I just bought this 91 CS Lim and trying to figure out how it has been modified.

Does anyone know what the pipe I've marked with orange is?

 

Help would be hugely appreciated.

looks like a new air con line, does it go to your heat exchanger at the front?

looks like the air con piping with foam wrap around it, only saying that cause it looks like a gas fill pipe on the strut tower. maybe a closer pic may help

beat me to it haha

Yeah its aircon, it has the telltale alloy filler bung on it half way along, and it runs from the ac dash connections to the condenser. May have had aftermarket air fitted. Is it cold?

Like everyone else has said, its aircon. There were two types, the integrated unit which strictly ran along the passenger side of the engine bay behind the radiator and into the compressor. Then theres this style which I never really understood, as it looks all over the place... as long as it blows cold thats all that counts.

It's the in cabin nitrous feed to the supercharger !