Carl Fausett

If you just want to buy a meter of the OEM replacement hose, I sell it here:
http://www.928motorsports.com/parts/hipressfuelline.php

Then you can make your own.

Like H2 said: the true original material is no longer available, and the replacement for it is better.

ROG100

Update
I have discussed the hose with most of the major hose manufactures and it is impossible to meet the design criteria with a hose that can achieve a 25mm min bend rad.
The braided hose shown earlier is also not suitable due to the min bend rad.
That does not mean it will not work but that the hose is in a situation that it was not designed for.
The original hose is preformed and uses a thermoplastic of some type.

Porsche looped the U hose under the MAF and slightly to the side of the cable pulley, trying to cater for a space and non-interference installation.
I have been able to find some suitable fittings that will allow me to run a standard EFI hose towards the rear of the car and loop it behind the fuel cooler.
This will allow a much better run for the hose and a larger bend rad. The hose should also be in a cooler position with some air circulation and perhaps last longer 8>)
I will report back when I have completed an installation and conducted some road tests.

Carl,
As this was your post I will be happy to share my results with you so that the solution is available from more than one source.

Thanks,
Roger

sharkmeister85

Roger,
Just to be clear, this problem with the bend radius applies only to the S4 "loop" because it uses different fittings from the 85-86 "loop". Correct?
Glenn

the flyin' scotsman

Roger...........did you get a solution to this hose ('U' hose)?

Sorry Roger, just read your update. shall wait for more details.

ROG100

Glenn,
Correct.

Malcolm,
Read post number 47 - you must have been typing while I was posting 8>)

Thanks,
Roger

piccardo

How big of aloop is required to go around the fuel cooler?

heinrich

If you have no fuel cooler, you need not go around it ... Roger thanks for the excellent info, this is what I had thought. I would not be wanting a hose there that was not either preformed or larger in loop, because I have seen too many aftermarket bends kink after a while. Sometimes a very slight loop in say a breather hose will kink and pinch **** at a fold. My solution is as yours is for now -- when I deleted the fuel cooler I went with a very large loop at the firewall, to ensure there is very little stress on the hose as it loops.

One must also remember, these are low-pressure return lines. Not high-pressure feed lines.

the flyin' scotsman

Heinrich.........how long have you been using your set up? Any pics?

I'm about to R&R my fuel lines (thanks Roger) but as the 'U' line is NLA I'm going with the EFI line and clamps as a replacement but as Roger cautions I don't want a kink.

heinrich

Hi there Malcolm, about 20k miles. The cooler is useless in my opinion, it cools return fuel to the tank, not into the engine. Realising that 90% of 928 ac systems out there today are inop, I have to conclude that the fuel cooler can be safely removed. It simplifies things and makes a lot more room to work behind the engine - I had this idea when I worked on an early car that did not have one.

PorKen

I really think the Engineers overdid it with all the little brackets on the '85-'86.

I reckon if you got rid of the brackets rigidly holding the regulator and damper to the head, you could put a straight hose, or even a rigid pipe between them, instead of that dorky hose. How much expansion between the heads were they expecting, anyway?

The fuel cooler is an emissions thing. Reduces vapors in the tank.

the flyin' scotsman

With the fuel cooler removed does your a/c work? If so did you run an extra line between the expansion valve to the existing line bypassing the omitted cooler? (perhaps a different thread).

I have an idea re. making a replacement 'U' hose from EFI line that I've proposed to Roger. A work in progress that may be a solution.

heinrich

Ken, I think the engine grows by about 3 feet ... Malcolm, replace the hose with a straight tube and the ac will flow through that tube..... I had an R-134a -compatible hose cut and crimped to two fittings to screw into the ac lines in and out exactly as the cooler would have. Does my ac work? No ... I have no compressor in there, hasn't been a priority.

H2

I still think that the braided and CRIMPED gas lines for NLA replacements are probably our best option. The steel braid should pre-empt any hose collapse. This is assuming that the braid covered lines are gas-proof. Plus:

1) An alternative approach to hoses that might "collapse" due to the sharp bending radius we're talking about could be taken care of by making a COMPLETE LOOP with the hose rather than just the horseshoe shaped bend. Maybe not popular...but race car drivers sometimes have to do this. A variation of this would be to just make the horseshoe hose shaped bend more of a FATTENED horseshoe shaped bend that would give more room and help pre-empt folding. All of this subject to space in the area the hose has to go.

2) I'm not a fan of screw on clamps for gas hoses. They can vibrate loose. Race car drivers who use these on low pressure hoses put wire retainers on the clamps to help keep them from vibrating loose. If you choose to go that route...it's an idea.

3) I'm still not pleased with the condition of either the hose or the fittings of the replacement '85S hose I got from an auto dismantler and would like to buy new fittings and toss the POS I paid $50 for. Someone crimped down too hard on the fitting and it's damaged so I'm not willing to invest another $50 or so to get a new hose put on it. Does anyone know the size of the threads of this gas line fitting? And/or a source for such? Am I correct in assuming they are metric?

4) And finally, is the U-shaped gas hose near the MAF a high pressure or low pressure hose?

In short, I'm leaning towards a crimped on steel braid protected, gasoline tolerant hose with new fittings...and perhaps a hose clamp on top of the crimp...just for an extra measure of safty on this part that's seldom visible for regular inspection.

Is this overkill? Too many guys with near-misses and crispy 928s out there to not be extra careful.

Harvey

the flyin' scotsman

The steel braid protects the outside of the hose; can't see how there's any prevention of interior collapse.


If space allows but in the '87 and younger cars the U shaped hose was changed.........not much room at all.


The EFI clamps are added as an upgrade from the OEM design where the ends a simply inserted into the hose with nothing securing them.


High pressure I believe

Do we know which hose (s) split burst to cause the fires? I would suggest that all rubber hoses (fuel, pwr strg etc) are all suspect and should be replaced.

Bill Ball

The loop that goes between the dampner and FPR is high-pressure. That's the main piece at issue in this thread. The original S4+ version appears to be a semi-rigid molded core.