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custom fuel rail

Posted: Fri Nov 11, 2005 12:53 am
by zambon
I am going to switch to megasquirt on one of my Verdes and I would like to get some o ring injectors (motronic style). It has been suggested that I get a 164 fuel rail for the job, but that wont work because the 164 rail is not compatable with 75milano intake runners.
I am now looking at buying some fuel rail stock and making my own rail. Has anyone tried this? Will I be able to bend it like the 75/gtv6 rail?
What types of problems will I have if I pursue this?

Posted: Fri Nov 11, 2005 4:15 am
by SamW
I played around with a 164 fuel rail on a GTV6 motor, I did not get very far with it, but I thought it would work if you ground off the mounting tabs for the 164 motor and put longer fuel hose between the two rails, but like I said, I just plyed with it for about 10 minutes. You can use the L-Jet big O-ring and clamps to hold them down.

Posted: Fri Nov 11, 2005 4:21 am
by Mats
I don't get it, If you want Motronic style O-ring injectors you need to modify the mounting point (seat) in the runner anyway.
Easier yet is to grab the flange from the 164 and make your own runners, that way you will have an OEM injector solution and can dump those restrictive standard runners.

win-win. :)

Posted: Fri Nov 11, 2005 11:57 pm
by zambon
Mats,
Are you suggesting that I use a 164 fuel rail and make original intake runners?
How do you recommend that new runners be made? From exhaust pipe?
Thanks
James

Posted: Sat Nov 12, 2005 3:27 am
by Mats
yeah, anything you can easily make a flange on for bolting down on the head. As long as it ha a 30 degree bend on it it will work fine.

Posted: Sat Nov 12, 2005 2:38 pm
by zambon
Mats,
Do you think that a fuel rail from a 164 ls 24v would fit? I sort of doubt it, but there is one for sale on ebay right now for 125 usd. with injectors.
Thanks for the help
james

Posted: Sat Nov 12, 2005 4:05 pm
by Mats
No clue, the 12v fits 100%.
I have that solution in the works on a friends engine in the garage.

Posted: Sat Nov 12, 2005 5:07 pm
by zambon
Mats,
Did you use mandrel bent tubing? I am tempted to use tubes that are not mandrel bent because a quick check of vendors did not yield a source of small diameter 30 deg. mandrel bent exhaust tube. False economy?
Anybody have a good source for mandrel bent tubes? I will start yet another thread for tube sourcing, I suppose... :roll:
Thanks again
James

Posted: Sat Nov 12, 2005 5:58 pm
by Mats
I haven't gotten that far yet. :)

Posted: Sat Nov 12, 2005 7:00 pm
by zambon
Ok Mats, that is fair enough...
Have you gotten to the part where you decide what diameter your new runners are going to be? On a different thread, Jim K suggests that 40mm is a nice target.
Unfortunately for me, I am stuck using 'Merican sized tubes. That means that I will most likely use 1.5in tubes (+/- 38.5mm) or 1.75in (+/- 44.5mm).
The 1.5 in would be more readily available and cheaper. Most likely I will end up going with that.
The next problematic specification is the center line radius of the 30 degree bend. Do you know what this radius would be? Would you mind taking a guess?
-James

Posted: Sat Nov 12, 2005 7:08 pm
by zambon
Note:
These runners will be used with an intake system that flows better than stock. I will be removing the AFM and running larger diameter intake plumbing. (Perhaps Greg's kit).
Therefore, should the runners be designed to a specification larger than what would be ideal for a stock intake system?

Posted: Mon Nov 14, 2005 12:28 pm
by Mats
Snapped a couple of pics the other day, so you can see what I mean.

Image
Dirty 2.5 head, without intake runners.

Image
164 3.0 intake flange with o-ring injector seats.

Image
Matches the head "pretty" well. :D

Image
Weird Fuelrail shot, maybe you get something out of it. :roll:

Posted: Tue Nov 15, 2005 12:16 pm
by zambon
Mats,

Those photos are great. I did not understand how the runners are constructed before. I thought that the flange was cast to each individual runner. I didnt see that there is a separate flange.
So I think that you have me up to speed.
As I understand things right now, I need:
164 3.0 fuel rail
164 intake runner flange

custom steel runners- 30 degree mandrel bend welded to a plate that matches the 164 flange.
It looks like the flange could be bored out easily to match runner diameter and increase flow.

Unknowns: Ideal runner diameter and length(complecated). Centerline radius of mandrel bend for runner.

Thank you very much Mats.

Posted: Tue Nov 15, 2005 1:57 pm
by Mats
Sounds like you are up to speed indeed. :)

Glad I could help.

Fuel rail

Posted: Sun Nov 20, 2005 5:34 am
by Reale
Hello-
I have made some little "hats" that go between the stock GTV6 fuel rail and modern o-ring injectors. The hats use standard clips to attach to the injectors. The OE snap-ring/rubber grommet setup holds the injectors into the manifold. The hats attach to the fuel rail with short lengths of rubber hose. I made them out of aluminum on a lathe. I can supply dimensions, if you like.
It is not a perfect solution, the height of the fuel rail is raised a little, and you thus have to relocate the throttle return spring to the right valve cover center bolt. We've been running it on two race cars so far with no big issues.
-Allen