Some calculations

[Tim]

what about the bit where u get depressed cos u drive a 1.6 with no poke? and youre wife leaves u cos youre a cheapskate and u lose your job cos youre always grumpy and then u have to get the dole?

I think the unseen costs of owning a 1.6L golf are far worse than the extra cash u may have to spend on a diesel.

[mikinoz]

All good points, however I would prefer to pay more and own a TDI than own another 1.6lt petrol! I still cannot see how you come at using the 1.6 vs 2.0TDI as the cost in purchase is more expensive that the illustration above.

TDI was for me a choice based around wanting a more economical car than a 2.5T Forester and keeping some performance, and not being able to justify the GTI for the use the car was going to receive.

[Big Al the Butchers' Pal]

Reply to the above two posts.

Sorry, my error in not being more specific.

I compared my car to the exact same car, but with the equivalent diesel engine. As far as I am aware the diesel engine that cost $2500 extra was the 77kW diesel engine. From memory the 0-100 time was 0.1 seconds quicker than the 75kW petrol engine.

As for the comments re the Golf 1.6, as far as I am concerned it is a better car than the Toyota Corolla, albeit with a less powerful engine.

The Golf was cheaper than a Corolla with the same safety features specification (as Toyota charged extra).

But then again, there is also some merit in having a simple 2 valve belt driven OHC engine with a simple Siemens ECU setup and a clutch that does not involve a dual mass flywheel.

I also see merit in the fact that the 1.6 sold in Australia is a destroked version of the 85 KW 2.0 litre engine. I prefer a short stroke engine with long connecting rods as it is free revving and easy to drive in manual form. As far as I am aware the Golf 1.6 is the only oversquare passenger car engine currently sold by any manufacturer. Even the Hyundai Gets 1.6 has an extra 20mm stroke than a Golf 1.6.

[TDI Dude]

Well gentlemen I'll just say one thing on this subject.... YOU BUY A DIESEL AS A CHOICE NOT BECAUSE THE ACCOUNTANT SAID SO!!!! P.S. cant wait for mine to turn up!!!!!!

[Logzy]

Im getting a diesel to satisfy my fetish i have at the moment with Turbo Diesels.
I just like the idea of them.

I wouldnt get a 1.6l petrol that needs to have the ring hole revved out of it to produce the power so for low fuel consumption a diesel is for me.

I'm going from a VXII 5.7l Clubsport that averages 14l/100k so the way i see it I'll be saving heaps in fuel and I'll have a engine that will last instead of a 4cyl petrol engine that needs to be revved.

The fuel price for me is about the same as diesel per litre as the clubby needs 98RON
I'll save about $45-$50 a week in fuel, not to mention another $360 a year in insurance and $$ in tyres.

[mikinoz]

As for the comments re the Golf 1.6, as far as I am concerned it is a better car than the Toyota Corolla, albeit with a less powerful engine.

I have to say the 1.6 MKV that I drove was reasonable and a huge advancement over the 1.6 MKIV in standard form! My company car is a corolla and they are 2 different beasts indeed!

[GermanwithaVdub]

can someone confirm what im about to infer.

i dont have much experience with an mkv fsi, but im guessing that if you're a person who constantly revs close to redline and always hard acceleration, that you're going to use exponentially more fuel than if you drive the same way in the equivalent diesel?

[Big Al the Butchers' Pal]

can someone confirm what im about to infer.

i dont have much experience with an mkv fsi, but im guessing that if you're a person who constantly revs close to redline and always hard acceleration, that you're going to use exponentially more fuel than if you drive the same way in the equivalent diesel?

You are correct. The efficiency of an internal combustion engine is proportional to the compression ratio. A diesel engine has far greater compression (11 to 1 vs 19 to 1), and is thus more efficient. The cost of this efficiency is however higher engine drag torque. This is the case because the internal moving and reciprocating parts are heavier and also because more work needs to be done to achieve the higher compression. The engines are also heavier. The 2.0 TDI engine is 140kg heavier than a 1.6 petrol engine. A TDI engine also needs to use 20% of engine output to drive the turbocharger via the exhaust stroke.

Diesel engines are therefore around 30% more efficient in producing power. This is why diesel engines are used exclusively for power applications such as generators, compressors, ships, pumps and trucks. Diesel engines are however less efficient that petrol engines in NOT producing power, because the drag torque is double that of a petrol engine.

So for aero applications and motor vehicles, where the engine spends the majority of the time at part load, the petrol engine will be more efficient in non full load situations. This is why I get over 900 km from a tank of fuel in my car, because I spend most of the time cruising on the highway at 80 to 100k/h at a 10 to 20% of full load application.

If I were however to go on the autobahn at 180km/h flat pedal, my car would drink like an Irish sailor. The diesel engine would be far more efficient in such a constant full load situation.

If you are a lead foot then the diesel will be a better choice, however driven ultra efficient, the petrol engine will be (in overall terms) more efficient than an equivalent diesel engine. This example was proved in the recent fuel consumption world record where a petrol VW Golf achieved that record.

[Big Al the Butchers' Pal]

Well gentlemen I'll just say one thing on this subject.... YOU BUY A DIESEL AS A CHOICE NOT BECAUSE THE ACCOUNTANT SAID SO!!!! P.S. cant wait for mine to turn up!!!!!!

You are correct in your analogy. I buy Benson & Hedges as a choice, not because my doctor said so.

