Fuel Filler hoses

[nick729]

Hey,

seems like i have not been provided with the correct fuel filler hose from the gas cap to the tank. I have the straight fuel hose, and the only other hose i have is a 90 degree silicon hose which fits, however, silicon and fuel is not a good idea as far as i am aware.

Any ideas why FFR uses such a strange way for routing the fuel to the tank? I am thinking of buying flexible fuel hose which in theory should eliminate 1 extra connection and i could just use the the flexible pipe and connect it straight to the fuel tank metal pipe? Am i missing something obvious?

My plan is to use this hose:
https://www.carbuilder.com/products/ultra-flexible-fuel-filler-hose-51mm

Hoses i was provided with:
206815

Any thoughts?

[edwardb]

Change it if you want. But my Coupe was built with the kit provided parts including the silicone elbow and it's been on the road for four seasons now without any issues. Not all silicones are the same. Some aren't suitable for fuel, others are. I've had no issues with the piece FFR supplied. I doubt they would miss something as basic as that. Plus it's not immersed in fuel. Just making the connection.

[Kbl7td]

That stuff is extremely stiff from what I remember, I don’t think you’ll get the necessary bend.

[nick729]

@edwardb - looking at your build, seems like you have the same hose as the manual shows and it looks like it might be from rubber rather than silicone. The hose i have is different shape, thus the instructions become irrelevant (not that it is a problem) and thus my confusion if i have the right hose, or if it is not the right hose can i still use it?! If the silicone hose i have is provided on purpose instead of the one shown in the manual, the question is where should i use the other hose labelled Fuel then? :) I do have a lot of wrong parts, duplicate parts, so i would not be surprised if these hoses are not the correct ones :)

@Kbl7td - if you are talking about the left hose in the picture, yes that hose is rock hard and you can't bend it at all and i have no idea where i am meant to use it...

This is the hose shown in the manual
206816

[edwardb]

Hopefully you are addressing your parts issues with Factory Five. My experience is they take care of them. My build was several years ago, and Factory Five certainly does make changes. The pictures in the build manual aren't always updated (often not...) so don't get too literal with what is shown. All I can say is I cut the parts they supplied like shown in the manual and it works. I did have to trim the aluminum side panel slightly. Mentioned in my build thread. I don't recall whether the part was rubber or silicone. But as I said, not all silicone is bad with fuel. Up to you. Heaven knows I've made lots of parts changes on my builds for no other reason than my choice.

[David Williamson]

I had hose that looked like yours but I don't think it was Silicone rubber. Check to see if it is lined, if not i would not use it. Maybe contact FFR to verify.
David W

[nick729]

Hopefully you are addressing your parts issues with Factory Five. My experience is they take care of them. My build was several years ago, and Factory Five certainly does make changes. The pictures in the build manual aren't always updated (often not...) so don't get too literal with what is shown. All I can say is I cut the parts they supplied like shown in the manual and it works. I did have to trim the aluminum side panel slightly. Mentioned in my build thread. I don't recall whether the part was rubber or silicone. But as I said, not all silicone is bad with fuel. Up to you. Heaven knows I've made lots of parts changes on my builds for no other reason than my choice.

I can ask them questions, but I no longer expect to receive any more parts from them as they told me that the last batch of missing/wrong parts was the last they will ever send me.. I suspect it is due to the insane shipping/duty and import taxes for shipping all those parts to me. So i am more or less on my own now, hence the many questions :) I have many changes to mine too, that's not a big deal.

p.s. from my own experience and from what i heard from others, foreigners especially from smaller countries are treated vastly different in comparison to locals/US citizens :)

[nick729]

I had hose that looked like yours but I don't think it was Silicone rubber. Check to see if it is lined, if not i would not use it. Maybe contact FFR to verify.
David W

Thanks. The 90 degree hose is pure silicone, the same as you would use for cooling system but slightly flimsier..

I've sent FFR an email, but it takes them usually 2 days to reply - this forum is much faster :)

[Just 1 More]

See if you can find a Gates 24717. I used one for relocating my fuel filler on my FFR 33

https://www.gates.com/us/en/search.p.4278-000000-000000.v.4278-07000.html

[Skuzzy]

You never want to use a silicone based rubber which is going to come into contact with a petroleum based fluid. It will deteriorate over time.

Best polymers for carrying fuel would be PTFE, Nylon, or Nitrile.

If the rubber carries the stamp "SAE J30 R6" or "SAE 30R6", then it is safe for carrying blended fuels.

[Smith is Retired]

I built my Gen I 21 years ago and faced this problem. I did not like the hoses provided, so I put together a mockup out of PVC pipe from my local Home Depot. The complicating issue was a bit of an offset bend that was required, but once I got it right, I took it to a muffler shop that bends its own pipe and asked the guy to replicate what I had put together. He did and it made the job much easier. I still have that PVC model.

