My crazy diff ratio change idea

Henry_b said:

nothing here makes any sense.

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badfluffy said:

as someone who drasticly changed hes drive train (manual box) in a l322 i looked at changing diff ratios, but decided against it as too much work for little gain, several things came from it, the forum was split about doing it ( one member was very against it and another wanted details on how i did it so they could also convert theirs ) all i can say is the only way to know what will truly happen is if someone does it and that may be you, either way id be interested in the results

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RRMaximus said:

I read threads a few months ago about people changing the L322 to a manual gearbox.

I stumbled upon them when I first had my idea and was doing some research online.

I might have seen your thread, did you use an X5 gearbox?

I watched a number of people saying that the people were not allowed to change their car to a manual gearbox, essentially because those people didn't want it for themselves.

There are also threads on here about people putting in coil suspension to remove their air suspension as they were sick of spending days and thousands chasing problems.

In those cases many of the comments told them that it was a dumb idea, offering no facts to support that opinion, rather than giving the person technical advice.

I then searched for coil kits to make this modification and found that there are many kits available online, meaning that it is a relatively common modification.

Plus there are many threads on this forum of people spending days and thousands trying to solve air suspension problems, without success, despite replacing most parts.

So the reason for changing to coil springs was a valid solution to an actual problem.

I have no problem with some people saying that they think that my idea might not work.

I have a problem with people insulting me and patronizing me because they think with 100% certainty that it will not work, when they know of no actual reasons why it will not work.

I hesitated even posting the question here, because of the reaction that I had seen to other people asking similar questions.

As I am not leaving for several months I do not need to try out the idea when someone else may have done it and can give me the results in advance.

What is that saying about smart people learn from their mistakes but even smarter people learn from the mistakes of others?

In fact several people on another forum have given me good indications that it will work.

I do not even have to do it, as it is just an idea at this stage.

For example I could just drive at a lower top speed during the trip.

But I certainly won't be renting a car, selling my car and buying another one, or installing a £3,000 LPG system and larger wheels and tires, as people have suggested.

I do not want to know if it will work, I just want the benefit of having done it, or to not waste my time trying it, if it will definitely not work.

For some people this forums seems to be the center of their life, but not for me.

I just want to enjoy my trip.

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RRMaximus said:

I read threads a few months ago about people changing the L322 to a manual gearbox.

I stumbled upon them when I first had my idea and was doing some research online.

I might have seen your thread, did you use an X5 gearbox?

I watched a number of people saying that the people were not allowed to change their car to a manual gearbox, essentially because those people didn't want it for themselves.

There are also threads on here about people putting in coil suspension to remove their air suspension as they were sick of spending days and thousands chasing problems.

In those cases many of the comments told them that it was a dumb idea, offering no facts to support that opinion, rather than giving the person technical advice.

I then searched for coil kits to make this modification and found that there are many kits available online, meaning that it is a relatively common modification.

Plus there are many threads on this forum of people spending days and thousands trying to solve air suspension problems, without success, despite replacing most parts.

So the reason for changing to coil springs was a valid solution to an actual problem.

I have no problem with some people saying that they think that my idea might not work.

I have a problem with people insulting me and patronizing me because they think with 100% certainty that it will not work, when they know of no actual reasons why it will not work.

I hesitated even posting the question here, because of the reaction that I had seen to other people asking similar questions.

As I am not leaving for several months I do not need to try out the idea when someone else may have done it and can give me the results in advance.

What is that saying about smart people learn from their mistakes but even smarter people learn from the mistakes of others?

In fact several people on another forum have given me good indications that it will work.

I do not even have to do it, as it is just an idea at this stage.

For example I could just drive at a lower top speed during the trip.

But I certainly won't be renting a car, selling my car and buying another one, or installing a £3,000 LPG system and larger wheels and tires, as people have suggested.

I do not want to know if it will work, I just want the benefit of having done it, or to not waste my time trying it, if it will definitely not work.

