VW Mk4 Golf Estate 1.9SDI

[euromodder]

Originally Posted by 1.9SDI

Documented fuel consumption is 44MPG on a mixed cycle but I can easily achieve 53MPG and can approach 67MPG on highways at 65MPH average. I never exceed 2000RPM except in 5th gear.

Sticking to 60-65 mph on the motorway gives a big gain.

I've already ordered a suspension lowering kit

It helps - every little bit helps - but don't expect miracles from it.

Same with the weight removal.
It helps, but it helps mostly in city driving. On the motorway you'll be hard pressed to see any + effect on fuel consumption.

So don't pend too much on these, as you're unlikely to regain the investment through the reduced fuel consumption (FC).

I've also bought some cheap used alloy wheels from an Audi A3 and increased pressures to 45PSI.

Light wheels with small openings are a bonus.

Planned mods after fitting the suspension upgrade is to convert to 100% biodiesel, saving me at least 25% on fuel costs.

And burning a renewable fuel.

maybe reduce the width of the tyres from 195mm to 165mm.

Same here.
When you need new tyres, fine, go ahead (if 165 is OK with the MoT).
If you buy them to reduce your FC, you won't get the investment back through reduced FC.

Buy LRR (low rolling resistance) tyres when you need new tyres.

I'd really like to know how to ease the airflow over the wipers, if anyone knows?

It already happens naturally as it's a high pressure area at the bottom of the windshield, but if you want to improve it further, you must somehow add a gentle upslope on the rear of the bonnet.

Also, does anyone know if it's worth swapping the hydraulic power steering to electric? The pump robs nearly 8HP under load (and a coresponding amount of fuel) and even when not in use still uses power to pressurise the system. Obviously this will put more load on the alternator but is the trade-off worthwhile?

It's been done and it results in lower FC, but it's not exactly an easy modification.

Also, on an alternator related theme, I could change the rear lights for LED versions and the headlights to 35/35HID bulbs. How much of a saving on the alternator load (and fuel) would this be?

The numbers are out there on this site, it isn't really that much.

But I also want to find out if the ECU can be mapped for economy, and find out if there are more efficient fuel delivery systems available (injection system)?

Most remappings are done for more performance, but they often have the side benefit of reducing FC (as an example, Rica claim 5-10% better fuel efficiency), especially when you hypermile the car .

The VW injection system is already very efficient.

Are there any other mods that are proven to be cost effective?

Before jumping in headfirst and buying all sorts of stuff to modify the hardware, modify the nut behind the wheel and do the cheap mods.

- grill block; air dam; shut off the airco if it's still on; covered wheels;

- drive slower on the motorway (driving 70mph / 110kph on the British motorways is what got me started on this ecodriving thing ); idle less; start coasting if you're not doing so already; eco-parking (manouevring with a warm engine rather than a cold one); ...

Go through the hypermiling tips for even more hints :
100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com
... and through the vehicle modding tips :
65+ Vehicle modifications for better fuel economy - EcoModder.com
... to see what you can easily change.

I go over them every now and then to add more tricks to my driving style once the other tips have become a habbit.

[lowglider]

Don`t forget about underbody aerodynamics.
I know WV has plastic panels beneath the engine, but there is always room for improvement, for instance check the rear if it`s parachuting. A good underbody is worth a lot more than removing mirrors or masking wipers.

[1.9SDI]

WOW thanks fellas, especially Euromodder! I think you've answered nearly all of my questions! Thank you VERY much.

To follow up on a couple of your suggestions, yes I am very aware of what sort of nut I have to adjust behind my wheel... My previous car was a very thirsty 4x4 with a massive fuel tank that needed filling constantly! By finding out exactly how much fuel I was burning (and how much that was burning my wallet) I decided to change the way I drive, using the on-board computer. The ScanGuage will do exactly the same for my current car. I can't wait to instal it and varify my estimated fuel consumption figures.

Also, I don't want to spend £1k - I want to spend as little as possible, otherwise the payback period could outlive the life of the car.

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

[1.9SDI]

Here's my costs so far. I don't know whether to include the cost of the car as I had it already as our family car - I didn't buy it for the purpose of an experiment or project. I'll include it anyway:

£1750 VW Golf IV 1.9SDI Estate
£ 119 ScanGuage II trip computer
£ 145 Alu Coil-over suspension lowering kit
£ 40 Audi A3 alloys
£ 30 DTM Cup door mirrors
£ 7 12V tyre inflator compressor (saves spare wheel)
£ 5 TyreWeld can (get me home fix in case of puncture)
£ 346 Total

Before I spend any more (or install anything except the SGII) I will do my benchmarking starting in a couple weeks with a 120 mile trip to Bristol, and 120 miles back again! Then another 200 mile round trip south.

Cheers, Steve

[1.9SDI]

Proposed plans for my Golf. This is not my car, mine is black, but you get the idea.

http://golf.citrusdm.com/

[Weather Spotter]

i have experience with the OEM on power steering systems. The short answer is removing it should net you ~2MPG. Most cars can work without any power steering but if you must have assist go electric. it costs $500 more new (to the OEM) but they claim it helps the MPG by 2 and drops about 30# of weight.

[1.9SDI]

All my parts have arrived finally. I'll be testing out the ScanGuageII at the weekend ready for a long drive the following weekend. At last it starts to get exciting!

[Vekke]

Originally Posted by Weather Spotter

i have experience with the OEM on power steering systems. The short answer is removing it should net you ~2MPG. Most cars can work without any power steering but if you must have assist go electric. it costs $500 more new (to the OEM) but they claim it helps the MPG by 2 and drops about 30# of weight.

I just took the powersteering belt off. Easier to test that way do you need the steering or not. I did not need it with my arm forces, but I am a quite big guy...

Non powersteered rack migh have different gearings still so you need to test a car with no powersteering and make your decicions after that.

On my car the effect was minimal 0.1-0.2 liters.

[robchalmers]

caster and a feww other Geometry items may be different on a non power steering car too

[1.9SDI]

Well, either I own the most economical production diesel car in the world or my ScanGuage is off. I did a 291 mile trip and my average consumption was 0.8LHK. All that money VW spent on the 1 litre concept car - they could have just borrowed my car!

I'll do another fill up tomorrow and calculate using traditional methods. I will recalibrate at this stage too. My fuel gauge reads half a tank left (a full tank is 55 litres) so that's 25.5 litres used in 291 miles (468km). This is a very rough calculation though.

More later...