Center tunnel fuel line replacement questions

[jsveb]

Hi guys

This is only marginally 930 relevant, but the resources I need is on this part of PP

I am going to change the fuel lines on my Carrera 3.0 and down the road on my 930 as well. The price of this stuff in Denmark is typically twice the US price so I might as well buy it now and put in on the shelf.

I have searched a lot, and asked questions, PM, as well. Thanks guys.

The best thread I have found was not surprisingly from Chris, TurboKraft.

2010: An EFI Hot Rod Odyssey

I have searched the inet for vendors, and can find lots, too much.

I'd prefer the same solution with alu tube as Chris chose on Toms 930, adapted for my Carrera 3.0

I simply don't understand all the AN measurements etc.

I think most of what was used by chris was from Earls. I have searched aeromotive, aeroquip and of course earls, but it is a jungle

So my question is: what specifically should I buy?

Do I need flaring tools etc for this?

I don't expect for someone to make a complete shopping list, I am just not sure for instance what fittings to use on the alu tube, and for that matter what alu tube to buy and where - Earls make some.

Hoses and fittings seems to linked together on the various web pages, so if I can just lock down the alu tube and the required fittings for this, I think I might be able to go from there

Thanks

[WinRice]

Jesper,

It depends on what horsepower levels you're looking at. I ran two -8 lines thru my tunnel using this stuff:

-8 BlackWrap SS Braided TeflonŽ Hose (10' length) | TechAFX

Unfortunately, it looks like they recently raised their prices.

My plan was to only do this once and have enough fuel flow for E-85 and any HP I wanted.

Braided teflon hose has a smaller OD than typical AN hose, for example the -8 I used had about the same OD as a typical Russel's or Earl's -6 braided rubber hose, so it fits a little easier. And being teflon, it should last forever.

Your Carrera 3.0 will be fine with -6 size hose.

You can get all kinds of AN to metric adapters to fit your needs from Summit Racing, Earl's, BAT, etc. I've been through this brain damage, so ask away.

[TurboKraft]

What we did for Tom's 930 was overkill for most any non-e85 engine. As WinRice said, you'll be fine with 6AN (3/8") lines. They will support 700hp without a problem.

We chose to use aluminum hardline because it has thin wall and a large ID. It would have been easier to use stainless/PTFE lines like WinRice did.

Another piece of advice: if you use PTFE (Teflon) hose, use the same brand of hose ends as you use hose.
You would think they are all interchangeable, and often they are -- but not always. Most companies (Earl's, XRP, etc.) actually have their hoses made by one manufacturer, but a few (Aeroquip, for instance) makes their own and their tolerances are slightly different.

Also, you can often find the stainless/PTFE line from commercial hydraulic shops for a lot less money than from speed shops. If they crimp it for you, they can also leak & pressure test it for you.

[jsveb]

Thanks for the responses.

One of my reasons for going this way, is that I want to be somewhat sure, this update will last my time, also considering E-type fuels or what ever they decide to throw at us in the future

One of my concerns was precisely to be able to get enough fuel through, but realistically 700 hp should suffice for the 3.0.
For the 930 I might go for the -8 I do not want fuel lines to become a limiting factor, which they prob won't, but you never know...

My Carrera 3.0 is completely apart now, so I don't think it'll ever get easier to do this.

Chris, I don't know if you mind sharing where you source what you use? If not, would this be ok for fuel line?

Earl's - JEGS High Performance

I'll be back with more questions later - thanks.

[Spenny_b]

Hi Jesper,

You may find exchange rates more favourable by checking out suppliers in the UK...Kr > ŖŖ may be better?

If so, I was recently at Think Automotive here in London (I was also chatting about this to Chris the other day on the phone)...I'm going to be doing exactly the same as you, new fuel lines and new oil lines, as part of my EFI conversion.

They have many options, from re-usable TFE (more rigid and ultra light and flexible) to rubber, to swaged on fittings on either PTFE or rubber...you name it, they can either supply it or make it for you. They also have in stock all the metric > JIC (ie, the -6, -8 fittings) adapters, etc etc.

They really were extremely helpful - I've been using them for 6-8years for fittings on my racecar (which uses the more rigid PTFE lines), thoroughly recommend them.

Hope that helps
Spencer.

[TurboKraft]

Jesper,
Jegs and Summit are two big online retailers.
We get most of our materials from local businesses, or direct.
Look into "Think" like Spenny's recommending -- having metric ends to mate right to your pumps and filter, no adapters, that's ideal.

[BoxsterGT]

You have a number of choices for the lines thru the tunnel.

The factory uses the black Polyamid line and its extremely durable. I have never ever heard of a failure with the tube itself. The problem has been the way it is installed in the vehicle. The factory made permanent connections to rubber hoses at the front, and the rubber hose is what always fails.

Many of us have gone to SS tube or Aluminum tube thru the tunnel. and these are available in 8mm & 10mm sizes. I believe our host offers the SS tube in both sizes. The usual way to make a connection is by flaring the ends and using AN or Metric flare fittings.

Look for postings by JeremyD or by Shaun 84 Targa on their engine swaps and fuel line installation. They both have later EFI motors in early cars with the fuel pumps moved up to the front. They kept everything Metric with fittings & hose I supplied.

On my own Porsche I am going to use the Polyamid tube Porsche and just about every other car company worldwide now uses, primarily because of the crazy fuel now being produced. The difference is my Poly lines will have M14 or M16 threaded male fittings so that the new multi-fuel rubber hose can be replaced when needed.

I have already made a few test lines and the results are very positive. I am importing the tube & fittings from Cohline in Germany, the original equipment supplier to Porsche. I expect the cost is about one half of what the factory OE lines cost at present.

