Why do the new diesel VW's get worse mileage than the old ones?

Question

I have a 98 Jetta Diesel that gets 55 mpg hwy. Why do the new ones only get 45 mpg hwy?

Answer 1

The engines are more powerful now. Especially if your old one wasn't turbodiesel and now you have a turbodiesel. The difference is significant, but still much less than regular gas engines.

Answer 2

Many possible reasons abound...

1/ they were mistakenly using british gallons before :) (all our cars get 45/38ths the milage of yours... because the measures are different!)

2/ the cars are bigger and heavier, both because of redesigns to meet crash regulations, and consumer demands for roomier, more feature rich cars without introducing a whole new model... therefore more energy needed to accelerate to speed, and to maintain speed with more drag area

3/ engine is bigger and more powerful? (thanks to the american drivers' and most the world's motoring press' obession with hyper-powerful vehicles... never mind that most people barely use a peak of 30hp in day to day driving!)... even if you drive the same way, the frictional losses, throttling drag and other "running costs" involved in simply keeping the thing ticking over are greater.

4/ method of measuring economy has changed since you bought the previous car? certainly in the UK, new regulations came in around 97/98 regarding how economy figures were calculated - my current 1998-vintage gasoline driven car has both listed in it's owners handbook.... unsurprisingly, it fares a good few MPG worse under the new scheme... although the diesels score slightly better, it's not a VW, perhaps they do worse.

5/ maybe they simply have gotten worse at building engines? (doubt it - their latest PDs are amazing pieces of work... what you want is a Polo Bluemotion 1.4PD... 73mpg british, or 3.9 litres/100km, evolved from the groundbreaking but tiny & slow Lupo "3L" Diesel... it'll go as quick as your jetta does i bet!)

((mind you, the effect is even visible in the Bluemotion - in 1984 they had a diesel powered Polo that managed over 80mpg, putting it to shame, but only sold as an incredibly limited edition sadly... admittedly it was only 40bhp, but so was the regular, 35mpg petrol engine, both being good for about 85mph and good acceleration thanks to a bare-bones frame, and it was 22 years ago!))

Answer 3

I have an old 81 Rabbit diesel and a 84 jetta, I would suggest the older ones anyway. The newer VW's have all of that polution stuff that makes them lose power and worse fuel economy.

Answer 4

Although there are lots of variables, I would suggest that more horsepower and a heavier vehicle weight are the main factors.

Answer 5

I wish I had one to convert to biodiesel and not worry about how many miles to the gallon it gets

Answer 6

Wow. Are they cheapening the vehicles now?

Answer 7

tighter desil regulationsmore power and weight

Answer 8

dont buy diesels