Hi all

I bought a new (used) caravan over the weekend and towed it 150 miles home. The car used a whole tank of unleaded to do the round trip (297 miles), sticking to speed limits etc. Is that normal? I've not towed with it far before.

I also found it sluggish on motorway hills (M1 from Bradford to midlands, so not exactly hilly!). Again, is that normal?

I've got a high-torque cam, magnecor leads, new (correct) plugs, new genuine maf, but everything else is standard, and engine runs well normally returning 16-20mpg unladen.

Caravan is 1500kg, twin axle...

Thanks all...

you only need to put an empty box trailer on them and the fuel use goes out the window , also the ECU hasn't set its self-up for towing but now it will tow better but your already their now, they also are not the most powerful thing to tow with.

I've found the thing that affects fuel consumption more than anything is aerodynamics. Even an empty box trailer will make a hell of a difference, particularly in a headwind, whereas a car transporter loaded with something that is lower than the P38, even though it weighs far more will have much less of an affect. I've also found that using Sport mode and getting the revs up makes quite a difference on hills. The speed can be dropping when the revs are down to around 2k but cause it to drop down a gear and get the revs up to 3k and it will accelerate uphill. If you can keep your speed up to 70mph, the hills don't have much affect at all as the revs are higher. Admittedly that would be illegal in the UK though (sorry officer, it has so much grunt I'd forgotten I was towing).....

Even with a Range Rover Classic on a trailer the other week, my fuel consumption was higher but not ridiculously high.

Mad as: does the ECU know somehow then???

Richard: Does 300 miles to a take sound normal? I know you run LPG but thinking you must have done the odd full take of unleaded when you are out of LPG?

The ECU learns your driving habits over time and adjusts accordingly. I always leave mine in sport mode when towing. As noted, they aren’t the most powerful or torquey vehicle for towing with. Better than a 4 cyl Landrover though!

I remember as a young fellow towing a boat behind my Landrover, flat straight road, but a gale force head wind, and being in third gear for over an hour when driving straight into it as the old girl wouldn’t pull top.

Reference the comment on aerodynamics.

j_rov wrote:

Richard: Does 300 miles to a take sound normal? I know you run LPG but thinking you must have done the odd full take of unleaded when you are out of LPG?

I think my fuel gauge has only ever got above half full about twice is all the time I've owned the car so have never run on a full tank of petrol. The petrol in the tank is regarded the same as the spare wheel, for use in emergencies only and for as little time as possible. In fact, I've worn out the track on the sender at just below the 1/4 full mark so it either reads below that or above it, when it hits that point it drops off the bottom, the low fuel light comes on and the dash comes up with Fuel Gauge Fault. At that point I bung another 10 litres in just to move the sender (and freshen up the stale petrol).

However, it's a 100 litre petrol tank so that is 22 gallons, 300 miles on 22 gallons works out to 13.6mpg. A bit low but with a twin axle caravan that is going to be higher than the car and being driven with the revs kept down, probably about right. Use Sport mode and give it some revs, travelling slower isn't the most economical as the revs want to be above 2,000 rpm.

Since I changed my gearbox, the new one changes up at higher revs than the old one did and my economy has improved as it is keeping it in the power band more.

Thanks, I’ll try more enthusiastic right foot then and see how we get on!!!

300 miles to a tank while towing 1500Kg doesn’t sound terrible to me (but my driving is in the mountains of British Columbia, so flatter terrain would give better fuel economy).

My experience with towing is far less than Richard's but I do agree with a proper "shape" the towing isn't that bad on the consumption. I recon 10 to 30% more depending on how enthusiastic you drive. There are other tow vehicles with are far worse ...
Certainly it isn't the fastest tower around, but is a good ride. I usually keep it out of D (4th) when loaded unless the road is absolutely flat, and engine is above 2k as above indicated. Between 2 and 2.5 I find is the sweet spot for a balance between a good response and a reasonable consumption.

Interesting how some vehicles respond on this issue. I had a VW Amarok and with the trailer on, there was little noticeable difference in performance, it handled it very well, however, it totally destroyed fuel economy, cutting it by almost 50%.

Indeed differently ... in the time I "suspended" use of the P38, I used an Audi A6 30V (this is the '90s model) quattro for towing duties. Performance wise it was okay even with a heavy load, and the manual trans was also not a problem, consumption difference was not noticeable, but the car's behavior was: butt-heavy (remember the original weight distribution in old Audis is horrible), but especially more fore-aft "shaking" - don't know how to define it, like the car gets "moved" by the trailer back and forth. This was with standard suspension.
I have as a plaything a S6 of the same vintage, with sport suspension and that lovely V8 (always in manual) and the effect is much less noticeable, while the engine pull is considerably better ....

The suspension on a particular car makes a difference too. When I first needed something to tow a car transporter to the south of France, I went for a 4x4 and, as it was needed at very short notice, I bought a Ford Explorer. Absolutely horrible to tow with. The towbar is attached to the body and that is attached to the wheels by the suspension. Being something designed for the US market, as standard it had suspension that made it handle like a blancmange so attaching the trailer to it made it wallow around like drunken elephant on ice. The trailer had far more control of the car than I did. I used it once and bought a Range Rover Classic LSE two days after getting home.....

I know a bloke who years ago closed one direction of the M6 for a while after flipping his large caravan and Ford Explorer (not Gilbert lol). I asked him how he managed that, he said he was doing 90mph when all of a sudden it started snaking... But I've been in cars with him on test drives, wouldn't want to be in the car with him driving at the best of times and especially not while towing.