914-4 EFI Conversion

EFI Frequently asked Questions: 

1) Why have we designed a kit to change from Factory EFI Carburetors to Electronic Fuel Injection?

We’d like to keep these cars on the road and with today’s poor fuel quality, increasing difficulty in finding parts, and increasingly costly repairs, in addition to the lack of tuneability of the factory setup, it was important to us to find a solution. 

 2) Do you make one for my car?

This Kit is Designed for a 1970-1976 914-4 but do make them for other applications as well (356 & 912)  .

 3) Why should I install this kit on my car? What are the benefits?

This kit has many benefits such as, easier starting, better drivability, altitude compensation, more precise control over fuel and timing. 

 4) How much time does this kit take to install and how difficult is it to install?

This kit was developed for someone moderately experienced working on 914’s. You can expect anywhere between 6-10 hours (possibly more, depending on skill level), not including removing and reinstalling the engine.

 5) What’s included in the kit?

This Kit Includes: 

• ECU
• Completed Pre-Terminated Wiring Harness
• Throttle Bodies 
• Fuel Injectors
• Intake Manifolds
• Throttle Linkage
• Sensors (Air Temp., Cyl. Temp., Throttle Position, Wideband O2 Sensor)
• Fuel Lines
• Fuel Filter
• Fuel Pressure Regulator
• Spark Plugs and Wires
• Distributor
• Ignition Coil and Module
• All Associated Hardware Components  

A few other parts may be needed , such as the side tins if converting from Zenith Carbs

 6) Is Tuning required?

The kit will ship with a base map that should get you started, however, due to many variations in engines the vehicle will have to be tuned . Ideally having it professionally tuned on a dyno would be the best route. With that said, you can do it yourself via a laptop (windows or Mac) or an android device. however it can be a very steep learning curve as there are many aspects that need to be thoroughly covered to optimize the tune to fit your particular application.

 7) How much permanent modification must be done to my vehicle when installing the kit?

A few small screw holes for mounting the ECU and Fuel pump. An O2 sensor bung is included in the kit and is strongly suggested to be installed in the muffler to aid both tuning and allow full functionality of the kit.

 8) How much does this kit increase horsepower?

This kit was designed for increased drivability and improved starting first and foremost, but from what we’ve seen there may be a significant increase in power over your old carburetors, especially on modified engines. It does vary car to car. With a proper tune, it will perform at least as well as your carburetors did. Our goal was to make these cars easier to drive in an effort to keep them on the road.

 9) How do I get one? When can I order one?

The kits are currently for sale. Please call us before ordering to confirm build details and current ETA. As each one of these kits are made to order, we have a couple of questions to help choose the best of several options to best suit your car.

 Options and which is right for you

• Throttle Body Size:
  • 36mm – we usually use these on lower output engines such as 356 1300, 1500, Normal, Super as well stock “C” engines or those requiring greater throttle resolution 
  • 40mm – The most common option used on 356 S-90, 356 SC, 912, 356/912 “Big Bore” (1720cc), 914 up to 2056cc with mild a cam. 
  • 45mm – We typically only use these on larger displacement engines greater than 1720cc that would require higher amounts of air flow such as 356/912 engine built to 1883cc+ or 914 engines 2056cc with warmer cams or larger displacements.
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  • This is only a rough guide for selection based upon common configurations. If you have uncommon engine combination that and are unsure of what size would work best for you the following formula can help you to get a rough determination of sizing for your specific engine
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    • Throttle bore diameter: D = (0.8 to 0.9) x (V x n)^.5
    • Where:
    • D = Throttle bore diameter, mm
    • V = Cylinder displacement, liters
    • n = Engine speed, RPM at max HP

• Idle Air Control:

•  Even though startup with the EFI conversion can be far better than with carbs a few things will effect this such as displacement, camshaft choice and ambient air temp /engine temperature

  • Typically larger engines ( greater than 1720cc ) and engines with more aggressive camshaft profiles require a bit more air at idle when cold than smaller ones, leading to a higher than desired idle when warm if set to idle satisfactorily when cold. This can be an annoyance and can be dealt with by holding the accelerator for the first 30 seconds or so of running followed by a lower than desired idle until the car warms up a little.
  • Cold weather (usually sub 40*F) can compound these issues and make cold idle less than stellar, This isn't a big issue for those of us that see the vintage Porsche as a “Fair Weather” car but others of us who drive in all manor of weather and climate this can be anywhere from an annoyance to a frustrating issue, depending on engine build and driver patience. This issue is typically only for the first cold start in the morning or after the car has sat for several hours after being up to operating temperature in sub freezing temperatures.
  • The Idle Air Control package once installed and tuned for your engine will handle control of all idle related duties automatically. Upon startup the RPM should raise to a cold idle set point, Usually around 1100-1200 rpm, and decrease to the target idle as the car warms up. This feature uses closed-loop feedback to constantly monitor and make adjustments to keep the desired idle at all times, even if running accessory such as air conditioning.

• Fuel and Ignition Table Switching
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  • This option will allow the change to a secondary fuel and or ignition map to be activated via physical switch this can be use for several things: 
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    • “Poor Fuel Quality” – we find this handy , the secondary maps can be configured to add a little fuel and pull a couple degrees of timing to allow safer operation on lower octane fuel
    • “Pump Gas vs Race Gas” 
    • “Power vs Economy” 

• Realtime Barometric Pressure Correction
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  • This Option includes a dedicated barometric pressure sensor for weather and altitude compensation.
    • The standard kit handles altitude compensation by taking a “snapshot” of the barometric pressure when the key is turned on before the engine starts and uses that for a reference it only looks at barometric pressure the next time the car is started. This is more than sufficient for the vast majority of the Eastern and central US. 
    • However this may not meet your needs if you experience frequent altitude changes in excess of 2000ft in a single drive, for example driving in a fairly mountainous, region such as a large percentage of the western US., it is not unheard of to see 4-5000 ft elevation change in a hundred mile drive. The optional on Barometric Pressure Correction kit allows the ECU to constantly monitor and make changes to the altitude compensation real time as you drive to ensure fuel mixture and ignition timing is correct for any given altitude any time in your drive, be it a drive to your local cars and coffee or to the top of Pikes Peak.

For any other questions, regarding this or any other inquiries, please use our Email Contact form on our website.