[TwinFins]

I know this thread is over a year old, but I just ran in to the same issue and didn't find another thread with resolution in my search. The hose I got, similar to the original poster, is silicone. I'd say its the same material and consistency as the coyote air intake hose with no DOT labeling that would indicate it is safe to use with fuel. I can imagine where to cut it to make it all fit, but is that the right path to take? Is everyone with coupe deliveries since mid 2024 ish getting the same hose now?

223733

[TwinFins]

Easy peasy (minus the clamps at this point), just a doubt about the fuel rating. Ill reach out to FF and see what they say.

223745

[Skuzzy]

You really want to avoid using silicone rubber where it will come in contact with fuel. Look, I get my information on this from a friend who has a PhD in Organic chemistry. He gave me a 45 minute dissertation on what happens when ethanol comes int contact with silicone rubber. He stopped at 45 minutes when he realized my eyes had glazed over,...then he just stopped and said,..."It's bad. Don't do it!".

If the hose does not carry the proper SAE ratings, then it will be a crap shoot. In my book, it is not worth the risk.

[TwinFins]

I dont disagree with you, but then why is that what they are including in the kits now?

[Skuzzy]

I dont disagree with you, but then why is that what they are including in the kits now?

I can only speculate on that. FF also says to use PTFE on brake line fittings and that is also wrong. I have another friend who owns a company that makes gas station fuel pumps and gauges for commercial fuel tanks. He is not an organic chemist, but an electrical engineer. He says he cannot use any silicone in his systems or they will not pass certification. He even asked about silicone jacketed lines and that was denied.

Think about this. Why does the hose not have SAE certifications on it? I can only think of two reasons. 1) The company making the hose did not bother with certifications as it will absolve them of any liability if/when the hose fails and 2) They did not want to waste the money trying to get certification as they know it will fail.

When blended fuels came along it required all new materials in the fuel management systems. Automobile manufacturers had to eliminate aluminum from the fuel delivery systems as the Ethanol was corroding the aluminum. Neoprene rubber went the way of the dodo. No automobile manufacturer has ever used silicone rubber in a fuel system.

At the end of the day, it is your car. I used to ignore SAE certifications, until I got friends whose very livelihoods depend on them. Learning why those certifications came along is an eye opening experience. For me, I will not bet my life on something, in the fuel delivery system, which has not been properly certified.

[warnertype65]

I too have the silicone hose that everyone is describing. Has anyone found a suitable replacement or should I just build one from new hose like this.
https://www.tanksinc.com/index.cfm/page/ptype=product/product_id=842/mode=prod/prd842.htm?srsltid=AfmBOoqboc-LFCL4LNA6pRq99eDKZOFz6zLKxNMXyFu_jOhfZmcC89xb

[Skuzzy]

I'll be using Gates fuel filler hose when I finally get there.

[Papa]

I haven't looked closely at what FFR sent with my kit, but I do see a lot of performance part places selling silicone filler hoses like this one:

Fuel Hose, 2" I.D. 90 degree Elbow, 6" Legs - Pegasus Auto Racing Supplies https://share.google/agdORo8DmOJQNr7Ks

Like others have said, not all silicone hose is the same and if the provided hose is something like what I linked, it should be perfectly fine to use.

[Skuzzy]

I haven't looked closely at what FFR sent with my kit, but I do see a lot of performance part places selling silicone filler hoses like this one:

Fuel Hose, 2" I.D. 90 degree Elbow, 6" Legs - Pegasus Auto Racing Supplies https://share.google/agdORo8DmOJQzx
3Nr7Ks

Like others have said, not all silicone hose is the same and if the provided hose is something like what I linked, it should be perfectly fine to use.

As long as it has the appropriate SAE certs on it, then it should be fine to use.

You never really know the composition of any rubber. Marketing has a way to use the most popular terms even if it only comprises what the paint stripe on the hose contains.

[TwinFins]

FF hasn't replied to my inquiry yet. Maybe I'll send a follow up, Ill let you know if they say anything. Being an engineer for one of the "big 3" i respect the DOT ratings and would like an official reply if this stuff is legit or not. Considering there are no markings I have doubts.

[nick729]

FF hasn't replied to my inquiry yet. Maybe I'll send a follow up, Ill let you know if they say anything. Being an engineer for one of the "big 3" i respect the DOT ratings and would like an official reply if this stuff is legit or not. Considering there are no markings I have doubts.

I was assured by FFR that the silicone hose (pic in the first post of this thread) is meant to be used for fuel filler..

I used this instead: https://www.carbuilder.com/products/ultra-flexible-fuel-filler-hose-51mm cut it to length, and avoided unnecessary joints. I did have to cut the hatch side panel a little bit more, but that might be due to position of the body. If i used the provided silicone hose I would have to do the same regardless, as there is very little space between the fuel filler neck and the panel/frame.