[GermanwithaVdub]

You are correct. The efficiency of an internal combustion engine is proportional to the compression ratio. A diesel engine has far greater compression (11 to 1 vs 19 to 1), and is thus more efficient. The cost of this efficiency is however higher engine drag torque. This is the case because the internal moving and reciprocating parts are heavier and also because more work needs to be done to achieve the higher compression. The engines are also heavier. The 2.0 TDI engine is 140kg heavier than a 1.6 petrol engine. A TDI engine also needs to use 20% of engine output to drive the turbocharger via the exhaust stroke.

Diesel engines are therefore around 30% more efficient in producing power. This is why diesel engines are used exclusively for power applications such as generators, compressors, ships, pumps and trucks. Diesel engines are however less efficient that petrol engines in NOT producing power, because the drag torque is double that of a petrol engine.

So for aero applications and motor vehicles, where the engine spends the majority of the time at part load, the petrol engine will be more efficient in non full load situations. This is why I get over 900 km from a tank of fuel in my car, because I spend most of the time cruising on the highway at 80 to 100k/h at a 10 to 20% of full load application.

If I were however to go on the autobahn at 180km/h flat pedal, my car would drink like an Irish sailor. The diesel engine would be far more efficient in such a constant full load situation.

If you are a lead foot then the diesel will be a better choice, however driven ultra efficient, the petrol engine will be (in overall terms) more efficient than an equivalent diesel engine. This example was proved in the recent fuel consumption world record where a petrol VW Golf achieved that record.

ah thanks for that, very clear now

[neil]

You'd need to chuck resale value into the mix. Generally this is higher on a diesel than on a petrol.

Servicing the diesel may also be slightly more expensive as (if you love your engine) you'd need to change your fuel filter more regularly than recommended, and I'd like to know the cost comparison between the cambelt service for the two engines.

Fuel costs vary greatly depending on global supply and demand. At present heavy supply of diesel fuel to Asia is pushing the price up. This was not the case 30 years ago when diesel was up to 10c cheaper per litre than petrol. Who knows how this will change in the near future

Driving technique can affect fuel consumption enormously. According to the computer I got 4.9L/100km on a trip to Launceston (300km) last Friday. This included 110kph on much of the Bass hwy, and also a lot of running around town, whereas 2 weeks ago it was 5.1 on a trip to Hobart when I was a little more "enthusiastic" in my technique

I won't go into why I love diesels, 'cos it's a personal thing.

Hey brackie.
Good to see you still around.
Have missed your posts re: fuel consumptions.

Did a trip from Sydney to Young via Boorowa approx 380km @ 4.7 L/100
Return trip, took it easier via Wombat 350 km @ 4.1 L/100
Was sitting on 4.0 until I hit the city.
Anyway how do these manufactures get the figures they state on the
brochure. I cant get anywhere near there estimate of 6.1 even in the city.
Take care Neil.

[evorobin]

You need to do the calculations for Golf 1.6 Petrol vs Diesel

This car runs on stock unleaded. According to my calculations

$2500 extra costs me 13% lost investment income in my share fund per annum = $325 per year.

Extra fuel consumption is 2 litres per 100km.

So, to even start paying off the $2500 cost, I have to save more than $325 per year in fuel.

You forgot to factor lost opportunity cost of the extra cost.

Also the fuel cost is now 15 cents cheaper for a 1.6 petrol vs diesel.

This equates to a 0.8 litre per 100km equivalent fuel saving at current prices.

Half of the saving in consumption is blown in extra fuel cost.

Even if I travel 20,000 km per year, I am still behind in cash terms and the $2500 outlay will never be paid off, no matter how long I keep the car.

Then you have the issues with dual mass flywheels that cost major dollars every few years etc.

And PRAY you never need to do major engine repairs on a diesel engine, as that is mega dollars.

And Pray you never get a shonky (added kero + heating oil) load of diesel or water in the fuel, as that will totally stuff your engine and require a full engine rebuild.

ABRZ from vortex australia has entered the building LOL

[Spoddy]

Anyway how do these manufactures get the figures they state on the
brochure. I cant get anywhere near there estimate of 6.1 even in the city.
Take care Neil.

We seem to have found the method.... short trips to the station where the car doesn't warm up Seems such a waste driving a car that way but then its my wife's car and thats the only way to get to work. We are averaging 6.8 whilst the silly MFD says 5.9 to 6.1.

[neil]

We seem to have found the method.... short trips to the station where the car doesn't warm up Seems such a waste driving a car that way but then its my wife's car and thats the only way to get to work. We are averaging 6.8 whilst the silly MFD says 5.9 to 6.1.

Interesting spoddy.

I'm quoting the MFD, I'll do a few manual calculations and see what
I come up with.
neil.

[GermanwithaVdub]

Hey brackie.
Good to see you still around.
Have missed your posts re: fuel consumptions.

Did a trip from Sydney to Young via Boorowa approx 380km @ 4.7 L/100
Return trip, took it easier via Wombat 350 km @ 4.1 L/100
Was sitting on 4.0 until I hit the city.
Anyway how do these manufactures get the figures they state on the
brochure. I cant get anywhere near there estimate of 6.1 even in the city.
Take care Neil.

you must drive VERY conservatively. i was lucky to get 6.1 or below on my 2.0tdi comfortline when i had it. mostly up around 7 or 7.5. and you cant count the cruising on a highway, i can make my car sit at 3 point something on a straight flat stretch, it has to be a mix of city/highway to have relevance.