My boredom = Fuel Rails (390cc DSM)

[SKOLJACK]

Nothing else to do when it's 20 degrees outside except play in the garage. I made some fuel rails in 20 minutes (that's just a poke at an earlier post by someone else)... It has been more like 2 weeks, with working on them 10 minutes here and 20 minutes there.There was a set of 390cc fuel injectors laying around my garage and I decided to try my hand at a little fabrication. I only have the right side put together (still need some finish & touch-up work on the brackets/intake and install Earl's/Russel/Aeroquip line fittings) for now. There isn't more than $50.00 in parts (not including injectors) for both sides, but I can see where the time involved could be costly! I also milled out the lower injector mount in the intake manifold to drop the injector pintle lower into the intake runner to put it as close to the factory injector pintle location.





Any input or questions from you other fuel rail guys may be helpful!

[Jason84NA2T]

Nice job!

Attachment to the lower intake will be interesting as some people will discover it's the hardest part of making the rails. Not only do the tabs need to be cut off, but there are two different lower intakes for the different injector types, and the mounting tabs are the only real difference.

Are those brackets bolted all the way through the rails?

How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

How/did you ream the injector holes to the correct size?

[Evil Z31]

If you were to make several for profit, then it would be a good idea to buy one of these: http://www.rossmachineracing.com/injectortool.html

[SKOLJACK]

Jason84NA2T wrote: Nice job!
Are those brackets bolted all the way through the rails?

How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

How/did you ream the injector holes to the correct size?

Yes, the stainless counter-sunk allen bolts go all the way through the rail to the bracket.

The 3/8" NPT tap took care of the taper.

Yes the rail ends are drilled and tapped for 3/8" NPT and I plan on adapting -6 AN afterwards.

I started with a 1/4" drill bit to set the holes all the way to the 1/2" rail bore, then used an equation from a fuel injection book [ I think it was: D-(T/4) or something close to that - I'll get the right equation later ] to mill the holes for the injector o-rings. Afterwards, lightly pollished the bore finish.

And Evil, that injector port tool would of made it a lot easier, but $130.00... Remember I'm a cheap @ss Z31 guy :wink:

[Evil Z31]

Yea, that's why I said it would be great only for a shop that will produce a LOT of them. Would make their job easier.

[Jason84NA2T]

Evil Z31 wrote: Yea, that's why I said it would be great only for a shop that will produce a LOT of them. Would make their job easier.

I actually have one of those on the way, funny you should mention it!

[StreetFighter]

Looks good... but I could have done it in 15 minutes using only my teeth.

I like the way you mounted the rails... pro.

where did you get the fuel rail stock? I like the finned look.

[Evil Z31]

Fuel Injection Specialties, here in SA, got me a foot of that same stock for like $12.

Here it is on my Tib:

[SKOLJACK]

Evil Z31 wrote: Fuel Injection Specialties, here in SA, got me a foot of that same stock for like $12.

Damn, that is a good price! Here is where I purchased both of my 12" (1ft.) rails because they were in stock and only a few miles from my house. http://store.summitracing.com/partde...5&autoview=sku


And on another note about injector bore sizing in the rail, here is what it says in the Motorbooks International Fuel Injection Guide by Jeff Hartman:
When drilling holes and reaming for O-rings, measure the diameter of the O-ring (D) and the thickness of the O-ring (d). The hole should be D-(d/4). A 1 inch O-ring that is .125 inchs thick requires a hole that is 1"-(.125"/4). That works out to a .96875 inch hole.

Hope this helps you guys out!

[Black 89Turbo]

Jason84NA2T wrote: Nice job!

Attachment to the lower intake will be interesting as some people will discover it's the hardest part of making the rails. Not only do the tabs need to be cut off, but there are two different lower intakes for the different injector types, and the mounting tabs are the only real difference.

Are those brackets bolted all the way through the rails?

How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

How/did you ream the injector holes to the correct size?

There are 2 Diff lower intake pleniums correct? The injector holes on a 89turbo one seems to be smaller than a 88 N/A. Can you use the N/A is what im wondering? Do oyu have to get some diff rings for it or somthin?

[G-E]

Black 89Turbo wrote: There are 2 Diff lower intake pleniums correct? The injector holes on a 89turbo one seems to be smaller than a 88 N/A. Can you use the N/A is what im wondering? Do oyu have to get some diff rings for it or somthin?

I would assume no one would bother to take the o-rings out of the lower intake before you got it... the inner diameter and injector cap is the same for all years afaik

[Evil Z31]

Like I said, if you have a drill press, then you can ream out the lower IM holes from 11mm to 14mm, so it will accept all 14mm o-ring injectors.

[crowbar]

That looks great but that aluminum is going to soak up heat.

[SATAN]

crowbar wrote: That looks great but that aluminum is going to soak up heat.

Yup, but no more than any other aftermarket aluminum fuel rail for any other car out there.

What are the stock ones made out of? Are they copper or somthing like that? those ones would soak up heat faster than the aluminum ones would. However, the bigger thicker aluminum ones will hold the heat longer.

[crowbar]

I believe they are brass. Stainless Steel would be a better choice.