Changing drive ratios

I've been contemplating using a 1:1 in an LT230 instead of the standard 1:1.2 so that cruising speeds are at a more sensible rpm. The car doesn't offroad and there is no need for super low gearing and the engine will be better suited to this sort of set up.

However, if I use the borg Warner TC it isn't possible to change the ratio as I understand? So then I'd be looking at doing so via the diffs.

What are the standard figures for the diffs in 3.9s? And what options are there in the market place? Most seem to be focusses on going the opposite way to where I want to go for obvious reasons.

As far as i am aware diffs are standard at 3.54 to 1. I know you can get lower diffs but not sure there are any higher ratio ones around. Have a look here or give them a bell. Ashcroft Transmissions

Thanks. I'm pretty sure Dave just offers a 4.1 and a 4.7 option so heading in the wrong direction. Obviously the most common demand is to compensate for bigger tyres etc so it isn't likely many want to go the way I am.

The LT230 1:1 change is perfect as a 20% drop is just about spot on but it would be good to find a similar solution when using the Borg Warner as I think that's a nicer TC for road use.

Does anyone have any knowledge Re this solution:

KAM528 – For Long Nose Differentials | KAM Differentials

Horse_Apple said:

Thanks. I'm pretty sure Dave just offers a 4.1 and a 4.7 option so heading in the wrong direction. Obviously the most common demand is to compensate for bigger tyres etc so it isn't likely many want to go the way I am.

The LT230 1:1 change is perfect as a 20% drop is just about spot on but it would be good to find a similar solution when using the Borg Warner as I think that's a nicer TC for road use.

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Think you may have to settle for what you have then.

Not sure why you'd want to kill the performance and likely ruin the mpg figure further with over tall gearing. If all you want to do is go slower everywhere get a diesel. V8's should be driven.

That said, the easiest solution is just fit taller tyres. On the right rims some 7.50's will probably fit and could be just under 32" tall. Difference probably won't be massive though.

I believe early 3 speed auto RR's used the 1:1 transfer box. Not sure it'll mate up on your setup though and they are like hens teeth.

Thanks. The 1:1 is just a cog you can buy from Ashcrofts and fit to the LT230.

Increasing tyre size won't work because of the limited availability of road tyres with the right ratings in larger than standard dimensions. The market caters more for offroading in that arena.

A change of 20% won't kill performance or MPG. Quite the opposite as it won't be a standard engine and sitting at a cruising speed of 2500 rpm will be better than 3000 with the OEM setup.

The key here is that my cars are strictly road cars so have no need to comprise their setup for what they were originally intended and cruising at 3000+ rpm isn't needed these days especially when the engine will have around 440 nm of torque from about 2400.

Oh it will blunt performance. Modded engine or not. In fact if modded for more power it makes even less sense to over gear it.

Also most/all auto Rangies don't use the LT230 they use a viscous centre diff (Borg & Beck or something). Hence only having Low, Neutral and High on the transfer shifter rather than centre diff lock as well.

300bhp/ton said:

Not sure why you'd want to kill the performance and likely ruin the mpg figure further with over tall gearing. If all you want to do is go slower everywhere get a diesel. V8's should be driven.

That said, the easiest solution is just fit taller tyres. On the right rims some 7.50's will probably fit and could be just under 32" tall. Difference probably won't be massive though.

I believe early 3 speed auto RR's used the 1:1 transfer box. Not sure it'll mate up on your setup though and they are like hens teeth.

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1.003 t/box was used for chrysler 3 speed auto, and will fit as any lt230 or the classic bw

300bhp/ton said:

Oh it will blunt performance. Modded engine or not. In fact if modded for more power it makes even less sense to over gear it.

Also most/all auto Rangies don't use the LT230 they use a viscous centre diff (Borg & Beck or something). Hence only having Low, Neutral and High on the transfer shifter rather than centre diff lock as well.

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Borg Warner, as per original post. The actual need for high low is irrelevant. Again, as stated in original post, it is a road car.

LT230 is stronger but noisier but has the advantage of having an off the shelf 1:1 option. It was used in plenty of 80s Rangies and much later in the Discos.

The two TC options are interchangeable as far as gearboxes and mounts go and only use different prop shafts.

And a 20% change won't blunt performance. Again, this aspect was covered in an earlier post. It's about choosing the right cam ultimately so that your torque curve matches your gearing. But the final result is that you are not revving the nuts off it just cruising.

jamesmartin said:

1.003 t/box was used for chrysler 3 speed auto, and will fit as any lt230 or the classic bw

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Hi James. Hope all is well.

Are you saying the the BW is adjustable? I was sure there wasn't a simple solution to changing the ratio as there is with the Lt230?

This would obviously be the solution of the case.

Horse_Apple said:

Borg Warner, as per original post. The actual need for high low is irrelevant. Again, as stated in original post, it is a road car.

