SQLGuy

What diameter of fuel line is needed back to the pump, and what pump upgrades are needed, so that you can actually take advantage of these larger diameter rails rather than just moving the bottleneck to a different part of the fuel system?

Imo000

You'll have to push a heck of a lot of HP to need anything more than stock rails.

Bill Ball

Just to add a point of fact, the stock rails, S4 at least, have multiple retention points. The two hold down brackets on each rail are only part. On the left side both ends of the rail are anchored by rigid fuel pipes to other components (rear and front fuel dampners) rigidly bracketed to the head. On the right side, the front end is free but the rear is fixed to the fuel pressure regulator which is rigidly bracketed to the head.

The injector to rail clips are essential with the stock rails, as everyone agrees, due to the limited travel in the rail fittings over the tops of the injectors. The clips are slightly tricky to get seated properly. Fail to seat the clips or leave them off and a fuel fire is a certainty, as I witnessed firsthand once. Also, if the lower tips of the injectors were held hard against the stops inside the manfold somehow, the pintle caps could bust off. I've seen this in some 87's where the manifold mounting points for the rails were missing some spacers, inadvertently positoning the rails too close to the manifold and locking down the injector tips against the manifold. Later manifolds repositioned the mounts and eliminated the spacers. I'm not suggesting any problems here with Carl's rails, just adding a few comments about the stock rails.

Anyway, Louis and others have been using this type of billet rail for a long time with the only issue I know of being heat soak.

auzivision

I just have an affection for all things shinny under the hood... Bling, Bling!

Imo000

Then why not chrome the originals?

Carl Fausett

I sell a lot of these billet fuel rails and they work very well. I suppose they have been in the field now for a coulple years, and I have raced them for several years as well.

They sure are a lot easier to install/remove than the stock system with the clips.

Not only do they flow more fuel, but the larger amount of fuel held in the rail provides the necessary hydraulic dampening for the injectors pulses, meaning the factory fuel dampeners are no longer needed. We still provide the dampening of the injector pulses, but do so thru the increased fluid content held in the rail.

dcrasta

Product looks great Carl > Cannot wait until you finish QA testing for the S3 -s

Thanks for your R&D and bringing this product out.

chewy8000

Looks great Carl. These are a must if your supercharging and want to upgrade to AN fittings and fuel lines. I'm sure the stock setup is fine but I like being able to run a BEGI, FMU, or pressure gauge where I like and in different configurations.

Imo000

Lets not confuse things. They might be a must if you want to use AN fitting and not a must for supercharging. The FMU, or any other type of fuel return line managemet, splices into the flexible section of the return line. And this is downstream of the rails.

928mac

Carl, Thank you for explaining some of your connections in e-mail the other day.
Could you please supply some pictures of how the lines at the rear of the rails connects to the regulator and what you did to connect the fuel line at the front to the line at the car (picture again please)

Thanks alot as this will help anyone else that is having the same trouble I am.

Brad

Carl Fausett

I'm sorry I have no photos of a non-supercharged 928 with these fuel rails installed. I did once, but we had a hard drive crash some time ago and some photos were lost - these being part of that.

I've sent you all the photos I have...

Perhaps a Rennlister can post photos of how he ran his fuel lines.

uncre8tv

this thread answered my question on using these rails as part of a full fuel system overhaul with aftermarket FPR and Y-block to the rails. Any cautions or caveats for this? I'd be doing this as an early stage (with stock pump, computer, etc) of a refresh.

End state hoping for NA engine with Megasquirt with full COP and individual injector control. Off of the Jetronic and a far physically simpler fuel delivery system. Pie-in-the-sky right now (and honestly, with my mild ambitions batch control would work - more of a geek 'because i can' thing.) But I've got nothing but time and laptops, and the occasional toy funds to get me there. Figure this is as good a place as any for "stage 1" of this as I don't trust my original fuel lines and need to take the fuel system apart anyway.

Speedtoys

Is that because fuel is compressible?

How's that work?

uncre8tv

IANAE, but - as Carl stated, it's a volume thing. The stock rails have less volume in them, so a pulse could conceivably starve a point in the rail. These rails have more volume, more fuel, at any given point in time, so the low point in a pulse wave doesn't drain them to the point of starving an injector.

Throw a big rock (making a pulse) and the wave could empty a kiddy pool. Throw the same rock in a big in-ground pool and the pulse is less impactful. (Kiddy pool to in-ground pool is of course a larger magnitude of difference than between stock and aftermarket fuel rails, but you get the illustration.)

ptuomov

+1