In my opinion the most difficult task is to determine the actual needed flow rate instead of relying on marketing info (..supports up to XX bhp). So what my approach looks like currently:
1. I'm running the stock mechanical fuel pump. According to the FSM, it is rated at 0,24-0,29 bar ( 3,41-4,27 PSI), 1600 cc/min @ 1000 rpm ( 96 l/h FREE FLOWING)
2. I never had any issues with fuel delivery, hence the above flow rate/pressure seems to be fine for my stroker engine. Assuming the stock pump doesn't deliver much more at higher engine speeds.. (?)
I would prefer a low pressure fuel pump with no external regulator needed. Right now I am looking at a HÜCO 133000 pump, made in Germany and part of the HITACHI group. There's a full datasheet available, link below. Apparently a high quality pump and very quiet (from what I've read).
They provide proper data (free flow rate and flow rate depending on pressure), most other manufacturers only provide the free flowing rate for marketing purposes. The Hüco is rated 125 l/h free flowing, 45 l/min @ 0,25 bar. It weights 850g so I expect some decent quality here. Right now I think I'll get this one (also very reasonable priced at around 50-80€). I like that it can be mounted similar to the OE electrical pump with inlet and outlet at the top.
The easiest way for some added safety is a generic Volkswagen fuel pump relay 321-906-059C (around 15-35€). I don't know why it isn't being used more outside of the VW crowd but it seems to be super straight forward: As soon as the relay gets ignition power, it provides power to the fuel pump for 3s (max). It then stops, only if it senses a trigger pulse from the coil negative it continues to run. Some of these even have a slot for a regular automotive fuse.
I'm not sure where to get the negative coil side close to the fuse box, though. Is it the same as the negative side of the current sensing tach?
Fuel pump datasheet:
https://www.ez-catalog.nl/Asset/06f...c0/Original/133000-Huco-productblad-DE-EN.pdf
Relay:
https://vwparts.aircooled.net/Electric-Fuel-Pump-Relay-321-906-059C-p/321-906-059c.htm