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Change the plastic fuel lines

 
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RPM2006  



Joined: 29 Dec 2009
Posts: 16
Location: Sweden, Stockholm

PostPosted: Wed Feb 29, 2012 4:34 am    Post subject: Change the plastic fuel lines Reply with quote

Hey. Begin to say that I'm not so good in English because I come from Sweden. If you're wondering as I am now using Google Translate.

I have a 924 from 1985. Would need to change the plastic tube that goes to the injectors. The high pressure is in the hoses? Do they have to be exactly the same length and have the exact same interior dimensions? Do someone know the dimensions?

Adds two images, one of the hoses and one on the car

/ / Markus

Lines:


Car:
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Horizonblue  



Joined: 13 Oct 2011
Posts: 303
Location: Sorring city, Denmark, Europe

PostPosted: Wed Feb 29, 2012 7:40 am    Post subject: Reply with quote

Hey

Jeg har spekuleret på det samme, men bygger nu elektronisk indsprøjtning på motoren, så er det jo lige meget. Har læst en historie om en person, der skiftede disse plasticslanger på sin 911. Han benyttede nogle andre højtryks slanger i plast. Resultatet var at motoren gik dårligt, når den var varm. Flere personer mente at de nye slanger blev for bløde (mjuke) når de blev varme og det betød at benzin leverancen kunne pulsere. Manden havde tilfældigvis et sæt gamle originale slanger som blev monteret i stedet for de nye, og med et gik bilen perfekt igen.

Dog tror jeg at længden spiller en rolle, de omtalte 911 slanger var ret lange. På din 924'er er de meget korte og chancen for problemer må være mindre. Jeg havde tænkt mig at bruge alm kraftig armeret 3 mm benzinslange, som kan tåle op til 10-12 bar, det kan købes ved "Mekonomen" i metermål. Dyserne åbner ved kun ca 3 bar. Kanske du skulle finde et ekstra sæt originale slanger/rør, inden du begynder på noget.

In English:
I was thinking about the same, some time ago, but I'm building an EFI system now, so it doesn't matter anymore to me. I've read a story about a 911 guy that replaced his fuel lines, with some new high pressure plastic lines. The result was that the engine ran terrible when hot. Some people believed that the lines became soft when hot, and the fuel was then delivered in pulses. The 911 guy actually had an old set of original fuel lines which he installed, and the engine ran perfectly again.

I believe that the length of the fuel lines plays a role in this situation, they were quite long on his 911, the 924 plastic fuel lines (after 1980) are quite short. The problem should be smaller, the shorter the lines, I think.

When I was working on this, I was going to use heavily armored 3 mm(1/8") fuel line, rated at 10-12 bar pressure. The injectors open at approx 3 bar.
Maybe you should find an extra set of fuel lines, before you do anything.
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"If you can't fix it, don't break it"

/P.G. Andersen
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RPM2006  



Joined: 29 Dec 2009
Posts: 16
Location: Sweden, Stockholm

PostPosted: Wed Feb 29, 2012 9:27 am    Post subject: Reply with quote

Horizonblue wrote:
Hey

Jeg har spekuleret på det samme, men bygger nu elektronisk indsprøjtning på motoren, så er det jo lige meget. Har læst en historie om en person, der skiftede disse plasticslanger på sin 911. Han benyttede nogle andre højtryks slanger i plast. Resultatet var at motoren gik dårligt, når den var varm. Flere personer mente at de nye slanger blev for bløde (mjuke) når de blev varme og det betød at benzin leverancen kunne pulsere. Manden havde tilfældigvis et sæt gamle originale slanger som blev monteret i stedet for de nye, og med et gik bilen perfekt igen.

Dog tror jeg at længden spiller en rolle, de omtalte 911 slanger var ret lange. På din 924'er er de meget korte og chancen for problemer må være mindre. Jeg havde tænkt mig at bruge alm kraftig armeret 3 mm benzinslange, som kan tåle op til 10-12 bar, det kan købes ved "Mekonomen" i metermål. Dyserne åbner ved kun ca 3 bar. Kanske du skulle finde et ekstra sæt originale slanger/rør, inden du begynder på noget.

In English:
I was thinking about the same, some time ago, but I'm building an EFI system now, so it doesn't matter anymore to me. I've read a story about a 911 guy that replaced his fuel lines, with some new high pressure plastic lines. The result was that the engine ran terrible when hot. Some people believed that the lines became soft when hot, and the fuel was then delivered in pulses. The 911 guy actually had an old set of original fuel lines which he installed, and the engine ran perfectly again.

I believe that the length of the fuel lines plays a role in this situation, they were quite long on his 911, the 924 plastic fuel lines (after 1980) are quite short. The problem should be smaller, the shorter the lines, I think.

When I was working on this, I was going to use heavily armored 3 mm(1/8") fuel line, rated at 10-12 bar pressure. The injectors open at approx 3 bar.
Maybe you should find an extra set of fuel lines, before you do anything.


Tack för svar! Danska är inte så lätt att läsa Ännu värre o lyssna o förstå. Längden kommer att bli mer eller mindre exakt. Har mätt och kom fram till att slangarna idag är 4,5mm invändigt. Men kommer att ta en slang som är 4mm, så att den pressas hårdare, och sedan slangklämma på det. Blir inget billigt Biltema skräp utan kvalitet från hydraulfirma.

In English (GTranslate:
Thanks for the reply! Danish is not as easy to read: P Worse still and listen and understand. The length will be more or less precise. Has been measured and found that the tubes today is 4.5 mm on the inside. However, will take a hose 4mm so that it is pressed harder, and then the hose clamp. It will not be cheap Biltema stuff, more quality from a hydralic company.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1448
Location: Somerset, UK

PostPosted: Wed Feb 29, 2012 9:43 am    Post subject: Reply with quote

My understanding is the line length within reason is not an issue as the fuel system remains at the correct pressure. The issue is if or when the pipes expand due to heat and or pressure. Pulsing will then occur and the injectors fail to perform.

The correct pipe is near impossible to source although I did find a US Ferrari website which managed to source bulk lengths of pipe from Germany for circa 20 cars. I'll search out the site. http://www.ferrarichat.com/forum/showthread.php?t=186689

I am also wanting to source and refurb my injector pipes on my turbo.
_________________
1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
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