How can I replace the hose in my '81 928 injetctor-rail lines

 

If your injection is L-jet , with short hoses from rail to electric injectors, I have no experience here - mine is CIS with hard metal injector lines. I believe that any injection rated (ie pressure rated >50psi, 3bar) attached with quality hose clips should be OK, but I am sure others with experience here will chime in. These hoses are well known for problems.
jp 83 Euro S AT 57k

 

Only use N-020-281-1 hose for this job. You can purchase it direct from Porsche or from any of our sellers. This is what I used when I redid my lines a few years ago.

It was specifically manufactured to be an exact replacement to the old hose and does not require hose clamps, just the ferules that Porsche used originally.

Cut the lines to exactly 55mm IIRC. They all need to be the same length as well or else the injectors wont seat right or you get a leak.

Using hose clamps on barbed fittings can cause fuel line failure and a subsequent fire.

Don't risk it, just do the job right the first time.

 

With respect The Forgotten On - The repair Kit is available from Porsche and for the record Porsche supplies EFI hose clamps with kit so it is considered safe if you use the correct hose clamps. There are sharp barbed fittings which can cause some detriment to the inner diameter of a fuel hose but these are not considered sharp.
We sell a kit which includes the hose (N 020 281 1 cut to length), correct EFI clamps, large & small seals for seating the connectors for $80.