Tdi intercooler delete, effects on FE / power?
 

Well, it's already been deleted by the previous owner, presumably with the same kerb which 'deleted' the engine undertray. Car currently has a piece of boost pipe bridging the gap. I've already noticed a drop-off in power when towing, which I don't need to do too often, but aside from the power trade-off under heavy load, will there be any effect on FE from running without intercooling? Positive or negative?

I'm guessing it won't be too important as the winter sets in, as the entire country becomes a giant intercooler anyway, but if there aren't any gains to be had by running without, I'll make the effort to source a replacement.

I've never seen any case of an intercooler decreasing fuel-efficiency in a turbodiesel.

Same here.

Diesels typically like cooler intake temps for efficiency (within reasonable ranges). Cooler temps help because higher intake air density means a higher air-fuel ratio. Thermodynamically, the cooler temps also help the specific heat rato. Basically the same reasons I put a cold air intake on my diesel.

Granted, at low boost levels there's not much to cool--so it shouldn't affect you much at low power levels and at low ambient temps.

I agree about the lower power levels not being too different. My concern I think was that the ECU might notice exceptionally high EGTs and reduce the amount of fuel injected under full power, leading to higher pumping losses for a given power output?

I was also thinking that if I'm going to run wothout an IC, I may as well delete all the unnecessary pipework and benefit from less lag?

If you'd really still run it without an intercooler, take the unnecessary pipes away. I don't understand why the previous owner retained it...