm (actually it will be 25% lower than that due to the 32" tyres) the engine is at less than half of its maximum power output. You can't shift down a gear from 1st low so reduction gearing is the solution to going quicker through the water.
I'm amused by the comment that a vehicle partly submerged in water is "illegal", presumably suggesting it's overloaded due to the mass of the water inside it? I'd like to see VOSA tackle that one!
I'm amused by the comment that a vehicle partly submerged in water is "illegal", presumably suggesting it's overloaded due to the mass of the water inside it? I'd like to see VOSA tackle that one!
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07 Jan 2024 02:36 #253322
by fordem
There's a contradiction here...
What does "down shifting" a gear do, what does reduction gearing do? They both multiply the torque, that's what gears are for.
Replied by fordem on topic Water and gearing
Torque is irrelevant, it's power that does work and at 2,500rpm (actually it will be 25% lower than that due to the 32" tyres) the engine is at less than half of its maximum power output. You can't shift down a gear from 1st low so reduction gearing is the solution to going quicker through the water.
There's a contradiction here...
What does "down shifting" a gear do, what does reduction gearing do? They both multiply the torque, that's what gears are for.
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07 Jan 2024 04:06 #253323
by Lambert
Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
ADOS Attention Deficit Ooooh Shiny!
Replied by Lambert on topic Water and gearing
Yes an no. Torque is the amount of work that can be done, power is that work being done over time. So by lowering the gearing either by selecting a lower gear which is not possible if you're already in the lowest one in the gearboxes or by proactively installing an entirely different set of lower gears you are able to have the engine work effectively in a rpm range where the available power is higher. There is no contradiction.
As to using a more suitable vehicle for wading I would suggest that partially submerging any vehicle regularly that is not specifically amphibious is going to cause maintenance issues at which point if you are going to be regularly fixing it anyway it doesn't matter what vehicle it is. Though personally if it were that regularly I might consider a boat or hovercraft.
As to using a more suitable vehicle for wading I would suggest that partially submerging any vehicle regularly that is not specifically amphibious is going to cause maintenance issues at which point if you are going to be regularly fixing it anyway it doesn't matter what vehicle it is. Though personally if it were that regularly I might consider a boat or hovercraft.
Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
ADOS Attention Deficit Ooooh Shiny!
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07 Jan 2024 09:40 #253325
by DrRobin
2020 blue SZ5 (one of the last to be registered in the UK)
Ex 2011 Blue Jimny SZ4
Northumberland Jimny Blog
Replied by DrRobin on topic Water and gearing
Torque is how much force there is at the crank, it’s measured in foot pounds.
Power is Torque multiplied by crank speed.
If your engine is providing more torque than is needed to overcome the force then it will accelerate, if not your engine will reach a steady rpm.
To go back to the original question once you reach peak torque the vehicle won’t accelerate any more as the force of the water increases with speed.
However, if the force applied by the water means that you can’t achieve maximum torque (the force of the water as speed increases is greater than the torque that can be generated) then lowering the gearing should help.
Power is Torque multiplied by crank speed.
If your engine is providing more torque than is needed to overcome the force then it will accelerate, if not your engine will reach a steady rpm.
To go back to the original question once you reach peak torque the vehicle won’t accelerate any more as the force of the water increases with speed.
However, if the force applied by the water means that you can’t achieve maximum torque (the force of the water as speed increases is greater than the torque that can be generated) then lowering the gearing should help.
2020 blue SZ5 (one of the last to be registered in the UK)
Ex 2011 Blue Jimny SZ4
Northumberland Jimny Blog
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07 Jan 2024 21:17 #253340
by Busta
Replied by Busta on topic Water and gearing
No contradiction, unless you know of a way to downshift from 1st low.
The question is would lower gearing help the car drive quicker through the water and the answer is yes. Anyone who has ever shifted down a gear in order to accelerate faster should understand this.
It's torque at the wheels that matters, and you can increase that with gear reduction. More reduction means that at the same forward speed the engine will be spinning faster, producing more power and therefore more torque at the wheels.
The question is would lower gearing help the car drive quicker through the water and the answer is yes. Anyone who has ever shifted down a gear in order to accelerate faster should understand this.
It's torque at the wheels that matters, and you can increase that with gear reduction. More reduction means that at the same forward speed the engine will be spinning faster, producing more power and therefore more torque at the wheels.
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