Anyone run an overdrive on their TD5 Defender?

[dhumphri]

Just wondering if anyone has fitted an overdrive unit to their TD5 Defender and if so what their experiences have been purchasing, installing, operating and maintaining it.
Thks Darren

[TuffRR]

Not sure why you would want an overdrive for a 5 speed TD5, or if anyone actually makes one.

I guess if you wanted to reduce rpm in high range you could fit a LT230 out of a discovery instead which has a 1.2:1 high as opposed to 1.4:1.

[BigJon]

They are available, or at least they used to be. I was reading an article about them only a few days ago. The magazine was a couple of years old though. I will try to dig it up and get some details.

[noddy]

GKN make an overdrive for the R380 (from what I understand it is more like a splitter). They are bloody expensive (think ~$3,000).

Bruce Davis Performance Landys in Sydney does fit them.

Apparently excellent for getting even better economy, but at $3,000 that is a hell of a lot of Kms to do before you were in the black. 8O

[noddy]

Here is some information on the GKN:

http://www.devon4x4.com/products/25/Overdr...5/GKN+Overdrive (http://www.devon4x4.com/products/25/Overdrive/295/GKN+Overdrive)

Just google 'GKN Overdrive and Land Rover' and you will get a stack of hits.

GKN I think are also the manufacturer of the diffs and driveline for the D3, so I presume they make good gear.

[Omaroo]

The GKN unit is $4,000 fitted. They are a ripper though, and cabin noise at 110kmh is far less intrusive. Reputed fuel economy at that speed for hours on end is around 7.5L/100km from a Td5 Defender.

[noddy]

Originally posted by Omaroo
The GKN unit is $4,000 fitted. They are a ripper though, and cabin noise at 110kmh is far less intrusive. Reputed fuel economy at that speed for hours on end is around 7.5L/100km from a Td5 Defender.

Just buy a 4 speed ZF instead https://www.aulro.com/afvb/

[dages]

Given Omaroo's figures, and that I get 10l/100km out of my Td5 Fender, that means it would take 123,000km to break even with fuel at $1.30p/L.

Then again you may extend your engine life by operating at lower kms, although this is my non educated stab at engine wear logic.

[tombraider]

However, being able to hear yourself think, hold a conversation and answer a mobile phone would be big pluses in my mind...

And give my TD5 runs 15l/100km its only 53 tank fulls for me to break even.

About 6 months :wink:

Cheers
Mike

[tombraider]

Fit some 36's change diffs to 4.11 will give a fender better acceleration.

Then fit the overdrive and highway cruise 110km sub 2400rpm....

beautiful https://www.aulro.com/afvb/

Cheers
Mike

[dhumphri]

Man $4000.00 is a bit rich - they are only $799 + vat in the UK - would think it would be cheaper to have one shipped here and fit it up at home if not too difficult a task - would love to be able to happily cruise at 110/120 without the deafening roar plus the improved economy - might contact devon4x4 in the UK and get costings for shipping.

Do you guys think this would make the drivetrain any less reliable??

[tombraider]

Get price on 2 units and shipping on 2 units :wink:
We may be able to pool resources and save a few $$$

Cheers
Mike

[disconut]

Originally posted by tombraider
Get price on 2 units and shipping on 2 units :wink:
We may be able to pool resources and save a few $$$

Cheers
Mike

Try this ratio upgrade instead.
http://www.ashcroft-transmissions.co.uk/ca...category_4.html (http://www.ashcroft-transmissions.co.uk/category_4.html)

If your TD5 90/110 or Tdi revs excessively on the motorway we are able to raise your transfer case gearing by 15%, by replacing the gearing in the existing 1.410 ratio transfer box with new genuine Q (quiet) gears, as used in the Disco II. This will not only reduce your revs but also reduce noise. This change will not effect Low Range and will leave your Speedo reading true. .

Gear Set only £225 new outright

Trev.

[Omaroo]

Originally posted by dhumphri
Man $4000.00 is a bit rich - they are only $799 + vat in the UK - would think it would be cheaper to have one shipped here and fit it up at home if not too difficult a task - would love to be able to happily cruise at 110/120 without the deafening roar plus the improved economy - might contact devon4x4 in the UK and get costings for shipping.

Do you guys think this would make the drivetrain any less reliable??

Are you confusing the Fairey O/D for Series machines with the GKN unit? $799 does not sound right. 800 quid does, and in our money that's still AU$1,980 or thereabouts. Have it shipped here, add import duty and then have it fitted properly. You won't be far off the $4k.

[noddy]

<div class='quotetop'>QUOTE</div><div class='quotemain'>And give my TD5 runs 15l/100km[/b][/quote]

Why are you getting such poor economy?

