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Replacing early 944 fuel lines with modern PTFE lines
Just ordered most of the parts for this project, wanted to share, as there isn't a lot of good info for the early 944 (Lart has you covered if you have a late car or 951).
I'm doing this for 3 main reasons..1) my fuel lines are a hot mess, as I have a 951 fuel rail in an early car, and some parts are damaged. Specifically, my hardlines are actually cut off near the torsion tube and it's bridged with rubber hose (!). 2) I'm going to be running E85 and PTFE is designed for that. These lines will outlast you and me. and 3) If I need to replace a line or add something in, it'll be straightforward once everything is standardized plumping (AN, JIC).
Starting at the tank and following the path of the fuel:
Gates Barricade hose connects the tank to the fuel pump, correct fuel injection clamps used (and will be used everywhere applicable).
Banjo bolt with -6AN fitting adapts to new PTFE line.
This new line runs to the fuel filter. Universal re-usable fuel filter with -6AN fittings is used.
Lindsay Racing sells compression fittings that adapt -6AN to the 8mm and 10mm hardlines. I'll use those to connect a PTFE line from the fuel filter to the 10mm delivery line.
At the other end of the hardline, the LR fitting is used again. This adapts back to -6AN.
This PTFE line runs to a 135* fitting with a female -6AN on the end. Why the angle? The damper is deleted, this will run into the port on the side of the fuel rail where the jumper line threaded to.
To achieve that, an adaptor from British American Transfer is used to convert the female -6AN thread to female metric 16 x 1.5mm thread.
And the return path:
3 bar FPR installed, since I'm running E85. 33# injectors and tuning capability already in place and working well.
5/16" Gates Barricade hose attaches the FPR to one side of the GM flex-fuel sensor. On the sensor side, it's connected via a barb fitting adapted from the quick-disconnect.
Likewise on the other side of the sensor (the fuel passes through it), a barb fitting is used. This goes to more Gates hose, which heads to the 8mm hardline.
At the hardline, the original swaged crimp is carefully cut off. This allows the 5/16" hose to be held on to the lipped line with a fuel injection clamp.
At the other end of the 8mm hardline, the LR compression fitting is used to adapt to -6AN.
A Push-Lok fitting can be installed to this. Gates hose is terminated to the Push-Lok, and runs back to the tank.
Are there are any gaping problems with this setup? Diagram:
I'll update this thread with pictures as I go through it...life is busy right now and it won't be done in one weekend. Right now the parts are in the mail. I've attached my parts list, which includes prices and URLs, as an Excel file.
What I did, was take all my stock fuel lines to the hydraulic shop.
Told them to salvage the fittings and fit with new HD alcohol-compatible fuel hose.
Took about an hour and $200 or so to do...all stock fittings reused.
I'd do that if I had stock fuel lines and fittings to start with, it would be about the same cost (if you don't look at the cost of the new FPR, flex fuel sensor, etc). Mine are hacked up and I've looked for good replacement fuel lines to rebuild, but said eff it.
Putting the sensor at the back is a fair idea, I'm just a little worried about the flow rate it would support, I don't want it to impede things (although maybe that is unfounded) and possible cavitate the pump. In theory I could put it at the back between the 8mm return hardline and the tank, but that sacrifices reaction time...should be as close to the rail as possible.
After messing with some braided line, I decided that it's not going to work well for this project because of some of the tight turns I'd need. Instead, I'm going to use Aeroquip Socketless, which is ethanol-compatible AQP material. It's much easier to work with, cheaper overall, and there are plenty of adapters available cheaply for converting between -6AN and Push-Lock. Arnnworx sells most of the fittings and hose material itself pretty cheaply, plus heat shielding.
I'd go that route but my rear lines are a train wreck. The hardlines were crimped by the torsion carrier when I was reinstalling it a few years ago and I had to cut out the damaged section. So in my case, may as well do custom everything.
I'd go that route but my rear lines are a train wreck. The hardlines were crimped by the torsion carrier when I was reinstalling it a few years ago and I had to cut out the damaged section. So in my case, may as well do custom everything.
Makes sense. I figured I'd throw out the Rennbay mention of only for those that give this thread on a search. You've got a hell of as build overall, so I figured you'd probably have some specifics that a stock kit might not cover anyhow!
I'd go that route but my rear lines are a train wreck. The hardlines were crimped by the torsion carrier when I was reinstalling it a few years ago and I had to cut out the damaged section. So in my case, may as well do custom everything.
hi
what is the size of banjo fitting on pump ? 12mm or 14mm
Sorry, this is no longer true. However, the Pelican link below can provide PN and supplier info for fittings. And the Aeroquip hose (in short lengths) can be bought at Pitstopusa.com
01-27-2016, 04:17 PM
Replacing early 944 fuel lines with modern PTFE lines
