Fuel consumption - pointless observations

[Peter Jones]

Just popped up to Loony's place to pick up some bits and pieces. Round trip was 1892km. Managed fuel consumption as low as 7l/100km, high as 8l/100km. Cruised at 120 to 130km/h indicated. Actual speed probably b/n 110 to 120km/h, the speedo's a bit out I think.

Didn't loose one drop of oil or water.

The oil and water temp was at a nearly constant 43° C (measured)

Tyres were inflated to 35psi. The fronts ran at about 35° C the rears ran cold at 21°.

Going there was was effortless, coming back we ran straight into a fierce headwind until past Canberra. Had to use a lot more throttle to compensate.

We passed a lot of cars! I would have thought some of these newer 4cyl cars would have had some go but we just pulled past them on the hills. 4wds were no challenge. Pensioners were terrifying!

The car
MK1 GLD 4 door
1800 8v MK2 K-jetronic, electronic ignition, extractors
Passenger and driver, one and a half interiors on the way back.
Enormous 8 pass oil cooler.
5 spd box (The tall ratio kind FF prefix)

Thanks for the bits and pieces Matt.

Pete Jones

[aprr32]

If your oil and water temps are accurate then your car is running far too cold to be working at it's optimum efficiency.Water should be at 87 C min otherwise your car is running on cold start the whole time and using more fuel than it needs to be.Oil temp should also be up at least the same as the water to burn off any contaminants and reach operating viscosity.

[Peter Jones]

I just took the temps at the top of the radiator and oil cooler with an infrared thermometer. I guess the contents might have been hotter. Temp gauge on dash was running on the first mark which I think is nominal. I suppose I should have taken block and head temperatures and stuff too. The car ran perfectly so I've probably just measured at the wrong spot.

PJ

[Golf Loon]

Glad you got back safely. Nice to see you both again. Not a bad journey in a 27 year old car.

Cant believe you had no radio, how did the ten million green bottles end?

[joshyd-mk2gti]

yeh i thought those temps were way too cold aswell. id expect them to be at least twice that figure. as an indication, the radiator fan on my 8v comes on at 90degrees c.

wish i got that kind of fuel consumption!

[imported_brackie]

Temps

Sort out your temps and you'll get even better fuel economy (and your motor will last a lot longer!)

Water temp should be ~92 degrees C (just over the halfway on a standard gauge) and oil temp varies greatly depending on the type of work the motor is doing (no thermostat in there!). It should be close to the water temp on a long, hard run. Remember it's better to have a lot of thin, hot oil circulating quickly than a slow flow of thick, cool oil. And as aprr32 said, "hot oil burns off contaminants". Lots of people, in particularly city dwellers who do short trips never getting the oil really hot, get an unpleasant surprise when they go on a long run and find the sump almost empty. This is because the high oil temp burns off the garbage (mostly acidic water and carbon) and leaves the oil. So what was trying to lubricate the engine while they were driving around the city??? That's right... Garbage!

[Peter Jones]

I'll have to check some different temps around the block and compare them to the gauge. The dash still has GLD instruments so I'm not sure if the temp gauge reads the same as a petrol one.

The fan runs at about 1 o'clock on the temp gauge. I never got any where near that on the open road even pulling up hills in 5th at 110. As soon as I slowed down for city driving the gauge headed for 12 o'clock but never got to the point where the fan kicked in.

At somestage I'll have to make sure it's got a thermostat fitted!

I have to confess that these watercooled things are still a mystery to me. I've had a lot more aircooled VWs, but the golfs are winning me over to the dark side.

27 years old 1892km and it didn't bat an eyelid. I'm going to have to take this out for a walk more often! Adelaide Doy of the VW anyone?

PJ