VW Mk4 Golf Estate 1.9SDI

[mad_despot]

Originally Posted by 1.9SDI

One interesting point, I drove 100 miles to my mum's house today at a steady 65MPH and achieved about 66MPG starting with half a tank and about 100Kg load. On the way back, and as VAT is going up tomorrow, I decided to fill up to take advantage of the lower fuel cost - about 43 litres. When I got home I calculated that I probably only achieved about 63MPG - and I only had a 20 kilo load on board. I can only conclude that driving with more fuel than you need is very wasteful indeed.

Cheers again, Steve

I think it could also be that the wind direction was less favourable on the return trip - weight doesn't affect steady speed fuel economy much.

[1.9SDI]

Originally Posted by mad_despot

weight doesn't affect steady speed fuel economy much.

Partly correct. It's effect is minimal on a FLAT surface but there's nowhere I go that's flat. Or doesn't have an amount of city driving at either end. In my journeys, weight is an issue.

A full tank will take me close to 600 miles. My longest journey is a 240 mile round trip so, accounting for detours, etc, half a tank should do me fine. However, while I'm calibrating my ScanGauge I will continue to fill up until I get accurate readings.

Thanks for your input though.

[1.9SDI]

I've finally refilled to show the following data:
295.7 Miles
22.1 Litres of diesel used
All driving was done in almost identical weather and wind over 2 days. The car had 2 adults and one baby, plus all paraphanlia that goes with an overnight stay with a baby ~100kg.

My calculations are:
13.38 miles/litre
21.53 km/litre
4.64 litres/hundred km
60.83 miles/gallon (UK)
50.65 miles/gallon (US)
I used about half a tank of fuel and filled up at the same pump.

Edit: I was travelling at a motorway speed of 65mph with a downward variation of up to 10mph on hills.

[1.9SDI]

Another 200+ mile round trip coming up this weekend so will use that to prove figures above. I also have a 150 or so mile trip next weekend to act as a double check. After that the mods begin to be put on. I'm hoping for some improvement, though I can't complain at what I already have.

[tricky_rik]

Hi - Just read your thread with interest as I have exactly the same car - Golf IV estate 1.9 sdi estate from 2001. I was previously running an old W124 300d merc on veg oil - did 40k miles over 3 yrs but unfortunaltey just lost my main veg oil supply and needed to get a replacement pronto which would run very efficiently on regular Diesel.

Only had the golf a few days and am curious as to the rpm of your engine when at 60mph in 5th gear. I'm sure mine is near 3000 rpm which seems a bit high for such a speed.....

I am yet to work out my mpg figures, but will be soon.

Many thanks
Rik

[1.9SDI]

Hello Rik

I haven't updated this thread for a while but have been updating my fuel log as I fill up. I recently had a full service done (£1400!!!) and found lots of problems, particularly with suspension, which had to be replaced. Luckily I had already bought a lowering kit - all good quality coil over shocks - from Belgium. That whole kit cost the equivalent of one set of VW spring/shock so at least I saved something. I also had the oil replaced with synthetic to reduce friction. It was always a good runner, being a fairly low mileage car, so I can't say that I've noticed a difference in the drive at all. While they were servicing I also asked them to replace the wing mirrors with aero DT Cup style mirrors to reduce drag.

The result is quite disappointing. I was regularly getting 60mpg (UK) at 60mph before the service and that figure has stayed the same. The only difference is that I can also now get 60mpg at 70mph, where before I was getting closer to 56mpg. So it looks like the aerodynamic performance has increased, but the economy has stayed the same. I'm a little confused by this.

To answer your question, at 70mph my rev counter says just under 3000rpm and I think at 60mph its about 2600, or close to it.

I'd be interested to hear your stories on running veg oil. This is something I definitely want to do - at least some cheaper alternative for diesel.

Please keep in touch as I'm sure we can work together to find some fuel saving tips for our cars.

Regards,
Steve

[1.9SDI]

Oh, I forgot to mention that I had my car lowered by 5cm when fitting he replacement coil-overs. A bit scary going over speed humps but at a slow speed it's fine.

[tricky_rik]

Cheers Steve,

My cars RPM \ mph figures are a little different.. not sure why
2600 RPM = 55 mph, 3000 RPM = 60 mph and just over 3200 RPM at 70 mph.
Bit odd and I'm sure doesn't help my fuel efficiency. Just wonder if at somepoint my car has had a replacement (mis matched) gearbox !!

Dont want to be a pain but would you be able to double check your reading as this does concern me a little.
I have a 100 mile trip tomorrow and i'll see what my mpg figures are, I suspect not so good.

Regarding Veg oil. Before I lost out to commercial collectors i was collecting waste used veg oil from pubs for free.
My Merc W124 300d merc loved the stuff straight. over 3yrs years and 40 k miles the engine still runs like a dream i will be gutted when i finish up the last of my 200 ltrs of oil

The old diesel mercs eg W123s and W124s were perfect for veg as they have a bullet proof fuel pump and are indirect injection - these cars will run unconverted with no engine mods at all. (got mine off ebay for £800)
Also some older Peugots and Citroens 1.9TD were good as they also has indirect injection (as long as they have the Bosch and not Lucas fuel pump)

More modern diesels like ours are direct injection and not so good - but can be converted to run on veg oil perfectly fine - needs a twin tank conversion and few other bits.. if i get a veg oil supply i will be doing this to the golf - kit cost approx £400 and a bit of technical know how.

The vegoil forum is a must read and a goldmine of info
vegetableoildiesel.co.uk

Hope this helps a little
Cheers
Rik

[1.9SDI]

It's been nearly a year since my last update so has given me plenty of evaluation time for the minimal mods that I have made.

While driving a steady 40-50MPH I can easily achieve 3.6LHK (65+ MPG US / 78+ MPG Imp), and driving at 70MPH will return about 4LHK (58+ MPG US / 70+ MPG Imp).

This has been achieved in 3 ways:
1 Regular maintenance servicing using quality oils (the car is trouble-free and rolls forever!)
2 Inflating tyres to 45PSI (low rolling resistance)
3 Lowering by 4-5cm to encourage more flow over or around the more aerodynamic surfaces

The only way I can dramatically improve these figures is to have some sort of electric assistance for pulling away from lights or junctions – this is my only major use of fuel now. Other than that, I can reduce fuel costs by converting to an alternative diesel. I've not considered fitting a supercharger/turbocharger or to use one of these performance chips. Any advice or experience gratefully received.

[kingsway]

I have the same car - a 52 plate.

My consumption is similar to yours, but using my Ultraguage I am doing things that I would'nt have thought of before. Like driving at 40 in 5th gear and seeing an indicated 110 mpg !!

My tyres are Michelin Energy Savers at 40 PSAI, and I have an almost full grill-block - just the very lowest slot in the bumper is open. This halved the warm-up time in the cold weather. I do hope to try adding an air dam and rear wheel skirts, but there is no doubt at all that it is driving-style that makes the biggest difference!!

I am a driving instructor, so by hypermiling between lessons I can still get something like 50mpg (imp) from tank to tank!

Cheers from Cambridge