Should I expect better fuel economy?

Hi Baraza,

Thanks for your informative column. I have two questions:

1. I have a Peugeot 405 station wagon on which I did an overhaul recently, even though I had been servicing it regularly with the best available oil and other consumables. All the bearings, crankshaft, and rings were “standard” (had not worn to the point of needing over-sized replacements).

However, the fuel economy has not improved. It is hovering around 10km/l on long journeys, and 7-8km/l in town. Is there something I am not doing right, as I would expect better from a 1600cc, naturally aspirated car? It has its original twin-carburettor, but its power is not as good as older, heavier cars like the 504.

I also have a VW Golf Wagon GT, 1800cc, twin-charged and I get similar mileage. Is there something I need to look at again or should I accept this as a fact and “move on”?

2. I would like to get in touch with the mechanic (Innovative Mechanic, Car Clinic, May 29, 2013), who had said tuned his carburettor to give 13km/l. You can share my email address and phone number with him so I can find him some business.

Thanks,

George M. Ochenge

Hello George,

1. Methinks you may be expecting too much from an engine with two carburettors, but before we leave it at that, I was wondering: Has the consumption gone up recently or was it always like that? If it was always at 7/10 city/highway then do not expect a miracle where none has been performed.

If the economy has gotten worse, there might be a change in circumstances that you have not noticed: Maybe you carry a bigger load. Maybe you drive faster than before… maybe you use the air-con more… all these because you say the car is mechanically sound.

The power might not be as good as the 504 because the 504 you tried had a bigger engine or a carburettor with a bigger jet. You have not mentioned the consumption of that 504… you will be shocked.

2. I would advise — possibly to the chagrin of said inventor — that you first wait for results from his project. I think it very unlikely that the technology has undergone extensive testing, so there is no telling the effects of long-term use. Nor of short-term use either because the result of strangling carburettor jets is that the car runs lean, which comes with a host of other problems, including stalling, power loss, and overheating.

Give it time before you try it unless you are ready and willing to be a guinea pig for the experiment.

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