LT230 High Range Gearing Change

[alexturner]

Hey guys,

Now that my Suzie is a little closer to being on the road and everything is sorted I would like to tackle my next problem.

My latest trip has really pointed out that the stock Defender really isn't a highway friendly car. Cruising at 100km/h (with 1 tonne) in the back I was copping it hardcore from the Yota's and Pootrols of the group.

I've decided to change my high-range gearing. I've never had any troubles with the 1.4:1 high range, it's never been to high for my liking and the car has always had enough grunt to do what it is i do in high-range.

I'm looking at dropping a 1:1.222 high-range gear in place of the current high-range gear. Is it possible to pick up the gear from LRAutomotive or some place or are more parts required? What are the spacings and tolerances in the box like? Is it possible to change the gear without touching the centre diff. What tools will I need?

Thanks guys,
Alex

[Tombie]

You wont want to tow anything at all heavy once you do...

And if you have cruise control fitted it wont work anymore!

Whats wrong with running 33" tyres and revving at 2600 rpm @ 110km/h

My Defender regularly out held Cruisers and Patrols up long hills... Sure they can top end you, but a Defender at 130km/h isnt too bad either...

I'd suggest you just speed up a bit, then they wont be givin you stick...

The TD5 Defender hardly uses more fuel at that speed - head winds have a greater effect on consumption.

[alexturner]

I'm thinking of swapping my LT230 for a Disco box. I don't tow and never plan on - I'm not the caravanning type. I have heard from people with Disco's that they have no troubles towing with the 1:1.222 gearing. Remember I have a 200Tdi and it was having a really time driving at 100kph with the load. The other cars in my convoy (who had a equal load to me) were well ahead.

[Tombie]

I'm thinking of swapping my LT230 for a Disco box. I don't tow and never plan on - I'm not the caravanning type. I have heard from people with Disco's that they have no troubles towing with the 1:1.222 gearing. Remember I have a 200Tdi and it was having a really time driving at 100kph with the load. The other cars in my convoy (who had a equal load to me) were well ahead.

People with Discos also have wheels a lot smaller :cool:

Instead of updating the gears - throw in a better intercooler, up the fuelling and free up the exhaust...

[awabbit6]

I think you'll find changing TC ratio will make the problem worse.

One of the reasons that I upgraded from a 300Tdi Disco to a Td5 Disco was a lack of power to travel comfortably at 100km/h once fully loaded for a camping trip. I found I was driving with my foot flat to the floor to maintain 100km/h even after giving the injector pump a tweak.

If you are finding similar issues with your Defender, taller gearing isn't going to help.

[alexturner]

I currently have 31"s and I wont be going any bigger than 33"s. I'm not getting rid of my Suzie, so that's out of the question, but I have read that swapping out the transfer case for that of a D1 does help it chug along. The transfer case swap will end up costing me nothing where as a new intercooler will set me back just shy of a buck.

So you think it's not a gearing issue, more of a power issue?

[isuzutoo-eh]

Those yotas and pootrols probably all have engines nearly twice the capacity of yours, and if petrol more power per litre anyway. Its not gearing that allows the Patrols and Toyotas to maintain higher speeds, its oomph. Squeeze more from your tdi and you too can maintain a higher speed.

[isuzurover]

I currently have 31"s and I wont be going any bigger than 33"s. I'm not getting rid of my Suzie, so that's out of the question, but I have read that swapping out the transfer case for that of a D1 does help it chug along. The transfer case swap will end up costing me nothing where as a new intercooler will set me back just shy of a buck.

So you think it's not a gearing issue, more of a power issue?

Taller gearing will make you accelerate (quite a bit) slower. It will also probably give you a lower top speed - unless you have a tail wind!

I own a stock 300Tdi disco with stock small wheels and 1.22 t-case. I also own a 110 with a 4BD1T (so about the same size engine as the cruisers and patrols you were with). The 110 would accelerate 0-100 quite a bit faster than the (lighter) 300tdi - even with a trailer attached!!!

There are several threads on here which explain how to tweak the fuel pump to get more power from 200 and 300 tdis. Just make sure you install an EGT first.

[Casper]

I will quite happilly swap out my Disco Tcase for your Deefa one for free, you won't have to do anything other than to bring it to me, then I may be able to tow my camper at 100kmh up a hill again.:D

Really it's not something you want to do, if your not holding 100kmh then there is something wrong with your engine as I have towed 3 tonne caravans with a 200Tdi deefa and other than being slow off the line due to the weight it towed fine and with just small trailer on the back or just gear it easilly held 100 to 110kmh.

Instead of changing out the tcase gears I would be more inclined to change diff ratios but again, that costs money.

Cheers Casper

[alexturner]

Thanks for all your assistance guys, because I'm a cheapskate here's what I'm going to do:

1) Remove the stock intercooler and centre the radiator in the mount
2) Source a decent intercooler from a Jap car and mount it in front of the Radiator
3) Replace all hoses with silicone hoses
4) Drill and tap a hole in the inlet manifold and screw a barb in the hole, run a hose from the inlet manifold to the waste gate actuator to compensate for the resistance in the new intercooler.
5) Tune the IP

What do we reckon fellow AULROians?

Alex

[isuzutoo-eh]

Unless you have already done it recently, flush your ic out, get everything else in great condition, then work on improvements once you have a 'best stock' baseline to work from. That'd be my plan anyway...

[LowRanger]

Thanks for all your assistance guys, because I'm a cheapskate here's what I'm going to do:

1) Remove the stock intercooler and centre the radiator in the mount
2) Source a decent intercooler from a Jap car and mount it in front of the Radiator
3) Replace all hoses with silicone hoses
4) Drill and tap a hole in the inlet manifold and screw a barb in the hole, run a hose from the inlet manifold to the waste gate actuator to compensate for the resistance in the new intercooler.
5) Tune the IP

What do we reckon fellow AULROians?

