Astra ECO4 thread

Hi all,

Just thought I would add my new car to the discussion.

It's an Astra ECO4, which was for sale here in Europe between 2000 and 2004 (I bought it used).



This model is a family size 4/5 seater car and was the most fuel efficient in the Opel range at the time. It was designed for enhanced economy with the following features:

• 1.7 CDTi engine, tuned for economy
• Aerodynamic undertray, spoiler and other fairings etc bringing Cd down to just 0.28.
• Very long 4th and 5th gear ratios
• Low rolling resistance tyres
• 112 mph top speed
• 80.8 mpg UK (highway), [which is 67.3 mpg US]

I have only had it a week, but in that time have the following observations to make compared to my previous Astra TD:

1) Fuel economy in mixed driving has been 68 mpg (UK), or 56.5 mpg (US) over the first tank. However it should be much better than this!
I found out that the previous owner had replaced the low rolling resistance tyres that are meant to be standard on this model with ordinary tyres, and had the pressures down to 30/32 psi ! I have now put the pressures back up to 38 (and to 44 psi when I get around to putting new LRR tyres on), so should expect better mpg results over this next tank.

2) The performance is great compared to the previous TD engine! I have been driving an old-skool indirect injection diesel before now, but the common rail CDTi unit in the ECO4 is way better by comparison. The torque is just huge at low revs, which means the acceleration is superb. I wasn't expecting this at all, and unfortunately have reverted somewhat to my old boy racer days, accelerating past everyone else at every opportunity, particularly off roundabouts! This has doubtless hurt the mpg rating quite a bit, so I'm going to drive a bit more sedately over the next tank !

3) Handling is great, it holds the road really well thanks to Lotus designed suspension on this model. I reckon this actually helps the mpg as there is less slowing down for corners!

4) Refinement on the open road is superb. The attention to aerodynamics means there is hardly any wind noise. The engine is always at low revs too (just 2,200 rpm at 70 mph on the motorway), so is barely heard too. No creaks or rattles either, which is nice compared to the old car, but there is still some road noise.

5) Road tax for 12 months is just £35, compared to £175 on my previous car.

This is meant to be a great car for 'hypermiling', so I'll write back with an update on how I get on with mpgs on a longer trip.

For example, these 2 journalists managed 90.6 mpg UK (75.5 mpg) at real-life speeds on real-life roads driving from one end of the UK to the other.

If you're dedicated and take things slowly though you can do much better than that! In a competition in Germany, an entrant managed 145 mpg (UK), or 120 mpg (US) in an ECO4 over 380 km of real roads.

I think it may be some time before I manage to crack numbers like that!

I'll write back with another update when I've had more time to find out what this thing can do....

 

OK, results from this latest tank are:

72 mpg (UK) which is 60 mpg (US).

Still not as high as I'd like it to be, but I suppose it can't be helped as I've spent about a third of this tank stuck in traffic! Still waiting for a long run to see if I can match the claimed highway mpgs....

PS, @ FWD, I don't think you can directly compare the ECO4 with the Prius as they are in very different price brackets. The cheapest 2003/4 Prius you can get here is about £7,000, whereas I got my ECO4 for £2,500. When they were new, the ECO4 cost £11,800, while the Prius cost £18,500.

 

As for urban driving, to be honest the ECO4 is not that great. The EU urban cycle figures for the ECO4 and the Prius are 39 mpg (US) and 47 mpg (US), respectively.

However, remember that I can run my Astra on straight vegetable oil, which is far more efficient to produce than ethanol or butanol that would be required for a gasoline engine and can come straight from algae to press to tank. That's where the real benefit of the diesel engine is, ie it's much more sustainable in the longer term.

 

I totally agree that electric is best!

Actually that's what I'm aiming for with my next car, or at the very least a DIY PHEV conversion of this one, which is what I'm currently thinking seriously about....

As for the potential of algae to replace crude, it's no problem. Canola oil can produce about 100 gallons of oil per acre and requires lots of fertilizer, good soil, heavy equipment, lots of water and of course lots of fossil fuel.

Algae oil, on the other hand, is grown in brine in sealed containers on desert land and can produce up to 10,000 gallons of oil per acre, requiring very little nutrients, water or energy input (most of it is recycled from pressing the pulp) and no food-producing land. It was calculated that the entire US fuel requirements could be provided by algal farming of the Salton sea (a large brine lake in the Southern desert).

Ironically, it was the USA Department of Energy that proved all of this with their aquatic species programme. Unfortunately that whole project was canned back in the nineties when they concluded that algal crude would cost double that of fossil crude. Of course that was back when oil cost $15 per barrel....

 

About a dozen companies around the world have recently confirmed the DOE's figures for algal oil production (one actually claiming a stupefying 20,000 gallons per acre!) and are gearing up for mass production right now. It's currently a flat out race between them to see who can start producing first.

You can expect to see their output used as feedstock for the biodiesel industry starting from the next year or so and after that once production begins to ramp up, as a replacement for crude in refineries.

 

Mileage update:

Fuel tank gauge has just come down to half full - 401 miles on the clock.

I've been doing some longer trips over this tank which appears to be helping a lot.

 

OK, another update on the ECO4's performance.

I'm just back from a long weekend visiting Wales, which was a good opportunity to see what it could do on a long run. Overall it managed 420 miles on 5 gallons, which is 84 mpg (UK), or 70 mpg (US). This was a mix of about a third on motorway (70 mph) and two thirds on the hilly Welsh mountain A-roads (50-60 mph).

Front tyres are getting pretty worn now, so looking forward to finally getting some low rolling resistance tyres on and the pressures up!