[tombraider]

Originally posted by Noddy
<div class='quotetop'>QUOTE</div><div class='quotemain'>And give my TD5 runs 15l/100km

Why are you getting such poor economy?[/b][/quote]

Seen the vehicle....?

Lots of power to spin those tyres, push the rack through the air, weights over 2500kg empty nowadays....

Cheers
Mike

[noddy]

Howdy Tombraider -- I cannot say I have seen your vehicle. But how much power are we talking about?

On our recent trip, 'Kimba' fully loaded with trailer was probably close to 4 tonne. With the remapped ECU (135Kw), aircon on we averaged 13l/100km (just over 14l/100km was our absolute worse (sand).

Is the 15/100km around town/highway/or soft sand? 8O

[tombraider]

15l/100km is about it everywhere.....

I'm chipped to 190kw with my own intercooler running 12.5" wide rubber on 10" rims, the fronts cut a fair bit so the tyres cop the full brunt of airflow and she feels this over 100km/h rather substantially.

Going to reprogram her in next 2 weeks for a more torque less power/less fuel chip on the spare ECU and see what happens.

Cheers
Mike

[noddy]

8O

Do you run an EGT? What temps are you putting out?

[JDNSW]

I would be very surprised if overdrive on a diesel had a significant effect on fuel economy without your changing driving style. Let's look at it objectively. You fit an overdrive, and it reduces the engine rpm at cruising speed. It does nothing for the amount of power required - this is the same.

And unlike petrol engines, the specific fuel consumption of diesels changes very little with the rpm or throttle opening, although I have not found a curve for the TD5. The only time that a diesel uses significantly more fuel per horsepower is when they are overfuelling to get the last few horsepower for that rpm - but this does not happen with modern diesels like the TD5. OK, losses such as from the fan are higher at higher rpm, but the differences are small and in any case minimised with the TD5.

Certainly it will make cruising more comfortable and quieter, and it should extend engine life. Also gives you another five gears to play with - although you need to check whether the GKN overdrive will stand the lower gears - I know the Fairey one won't.

But don't expect to get a payback on your fuel bill. You could save more on that by knocking 10% off your cruising speed or leaving the roofrack at home or checking the tyre pressure.

[Omaroo]

Originally posted by JDNSW
I would be very surprised if overdrive on a diesel had a significant effect on fuel economy without your changing driving style. Let's look at it objectively. You fit an overdrive, and it reduces the engine rpm at cruising speed. It does nothing for the amount of power required - this is the same.

Having spoken directly to a bloke who has fitted the GKN unit to his 90 Td5 - this is absolutely the case. He's consistently getting mid 8's on his way between Sydney and Melbourne every week. I understand where you are trying to go with this and I also understand the basic difference between a modern diesel's consumption and a petrol's - but his wallet is apparently telling the story. He used to average just over 10L/100km on the same trip.... week in, week out. He is trying to maintain the same road speed in his comparisons - well... as much as the absence of cruise control will allow. He is not approaching it in a really scientific manner such as running it on a dyno for an extended series of tests - but is rather doing the distance and filling to the top (as we all do) to see what his consumption was. Maybe the difference in fan spped is more significant than you reckon. I know mine holds me back after a high-speed run - where I try to accelerate back to cruising speed I can hear the fan wailing loudly as the clutch forces it to spin at engine speed for a while.

B. Davis does indicate that fuel consumption drops - and I'm not sure that reputations are easily kept in Australia if you outright lie about your product as the average Aussie psyche loves to see people cut down over small things.... so people like this have to be careful in what they promise. I'm not trying to defend him in any way - I don't have any personal interest in his company, but unless anyone knows any different through personal experience I have to believe him.

[dhumphri]

Omaroo here is the text from the website re price of the unit:

GKN Land Rover Overdive for a limited period is available for £799 plus vat,[whilst stocks last] we would be please to fit the Overdrive for you in our workshops - please call for price, curtosey vehicle available whilst your fitment takes place.
Place you order now, whilst we have stock 01769 550900

From www.devon4x4.com, am pretty sure this is the right unit.
Thats $1938.00 plus shipping plus import duty (import duty and shipping surely are not worth $2000.00??) - am fairly sure fitting these units up is also not too difficult.

If the economy improved that would be a bonus - intend to do a lot of touring in the vehicle and would like to be able to do so without the engine screaming its head off - if this can be achived with the gearset mod mentioned I may follow this route.

[noddy]

<div class='quotetop'>QUOTE</div><div class='quotemain'>The only time that a diesel uses significantly more fuel per horsepower is when they are overfuelling to get the last few horsepower for that rpm - but this does not happen with modern diesels like the TD5.[/b][/quote]

I think this exactly explains Tombraider's 15l/100km with his remapped ECU. It is why I am also interested in the EGTs from any overfuelling.

