Fuel system

[Alexb944]

Well here I am again.
So I have had a hell of a time getting this thing up and running correctly (85.5 944 lux)
well I will have to replace the clutch probably this winter as I do not have time to do so right away so its going to be in storage for a while.
Now Ive been seeing alot of 944's catching fire, and well.. I dont want mine to... so What do I need to do to future proof it? Ive priced everything from the tank line to the injectors(O-rings) priced it to just under 1400. all SS line, and LR rail.. (everything from LR) what are your thoughts? Am I a little overzelous? or Ultra overkill?

[IdahoDoug]

Chiming in and hopefully not a hijack to ask if there is a route forward purchasing quality bulk fuel line and a bag of proper fuel line screw clamps. I am in the same boat with an 84 that has original fuel lines on it. Watching the thread.

Doug

[v2rocket_aka944]

don't waste your money on the fuel rail or anything...
buy a spare stock rail and have it leak tested and brazed if necessary by a local radiator shop.

buy the r e n n b a y fuel line kit for $120 or so and just stick it on for the next 15 years.
SS lines are really overkill and a pain in the ass to work with/around in the future, rubber is just fine.

injectors...they can die but they are very long lived, just get the o-ring kit from one of our 944 suppliers or you can get them from your local auto parts store (same type of injectors used on almost all EFI cars from 1980s-1990s)

new injectors can be sourced if needed (stock NA needs 220-240cc @ 3BAR, low-z 2.4-2.8ohm coils, there are other car injectors that can be made to work if needed)

[John_AZ]

+1^ ---+10 on the L B kit.

Match the injector kits and be sure the plastic "hat" is the same as the one removed'

WitchHunter can do the best job of cleaning and testing the injectors.
WitchHunter Performance - Injector Cleaning & Flow Testing Services

...and here is an enjoyable read:
Fuel line replacement-924S & early 944s

J_AZ

[Alexb944]

So just get a factory fuel rail? what is flow tested and where would I be able to have it done? also just the rennbay kit. nothing else?

[v2rocket_aka944]

- Fuel pump is probably fine until it dies, it's a 20 minute job to change out when needed.
- Fuel filter is $20 or so here on Pelican.
- You might want to climb under your car and inspect the hoses from tank to pump, and pump to filter.
---If they look worn out you can buy new Porsche ones, or take the old hoses to a hydraulic shop and have them rebuild them for less.
- Unless you live in a winter-salt state your hardlines under the car are probably OK.
- The fuel lines from the pass. side wheel well to the fuel rail you can get from Rennbay.
- Stock fuel rail is fine, used/proven past 500hp on the turbo models, they are everywhere and cheap, just get it leak tested and fixed if needed like I said previously. The LR and similar rails are "bling" and nothing more.
- You can send your fuel injectors to witch hunter in OR, RC eng in CA, or some other places (google "injector cleaning service), they will super-clean the insides of your injectors and replace the little internal filter and give you flow-test results, you'll be amazed at how well the car runs after the injectors are refreshed (they cannot be rebuilt, only cleaned out very well), usually this is about $20 per injector
- replace the injector O-rings, you can probably ask the fuel injector service place to include a set when you order.

[djnolan]

Originally Posted by v2rocket_aka944

- The fuel lines from the pass. side wheel well to the fuel rail you can get from Rennbay.

On an 85.5 model car, you have to get creative to replace the original crimp collar connectors and lines. Your two choices are

1. the Rennbay kit involving hardline cutting and adding fittings
2. Good old fashioned fuel hose clamps (perhaps doubled) and new fuel line/insulation.

For option 2 there is upgraded fuel line sold that is more heat resistant, too such as aeroquip. There is also stainless steel braided insulation you can put over rubber or upgraded lines.

The hardlines are single barb and are only good to certain fuel pressure you probably would only (never?) exceed at the track

The same general principal applies to the tank lines, too.

[v2rocket_aka944]

early model 944 has that as well, just cut off the old fitting and use a compression fitting.

fuel pressure will never really get past whatever the FPR is set to (on a 944 2.5 bar, the 1989 8 valve and the 16 valve cars used 3.8 bar) but even that isn't really out of the pressure range of a "fuel injection hose clamp" you can get at the FLAPS