P38A 4.0 mpg when towing car trailer?

Had a look online but can't seem to find much information on mpg figures for towing. I've a 400 mile round trip to collect a classic 4 door and I'll be using my dad's '98 P38 4.0 auto. So I've got 200 miles towing car trailer then 200 miles with the RRC on the trailer. Nearly all motorway, can anyone give me some idea of what mpg i might expect? Was hoping to use my '92 Tdi but needs a few things doing and won't be ready in time.
Thanks

Any number of things will affect the mpg. Just drive, when it runs out fill it up.

9-12 round trip

cooltide said:

9-12 round trip

Click to expand...

oh cr*p!!

rangie1998 said:

oh cr*p!!

Click to expand...

You may do better. Just tuck in behind an artic. My rrc 4.6 used to average 11- 13 doing fencing work. Mixed driving, 12' trailer. Rarely had 2 tonne payload though

Stick around 50 - 60 mph. The drag will be proportional to the square of the speed so a little change in speed makes a big difference. Around 50 mph it should tick over nicely with the torque converter locked. Drive looking well ahead so you don't have to touch the brakes and keep your foot off the floor and you won't do so bad.

cooltide said:

You may do better. Just tuck in behind an artic. My rrc 4.6 used to average 11- 13 doing fencing work. Mixed driving, 12' trailer. Rarely had 2 tonne payload though

Click to expand...

Grrrrrr said:

Stick around 50 - 60 mph. The drag will be proportional to the square of the speed so a little change in speed makes a big difference. Around 50 mph it should tick over nicely with the torque converter locked. Drive looking well ahead so you don't have to touch the brakes and keep your foot off the floor and you won't do so bad.

Click to expand...

Thanks for the replies. I'll certainly be driving it like a nun on her way to church!! Hopefully i can keep the fuel bill under £200. Have had a quote of £250 for car to be transported, thought it was a lot but considering it now!

To be fair, the weight doesn't make a huge difference. It will make some especially over hilly terrain.
The biggest hit is the drag as has been mentioned.
When I towed my trailer to Czech (twin axle 6mtrs long) I actually got better mpg than driving down solo as I drove at 65-70 instead of the usual 80+ on the autobahns.
You might suffer a bit coming back as you'll be presenting a much bigger sail to the wind but as grrrrrr said, it's proportional to the square of the speed so drop 10mph off and you'll make a massive difference.
For what it's worth, on the couple of short caravan tows with the rangy, I was getting about 12 but that was up and down twisty country lanes from the storage. On the same route solo I only get about 15-16mpg so not that much worse.
In August, I've got to bring the caravan home on the rangy, 950 miles so I'm hoping for minimum of 12mpg, 14 would be a big bonus!

I tow a 32" caravan (2200kg) with an S63 AMG. Needs approx 10mpg. (Doing 90mph all the way on the motorway though).

You're buying a classie and conerned about fuel consumption

If mpg is an issue dont buy/use a Range Rover.....it will be eye watering at the best of times...but you dont buy/use them if mpg is a concern.

ukadamwest said:

You're buying a classie and conerned about fuel consumption

Click to expand...

Not concerned with mpg on the classic, I've had a few so i know what they're like! Plus it's more of a project and won't be used all that much.
A rarely use my dad's P38 and the reason for asking about mpg when towing was so that i could consider other options, i.e pay a transport company to collect it. I would rather collect the car in person and seen as i should be able to keep the fuel bill under £200 i think this is going to be the best option. I'll post the mpg figures on here after the trip!!

Saint.V8 said:

If mpg is an issue dont buy/use a Range Rover.....it will be eye watering at the best of times...but you dont buy/use them if mpg is a concern.

Click to expand...

I've had a '71 3.5 on carbs, '87 3.5 EFI, '92 3.9 which i converted to a 200 Tdi and still have, although not quite road worthy at the moment. So i couldn't agree more, don't buy one if mpg is a concern! I just wasn't sure on how much difference towing would make as I've not towed much with the P38.
Speaking of the P38, here's a couple of pics i took the other day, only done 75k miles, full LR service history and my dad's had it 13 years! [GALLERY=] [/GALLERY]

Sounds like you are aware of the mpg issues then.

She looks like a tidy beast....look after them and theyll reward you greatly.

Saint.V8 said:

Sounds like you are aware of the mpg issues then.

She looks like a tidy beast....look after them and theyll reward you greatly.

Click to expand...

Completely agree, the P38 has been both reliable, touch wood! and a pleasure to drive, that's why my parents have had it so long. I suspect I'll have to take it off their hands when they do change it Just running out of space to keep them all!

Is MPG on the L322 4.2 any better?

That's one handsome P38.

allanw said:

That's one handsome P38.

Click to expand...

Thanks, they seem to be getting thin on the ground in this condition. My dad bought it in 2004 from LR main dealer and it's been serviced there every year since, does on average 3k miles a year so mpg not a great concern. Keep looking at changing it but for the amount you'd need to add to it doesn't really seem worth it.

rangie1998 said:

Thanks, they seem to be getting thin on the ground in this condition. My dad bought it in 2004 from LR main dealer and it's been serviced there every year since, does on average 3k miles a year so mpg not a great concern. Keep looking at changing it but for the amount you'd need to add to it doesn't really seem worth it.

Click to expand...

£500 and a bag of Midget Gems?

Grrrrrr said:

£500 and a bag of Midget Gems?

Click to expand...

I'll raise you a bag of Werther's original and a tartan blanket