Golf TDI got 97 MPG!

[yfo866]

I used to think that 45mpg was good, 50mpog amazing and only expensive new cars with very low mileage got any better than that.
Then at the beginning of last year, I needed a car that was taxed and had an mot. That was my only criteria. I spotted a fairly battered high mileage Seat Ibiza 1.9 SDi for £430 on flea bay.
It had tax and mot so I bought it. It's been good on fuel. Last june, I went to collect a kayak I'd bought on flea bay. It was roughly a 400 mile round trip. I'd filled up a week or so before and the gauge was showing just over half full. I set off on a Saturday morning driving at a steady 60-70 miles per hour. When I got there I removed the blow up single mattress from the boot, blew it up and then put it onto the roof, the kayak on top of that and strapped it all down using ratchet straps. One through the two open front doors and another around the hinges of the hatch back. The gauge was showing just under half way.
I was going to fill up when I collected the kayak, but after seeing how much I hadn't used I thought I'd see how far I could go.
I set off driving between 50 and 60 mph. I got a lot further than I thought!
The journey was between Bromsgrove and Great Yarmouth. I had managed to get back to the Coventry area on the M6 before my clenched buttocks couldn't take the stress of running out of fuel any longer and I pulled in to the services on the motorway. I brimmed the tank, as I had at my last fuel stop. When I got home and worked it out I had managed 67.7 mpg.
Considering I had done a couple of weeks of commuting and then nearly 200 miles with a mattress and kayak on the roof it makes me wonder how many miles I'd be able to go at a steady 50mph on the motorway?
The car was around 150,000 miles at the time and judging by the state of it hasn't seen regular servicing!
I'm prepared to believe a modern eco diesel could do 97 mpg. The question is, could my 14 year old non turbo shed of a car get anywhere near that?
I am regularly getting 60mpg out of it commuting the 20 mile round trip to and from work.
I put £30 of diesel in at a time which is around 22.57 litres and I get 300 miles plus before the fuel light comes on.
As this is only used for running around and commuting, I'm considering chopping the roof off and maybe lowering the top of the windscreen a couple of inches, removing the back seats and taking the roof line from the top of the screen straight back to the top of the rear lights. Then cover the rear wheel arches and widen the front wings to allow the front wheel arches to be covered. Remove the rear bumper and bring the tail straight down towards the ground, to produce a 'Kamm tail'. Add some bodywork to the front to smooth the air onto the front of the car. Also, i'll lower the car by an inch or two and add aluminium panels to the underside to smooth it all down.
I'd add a rollover hoop at the B pillars to add some protection as I'd replace the existing steel roof with either carbon fibre or fibre glass.
Does anyone else have any other suggestions?

[Draigflag]

They seem like extreme modifications to me, for a car worth very little (no offense!) It would be good as an experiment I guess, personaly I wouldn't go that far, i'd be looking into things like servicing it, flushing the engine out maybe and perhaps changing the wheels and tyres for smaller, economical ones and see what a difference that makes.

On my current tank im getting 68.4 MPG, used 3 quarters of a tank but i've still got 250+ miles left, like you I wonder how to get the best out of the liquid gold we put in the fuel tank! Im hoping with just 6000 on the clock, it will be breaking in soon qnd the economy will improve. As winter approaches, im connsidering changing my wheels to 15" with winter tyres as the 17" on there now alone use 5 MPG.

[trollbait]

I'd start with minor, easy to reverse aero tweaks first; a grill block, wheel skirts, air dam or belly pan, etc. Also keep tire pressure at max side wall.

There are some ideas for more extreme ones at this site. http://www.aerocivic.com/
I've seen photos of Geo Metro/Suzuki Swift which had the passegner seats, windows, and roof replaced with a flat sheet of metal level with the hood.

[CobourgVeeDubYah]

97 MPG is not hard to imagine in a Diesel. Diesel Fuel gives a specific (fairly constant) amount of HEAT per Litre of Fuel Combusted. IF the AIR TEMPERTURE is kept constant, and As the Engine Heats up to Running Temperature (90C for Jetta TDI), then you keep the additional weight to a minimum, (Spare Tyre,Wrenches, Extra Fuel, 200# of mechanics tools, etc, Mother-In-law etc..) Even running over hill and dale, (max 5% grade), the only thing preventing excellent figures is how heavy the foot is. (Cruise Control is wonderful for the Expressway)

But remember this is AFTER the engine gets WARM!

While it is COLD, the Fuel, is being burnt to not only push the car, it also is being absorbed by the block and the Radiator.

This is the Big Advantge of Diesel over Gasoline, It Ignites at a Higher Pressure inside the chanber, but, it does so with a lower temperature, than Propane, or Gasoline does.

So, its not only the Heat that it produces, its the Mechanical energy, that is produced by the burning of the fuel.

IF the engines got better with the designs, you would see less waste heat through the Radiator/ Warm Cabin exchanger, and a better amount of heat converted to energy (mechnical) called Torque, applied to the driveshaft.(CV Joints on FWD).

