Making my own EFI intake system

[Derek]

Hi

This is my first post here. I have a 73 240 that I've owned for 26 years. It's been in storage for the last 10 and i recently decided to get i on the road again. I'm a CNC pattern maker for the sand casting industry and have my own shop. I decided that I needed to design and cast something cool for the car and thought I'd do something unique like a triple SU set up. Then after digging around a little I see that Z therapy is coming out with one. So much for being unique! After some more digging I came across the Megasquirt site. This seemed to be a lot slicker than three SUs and and being a bit of a geek I love the open source concept of it.

So here's my design criteria:

#1 Look Cool

#2 Look Really Cool

#3 Actually Run

I'm opting for 6 individual throttle bodies in two banks of three. I'm running a stock L28 block with a E88 head. I plan on keeping the throttle bodies fairly long to improve my bottom end. The throttle shafts will be vertical as opposed to horizontal for ease of machining.

Right now I have the the head and exhaust modeled in 3d and I'm starting to do some preliminary design on the throttle bodies.

Here's a few questions.

Is there any benefit to tapering the throttle body. I drew it up going from 2” tapering down to 1.5” because it met design criteria #1 and #2

Is there any reason I shouldn't mount the injector as close to the intake port as possible.

I've attached a jpeg of where I'm at right now.

Thanks in advance

Derek

[Jeffrey]

Interesting project Derek. We have a thread going about an L28 intake design on our club site. Stop in an have a look. I think you could model it after an RB26 design and end up with a great performing intake. I'm sure the Nissan engineers did plenty of design work while producing it. http://atlanticz.ca/index.php?option=com_smf&Itemid=98&board=25.0

[Derek]

Ok

Here's the latest design.

Overall legnth is 10” which is the distance from the face of the SUs to the head. The downward angle is 16 degrees which lines up pretty well with the port entrance. The individual throttle bodies will be angled in the horizontal plane so that they're all the same length. The bore comes out straight for 3” and then tapers out 2.5 degrees for 7 inches.

Some things I need to finalize.

Injectors. I really don't like the look of fuel rails and they ad a level of complexity on the machining end. I'd love to locate a screw or clamp in style with a threaded top that would accept a banjo style fitting. I could hard line it to a central fuel block with more banjo fittings. I think this would have a very old school mechanical injection look and would satisfy my design criteria #2 “Look Really Cool “

Air filtration. I suppose I could put flanges on the ends of the throttle bodies and use an air box. I'm not too crazy about the looks of an air box and would love some sort of alternative. I could cast a step on the inside of each throttle body and use some sort of mesh-foam-mesh arrangement that would fit inside them. I really don't know how practical this would be. Cleaning air filters every other day might not be very fun.

Linkage. At this stage I'm thinking separate levers and rods connected to a central bell crank and cable driven. I'm also working out the individual idle screw and return spring design.

Here's a cool shot looking down the throat WFO

Thanks for all the help.

Derek

[Derek]

I stopped updating this thread because this wasn't exactly a classic Z item so I was posting over at HybridZ.

I figured I would give you guys an update. I'm in the process of doing the machining and fabrication on the front manifold. When I have all the details worked out on the front manifold I'll make the patterns for the rear.

My design inspirations has been old school injection systems.

Here's a link to the pattern development thread

http://forums.hybridz.org/showthread.php?t=121021

and a link to the casting thread

http://forums.hybridz.org/showthread.php?t=129941

Thanks for looking

Derek

[hls30.com]

Derek!

That is absolutely beautiful!

Will

[hls30.com]

I am going to have to spend a little more time over there-I missed all of that-Wow!

Will

[280~Master]

Dam it Derek. Now I am going to have to redo the whole thought process of my EFI system.

That looks very interesting. Now where to I insert the shot NOS?

[240znz]

Nice work derek. They look awesome!!!!

[e_racer1999]

very nice! I was going to post that someone was building the same thing over at hybridz, but then I read your post!

[76Datsun280z]

That's very cool, wow!

[Curtis240Z]

Nice job Derek. I have a Megasquirt with TWM ITBs on my 240Z. Check it in my photo gallery. How are you mounting your TPS and MAP sensor?

[JonnyRock]

Very cool Derek. I hope to do some casting @ school this summer and next year, I'll have to read up on your posts.