We bought another old Nissan (Sunny 2.0 Diesel, 1993 model), two weeks ago.
It is technically perfect, and have been using group 4 & 5 oil in the engine, all of its 321000 kilometers life.
However, it is so underpowered, that you wouldn't believe it. I have been driving a Mercedes 240 diesel(123 series) several years ago, and the acceleration is similar.
It is an amazing difference from the Nissan Laurel 2.8 diesel we have had for 3 1/2 years, but on the Laurel, I have been using some additives to the oil
and in the diesel.
Of course it can be a partly clogged diesel filter, that is playing us a trick on the Sunny, but I think the difference is because this Sunny has never seen any additives in the diesel or in the oil.
It has always been used the best quality of fuel and oil in the Sunny, as well as regular maintenance and service on it(only 6000 mile OCI, and you know what I mean about that(totally waste to change that often, if using the right additives).
Another thing worth noticing, is that both cars have almost the same MPG, now, when driving the same route.
The difference should have been at least 12-14 MPG in favour of the Sunny, considering this: Laurel weight is 1370 kg and the Sunny is 1120 kg. The Laurel engine is a 2.8 liter six cylinder with 90 hp and the Sunny is a 2 liter 4-cylinder with 75 hp.
Actually, the Sunny has 14,9 kilo for every horsepower, and the Laurel has 15,3 kilo for every horsepower.
When driving, it feels like the Laurel has 40 horsepower more, even though the difference should only be 15.
I have seen this in real life, too, since a friend of mine rented a VW Passat with a 105 hp turbodiesel, and it was slightly SLOWER than the Laurel.
This was in acceleration from 60km/h up to 130 km/h(didn't try it in higher speeds, because of police-fear).
We found this to be rather strange.
I will try Rev-X in the Sunny's engine, within 3-4 weeks, and see if it can do something.
When I filled the fuel tank on the Sunny, it had been using 0.61 liters per 10 kilometers.
The Laurel had been using 0.63 liters every 10 kilometers.
In MPG, it translates into 37.33 for the Laurel and 38.56 for the Sunny.
Not bad with a lot of idling, because of the cold weather.
Down to -22 degrees Celsius(-7.6 Fahrenheit).
And remember, on both these cars, it's a mechanical diesel pump, with no electronic stuff.