It's too bad, Toyota, GM, Ford, Nissan, Honda don't produce enough of the 'Complaince Type' Vehicles for the rest of the world.

I'm waiting for the grand engineers to put a Trailer-Diesel APU in behind an Electric Vehicle for Extended Range, and a Tiny Battery to Just Absorb the amount of energy from slowing down approaching a stop, and be able to push the car to a rolling speed of 25 MPH.

Goodness knows, the politicians, will figure out how to TAX electricity for ROAD USE as high as petroleum products are today.

The 1% club will not worry either way, but the rest of the 99% are waiting for GM and Toyota to get their manufacturing acts together.

[Jay2TheRescue]

Originally Posted by CobourgVeeDubYah

I'm waiting for the grand engineers to put a Trailer-Diesel APU in behind an Electric Vehicle for Extended Range, and a Tiny Battery to Just Absorb the amount of energy from slowing down approaching a stop, and be able to push the car to a rolling speed of 25 MPH.

You've pretty much described a Chevy Volt. I would be curious to see what a Volt could do if it had a diesel engine.

[CobourgVeeDubYah]

Not quite a Volt, more a iMEV with a Ski-doo motor attached, Drive Farm Diesel (No Road Tax), and then Generate the 3-5 Kwh for the iMEV in highway mode.

Chevron already killed the high-Density NiMH Battery of a moderate capacity. May Stan Ovahinsky Rest in Peace, as he was the inventor that 'Won the CM competition" for the best battery at the time, for Automotive use.

But you are along the right track. If the Total Weight of the Vehicle Can be reduced (say with 1/2 the Battery pack of the Volt), and Detatch the Engine Part from the actual Cab, as a Range Extender would, you would no longer need to carry along the weight of the batteries, as they are being depleted of initial charge.

See EVP Tender

[CobourgVeeDubYah]

Chevy won't admit to using a Diesel engine in a start-stop environment, because the engine takes time to get 'Up to Temperature' so that the performance of the design is better than the gassers.

They also do not prefer to buy the licence to the BOSCH fuel pump to deliver the fuel to the injectors, they prefer to use their own patents, and design the chevy Cruze with only 1 interior option, (Black cloth) ,and only 1 transmission option (Automatic).

A good read (IF you are up to it) is the GM Ignition Report to Executive from the Lawyer Anton Valukas.

GMs Opel devision makes lots of Diesel engines, yet they are not imported to North America in quantaties yet. (Cruze Diesel has a 3-5% Build rate), meaning that 95-97 out of 100 cars are gasser's for 3-5 that get built for Diesel.

I suspect that the VOLT is a COMPLIANCE only vehicle, and they will not improve the batteries to last 10 years, until they have sold their last gassers and are at bankrupcy's door again.

[OliverGT]

Originally Posted by Charon

One, once. A statistical anomaly. When several do it, I'll take notice.

I get 80 mpg out of my 12 year old 206 1.4 hdi. I would say 97 mpg is quite possible from a modern diesel.

Don't forget these are imperial mpg figures, not US mpg figures. (97 mpg = 80 US mpg)

Oliver.

[yfo866]

Originally Posted by Draigflag

They seem like extreme modifications to me, for a car worth very little (no offense!) It would be good as an experiment I guess, personaly I wouldn't go that far, i'd be looking into things like servicing it, flushing the engine out maybe and perhaps changing the wheels and tyres for smaller, economical ones and see what a difference that makes.

On my current tank im getting 68.4 MPG, used 3 quarters of a tank but i've still got 250+ miles left, like you I wonder how to get the best out of the liquid gold we put in the fuel tank! Im hoping with just 6000 on the clock, it will be breaking in soon qnd the economy will improve. As winter approaches, im connsidering changing my wheels to 15" with winter tyres as the 17" on there now alone use 5 MPG.

Extreme? Maybe. Cheap car? Most certainly.
You don't think I'd hack away like this with a car or your age?
How do you estimate your 17 inch wheels are costing you 5mpg?

[yfo866]

Originally Posted by trollbait

I'd start with minor, easy to reverse aero tweaks first; a grill block, wheel skirts, air dam or belly pan, etc. Also keep tire pressure at max side wall.

There are some ideas for more extreme ones at this site. http://www.aerocivic.com/
I've seen photos of Geo Metro/Suzuki Swift which had the passegner seats, windows, and roof replaced with a flat sheet of metal level with the hood.

I can't block the grill, I need air to cool the rad. I planned to widen the front wings to the point that they would cover the wheels when on full lock. I keep my tyre pressures anyway. The underside of the engine bay has a cover, so Seat have thought a bit about things...
I also plan to replace the bonnet(hood) with carbon fibre or fibreglass to reduce weight.
With the roof, bonnet and hatch all replaced with composite I'd be losing a lot of weight. That in itself should get me better mpg.
I'll be starting cutting next month as the Seat's road tax expires at the end of the month. I'll be switching over to my other car, a Land Rover Discovery. If ever there was a car that needs to lose some weight, THAT'S ONE!