Good evening all just wondering what the limit is of the standard fuel lines ie how much fuel are the able to run power wise and if anyone knows the internal diameter of them?

At the moment i have a Bosch 44 pump and its having to push the fuel through the standard fuel filter so im wondering to fit the high flow filter (15mm in/out) but wanted to keep the standard lines

any help as always is much appreciated

I've never heard of any modded Coupe being held back by the OE fuel lines - they seem to be capable of delivering enough fuel for over 600bhp, so I really wouldn't worry too much

I'm using a Walbro pump but a standard filter

My only issue is fuel starvation when the tank is around a quarter full and I'm at max boost for more than 10 seconds or so - I guess I could do with a lift pump to a separate swirl pot

I replaced most of my lines as like you, I went for a 044, swirl pot and separate fuel filter. Can't remember the size that I went to, maybe 8mm ID as when you start looking at fuel line sizes everyone talks about -4 -6 -8 JIC and I have no idea on what the ID mm is from that! In the end, I bought 10m of braided fuel line, took all the bits to thinkauto and got them to give me all the necessary adaptors to install it correctly

cheers for the reply guys

I have got rid of the standard fuel filter for the hjigh flow one, so i managed to getting a fitting to go from the 44 pump back into the standard fuel line so all done and now moving onto the next part of the things to do list.

I think the tuning guy Kj16 or whatever changed his to allow more fuel but I 'm not sure...hopefully he will pop along....

as Nigel has highlighted there are coupes running 600bhp with standard fuel lines so i wont be replacing just yet im only at 450Bhp and 3 bar fuel pressure so im along way off needing to change them

Hi. That's right, I changed the outgoing hose to 6mm (or was it 8mm??). But I was also running an overkill fuel system because I originally intended to add nitrous too; I had two 255 lph pumps running in parallel and the stock fuel line was strangling them.

I've since changed to a single Walbro 400 lph pump, which flows much better than the two pumps in parallel anyway!

It's fairly straightforward to up-size your outgoing fuel hose, so try running the stock hoses first and then you can easily upgrade if it becomes necessary in the future.

Nothing special needed for the fuel filter. In my case I just used the first similar-sized one in the shop that had 6mm hose tails

KJ16v did the 6/8mm braided line fit in the original fuel pipe routing clips? or how did you run the lines i dont really want to start drilling holes in the underside