So some questions. Are all TDis twice as economical as V8s?
Um, No.. a good Tdi will be twice as good as a bad V8 in terms of fuel. They are of course more fuel efficient, but I wouldn't be expecting twice as good.
What would all have to be changed? Can a kit be bought with all parts?
Exhaust System, some mods to the fuel system, some changes to the igintion wiring, either swap the gearbox or find an adaptor kit, engine mounts, and lots of little fiddly bits depending on the exact engines.
So some questions. How much am I looking at for a TDi? How much could I expect to get for a V8?
Tdi engines start at about 800 quid, and can be up to around 2000 for a really good 300 tdi. Depending on the engine, a V8 is worth anything from 100 to 500 quid. (Unless it's something a bit special)
As to whether it is a worthwhile process depends on how many miles you are going to be doing.
Thanks![/quote]