I'm starting on my fuel system in my 3rd gen but I wanted to ask a few questions about fittings..

Basically I'm going with an after market secondary fuel rail with 6AN fittings. I want to also run 6 line to the primary rail.

The front of the primary rail has a banjo bolt in it. What thread is this? I should be able to get an adapter to work here.

What is everyone else doing to the primary rail where the fuel pressure dampner is? do I just remove it and tap the back of the rail for and 1/8 npt and put an 6AN to 1/8 adapter in place?

How important is the dampner?

Anyone have some advice?

 

no ideas?

 

This will be my early winter project on my car. -6AN fitting in both the primary and secondary fuel rails. I haven't taken anything apart, but I don't think a 1/8" NPT will be big enough. Aeroquip offers 1/8" - 3/4" NPT adapters for the -6AN, and I think the 1/4" or 3/8" NPT should work. The dampner is to smooth out fuel pressure spikes I believe, and a big source of failure in the stock system. I will be removing mine, which I think is the norm for an aftermarket fuel system. It'll be real sweet when it's finished, but likely cost around $900 US, not counting the pumps or injectors!

 

I used 1/4npt to 6an 90deg fittings on my primary fuel rail. 3/8 is too big not enough metal there to be safe.

Hope this helps.

 

That's what I was hoping to hear! I would like to use a straight adapter then use 90 or 45 deg. hose ends for a smother bend, though.

 

they make a fitting for the secondary rail to use 6an line. email me i can get you one rob@jouleusa.com

 

This is my exact idea. The hose ends are also less restrictive than the 90 deg adapters.

Ok, 1/4 to 6an adapters for the primary rail. Will I have to tap the primary rail to make the adapters fit? I believe one side is threaded with a banjo bolt and the other isn't threaded.

Unfortunately my daily driver is broken at the moment so I can't pull the primary rail out of the car ahead of time.

Also, what size line is everyone using from the pump to the front of the car. I'm thinking about running 8.

 

I just wanted to inform you guys a bit since I have done this modification already. 1/4 NPT is correct for the rails, you will need to retap some parts, and drill and tap others. You will have to use 90 degree 1/4NPT to -6AN adapters on both sides of the stock primary rail, this is because of the vacuum nipples on either side mounted on the rotor housings.. not sure what they are for w/o looking at the diagram. I tried to use straight fittings there, there just isn't enough room.. it becomes impossible to mount the fuel rail flush to the housing like it should be.

I ran -6AN all around, -8 will be overkill unless you plan on running a T78 or some other massive turbo. -6 will support well into the 400HP range.

Matt

 

I think the nipples you're talking about are the two Oil Metering Pump fittings.

--
pedalpusher

 

Yes, the oil injectors.

 

If you want an easy fix for the threaded side of the secondary rail then get a Solex carb adapter.......M12 x 1.25....to -6.

I've got every single hole plugged with alum. fittings from oil to vacuum to fuel. It was a hell of a time to find all the right adapters!!!! I found them all though.....except for a few.....those i just tapped. If your good it will only take you a few weeks......here's a hint......you won't find them with just one supplier or in the places you would normally look.

Good luck

 

at the moment mine are tapped with 1/4 pipe to -6 straight. i am using a haltech so no oil injectors to worry about
with using a 90 or 45 deg pipe to AN, how can you tell when the fitting will "stop" at the right angle without forcing it?

 

i was just wondering this too, im about to start mine i have all the parts already.