I am in the midst of adding a fuel pressure regulator to my car and upgrading the fuel pump. It's an 82 rx7 with a Turbo 13b swap. So, nothing in the fuel system is totally stock or unmodified.
When I put the car together earlier this year, I used as much of the stock fuel lines that are steel with bubbles on the end to clamp rubber hose. For all the new components I added, I just used hose barb adapters and rubber hose to connect to the hard lines. I also made up some NiCopp lines for places where the stock lines didn't work.
It all turned out ok, but I never got a good method for making bubble ends on the NiCopp lines. All i had was a cheap autozone tool intended to make single and double flares, not bubbles, and >50% of the time the line didn't expand uniformly - creating a lopsided bubble that was almost flat on one side. I don't have any leaks, but those Nicopp lines concern me a bit.
Now that I need to dive back in to add the fpr and larger pump, I'm revisiting options for my fuel lines.
My number one consideration is that space is tight on my car where all of the new components are. So bulky lines and especially fittings don't fit well, and the space to tighten fasteners is limited.
I don't particularly like AN fittings and braided lines. Pretty bulky, so not great in tight spaces, and pricey.
I instinctively prefer hard lines running on the underside of the car - thinking they will be less likely to get damaged.
Vinyl lines look to be easy to work with and not bulky - do they hold up well? Do they need protection from rubbing on the chassis?The only experience I have with vinyl lines are on my 2017 F150 where one of the lines split for no apparent reason. Also , not sure how to get the vinyl line to conform to all the twists and turns needed to snake through the chassis like the steel lines do.
so tldr:
1. What works well for non bulky fuel line and connections?
2. How can I make bubble flares on the hard lines I make? I couldn't get the cheap parts store flare tool to work well at all.