LT230 is stronger but noisier but has the advantage of having an off the shelf 1:1 option. It was used in plenty of 80s Rangies and much later in the Discos.

The two TC options are interchangeable as far as gearboxes and mounts go and only use different prop shafts.

And a 20% change won't blunt performance. Again, this aspect was covered in an earlier post. It's about choosing the right cam ultimately so that your torque curve matches your gearing. But the final result is that you are not revving the nuts off it just cruising.

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1.003 wasnt used in any production discos, front prop is the only one that differs between lt230 and bw also only rhs mount

jamesmartin said:

1.003 wasnt used in any production discos, front prop is the only one that differs between lt230 and bw also only rhs mount

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Yup. I was referring to the LT230 TC as opposed to the 1:1 ratio. I was just rereading my post and thought it was misleading. They retained the LT230 in the Discos to keep a clear separation between the two products as they took the RR upmarket.

Horse_Apple said:

Yup. I was referring to the LT230 TC as opposed to the 1:1 ratio. I was just rereading my post and thought it was misleading. They retained the LT230 in the Discos to keep a clear separation between the two products as they took the RR upmarket.

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they did ,but that doesnt mean the bw is any stronger its just the vcu that either makes it better or not depending on your point of view

jamesmartin said:

they did ,but that doesnt mean the bw is any stronger its just the vcu that either makes it better or not depending on your point of view

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But I've never said it was stronger! Merely stated that the Disco carried on using the LT when the Rangie changed in the mid/late 80s to the smoother BW that was perceived as a differentiator between the two products and where they were placed in the market.

The LT230 is stronger than the BW but the BW is quieter and smoother. The BW can also take 350 lbft all day long in road use so strong enough for what I want.

The only single issue is whether the 1:2 can be replaced by a 1:1 like with the LT230. I have a faded memory of learning there were no such options for the BW. But your early post read as if there was a 1:1 option so I'm very keen to learn more.

Horse_Apple said:

But I've never said it was stronger! Merely stated that the Disco carried on using the LT when the Rangie changed in the mid/late 80s to the smoother BW that was perceived as a differentiator between the two products and where they were placed in the market.

The LT230 is stronger than the BW but the BW is quieter and smoother. The BW can also take 350 lbft all day long in road use so strong enough for what I want.

The only single issue is whether the 1:2 can be replaced by a 1:1 like with the LT230. I have a faded memory of learning there were no such options for the BW. But your early post read as if there was a 1:1 option so I'm very keen to learn more.

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bw iis one ratio 1.2 , im not sure it is any smother or quieter ,ive fitted plenty in other models ie defender and disco and apart from vcu,it isnt noticeably any different

Horse_Apple said:

Borg Warner, as per original post. The actual need for high low is irrelevant. Again, as stated in original post, it is a road car.

LT230 is stronger but noisier but has the advantage of having an off the shelf 1:1 option. It was used in plenty of 80s Rangies and much later in the Discos.

The two TC options are interchangeable as far as gearboxes and mounts go and only use different prop shafts.

And a 20% change won't blunt performance. Again, this aspect was covered in an earlier post. It's about choosing the right cam ultimately so that your torque curve matches your gearing. But the final result is that you are not revving the nuts off it just cruising.

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A different cam won't change what rpms the engine revs at under cruise.

I know what you are wanting, higher mph per 1000rpm in top. But doing this WILL blunt performance. There is no debate on it.

Maybe you won't care about the drop in performance, but that isn't the same thing as there actually being a drop in performance.

And without being picky, if it's 100% road use and you don't need low range, then one would have to question why a Land Rover at all. You'll simply get a better car & better performance from a regular car. shocking, but the truth.


If you really want to persist with a road only Range Rover, then there are plenty of 3rd party transfer cases that with the right money and motivation could easily be made to fit. And give you what ever gearing you like.

Alternatively, you could look at fitting a different auto box, maybe a newer 6 speed auto. It'd be a lot of work, but you'd probably be able to achieve your higher cruise gearing this way, and still retain the lower gear performance benefits.

But it all comes down to how much £££££ you want to spend and how far you are prepared to move away from a production vehicle specification.

300. I really don't know what you are going on about. Who said cams change rpms!!! That's a farcical observation.

And clearly you are not up to speed on modern auto boxes and how to tune and manage changes via third party TCUs. Trust me, you can get them to talk well enough for street racing but not for what would ever be considered normal driving.

Anyway, thanks for your input but as historically normal it's all missing the point.

300bhp/ton said:

Oh it will blunt performance. Modded engine or not. In fact if modded for more power it makes even less sense to over gear it.

Also most/all auto Rangies don't use the LT230 they use a viscous centre diff (Borg & Beck or something). Hence only having Low, Neutral and High on the transfer shifter rather than centre diff lock as well.

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They use a normal differential, the viscous is the diff lock.