Design Review Please (EFI Manifold)

[SchmidtMotorWorks]

OK, ready for something different? I wandered around a lot on this design and thought I would just stop at this point and get some feedback.

So now it looks like a roasting pan, no horns, blended entry, runner length can be adjusted with spacers, no V plenum, injectors above the runners, throttles in the runners. I can make this for less casting cost than the tunnelram I make now.

Let me know what you think, please.

[larrycavan]

.....Also, there are power gains in placing the injectors higher up on the runner (or even on top of the runners in the plenum). If you do place the injectors at the lower portion of the runner you should aim the nozzle to spray right on the back side of the valve.
Greenlight

I was looking over some BMW engine informatin this week. This is from the site: http://www.bmwworld.com/engines/12cyl.htm

"Direct fuel injection means injection of the fuel directly into the combustion chamber, rather into the intake port as is the norm. It has been chosen and developed by BMW's power train engineers to boost power output and fuel efficiency to higher levels than could be achieved with conventional fuel injection."

Have look and draw your own conclusions. ...

Larry C

[67RS502]

I like the runner length adjustability. But the pan that holds the injector will be an air restriction, can you make it smaller? And why is curved up at the edges, curve it down. I wonder how far away the injectors need to be from the runner entry, some R&D may be needed there.

[larrycavan]

I realize direct injection like the BMW setup is not a viable alternative for your project. I just though I'd pass on the info on to you.

One thing I wonder about the new drawing is whatever method you're going to have to devise to seal the wiring for the injectors, poses a potential leak area....It might not be anything that you can't easily solve..It's just something I noticed.

Will it be available by Thanksgiving...what size turkey will fit under the injector plate....and...can liquified butter be forced through the injectors... ....That thing is making me hungry!

LarryC

[larrycavan]

Look at where Renault positioned the injectors on their F1 engine. There's a video link to it in another topic here on speed talk.

Larry C

[Bad95Gts]

If you introduce the fuel too soon into the intake charge it will have the same issues as carbs and there intakes.
The idea behind fuel injection is too be better than a carb setup so why design it as such.

Runner length is a non issue with Fuel injection if the intake is not a restriction.Plenums just help overcome an intakes flaws.
There is a reason why direct injection is being used by BMW.

[SchmidtMotorWorks]

Will it be available by Thanksgiving...what size turkey will fit under the injector plate....and...can liquified butter be forced through the injectors... Very Happy ....That thing is making me hungry!

I'm working out the details now, Martha Stewart just called and promised to order 2,000 of them if I can finish them by tomorrow.

[SchmidtMotorWorks]

One thing I wonder about the new drawing is whatever method you're going to have to devise to seal the wiring for the injectors, poses a potential leak area....It might not be anything that you can't easily solve..It's just something I noticed.

Good point, I will have to start thinking about that soon after I get a basic configuration that makes sense.

[SchmidtMotorWorks]

I wonder how far away the injectors need to be from the runner entry, some R&D may be needed there.

Me too, I did a test on a flow bench once on how close the top of an aircleaner could be to the top of the carb and I couldn't notice a difference until it was closer than about 1 inch as I recall (many years ago)

[SchmidtMotorWorks]

This is the video of the fuel injectors above the runner.

http://wmediavod.coltfrance.com/wmeuros ... 20x240.wmv

Maybe I should copy that. Anyone see any problems with that design?

[larrycavan]

This is the video of the fuel injectors above the runner.

http://wmediavod.coltfrance.com/wmeuros ... 20x240.wmv

Maybe I should copy that. Anyone see any problems with that design?

It sure worked good for them this year! I managed to get the vid onto my computer and I've watched it probably 10 times and paused it at the injector close up shots.

Here's something to think about. Maybe it's pure folley but then again.... What if you put the injectors on the bottom side of the runners, angled to spray the fuel from bottom up toward the top of the runner. Mount them down close. It seems to me that spraying the fuel from the top of the runner down on an angle provides less benefit than spraying it the other way.....

JMO

Larry C

[SchmidtMotorWorks]

What if you put the injectors on the bottom side of the runners,

No machining access unless I made the runners removable. I'm trying to make this as inexpensive as possible for the end user.

[Greenlight]

When I researched this topic several years ago I could only find one SAE paper and one other paper. One of the two papers tried varying tapers from zero to 10 degrees (from memory) and the other paper did not give all of the test data.

One paper distinctly said that no performance gains were noted above 3 to 3.5 degrees taper when tested with (several) different engine configurations. They actually stated that above 5 degrees (again from memory) the performance dropped off considerably. The other paper (from memory) only tested one engine setup and had similar results.

However, on the exhaust side the literature that I found showed gains up to 8 degrees (included angle) on exhaust cones (megaphones). These results are in line with almost all literature that deals with flow through an expanding nozzle (like a jet engine or rocket engine, etc.)

Again, I didn't do the testing. I'm only repeating what I found when researching the topic.

If anyone has hard evidence otherwise (i.e. an A - B - A test on the dyno, etc.) please let me know.


Greenlight

[larrycavan]

Isn't there a way to upload images to this forum?

I managed to get some pics of the Renault F1 Injector setup for you to look at close up but I can't find a way to upload them here.
They're small in size...about 80k total for all 4.


Larry C

[SchmidtMotorWorks]

I post them on

www.imageshack.us

If you don't want to use them, you can email them to me and I'll host them from my web site.