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Just call those left and right busses fuel rails and be done with it

and no amount of air circulation will eliminate the heat generated in the AC heads and wicked up the intakes

and I'm not worried about the heat in the injectors--I'm worried about the heat in the fuel on delivery -- cold fuel is always the best

I don't really see the major point of this except they look great. What's the pro's over (well designed) fueal rails? More stable fuel pressure, less fluctuations when the injector open/close, more even distribution of fuel?

The type 1 with L-jet used a common buss on both sides inside of a loop. Call is a fat rail...but it waas still on a loop.

Ther are several problems (one potentially a serious problem) with the buss situation as you are showing it in your pictures.
(1) As mentioned....they can pick up heat fast. Depending upon routing this may or may not be a serious problem
(2) Without having a flow through loop....meaning a normal ring main....whose excess volume is close at hand to the injector, you have no way to damp the pulsations from each injector opening and closing. This harmonic can be detrimental to accurate feeding. This can be worked out though
(3) This one is actually serious. This is also NOT speculation but a known problem. With a dead is line going to each injector, any air bubbles or cavitation can leave potentially a hundred or my cycles of a cylinder running on vapor...meaning no injected fuel or very little. Very little is horrendously worse than none at all. This problem frequently happened in early CIS injection which is also dead end. It is one of the primary reasons....other than stable fuel pressure...that CIS systems almost universally came with a feeder pump and a charging chamber within teh gas tank. Its main function was to separate air long before it could get ingested.
With a fuel rail...or ring main....there could never be more than about 1-2" of fuel line filled with vapor or air. Also since most injectors are installed with an up angle to the feed line....the chance of that vapor being fed into the injector is nil.

In order to feed uniform fuel pressure to each dead end injectro line like in your picture....the fuel buss MUST be builty properly internally...which is like a fuel rail in the inside....meaning central feed tube with slot type exit facing away from injector openings. It helps equalize pulses. Also....if you have not done it already...the farther away from the buss you can place the regulator the better.
They are finding this to work better on current vehicles in the past few years. The highest level of pulsation will be at the regulator port.
For instance the new Jettas...regulate gross fuel pressure at the pump and tank....and do minute regulation at the rail. Ray

WOW!

Thanks for that comprehensive post! Thats the kind of knowledge that is priceless!

So it sounds like this style of injector is fine if your extremely clued up on this kind of system, but as Im not, I think the fuel rail way sounds like my best option.

Shame as I do LOVE the simple look and appoach of this style housing.

Thanks so much for posting your views on this matter.

Regards,

James

I wouldn't dump the idea just yet....there are many simple ways to get around this if you start thinking about them. There aree some advantages to the system in its plumbing. Ray

raygreenwood wrote:I wouldn't dump the idea just yet....there are many simple ways to get around this if you start thinking about them. There aree some advantages to the system in its plumbing. Ray

If anyone has any ideas (Ray ) on how to make this system 'safer' for regular street use and LONG European journeys, then please let me know. Im new to this FI business and dont really wanna be stuck at the side of the road roasting marsh mellows over the corpse of my buring 56 bug wishing I had used rails hehe

Many thanks

J

I have steel bottomed versions of these injector holders in hand (50$ each). They look pretty much the same and are a lot easier to weld to steel than the all aluminum bodies.

raygreenwood wrote:the farther away from the buss you can place the regulator the better.
They are finding this to work better on current vehicles in the past few years. The highest level of pulsation will be at the regulator port.
For instance the new Jettas...regulate gross fuel pressure at the pump and tank....and do minute regulation at the rail. Ray

like this ?:

Exactly!
Ray

since its not in english, i'm assuming that the drawing is depicting:

tank -> fuel pump with regulator/return line built in <- to tank -> to fuel rail with some sort of valve to let the air escape?

what kind of "valve" is this? any suggestions for fuel pumps?

still learning all this stuff.

thanks.

bj

bj wrote: what kind of "valve" is this? any suggestions for fuel pumps?

Air bleed.

any dangers of vapor or fuel leaks from these valves when they "purge" air?

i'll do more research on these instead of asking dumb questions

bj

Sorry for the long delay. I wanted to make sure that Ethan was OK with me posting his personal phone number. I've posted his email and cell phone on the temp page on his site. The absolute fastest way to contact Ethan is via text message. He's very good about replying to a text message. If you contact him and let him know what you want, he can send you a PayPal invoice pretty quick.

http://doubledayracing.com/

He has a new batch of injector holders that are all CNC machined. (They're nice!) Both aluminum and steel bottoms are available.

bj wrote:any dangers of vapor or fuel leaks from these valves when they "purge" air?

i'll do more research on these instead of asking dumb questions

bj

Sorry for the long delay. What you are seeing is the identical set-up used on my 2006 jetta with a 2.5L 5 cylinder. The object is this:

In a perfect world we would be using a fixed and carefully regulated fuel pressure on our systems instead of a rising rate system like most vehicles are still using. The problem is that its very difficult to get fuel injectors that can complete a full dosage within available pulsewidth...and work at low rpms with very short pulsewidths. things are getting better across the board with better ECU's, drivers, injectors etc...and this system is teh first step toward getting EFI back to fixed pressure.

It can work two ways.
(1) On my Jetta....it is plumbed excactly as you have in the diagram. That three legged filter is a very large and high volume filter. VW says its good for the life of the car....I say change it at 40-50k miles. It contains a large two stage filter and a regulator diaphram that controls fuel output pressure to 4 bars . Thast more than the injectors normally need. Pressurized fuel comes to the filter and return comes directly from the filter back to the tank.
Now....the Jetta also has a rising rate regulator on the fuel rail that only does fine adjustment. the return goes to the tank.

The bleeder valve is not a constant bleed. It is simply th schrader valve where you check fuel pressure...and you also have to bleed these systems of air after a filter or pump change or VW says it WILL damage the catalyst.

(2) And this is cool.....all of the above applys except for the rising rate regulator at the rail. In place of the schrader valve...install a constant bleed orifice with a return to the tank. Maybe .005"-.010". You can by them from Carr-lane. They are screw in ceramic precision orifices. In this manner you cna produce 4 bars at the fuel filter and bleed it back to a very constant and precise level at the rail...and it will remove any air bubbles that get to the rail.
You will also need a check valve on the return line of about say 23-25 psi so you get good hot starting.

The reason why they went to the regulator far from the rail...is because with both the injectors cycling and the rail mounted regulator modulating...you get a lot of difficult fuel pressure modulation at the rail. The tighter you can maintain fuel pressure....the less the ECU has to chase by modulating pulsewidth in response to changes at the 02 sensors. You get more uniform fuel mixture.

Of course with option 2 which is basically a fixed presure system...you will have to have the engine size, injector size etc...worked out enough to allow something like Mega squirt to fully control what you need for fuel by pulsewidth alone. You should be able to do this. Talkf to Miniman82. He knows the system well and could probably offer tips on engine dispalcement that corrsponds to available injectors that can handle this with MS...without a rising rate fuel pressure regulator. Ray

You don't have to use a bus.... Mine is set up in a loop...

These are the first set made and tested.... They work great...

Forgive my work... I don't have Ethan to do all my welding and fab work at my fingertips anymore.... [attachment=0]