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Fuel rail fabrication


tomek

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Here is my dilemma,I need to install Adjustable FPR on my RX7.

option A :

Stock fpr is an integral part of secondary fuel rail (about 7/8 " OD),I would have to cut it off and weld in 6AN adapter.OF course it is gonna screw up zinc plating on the rail (possible problems with rust ?),and I only have flex welder.On the other hand it is easier, less expensive and faster.

Option B:

Buy bulk extruded alu.fuel rail and do whole nine yards,more work of course.

BTW,what king of clearance for injector fittings ?,those are top fed 10 or 11 mm NDs.

Whether I go with A or B Summit Racing has all the necessary firrings,adapters,hoses,etc.

Elixxir ? cbrquad ? zeronetgain ?

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Here is another possibility. Would it be possible to just put the new adjustable regulator downstream of the old one? If the outlet of the original regulator can hold off the new pressure, then a series connection should be ok. This is of course assuming that you wish to have a higher pressure than the stock setting.

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Interesting,but I`m wonder whether it would work reliably in my case.The OEM regulator was unable to bleed enough fuel during low load conditions with high flow pump that I really should run.Now it gives all symptoms of going south anyway,it needs to be replaced.

OEM part,regulator and rail is ridiculously expensive.I can get nice adjustable and rebuildable quality FPR plus custom fuel rail for less.

My main concern with weld-on bung is long term reliability,the rail is zinc plated for a reason or am I too paranoid ?

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Zinc plating is important to keep pipe from developing pin hole leaks from salt corrosion, I would think.

Zinc fumes are very dangerous, must have good ventilation when welding. Are you good enough welder to join the thin wall pipe to AN fitting? If you weld it properly, I would not worry about long term problems.

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Maybe I'm ignorant but what about simple paint as a rust inhibitor after welding?

Don't get Tom started with paint, he'll end up with a lime green, brown and pink fuel rail. I'd swear the guy is channeling a Mexican every time he paints his XX.

Sorry, nothing constructive to add here...

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You know I am able to, and glad to do what ever you need Tomek.

Not knowing what you are looking at, and guessing yours is steel and plated, zinc, I can still weld the proper fitting on and have it replated. Or machine an aluminum one, from scratch. The holes for the injectors are sized for the oring. no biggie.

I know you can buy aluminum raling and cut the holes for the injectors, and machine the ends for the fpr and banjo fitting.

What ever you think, is fine with me.

Oh, also I am going to send you a new keeper tool. Ordering tonight. I will just keep your old one. Less money that way.

Let me know.

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Maybe I'm ignorant but what about simple paint as a rust inhibitor after welding?

Well,I`m more worry about the inside,I do run auxiliary methanol/water injection.

Skull,rx7 store only have rails for Bosch style injectors,bigger O.D. of fittings,maybe thicker O-rings would make it work but ,,,,.

Redbird,I have really nice Violette Kandy that I`d like to try on something.Your new lid would make a perfect candidate.Keep in mind it is real candy,basically tinted clear.The fluer-de-lis would still be clearly visible under the paint. :icon_twisted:

I`ve pretty much made up my mind and gonna order enough parts to go either way.If I`m not happy with welded up stock rail,etc I`ll just build custom aluminum rail.This way I won`t be without a cage for a week or so waiting for parts.I can always send back unused parts,Summit has good return policy.

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I believe Aluminum and methanol do not get along so well unless it is anodized, and in my experience most anodizing is not as durable as zinc plating.

What about ceramic coating like they do for exhaust pipes?

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Yea,it is simple water/meth system injecting into airstream.

Now I realize I had a case of brain fade by bringing this up,it is totally irreverent to my gasoline fuel rail. :icon_redface:

I do know a thing or two about detonation in rotaries,it usually means quality 4-5 hours trying to yank out the engine from the car.And 1000-1200 $ in parts minimum.But you would still have to pry this car out of my dead,cold fingers.I absolutely love this car.

BTW,my AEM FPR arrived today.

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You know I am able to, and glad to do what ever you need Tomek.

Not knowing what you are looking at, and guessing yours is steel and plated, zinc, I can still weld the proper fitting on and have it replated. Or machine an aluminum one, from scratch. The holes for the injectors are sized for the oring. no biggie.

I know you can buy aluminum raling and cut the holes for the injectors, and machine the ends for the fpr and banjo fitting.

What ever you think, is fine with me.

Oh, also I am going to send you a new keeper tool. Ordering tonight. I will just keep your old one. Less money that way.

Let me know.

Yea,just make sure it is correct size,size of valve steam.IIRC there are two different sizes available from Motion PRO.I think mine was the smaller one.

I`m ordering blank,extruded alu fuel rail,rather simple project,only two injectors.Summit Racing has everything that I need.

I`ll just have to find cheap M14x1.5 tap.I`m gonna bolt M14 to -6AN adapters on the ends of the rail and go from there.I.D. of the rail is 1/2"

You gotta give those O-rings some squish right ? I`ve heard 0.5 mm less is about right,of course I can always measure it on my old,steel rail.

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