New to Fuel Injection Control

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Bullhoose
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New to Fuel Injection Control

Post by Bullhoose »

Guy's, I'm needing all the help I can get. I'm new to fuel injection all together. This is my project: Im building a Porsche 914-4 powered rail buggy. The engine has dual carbs now, but id rather have the throttle response of fuel injection.
I'm wanting to install fuel injection but don't want to spend thousands of dollars on 4 injectors, an O2 sensor, two throttle bodies and a controller. Could someone please recommend a setup that I could build? I do know a little electronics and wiring.
Abricos
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Re: New to Fuel Injection Control

Post by Abricos »

First welcome to the candy shop ...
Second what sensors do you already have on the motor ???
need more information what kind of motor what kind of car year ?????foto video info !!!
ZHoob2004
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Re: New to Fuel Injection Control

Post by ZHoob2004 »

The 914-4 originally came with a Volkswagen type-4 engine and a Bosch k-jetronic? EFI system. I don't know much about it, except that it was totally analog and completely open loop. I don't recall much in the way of sensors, aside from a switch on the throttle body to differentiate between idle, part-throttle, and WOT. It's little wonder that the first thing anyone does with these motors is switch to carbs...

As for converting back to EFI here's what you need:
  • Intake manifold - Somewhere to put your injectors and throttle body/bodies. It sounds like you've looked at individual/dual throttle bodies already, and found that they're quite expensive. If you can find a factory intake manifold, that has a single throttle body for all 4 runners and should do nicely.
  • Throttle Body (maybe more) - Not complicated. A door to let air into your engine, much like the butterflies on your carbs. Nothing particularly special. More throttle bodies quickly add more cost and complexity. You will also need a throttle position sensor for better engine response.
  • Injectors - Injectors are all pretty similar in size, and can be made to work as long as you have the right flow rate for your engine. I'm not a very good source on this. The factory injectors used little stubby fuel lines to connect to a common fuel rail, but modern injectors use o rings.
  • Fuel Rail - Not explicitly necessary, but makes connecting to your injectors easier. See above. I've done some searching for 914/type iv fuel rails in the past, and not come up with much so it will likely have to be custom. A vendor in the Datsun community that goes by pallnet makes custom fuel rails and could probably be helpful for not a lot of money.
  • O2 sensor - Not actually necessary! (Not exactly anyway). RusEFI and many other engine management systems operate in what is called "open-loop" mode, meaning there is no feedback and self tuning. Once the engine is tuned and the tables are saved, the O2 sensor is just dead weight (as far as the EMS is concerned)
  • Engine Management - You're on RusEFI forums, so that's going to be the top recommendation. You're probably jumping in the deep end here, but it should be totally manageable. Get a preassembled board (you'll understand why I say this if you don't) and get ready to learn.
  • Other Sensors - There are a number of different algorithms, and each requires some different sensors. Intake Air Temperature (IAT) and Engine Coolant Temperature (Oil Temperature in your case) are good things to have no matter what you use.
Hopefully some other members will be along shortly to point out everything I missed.


As an aside, if you're looking to sell your carb setup I may be interested. I'm helping my brother get a "barn find" 914 on the road and carbs would be a nice shortcut to fixing the factory setup for now.
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kb1gtt
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Re: New to Fuel Injection Control

Post by kb1gtt »

Where is the ECU going to be located? Is water a concern or is this in a dry location?

You likely would need the assembled Frankenso.
https://rusefi.com/wiki/index.php?title=Manual:Hardware_Frankenso_board
Welcome to the friendlier side of internet crazy :)
Bullhoose
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Re: New to Fuel Injection Control

Post by Bullhoose »

Thank you guys for your response’s.
I do have access to different machining tools, equipment and several local salvage yards.
As far as hardware I have nothing. I don’t have a problem Frankensteining the hardware side together and getting it to work either.
As far as location of the EMS it will need to be water proof or highly water resistant.
Thank you guys once again for your response’s. I look forward to learning!
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kb1gtt
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Re: New to Fuel Injection Control

Post by kb1gtt »

Frankenso is not water resistant. It's a replacement of a dash mounted ECU. You could likely mount it in a waster resistant box. However I do not know anyone who has done that yet.

Prometheus might be easier to make water tight.
https://rusefi.com/forum/viewtopic.php?f=4&t=1215

Would you consider adding a second O2 sensor? AKA can you have 2 ECU's one for each throttle body?

Can you merge the throttle bodies, such that you have one throttle body?

Is this a boxer horizontal opposed engine? Could you use a Subaru manifold or similar to get one throttle body?
Welcome to the friendlier side of internet crazy :)
Abricos
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Re: New to Fuel Injection Control

Post by Abricos »

Is the double carburetors stock options ???
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AndreyB
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Re: New to Fuel Injection Control

Post by AndreyB »

ZHoob2004 wrote:
Thu Jan 10, 2019 11:49 pm

As for converting back to EFI here's what you need
This is some great content! One day we shall copy-paste it to https://github.com/rusefi/rusefi_documentation/tree/master/FAQ maybe even today is the day :)
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