Defender 110 3.5l V8

Hi there,

I am looking at a 1991 Defender 110 3.5l V8 twin carburetor to buy but am slightly concerned about the fuel consumption, from what I have read it seems very high. I intend to use it for safari in Botswana but will also have to use it around town. My knowledge of mechanics is quite basic and am wondering if anyone could shed some light on this "beast" for me.

Much appreciated,

Hi J, welcome to LZ.

Yes they do generally have a high fuel consumption (around 8 to 18mpg) but that can depend on the gear/transfer box ratio, tyres, road conditions and how you drive it.

with disco gearing around 10-12 round town and possibly 22-26 on a motorway type drive, a lot less with standard defender gearing

Hpe you have a very understanding bank manager ...

You should get 12-18mpg AVERAGE. On a run you might get a little better, but unlikely from a twin carb one. If you are getting less than 10mpg for any use, then there is likely something wrong with it.

I often use a factory 3.5 V8 90 and I'll typically see 15mpg from it.

Something like a Tdi for the same use will be a 22-27mpg vehicle, averaging out at around 25mpg. Anyone claiming 30 and above regular average from any Defender is either lying or working it out wrong.

2.5 NA, tuned by me, around the doors 28-30mpg and 34-36mpg on a run!
I tune engines!!
These range from Lister Blackstone, to Gardners, to Perkins, to Mercury, Volvo and some very old Catapillars!
Naturally, I have no idea what I'm talking about!

How much is a gallon of petrol in Botswana?
If prices are low, 15mpg might not be the issue it would be here in the UK.

Needing help n Reg rangey vogue 2.5 bmw engine driving fine yesterday won't start at all this morning . Normally wait for glow plug light to go out turn for bout 5 seconds struggles a little fires up n smokes for 3 seconds then perfectly fine all day after first initial start now won't start at all feel like smashing it up tbh well stressed out

Fat phil said:

Needing help n Reg rangey vogue 2.5 bmw engine driving fine yesterday won't start at all this morning . Normally wait for glow plug light to go out turn for bout 5 seconds struggles a little fires up n smokes for 3 seconds then perfectly fine all day after first initial start now won't start at all feel like smashing it up tbh well stressed out

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Might I humbly suggest that you move this to the Range Rover section, as it a Tratter in disguise, it ain't!?

300bhp/ton said:

Something like a Tdi for the same use will be a 22-27mpg vehicle, averaging out at around 25mpg. Anyone claiming 30 and above regular average from any Defender is either lying or working it out wrong.

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Not really, I filled up my 90 this morning and it came back with 31.5mpg - average over past year is 31.67mpg with a low of 24mpg (towing another Land Rover on a trailer) and a high of 35mpg (wind on my side that day).

Yes I get 30 mpg average from my mildly tuned td5 90.

I work it out every single fill up, and I drive accordingly. I service it very regularly and do a 110 mile commute in it 3 days of the week.

Checked mine yesterday, always fill to brim at same garage and speedo is spot on not 10% out like most
My 200 tdi was returning 26mpg every tank full but after shortening the turbo boost valve rod the last tankful returned 28mpg
I'm going to alter the off boost fuelling next as she smokes a lot on start up and a lot of my driving is urban so at low revs.

Thanks for the tips! I have arranged a viewing with the owner next week.
He says he doesn't know exactly what the consumption is but that it is extremely expensive for him to run.
For me as long as its costing no more than 20/22 Litre/100km then should be fine.

Lightning, petrol is cheap in Botswana, around BWP8/Litre, so 0,80€/Litre.

Retroanaconda said:

Not really, I filled up my 90 this morning and it came back with 31.5mpg - average over past year is 31.67mpg with a low of 24mpg (towing another Land Rover on a trailer) and a high of 35mpg (wind on my side that day).

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With all due respect I don't really believe you.

I'm not saying you can't get 30mpg out of one, but you really do need to drive like Miss Daisy, i.e. never ever put your foot down and in a 90 only cruise at about 50mph. If you do this on fairly level open roads, then ok. If however you know you put your foot down a bit and run at 65mph, then nope, it ain't happening.

But I don't believe 35mpg, sorry. The only way to get that is to miscalculate or use wrong data, such as your odo claiming you've done more miles than you really have. Or you put in less fuel than you think you did.

