94-97 Fuel Rail

[Tom @ Fast Forward]

I am almost out of stock on the 94-97 fuel rails and would like some feedback from those who have installed them. Any change/improvement thoughts? I know there was some fit issues with the FPR. I have re-designed the EGR plates so there will be less interferrence back there. Should I move the mount for the FPR? If so, where.

Thanks guys.

[bogey]

Shorten the front of the rail by 1/2 inch. The FPR fits on the front, but makes contact with the manifold cover. Shortening this section would let it fit better and allow removal of the FPR without removing the whole fuel rail.

The rear feed is useless and has to be capped because of the EGR valve.

The side port is fine for fuel line input.

An alternative to shortening the front of the rail would be to plug the end and tap a port at a 45 degree angle so the FPR could be installed sticking up vertically from the rail. But this would be rather complicated to build and would not really be any better than the end mount for the FPR.

[Tom @ Fast Forward]

I have just modified the EGR assembly to fix the clearance problem at the rear of the fuel rail. That should help allow fuel connection back there. Would the top fitting be necessary anymore then?

http://www.FastForwardSuperchargers.com/94-97fuelrail.jpg

[bogey]

I don't think a top fitting is necessary if you can shorten the front of the rail. Right now it extends about 1-1/2 inches in front of the fuel injector connector. If you shorten this slightly, the FPR will fit in front much easier.

I dont think the side feed is a problem for the incoming fuel line. And capping the rear is just fine.

[Tom @ Fast Forward]

Can you send me a picture or two of yours?

Now that there is clearance at the EGR, could I lengthen the back and then feed it there? I would really love to eliminate the top fitting and just have one front and rear.

[bogey]

The front of the rail is here:
http://www.thebogarts.net/miata/DSCF0009.JPG

The rear is here:
http://www.thebogarts.net/miata/DSCF0009.JPG

You can shorten the front of the rail about 1/2 inch and still have clearance for the return fuel line. If is is back much further, it will be blocked by the intake manifold.

The rear is tight against the EGR valve. The side feed works fine.

The FPR will only fit on the front, there fore fuel needs to come in from the rear area. There is just not enough room for other options.

[bogey]

Woo Hoo! I advanced a ranking!

[Tom @ Fast Forward]

You made both pictures the same. No back end.

I can easily take 1/2" off the front. No room to stretch the other end and connect fuel there now that the EGR doesn't interfere? I would love to feed one end and FPR the other. If we still feed the top (like the current version) should that move one direction or the other? I would just prefer to have the fuel feed in line with the bore rather than 90*.

[bogey]

This is the rear of the fuel rail.

http://www.thebogarts.net/miata/DSCF0010.JPG

[bogey]

I do not know about feeding from the rear. I guess it really depends on where the EGR is placed.

The feed to the top is far enough away from the EGR that it is not exposed to the heat. I would be concerned about routing the fuel line around the back near the crossover tube. Would the fuel line be touching the EGR pipe? How hot does that get?

Why does it matter if the fuel is fed in the end? Is it a concern that the rear injector would not get the same pressure as the front three? I find that one hard to believe. The rear injector is the closest to the side input, and should receive ample pressure.

[Tom @ Fast Forward]

So, cut 1/2" off the front end and that'll do it. Would it help to rotate the side fitting to the top? Or leave it where it is?

[bogey]

The side fitting is perfect the way it is.

Take the 1/2" from the front, making sure you still have enough depth for the FPR fitting threads without interfering with the injector. (this should not be a problem as the threads on the FPR fitting are about 1/2" long and the injector would still be about 1" back from the end of the rail.)

Of course if you build them this way and they don't fit, please don't blame me!

Does everyone/anyone else agree that this would make it fit better on a 94-97?

[Tom @ Fast Forward]

I won't blame you. :)

I'm just looking for feedback. I see 99-05's all the time but almost never see a 94-97 here.

[bogey]

I'll show you mine in July when I travel west. You can test fit the new rail on it then.

[Gord96BRG]

So, cut 1/2" off the front end and that'll do it. Would it help to rotate the side fitting to the top? Or leave it where it is?

Hi Tom, haven't been around lately - thought I'd chime in. I know mine is a hybrid, and I'm using a 99 head with your 99 fuel rail - but if I may, I'll offer a few suggestions.

- Shortening the front of the fuel rail a bit would be perfect for fitting the FPR there - for those wanting to feed at the back and return at the front, that's perfect.

- for those wanting to dual-feed, the side fitting definitely didn't work for me - I couldn't even fit an elbow on it without interfering with the TPS. I drilled and tapped a hole just aft of the #2 injector port, on the top of the rail (in cross section, the square of the rail mounts at about a 40* angle from vertical - I have the FPR mount coming nearly vertical from the rail, ie from the top corner of the cross-section). The position I chose allows the return to go in the "middle" of the rail (ie between #2 and #3 injectors), and two injectors are fed from each end of the rail. Flyin Miata recently released pictures of their fuel rail, and it looks like they put their FPR return port in the nearly the same location as I did, perhaps a bit forward of mine: http://www.flyinmiata.com/Store/images/04-46575.jpg

(although theirs is on the flat, which would be leaning towards the SC on a Coldside installation - I don't know if it would interfere).

Regards,
Gordon

[Hrogi]

WHat are the ideas of mounted the FPR on the Firewall away from Heat and Vibration of the Motor?

I am not trying to start a flame fest, just adding another Idea.
I know FPR are pricey as heck for these cars.
I looked from $200 to $350 is what I came up with..

[Tom @ Fast Forward]

What if I made a mount to mount the stock FPR on the firewall? Would that help or hinder?

[Mark]

I see 99-05's all the time but almost never see a 94-97 here.

Wish I lived closer. I'd be more than happy to let you use mine as a guinea pig for a few days! :)

[bogey]

What if I made a mount to mount the stock FPR on the firewall? Would that help or hinder?

An option would be to plug the rear and side connector, feed from the front. Then "T" the fuel line with one side going to the FPR mounted on the wheel fender near the incoming fuel line. A fitting could be installed there.

I don't see why this would be any different than having the FPR inline vs off a branch. It would still regulate the pressure.

However, the fender is getting rather crowded. A solution is needed to allow mounting all the sensors and stuff. (FPR, IAC, emissions controls, etc.). The firewall is too crowded already with the VDB. Perhaps designing a Christmas tree bracket with attachment points for all the miscellaneous stuff...

The existing rail mounted FPR is fine if it had a little more clearance. But having an option to relocate it might not be a bad idea.

[Gord96BRG]

WHat are the ideas of mounted the FPR on the Firewall away from Heat and Vibration of the Motor?

I am not trying to start a flame fest, just adding another Idea.
I know FPR are pricey as heck for these cars.
I looked from $200 to $350 is what I came up with..

Pricey? I got one free, it came with my 96 from the factory. You're likely referring to an aftermarket adjustable fuel pressure regulator - which isn't needed with the PC Pro, and isn't needed with an aftermarket full ECU or most other piggyback ECU systems (I'm running an FM Link ECU).

I tend to agree with bogey - my firewall is full, I could barely fit the vacuum block (ABS has lots of brake lines running around), and the factory FPR lives just fine on the fuel rail. I'd think just changing the mount location on the rail would be the ideal fix!

[Tom @ Fast Forward]

Gord,

where would you move the fittiing?