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Derek

Making my own EFI intake system

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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

post-14222-14150800189445_thumb.jpg

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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

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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

post-14222-14150800192683_thumb.jpg

post-14222-14150800193139_thumb.jpg

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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.

DSC_0026.jpg

DSC_0032.jpg

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

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

Will

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

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

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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?

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

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

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

Anywhere you want! The wall thickness is enough that it can be drilled and tapped.

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?

I'm not sure where the TPS is going to mount. Probably on the pedal side of the linkage. The rear manifold will have a boss on the bottom of #6 for the air temperature sensor. A lot of this stuff I'm winging as I go. But that's what tig welders are for!

I'll update the post here as this progresses since there seems to be more interest than I thought. Things go in spurts according to work load. Although the closer I get to having the front manifold done the more of a priority it's becoming!

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You will also have to put a boss on every runner for the MAP sensor.

It was my understanding that the Megasquirt has the map sensor built in.

Derek

edit

ok I just went to the TWM site. there is a port on each runner for the map sensor.

Derek

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I think I have everything mocked up at this point.

Here's a shot of the linkage with the throttle closed.

DSC_0037.jpg

And open

DSC_0038.jpg

This is just a practice butterfly. I need to make a jig for my lathe so I can make these as a turning operation. Milling them just isn't giving me the results I want.

DSC_0040.jpg

Say AHHH!

And yes that is a giant step between the casting and the throttle tube. I have a fix for the next manifold. I just need to figure out what I'm doing on this one.

DSC_0041.jpg

This is the vacuum bleed for synchronizing the venturis. I need to lower the rear boss. Also the throttle shafts will be shorter. It looks a little shabby this way.

DSC_0039.jpg

At this point I think I have enough info to finalize the design for the rear manifold.

Now all I need is time!

Derek

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I read your threads over on hybridz, and may have missed this....how much air does that flow? Will you/have you experimented with horn length, injector placement, trumpet diameter and venturi effect etc? (not a designer of intakes, so my terminology is probably incorrect)

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Are you planning on selling these?

Things are going well on it so at this point it's a definite maybe. It all depends if it runs or not. It won't be cheap though!

I read your threads over on hybridz, and may have missed this....how much air does that flow? Will you/have you experimented with horn length, injector placement, trumpet diameter and venturi effect etc? (not a designer of intakes, so my terminology is probably incorrect)

I really didn't put a lot of research into this. That may sound strange but that's just how it went. I did some research on the best taper degree and where the injector placement should be for the best torque. After that it was a matter of fitting the longest runners I could in the given space and making it look cool. I've seen so many projects like this get bogged down with too much theory.

Here are my levels of success on this project:

It starts and idles. Amazing!

It runs better than the 25 year old SU carbs. Really amazing

It runs better than a MegaSquirted factory EFI manifold. Freeking Amazing.

As you can see my expectations aren't too high!

For me it's all about the look more than the performance. I wanted something unique that wasn't a mass produced piece. I really enjoy the challenge on a job like this and it makes me a better pattern maker and it's also a good way to show my clients what I can offer them.

Derek

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Pretty freakin' sweet. Keep us updated, don't keep it to only HybridZ. There are plenty of people here who have an appreciation for what you're doing, even if its not what we're personally planning :-)

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First off I know I could have picked a nicer head and valve cover but this is the best I could come up with.

DSC_0046.jpg

DSC_0047.jpg

This is probably the last I'll be doing on the manifold for a month or so. I'm super busy right now and in this economy I better get while the gettings good.

I will be doing the final design on the rear manifold in the meantime.

Derek

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Well a lot has happened since my last post! I figured I'd throw up the latest pictures. If you want to see how I got to this point you can check out the post over at HybridZ. Although there's 21 pages and over 400 posts!

First off my engine compartment is really ratty. But making the manifold has kept me pretty busy. The manifolds aren't permanently installed yet but I hope to have it running this week.

DSC_0003.jpg

DSC_0013.jpg

Art shot 1

bwintake.jpg

Art shot 2

Which looks strikingly similar to this historic photo!

bobsharpintake.jpg

Now I didn't set out to copy Bob Sharps turbo manifold but it kind of worked out that way!

After I started designing my manifold I posted some early renderings on this site. Jeffrey directed me to a post on the atlantic forum about a manifold they were trying to build. This was one of the pictures they had posted. I perused the thread and promptly forgot all about it. The other night I was revisiting some of the early posts and decided to have another look at the thread and saw that shot so figured I'd have a little fun.

I'm in no way comparing my manifold to Bob Sharp! But it's nice that it has the right feel for the era.

Here's the unedited shot which I really like.

DSC_0005.jpg

Sorry for the long gaps in updates but it's all I can do to keep 1 thread going!

Thanks

Derek

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Derek,

That looks great-Horns, hard fuel lines to a distribution block at the back of the engine, short ignition path-seriously cleaned up the engine bay!

Will

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