I only say this, because as a family I think we've owned probably in the region of 30 or 40 different Tdi vehicles. They have been used for all sorts of driving, on different types of terrain and by different types of drivers. Nobody has ever got close to that kind of return, including Land Rover, who never quoted anything even close to 35mpg for a Tdi.


I also like to think I can drive pretty frugally too when required. Have clocked 78mpg from a 1.5d Pug 106, 67mpg from a smart Roadster and 31mpg from a 5.7 V8 Camaro. I've never managed more than 30mpg out of any Tdi 90 I've been in.

About the best I've seen is 33mpg from a Disco 1 300 with the latter aero skirt on the front bumper. That was for full on cruising for most of the tank, about as economical driving as you can get.

BTW - I'm not trying to make this personal, but on forums you occasionally get a couple of people claiming way better mpg than everyone else (and usually a few way lower too). Occam's razor would suggest that the claims of the highest and lowest are most likely erroneous.

However, I'm happy to be proven wrong

300bhp/ton said:

With all due respect I don't really believe you.

I'm not saying you can't get 30mpg out of one, but you really do need to drive like Miss Daisy, i.e. never ever put your foot down and in a 90 only cruise at about 50mph. If you do this on fairly level open roads, then ok. If however you know you put your foot down a bit and run at 65mph, then nope, it ain't happening.

But I don't believe 35mpg, sorry. The only way to get that is to miscalculate or use wrong data, such as your odo claiming you've done more miles than you really have. Or you put in less fuel than you think you did.

I only say this, because as a family I think we've owned probably in the region of 30 or 40 different Tdi vehicles. They have been used for all sorts of driving, on different types of terrain and by different types of drivers. Nobody has ever got close to that kind of return, including Land Rover, who never quoted anything even close to 35mpg for a Tdi.


I also like to think I can drive pretty frugally too when required. Have clocked 78mpg from a 1.5d Pug 106, 67mpg from a smart Roadster and 31mpg from a 5.7 V8 Camaro. I've never managed more than 30mpg out of any Tdi 90 I've been in.

About the best I've seen is 33mpg from a Disco 1 300 with the latter aero skirt on the front bumper. That was for full on cruising for most of the tank, about as economical driving as you can get.

BTW - I'm not trying to make this personal, but on forums you occasionally get a couple of people claiming way better mpg than everyone else (and usually a few way lower too). Occam's razor would suggest that the claims of the highest and lowest are most likely erroneous.

However, I'm happy to be proven wrong

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I do drive like Miss Daisy though!!

300bhp/ton said:

With all due respect I don't really believe you.

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I have data for the last 100,000 odd miles I've driven in my 90, every tank full has been recorded in the app on my phone. It corrects for tyre sizes when given the % error, which I calculate each time the tyres are changed using GPS comparison to the speedo. Yes there is a margin of error in the fuel pumps too but given the hundreds of fill-ups this would balance out. There is also a margin of error when filling up to the same point each time, but again this will balance out over the miles.

The car spends approx. 70% of its time in fifth gear on open country roads doing around 55-60mph, with probably 25% on motorways doing 60-65mph and the small remainder in towns. I do a lot of miles and going 30 miles without changing gear is common on my largely empty A-roads commute. Very little traffic so minimal stop/start nonsense. I don't drive like Miss Daisy and don't hang about, unfortunately because Argyll is full of dawdling idiots as well as HGVs on single carriageway roads I have to do a fair bit of overtaking. However equally I don't hammer the car on the motorway at 75mph as, not only would the fuel economy plummet, it also makes it a far less pleasant place to be.

The upper figure of 35mpg (35.3 is the actuall peak) has only been achieved twice in all those miles, both times with extremely favourable conditions, so is not indicative of what I was claiming. As I said the average over the last year has been 31.67mpg - when I extend that to the nearly four years I have data for it drops to 30.58mpg. This is due to a different driving pattern a couple of years ago resulting in less favourable conditions mpg wise.



I agree with your Occam's Razor hypothesis, however I have the data to back it up and wouldn't make the claim if I didn't believe it. What I would say though, in an attempt to make this slightly less off topic, is that I agree that for the use that the OP is talking about a Tdi will more likely return mpg figures in the mid-high twenties.

I've never achieved 30mpg in my TD5. I get an average of about 26mpg.
On the way to Scotland this year l'm going to try sitting at 60mph and see if that will do it.

So can anyone give any tips on things to look out for when going for a look at this vehicle?
Cheers!