But you would have to think that a considerable drop in cruising rpm (and therefore fueling) would also have a big impact on consumption. :?

<div class='quotetop'>QUOTE</div><div class='quotemain'>intend to do a lot of touring in the vehicle and would like to be able to do so without the engine screaming its head off - if this can be achived with the gearset mod mentioned I may follow this route.[/b][/quote]

Might be worth also considering a noise deadening kit. Pretty sure some people here have invested in them. Might be worth dropping a PM to 'rmp'.

[Tusker]

I've just had the 1.2Q gears fitted. Haven't been far on the open road yet to determine any difference in consumption.

But it is so much quieter its not funny. Instantly noticable. Well worth it.

Regards
Max P

[Omaroo]

Originally posted by dhumphri
Omaroo here is the text from the website re price of the unit:

GKN Land Rover Overdive for a limited period is available for £799 plus vat,[whilst stocks last] we would be please to fit the Overdrive for you in our workshops - please call for price, curtosey vehicle available whilst your fitment takes place.
Place you order now, whilst we have stock 01769 550900

From www.devon4x4.com, am pretty sure this is the right unit.
Thats $1938.00 plus shipping plus import duty (import duty and shipping surely are not worth $2000.00??) - am fairly sure fitting these units up is also not too difficult.

If the economy improved that would be a bonus - intend to do a lot of touring in the vehicle and would like to be able to do so without the engine screaming its head off - if this can be achived with the gearset mod mentioned I may follow this route.

AU$2,287 including VAT. Would we need to pay that if we are having it exported?

[noddy]

You should not have to pay VAT, but the boys at Customs might want to hit you with a duty as it comes in. :wink: I think anything over $800 is meant to be dutyable??? :?

[dhumphri]

Tusker where did you source the transfer case gears and how expensive was the whole job if you don't mind me asking. Daz

[JDNSW]

A secondary effect that I did not consider is that unless you change down, the overdrive effectively limits the available power (and hence fuel consumption), although the effect of this will be very dependent on road conditions. For example, on the Newell Highway (straight and flat) I would expect no effect, whereas on the New England (hilly and bendy), a lot.
Most drivers would not bother to change down, but would put up with slower acceleration out of curves and accept slowing a bit on hills rather than change down.

My comment about modern diesels not overfuelling does not necessarily apply to one with remapped engine controls, although in most cases they will also have increased boost so specific fuel consumption will not have changed much. But if additional power is there it tends to be used, particularly by those types that go to the expense of doing it in the first place, and this additional power shows up on the fuel bill (and usually on brake wear as well).

[cewilson]

Whilst mine isn't a Td5, it is a 200Tdi, I did a similar thing to it.

The transfer case gears where stuffed after a trip through the Oodnadatta, so I replaced the gears with Maxi-Drive reduction and Disco high-range. I sourced all of the parts from Maxi-Drive costing around $3,200.

It did make a big difference, however up here in the NT I found that my fuel consumption went through the roof. But speeds of up to 140km/h where easily reached. I also did find though, that 5th gear is now definetely only an overdrive gear - it basically has no pulling power at all.

When I relocated it down to Tassie, where the speed limits apply - the fuel consumption was down to around 8.5 - 9 litres per 100km's. That is driven fairly hard in places - as it isn't exactly flat! I really don't use 5th gear that much unless I'm on the highways, as it's a waste of time engagin under 90km/h.

Personally, I'd recommend this course of action over an overdrive unit - because basically you get the best of both worlds. I now have a vehicle that crawls slower than a baby, and one that also cruises quite comfortably, and a lot quieter.


Cheers
Chris

[JDNSW]

Originally posted by Noddy
You should not have to pay VAT, but the boys at Customs might want to hit you with a duty as it comes in. :wink: I think anything over $800 is meant to be dutyable??? :?

You will have to pay import duty not sure what it is these days, probably about 15%, and GST at 10% on the price plus import duty.

You can get away without them for costs below some figure - I have seen the $800, but you won't for the price we are talking about. It may be worth asking a customs agent about bylaw entry - this used to apply for goods not available here, but I don't know if it still applies. And you would still have to pay GST.

[George130]

With the comment about the LT230 and ZF 4 speed thats what I have with a lower ration low range and custom torque converter. I'm getting 11.4l/100km. My daily commut is 150km. I have been offered a 5 speed ZF but need to know about the hassles of fitting and also the ECU issues.

Bassed on the 7l/100km it would take my just under 2 years to save the $4000.