I expect my first shipment of tube & fittings to arrive by early March. Once assembled I will post photos.

I hope this helps.

Len at Autosportengineering dot com

[gsmith660]

I am going to use 1/2 inch stainless steel seamless tubing to go through the tunnel.

[TurboKraft]

Len brings up a good point: make sure any hose you use is compatible with alcohols.

Many of the braided stainless & rubber hoses on the market are not rated for alcohol, which means they will degrade from pump gas which is often a blend of 10-15% alcohol.

Most current production cars' hoses are completely compatible with alcohol fuel.
Judging by the breakdown of 930 CIS injection hoses (ex: on WUR) when running modern fuel blends, I don't think the stock hoses are alcohol compatible.

[jsveb]

Len, if I screw my DIY attempt I'll be contacting you about this. Looking forward to you posting results.

One of the reasons for me doing this is exactly to be able to run alcohol fuel.

Being partner in a Whisky distillery, this only makes sense

[nreed]

Originally Posted by gsmith660

I am going to use 1/2 inch stainless steel seamless tubing to go through the tunnel.

Good luck getting it to not interfere with your shift rod...it's tight in there.

[gsmith660]

The -6 braided hose I have in there right now has a larger OD than the tube I am going to use with no interference I don't think it will be a problem

[proffighter]

I have braided hoses AN-6 there too. No problem... and they are in a seperate tube inside the tunnel anyway, so can't touch the shifter rod at all

[BoxsterGT]

For race car use, where EVERY-thing gets inspected on a regular basis, the braided SS hose is fine. However, in a tunnel where no inspection of any kind is possible I would not use hose, only seamless metal or Polyamid tube as per the Porsche factory.

I would also not use braided hose for street use or where the fuel hoses will not be inspected often. Plain rubber hose on inspection will or should show symptoms of a failure in time to prevent any catastrophies from happening. When is the last time you personally inspected every inch or mm of fuel or brake hose on your track vehicle? Most braided hose has the same rubber compound as normal hose, and it ages/fails at the same rate. The benefit of braided coverings is for abraision protection, and of course bling.

How many Pelicans still have some or most of the original hoses that our Porsches came with? They are decades old. They will soon fail, and the replacements, no matter how much their rubber compounds have improved, will still fail as well. Its only a matter of time. Preventive maintenance is essential. Using the best possible materials available in the replacements is key.

Just my 2 cents.

Len

[gsmith660]

Doing more research on the horsepower lines will support I found a thread on a camaro forum that stated GM engineers stated that stock 3/8 fuel lines will support up to 2200 hp I find that far fetched but maybe that is on a test bench with no bends or bottlenecks from the tank to the fuel rails. So my plan now is -10AN supply to the fuel pump then the fuel pump already has a -6AN banjo on it I don't know if I can get a banjo that goes to -8AN or not I am running a stock pump for now but will need to go to a 044 for the new motor. A question I have is the banjo coming off the stock fuel pump a 14mm banjo? then I will run 1/2 inch lines through the tunnel to the other side where I plan on scrapping the stock accumulator and fuel filter for a full flow filter -8AN and then I will go -8AN lines to the rails where I will have to neck down to -6AN for now because my rails are machined to accept a -6AN o-ring fitting then I will also go -8AN for all other hoses just in case I need to replace the rails later then I will need to make up -8AN lines for the return but will have to adapt the lines to the fuel press. reg. I have as it will support what I am doing right now but will need to upgrade later. So does anybody see anything lacking here or recommend any changes please?

[garywo2000]

I always liked that saying. Air cooled is the only way to go!

[BoxsterGT]

Just received my shipment of Poly fittings from Germany, and made this up for a local fellow...........




Its the same 3011 Polyamid tube as original & has M16x1.5 Male fittings on each end. Normal hose assys can be made to order and connected with ease. Move that fuel pump up front like you always planned to do.

Please, email ONLY for more info.

Len at Autosportengineering dot com

[BoxsterGT]

After being unable to find the correct M14x1.5 fittings to make these Polyamid lines a direct fit on the SCs and 3.2 Carreras, I modified fittings I could buy and came up with this................






I sent out my first set yesterday and once installed I hope to have feedback & photos to post for all who may be interested. These are the M14x1.5 fittings compatible w SC's & 3.2 Carreras.

Len

[mrm930]

I am doing the same thing to my 78. Chris has done a few projects for me and I have purchase turbo upgrades along with the billet aluminum injector blocks, intercooler, etc. from TurboKraft.

I gave up running the hard lines through the tunnel. Chris told me that on Tom's car it was a major motherf****r! So I gave up - you need at least 2 people to do this and not alot of room - also I need to run WMI lines from the trunk to the motor. After a few discussions with Chris, I have decided to run these lines along the drivers side of the tub. Similar to the brass oil lines on the other side. I will use the braided stainless lines (-8AN) from BAT. Chris also pointed out that if the car was incorrectly lifted at the lines - these will not crush like the hardlines and usually come back.

Anyway - I will post once I have this done.

Good luck.

Mark

[BoxsterGT]

Here are the first of the photos showing the Hoses from the Fuel Pump to Tunnel and from Tunnel to the Tank...........






Now that these Polyamid Tunnel lines have been installed and the front & rear hoses fit as intended I will begin building them in quantity. The M14 fittings must be made from two fittings that are machined, brazed together and plated, so the process is very slow & time consuming. Looking into having my German supplier make a special run for me, but this will be long into the future.

Please email me for details & pricing.

Len at Autosportengineering dot com