Alex

You may regret fitting a front mounted intercooler without fitting a larger radiator.There are plenty of instances where restricting the airflow with a front mounted intercooler has lead to overheating ,particularly in summer

Wayne

[RVR110]

Alex, have you got the radiator fan and temp gauge sorted since that Turon trip?
x2 what Isuzutoo-eh said - get the stock setup in top shape so that you have a solid baseline prior to making mods.

[cewilson]

For some reason my Disco high range gears work well in my 200tdi Defender, and I tow a Trak Shak camper trailer everywhere I go.......

Standard size tyres running MTs. When the wind carries on a treat I can still hold 4th gear at 100km/h comfortably and 5th cruises really nicely.

Only downside is the extra 'riding' of the clutch on hill starts but it's not really that bad. Well I've been doing it since 2005 so I'm probably used to it. Still to replace the clutch since I've owned the vehicle and I have some real serious km's on it.



Mechanical sympathy makes a huge difference!



Cheers
Chris

[goingbush]

Never say Never, I said I'd never drag a Van and I just ordered my 2nd off road van. Anyhow my TD5 Defender has standard Gearing with 235/85R16 tyres and I'm as happy as larry with its towing performance & economy and absolutely craps all over my 100 series Toyota in both respects. I might add I do have a Tombie chip and a free flowing exhaust.

Just got home from a 2500klm trip towing 1.3 tone Jayco Outback Penguin , sitting on 100 /110 kph as applicable & returned 12.5 l/100km and I certainly do not drive for economy. The Toyota gives about 16.5l/100km & no where near the power.

[flagg]

Unless you have already done it recently, flush your ic out, get everything else in great condition, then work on improvements once you have a 'best stock' baseline to work from. That'd be my plan anyway...

^ wise words.

Also look at injectors.. made a huge difference to my old tdi getting them done

[CraigE]

A bit different but when I do my clutch I am going to do similar with my TD5 Defender. I have the transfer case waiting to go. So will se how it goes. However I will not be parting with the Defender trans case in case it does not have any benefit and I can change back.
I find the Defender revs to hard at 110 in stock form, around 2800rpm, if I can bring that back to 2600rpm I will be happy.
It was mentioned that the Disco and Defender run different tyre and wheels sizes. Not sure on that as my Tdi300 Disco, RRC and Defender have all had the same size wheels and tyres as standard.
My advice is go down the complete trans case route, because if you dont like it it is an easy change back and you can on sell the trans case.
The Tdi may struggle a bit, but may be worth a try.

[isuzurover]

...

Not sure on that as my Tdi300 Disco, RRC and Defender have all had the same size wheels and tyres as standard.

...

Impossible.

All defenders have ~31-32" diameter tyres as standard. No disco or RRC has ever come from the factory with tyres that large a diameter. They typically need mods to fit tyres that large!

[CraigE]

Impossible.

All defenders have ~31-32" diameter tyres as standard. No disco or RRC has ever come from the factory with tyres that large a diameter. They typically need mods to fit tyres that large!
I can straight up state that the Defender and RRC tyres & wheels were the same size as I keep the alloys off the RRC for my camper and had the Defender & RRC at the same time. Now I do remember the tyre sizes may have been different as stamped, but rolling diameter they were identical (stood side by side) and I could interchange them as spares. These tyres fitted under the RRC no problem, though it did have a 2" lift. Wether they were standard or the technically correct tyres I do not know for sure. I also had a set of 15" Sunnys for the RRC and even with those the rolling diameter wasonly about 5mm or less difference. After I got rid of the Disco I did keep some tyres that were the same size as the RRC but these were a set of BFG ATs, I think the original Michelins were somewhat smaller rolling diameter, so I had to get 5, but ended up giving the Michelins away aand that may have been why. All 3 were 16" wheels, but may not have had standard size tyres. I just know they were all interchangeable and when laid side by side were same rolling diameter. I do know the ones on the Rangie tyres looked quite tall for a RRC.
What are the standard sizes?

[lambrover]

disco run 29 inch or 235/70/16 from memory. defender run 235/85/16 31 or 32inch.

i run 285/75/16 33 inch. If you can't maintain 100km with the standard gearing than the taller gear ratio will make the engine work harder under the same conditions ie more torque is required to turn taller gears. It sounds like your engine needs a good birthday then mooore boooost:p

mate i will be in sydney in the new year if you can wait, i could help out with a tune.

[CraigE]

Ok I am wrong,
It appears the tyres I am talking about may have been non standard. Just looked at some pics, the original Michelin tyres on the Disco were 235/70R/16 so around 29". The second set on were substantially taller but have not been able to find a pic that I can see the actual size and they did not foul, but I think were 235 or 245 /80. I do remember talking to the Tyre Power guy about fitting slightly larger tyres, but that was 12 odd years ago, but I thought it was in the standard range.
The ones on the Defender 235/85R/16 which we know is standard.
The RRC most likely had a tyre size change well before I bought it and I need to find a pic that shows the tyre size. So obviously not original size. I dont think they were 235/85R/16 but overall were the same diameter, give or take a few mm. Possiblly 245/80R/16 which would mean less than 1/4" difference. Maybe as the RRC ones were 60% worn and the Defender ones new were real close in overall diameter?
Did not know the RRC ones were not standard fit.
Something to watch out for though I suppose.
I know when I did put new tyres on the Disco it changed the fuel economy slightly from 10 or 11 to 9 or 10 litre per 100kmph, maybe due to the increased OD. Can not say I noticed any significant loss of power though.