Fuel hose tends to shrink a bit with exposure to modern fuels, especially non FI rated hose which can shrink rather alarmingly. High quality OEM FI hose that the major manufacturers use will exhibit almost no shrinkage. Note that most manufacturers today do not use screw clamps on their high pressure lines, but rather the crimp type which are much maligned and misunderstood on this forum due to using incorrect type, size and installed with incorrect tools.
I would add that to use crimp type hose clamps on high pressure FI systems there are requirements:
Use only stainless steel clamps to preclude corrosion related failures
Use only clamps that fully wrap around the hose (oetiker stepless type) sometimes called wrap and a half as they have an overlapping wrap
Use the smallest diameter that will slide over the installed hose to insure proper tensioning
Use the correct parallel blade 'pincer' tool to install
Using the above guidelines (which I have been doing for the last 30 years or so) you will not have a clamp related failure or leak.
If you are using the cheap parts store fuel hose, you will want to replace that every few years or better yet get OEM spec FI hose from a dealer (think BMW, Porsche, etc)
Unlike oetiker type clamps which maintain clamping pressure over time through constant spring force, screw type clamps are not dynamic, i.e. once set, you will have to nip them up over time to compensate for hose shrinkage. Screw type clamps, unless the double wrapped type, will also deform and perhaps damage the outer laters of the hose.
As an interesting side note and testimonial, stepless stainless oetiker clamps (along with smooth ring type copper clamps) have been used in millions of Pex type plumbing installations (in the U.S. at least) for over 20 years without issue.
Last edited by Bitsobrits; 03/09/22 01:32 PM.
