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3D printing your own fuel injection set up


michel
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Yes, that's the idea.  For me, the only 3D printed parts would be the manifolds with injector bosses and the bosses would have metal inserts anyway.  Everything else would be off-the-shelf components (throttle plates, trumpets, linkages etc) in metal.  The big question is longevity/strength of ABS (PLA is definitely not suitable).  To get sufficient strength, they would have to be a lot more substantial (i.e. bigger) than their alloy equivalents.  Also, I can't see the point 3D printed fuel rails when proper alloy extrusions are so cheap!  In the final analysis, unless it can be done substantially cheaper (i.e. <50%) than PMO, Jenvey, Clewitt etc it becomes somewhat moot.  Anyway everything's parked until my sodding renno/extension is finished :(

BTW, I'll take a few pics of several details of my 914 that might give you food for thought for your project.  Hopefully I can get a round tuit on the weekend...

Cheers,

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  • 3 weeks later...

I've had reasonable success with dimensional accuracy, just printing PLA with my Deltaprintr.  It was a kit from the States.

Some settings needed adjusting (a lot of adjusting actually) but I got the desired results I wanted.

Using a material like Nylon 66 may be an entirely different kettle of fish, but with a good hot-end (Prometheus v2 is perfect!) I think it's doable.

In terms of design, I know ITBs are the in-thing, but I'm actually leaning towards something like the Carrera GT intake:

2moo56f.jpg

So you could do a single or twin-throttle setup with this layout.  With some imagination, you could probably use a Boxster intake T-piece and Throttle for this application.

I'm just dreaming out loud of course :)

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  • 1 month later...

Giving this topic a bit more thought, I decided the way to proceed is to actually get the injector block modeled up.  No matter if you intend to make ITBs or some sort of plenum arrangement, this part will need to be made... Unless you fancy paying $600 USD for a set of alloy injector blocks for EFI (as I've seen available for the 930.)

With this thought in mind, I purchased a relatively cheap stock 930 injector block for CIS Injection to copy from.  It has a 32mm intake diameter, where as my SC has a 39mm intake port, but other than that, I believe they are compatible (in terms of mating to the head and injector position.)

2vm6bdx.jpg

My intention is to copy the shape in Inkscape and then export to OpenSCAD format (my modeler poison of choice.)

I'm still in two minds whether or not I want to go ITBs or not.  I'm actually rather keen on a plenum for technical reasons (potentially more power, a single throttle to tune, use modern Porsche parts, easier SD tuning, etc.)  But ITBs do so very much look old skool and era correct. ;)

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I do agree.  The SC runners are not a pretty thing (IMHO.)  I've seen some people clean them up, even polished, but I'm still not particularly keen on them.

Also, once you remove all the K-Jet/CIS components, you're also left with a lot of ugly tabs (for the WUR, etc.) on the runners that also detract from the visual appeal.

So when I talk of a plenum, I would actually like to copy something like this visually (at least roughly)

242ipaw.jpg

This is an MFI induction system, with air filter housing.  Of course with MFI, you have a throttle for each cylinder.

My idea would be to model the injector blocks and a tapered throat, but into a common plenum (for each cylinder bank.)

They could then be joined with a Boxster induction "T-piece" and throttle.  You get the Vacuum and TPS sensors outputs from there.

Anyway, that's one idea.  Or I just go with ITBs.  I'll cross that bridge when I get to it!

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Yep, that's certainly an option.

Actually, if one wanted to go down that track you could pick up the Rasant EFI kit from the states, or the T-Bitz racing EFI kit and just about be done with it.  I've seen some very neat engine bays with that setup.

However, one thing I would prefer to do is be able to sell off the complete (unmolested) CIS induction components.  In working condition, these things seem to fetch a decent amount of money, which could go someway to offset the cost of the rest of the EFI conversion.  Or even a set of PMOs!

Anyway, I made an outline of the induction block today and scanned it into the computer.  I'm cleaning up the imagine now and then converting it into vector format.  There might be a more efficient way of doing all of this, but I think my approach is workable.

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Pics of your model then...

It's nothing special yet...

imup8o.jpg

Note: This is the underside, that mates with the head (with a gasket between it.)

The scan I made of the outline really wasn't that helpful.  It's good as a reference, but in the end I just broke out the vernier and took some measurements.

I'm making good use of the OpenSCAD "hull" function here.

Anyway, I'll print this ASAP and see how well it matches with the real injector block.

The next tricky part will be to measure the angle of the injector seat (if that's the right term?)

 

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  • 4 years later...

I went in a totally different direction, but 3D printing let me achieve it.

I'm adapting a 993 intake manifold (with functioning resonator) to the 3.0 SC motor.

This isn't totally new territory.  Race shops in the states have done this with 964 manifolds/injector blocks.

Anyway, I designed the adapter blocks in OpenSCAD, then had them machined by a company in Italy, called Weerg.

I must have printed 30 prototypes to get it right before sending off the final design.

The fit is "perfect" - but this is just one part of many steps to getting EFI going on this car (which is a topic in itself.)

I reackon I'm at least a year away from a first start...

image.thumb.png.f3848fe2df6b0564c8c7aedf1753e9ee.png

image.thumb.png.2512c4f6ee7f5c330380100bc098de56.png

 

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wow!! looks amazing bro!!! keep going! For me, a 3D printer was too expensive for using it, because of it not so cheap cartridges. But I still needed cartridges for my usual ink printer. These guys https://www.mrdepot.ca offer quality cartridges and printer from trusted brands. I ordered a couple for me without doubts and have no regrets! All work perfectly now! So if u want, u can look through this site for more info! wish u good luck!

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Cheers mate!

But, I think, I probably shouldn't hijack this thread any more than I have. 🙂

If enough people are interested - I can start a thread on my EFI conversion - which includes a lot more work than just the intake (all of which is just a part of my 911 hot-rod project.)

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2 hours ago, DRA911 said:

Cheers mate!

But, I think, I probably shouldn't hijack this thread any more than I have. 🙂

If enough people are interested - I can start a thread on my EFI conversion - which includes a lot more work than just the intake (all of which is just a part of my 911 hot-rod project.)

start a thread for sure

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Ok, here it is...

<Thread Deleted>

Edit: Almost 2 years on, I got it working... And also refurbished the entire underside of the car (suspension, brakes, etc.)

Sorry to anyone following at the time, I simply preferred to do this privately and explore my own ideas without restriction.

image.thumb.png.3554d8ea2779d69092c75fd48fd20606.png

Yes... It works. :)

No, it's not 100% finished.  It's nowhere near tuned.  But it idles nicely and already sounds awesome!

image.thumb.png.aca0ce4ac8df85de7e815b1a95cf7751.png

Enough teasing for today! :D

 

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