If you press fit parts together the melted material will not go between the surfaces and you can end up with a joint that is as strong as the press fit and the strength of the brazing material in tension which is not much at all.
Brazing, silver brazing in this case and soldering rely for strength on shear strength not tensile strength.
As the video says the correct silver alloy used is important, you can get solder containing silver and it is of no use for this job.
When the joint has to be above 840°F (450°C)for filler material to flow it is brazing, below that temperature it is soldering.

 

Yes you are right. Not press fit, push fit I should have said. The process was like sweating water pipes in your home. I had to heat the rail almost red hot. I think the inlet in the center of the rail like boostmonkey did would need to be welded. Cool project boostmonkey!

 

"You can't fit dual 3" aluminum intake tubes around the radiator."
"You can't weld aluminum sheet with a MIG."
"You can't fit 8AN fittings on the end of the fuel rail."
"You can't weld thin wall pressure tubing with a MIG."
...

I've heard it all. The thing is, I am move of a "I can" kind of guy than "I can't." I'll find a way.

I think it will. I did measure. Notice the short-radius 90* swivels on my sketch. AN hose ends are not the first fittings connected to the rail.

Yep.

I agree. I did.

This is what I would tell you also if I were a fabricator with expensive equipment trying to sell you my services.

That's four Y fittings! The good ones are ~$50 each. The reason I installed the inlet fitting in the back of the rail rather than cuting the rail in two was to avoid buying one Y fitting. This isn't the Porsche forum. It's HP/$ here, not HP/HP.

I do REALLY appreciate you sharing your advice and former SLK experiences with me Steve. In fact, you've been more help than anyone! (except for the local wrench-turners) But you should realize by now that I am going to build an SLK32 that is faster than yours was, for a fraction of the cost.

Thanks Anthony. I BUILT one for me. I'm set. I posted the information, instructions, and offered my services (not free of course) to anyone else interested in a better fuel rail at below-unobtanium prices. I am not a consistent poster, but I do try to share what I have learned or done. 12.2 and not even tuned yet.

They'll hold. Nothing I weld leaks. What pressure do you think I should test them at? 150%? 5/3 like DOT testing for cylinders?

THANKS!!!

 

Nice video... With the spare fuel rail, we ought to be able to come up with something similar... thanks for sharing....

 

i hope you get what you looking for. just understand bruce and i spent over 6 months and hundreds of $ in lines and fittings, s/s braided line to make the ttm rail. it wasnt done overnight

 

I like the design of your rail system, good job Matt!


Any pics of the new fuel feed 8AN line?

 

BTW...I appreciate how hard it is to weld something that small and tedious with a MIG. I do have a TIG available to me, but brazing appeals to me too. We had to use that method long before TIG, or MIG was available. Either way, it is another idea in rethinking the fuel delivery. Thanks again...

 

Just a thought/idea/hint/$.02 about those AN fittings. They are the exact same thing as a hydraulic JIC fitting, which can be bought from a hydraulic supply store for WAY less than those super nifty AN fittings. Heck you would probably find it cheaper to run hydraulic hose that is gasoline compatible than the SS braided stuff you are all using. Sure, it may not look as pretty, but I would take 4 braid 4000+ PSI hose over some teflon tube surrounded by 2 SS braids any day of the week. Also consider the heat rejection benefits the thicker rubber hose will have over the SS stuff.

 

Would this be a worthwhile mod for us NA guys?

 

I wouldn't think so.... As we add more boost (air), we need a higher volume of fuel delivery at peak operating rpms...

 

Thanks!!!

I don't have it installed yet. My car is put away in the barn for the winter. Pics will have to wait until spring.

The funny thing is, I actually asked about it casually when I was at a hydraulic supply store picking up some stuff for work recently (for big engines, 2500 HP continuous rating). They said they could order hose that would work. Will JIC fittings attach directly to AN fittings?

I agree. The stock fuel rail (and likely entire fuel system) is sufficient for NA cars.

 

JIC has 37½° taper, what is the AN? SAE is 45°. Curious about AN, I don't know.

 

Ok I just found this site: AN Fitting Guide - anfittingguide


In the download guide It says AN sometimes is referred to as JIC.

 

I downloaded this. (CLICK)
AN and JIC being two different standards.

 

AN is a JIC fitting produced under tighter tolerances for Aviation use. We are talking temperature extremes that require a very tight fit for proper sealing. They are the same 37* flare, same thread pitch and everything else, the JIC is just the industrial equivalent that isn't rated as highly. For use in machinery and automotive environments it is overly sufficient.

 

Thanks for the info!

 

The Ultimate Fuel Rail is done!

It works great! No leaks, pressure tested at 100 psi. I have a few hundred miles and many dyno pulls on it. Here are some pics.

New center 8AN inlet.

20140315_114647_GreenPointeDrS_zps4daa8bcf.jpg

Passenger-side 8AN outlet, 90, and reduction to 6AN line to AFPR.

20140315_114558_KinselAve_zps8f857745.jpg

Driver's side 8AN outlet, 90, and reduction to 6AN line to AFPR.

20140315_114518_RohrRd_zpsa7a7d319.jpg

But wait a minute... an 8AN fitting WILL NOT FIT on the driver's side end of the rail, right?

20140315_114500_RohrRd_zps9b40424a.jpg

What is going on there?

The 8AN 90* elbow coming off the welded fitting did in fact hit the air injection valve. But I said I would find a way to make it work didn't I? So I cut the air injection valve in half. I found that a 1/2" aluminum pipe was a surprisingly perfect fit inside the outlet of the valve. I brazed a section of the aluminum pipe to the halves of the valve with some low-temp aluminum rod and a MAPP gas torch, thus extending the valve forward and out of the way. Everything fits great now. No codes, no leaks.

20140315_114329_RohrRd_zps1a505b86.jpg

 

I had Boostmonkey weld the rear fitting on my spare rail and his work looks great. Thanks!

 

Wait.. You're pounding fuel in from 3 locations? This thread should now be XXX rated.
Very industrious work there, nice job.

 

no, he has 6AN inlet feeding the back center of the rail, then on each side at the rear of the rail are teh return lines to the adjustable regulator. great set up!