Well, years ago I experienced the dreaded failed pulsation dampener near disaster and did the banjo bolt swap with great success. Fast forward to yesterday and again with the extreme gasoline smell (stock FC/S4 GXL- except for RB header and high flow cat).
This time it's the hose that comes up from under the UIM and then hits the fuel rail. Pinhole leak-spraying directly onto the header (that's cute). Tried a "quick" fix: cut and slide in a fuel union, but the whole hose feels brittle and I think it's just a matter of time before it gives out.
Did a little research and found that Mazda did a recall on later models for this exact problem, but could not find what the better, more heat resistant replacement hose might be.

So...is there any recommended fuel hose type for life under the UIM?

 

the best hose is the OEM hose, its excellent, it will easily last 20years, however its also really expensive.

the FD had a fuel hose recall, but they didn't change material of the hose, they changed the clamp/crimp style.

next best is either hose from BMW or Mercedes, for about $15 you get a 1 meter length, every dealership will stock it, its not as good as the Mazda stuff, but its decent.

the parts stores (autozone/pepboyz, etc) sell high pressure fuel hose, but its not metric, and its just not as good as the OEM solutions, and isn't really any cheaper, and sometimes they don't have it...

 

Use a caliper and measure. You can find the shitastic united states measuring system fuel hose that is extremely close, it does not matter once you tighten it with clamps. I can not comment on it's quality. Every napa would have it.

If you want quality, I'd look into ordering some stainless steel braided fuel hose and appropriate fittings. That can get expensive though.

 

Many thanks!
Looking into the price of the OEM hose, but can't seem to find my FSM for the part number. Oh well, more digging around.
This will be my first UIM removal and I'm bookmarking all the tips and guides. Wish me luck!

(Except for the fuel leak she runs/idles rock solid. Hope it comes back normal after I finish with this UIM project.)

 

Parts finch 1-H4. It's hard for me to decipher what is what because I only worked on S4 T2's. Which hose(s) do you need?

 

Buy calipers. Don't take advice from anyone unless they own calipers. Harbor freight has some cheap 6" digital calipers. Figure out the inner diameter (ID) of the fuel hose. Measure the OD of the metal tube the hose slips over. Write it down. That's the ID of the fuel hose. Get a measuring tape and measure the length of hose you need. Overestimate. Buy some hose and clamps. You want nitrile rubber.

Low-Pressure SAE Fuel Hose
McMaster-Carr

 

The factory hose is 8mm, everything in the us is going to be 5/16 which works.

You need high pressure hose for EFI

 

I'll go out on a limb and claim that the current Goodyear fuel injection hose is as good as it gets.

5/16" hose is an excellent fit for the stock lines.

 

aircraft grade AN line is the BEST option, however it is not the easiest nor is it very cheap.

I've used high quality transmission cooler hose for years (5+) with 0 issues. however I changed every rubber line in the engine bay when i removed the rats nest and used some wire loom cover over the hose so that it was not laying directly on top of the engine and also used stainless steel FI band style hose clamps (not worm-screw).

I went through this spring and redid all of the vac lines with silicon hose and replaced all of the fuel line again because i decided to change the routing and wanted to inspect the hose for possible damage. All of the transmission cooler hose was all just like the day i put it on. I replaced it anyway with new clamps (only $2 a foot at most parts stores) and decided to up my hose protection with some DEI heat sheath hose sleeve. for the parts that run over the top of the engine and under the intake manifold.

In conclusion, the trans cooler hose is rated for silly high pressures compared to a common FI system (the hose i used had 300psi max printed on it) and ATF has so many aggressive cleaners and additives that it must be able to cope with gasoline without issue.

 

Yes, SAE 30R9 is good stuff, as mentioned previously by cone_crushr. You can get it at your local generic auto parts store or online dealers like Jegs, usually listed as "EFI" hose.

That's a common misconception. AN (Army/Navy) is the fitting type, not the hose. The hose itself can be any of several different grades. The more common, CPE-based hose will degrade faster than most of the modern EFI automotive hose on the market. The fact that it is good for 1,000psi is a moot point when your fuel injection pressure is only about 50psi.

Low-pressure SAE J30R7 hose is sub-standard for EFI. However, it will work fine for carbs if you don't premix.

I own digital calipers, so you can take my advice.

 

SAE 30R9 looks like the stuff I'll be picking up. No worm screw clamps.

 

What's the stock fuel pressure?

 

about 38-40 Psi.

..and just a side note, I would recommend Fuel injection clamps when doing this rather than worm gear clamps or those old stock clamps..
Oh..and High Pressure EFI Only hose,..the regular gas line is only rated to about 15psi..