Originally Posted by jwalker
You've posted that a couple of times, Codders but Kero +5% oil does not equal diesel.
You speak as though torque and power are not related. If you have high torque at a given rpm, you'll also have high power at that rpm. Diesels generally produce more power at lower rpm than equivalent petrol engines but they run out of breath as their revs rise so they don't ultimately manage the high power that a petrol motor does. The fact that they have lowish maximum RPM doesn't matter because the lower unit gearing can take care of that to ensure a satisfactory prop speed.
Power = Torque x engine speed.
The reason petrol engines make more power is partly because they can rev higher. A diesel engine's torque curve is pretty flat, whereas a petrol engine's is low at first, then rises gently, then falls off at higher revs. But even as it falls off, revs increase, and therefore power remains stable.
So yes, diesels make more torque at low revs and therefore more power, (than a petrol) But their torque drops off quickly at higher revs, and therefore their peak power is lower than that of petrol engines.
(At least that was the classic doctrine when I did mechanical engineering at university - modern technology is changing all the time, and diesels are quickly overcoming their old shortcomings).
As for the whole jet / diesel thing, perhaps I can add some info as I was responsible for international jet fuel cargo trading for the 4th largest oil major for 10 years.
Yes, the US Forces have successfully converted their motors to take JP8 (almost identical to Jet A1 used in commercial aviation). But this does not necessarily mean that you can do it with your Golf TDi. They also use a very high flash jet fuel, JP5 for aircraft carriers.
Codprawn, you need to be careful what you say regarding diesel unless you're very sure. It's a complex subject, and EN590 (Euro DERV) has about 20 specifications. It is a very high spec fuel. Modern diesels CANNOT run on any old rubbish - they are now using ultra high pressure injectors and lubricity must be good. The spec is 460 microns max, where a test plate is worn using the diesel as a lube. The scar must be no more than 460 microns deep. Also, the minimum cetane is 46/51. This is not guaranteed for jet fuel or heating oil. Viscosity has to fall within a certain range, as does density. Flash point must be above 55 or 60'C. Jet/kero is only 36'C, so watch out on hot days!
Adding veg oil as a lube may or may not work, but I wouldn't bank on it. In any case, the higher sulphur content in heating oil acts as an excellent lubrifier. (In fact it was the reduction in the sulphur in diesel in the late 90's that caused all the lube problems).
This is a big, complex subject, and cannot be dealt with lightly!