RngTrtl

Dear All (1985, USA, AUTO)

I am wanting to replace my fuel lines in the engine bay (the horse shoe at the back and the straight one up front). All I can find is fuel line that is rated at 50 PSI (I checked Autozone, O'Reilleys, and NAPA). I know that the fuel pressure will not exceed that, but is it rated high enough?
I did a search and found some godo information, but nothing definitive. Any advice will be appreciated.

Thanks,
~J

Giovanni

Check out this thread: https://rennlist.com/forums/showthre...light=fuel+psi

If you ever decide to SC your 928 you will need to replace the 50 PSI hoses with high pressure hoses. You may as well do it right the first time :-).

RngTrtl

If/when I do SC the car, I will repalce all the lines with SS braided probably. Now I just want to make sure the car does not catch on fire

FlyingDog

I'd go higher. Stock pressure for your car is 36psi. Many people with adjustable FPRs go up to low to mid-40s. All if takes is an FPR failure or return line clog and 50psi is not unthinkable with either stock or aftermarket FPR. The pump will put out well over 100psi with no problem...

mark kibort

I'm at 74psi fuel rail pressure with my stock S4. (w/RRFR) . vacuum pull back brings it down to 68psi when idling. our fuel rails are only rated for 50psi???? thats a little scary!

mk

FlyingDog

WTF did you get that the rails are only made for 50psi? Your stock pressure (87+ 928s) is 55psi. As far as I know nobody has blown a fuel rail and the Murph guys run well over 100psi.

DR

J,

Youy need to get Fuel Injection hose rated at 30R9, sounds like you are getting regular 30R7 hose and it NOT acceptable for fuel injection systems (most hoses like that are actually labeled "Not for Fuel Injection"

Go to Advance Auto parts and ask for part #P1503 . IF you ask for 30R9 hose they will probably look at you funny.

RngTrtl

Thanks for all the great infomation guys. I am glad that I consulted y'all before I did something stupid.

Mrmerlin

just a bit more info if you find fuel line you can usually tell by looking at the end if it is low pressure or Hi pressure by the amounft of threads running thru it most of the Hi pressure lines we use have atleast 12 threads the low stuff has about 6, Hi pressure line usually has an inner and outer line bonded together with the treads between.

Brett928S2

Hi

DONT think that Stainless Steel braided makes any difference !!! Its the pipe INSIDE that takes the pressure NOT the SS.......

MAKE SURE THAT THE INNER PIPE CAN TAKE THE PRESSURE YOU NEED !!!

Using Nitrous my pipes need to take 2000 psi and they are plastic lol...there ARE SS versions....but that makes no difference to pressure capability...

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH, K&N, WIZARDS OF NOS - NITROUS KIT 150 HP JETTING - 505 BHP / 500 FT LBS TORQUE
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

ROG100

As Brett says stainless braid is there for abraision or as a pressure restraint on high pressure hoses. These are not high pressure hoses in the true sense of the word. 5000psi is high pressure.
As Dave says you need EFI hose rated to SAE 30R9. Most auto stores know it as EFI hose. Fuel hose will not cut it.
If you are replacing the U hose do not use SS braid as the hose is not rated for the 30mm min bend rad. SS braid restricts the MBR and makes the hose stiffer. SAE 30R9 will give you the bend rad for the U hose on the 85/86 cars (not 87+) without kinking if you allow some extra length to relax the bend rad a little.
SAE 30R9 is rated for a working pressure of 125psi and a min burst of 900 psi.