For some people this forums seems to be the center of their life, but not for me.

I just want to enjoy my trip.

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Datatek said:

The OP doesn't understand the equation:- taller gearing = lower revs = more torque needed = more load on the engine.
Even if the electronics do not throw a wobbly and he can get it into top gear with the torque convertor locked, it will be like constantly driving up an incline.

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RRMaximus said:

You are talking about a situation where a car is accelerating in a higher gear than the optimal gear, requiring more torque.

When driving at a constant speed on the highway for several hours this will not be the situation I will be facing (as I explained I will be doing in my initial question and multiple times since then).

At a constant speed engine torque is needed to overcome engine friction, air resistance and rolling resistance, which do not change based on the gearing, only the speed of the car.

The optimum situation perfectly balances engine RPM, torque and fuel consumption and is not always available as gearboxes give steps of efficiency not a perfect line.

A variable ratio gearbox is the only gearbox that can always achieve this perfect situation.

More torque uses more fuel, and yet running at a higher gearing ratio for the same speed uses less fuel, hence we have overdrive gears and higher final ratios in more modern cars.

So I will simultaneously be using less fuel, at a lower RPM while creating more torque?

If you know how to do that then patent the idea because your idea will be worth billions.

A torque curve shows the torque for every given engine RPM but you believe that at a lower RPM my engine will magically produce more torque?

You have not seen the torque curve for my engine which I have posted here before?

When I was young my father had a car with "three on the tree" which means it had a three speed manual gearbox with the gear shifter on the steering column.

My first car came with a four speed gearbox.

My L322 Range Rover has a five speed gearbox but later models had a six speed gearbox and then an eight speed gearbox.

This increase in number of gears is to help achieve the optimum balance of factors.

My 5 speed gearbox was not optimized just driving at highway speeds.

My 5 speed gearbox was optimized for multiple uses from city driving, towing, accelerating quickly, and highway driving.

If I was planning on using my car for a wide range of uses then I would never be considering this modification.

But there is nothing from an engineering sense that I have been told by anyone here that invalidates me modifying my car to be better for a specific unusual use case.

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RRMaximus said:

You are talking about a situation where a car is accelerating in a higher gear than the optimal gear, requiring more torque.

When driving at a constant speed on the highway for several hours this will not be the situation I will be facing (as I explained I will be doing in my initial question and multiple times since then).

At a constant speed engine torque is needed to overcome engine friction, air resistance and rolling resistance, which do not change based on the gearing, only the speed of the car.

The optimum situation perfectly balances engine RPM, torque and fuel consumption and is not always available as gearboxes give steps of efficiency not a perfect line.

A variable ratio gearbox is the only gearbox that can always achieve this perfect situation.

More torque uses more fuel, and yet running at a higher gearing ratio for the same speed uses less fuel, hence we have overdrive gears and higher final ratios in more modern cars.

So I will simultaneously be using less fuel, at a lower RPM while creating more torque?

If you know how to do that then patent the idea because your idea will be worth billions.

A torque curve shows the torque for every given engine RPM but you believe that at a lower RPM my engine will magically produce more torque?

You have not seen the torque curve for my engine which I have posted here before?

When I was young my father had a car with "three on the tree" which means it had a three speed manual gearbox with the gear shifter on the steering column.

My first car came with a four speed gearbox.

My L322 Range Rover has a five speed gearbox but later models had a six speed gearbox and then an eight speed gearbox.

This increase in number of gears is to help achieve the optimum balance of factors.

My 5 speed gearbox was not optimized just driving at highway speeds.

My 5 speed gearbox was optimized for multiple uses from city driving, towing, accelerating quickly, and highway driving.

If I was planning on using my car for a wide range of uses then I would never be considering this modification.

But there is nothing from an engineering sense that I have been told by anyone here that invalidates me modifying my car to be better for a specific unusual use case.

Click to expand...