911S 1971 Standalone EMS conversion

[Tiago/Tecnomec]

Hello, greetings from Brazil. My name is Tiago, and I am a race car mechanic in São Paulo city. I have a garage Tecnomec if you want to see it.

I have had my 1971 2.2 liter 911S for 16 years now, with great joy and respect. The issue over here is the MFI pump, while it works great, there is only one place that services it, and its absurdly expensive. Last time it had problems, they wanted to charge me about US$ 3000 dollars just to rebuild the pump.

So, I took a bold decision. I would convert the car to programmable electronic fuel injection, using quality parts from domestic cars from VW group, and without ruining (cutting, drilling or welding) the car.

Here are some pics:

This is the car, before I bought her, it had been abused and was sitting for 10 years in a barn. I then restored it myself in my afterhours from 1996-1998, and caressed it ever since (but put her to work on a few local track days at Interlagos, and some hillclimbs too):



Here is a pic of the completed EFI converted engine, I think it looks really clean:



I fabricated the fuel rails, and adapted 6 direct fire coils from VW Passat (still have to make stands for the coils):



The crank-fire trigger wheel and sensor, it gives optimal precision to the ignition with virtually no maintenance:



I have to go now it´s late here, but I´ll be back with more info.

Hope you guys liked it, and remember THE CAR IS NOT RUINED, no cuts or holes were drilled, and I have the whole MFI parts neatly stored in a box, so it´s totally reversible.

The engine is already running smoothly, it idles at 800 like a watch if I want it to, and stars instantly even when cold.

Soon we will strap her to our dynamometer and do the power tuning. I´ll keep you guys posted!

Regards from Brazil!

Tiago

[MdR]

Very interesting work - I like it

[jpnovak]

NIce work. How did you seal the injectors into the threaded hole in the cylinder head?

[Scott R]

WOW! I would like more details on your setup as well. Very nice work BTW. Can you post dome details on the coil over plug setup? How are you driving it?

[tobluforu]

That is awesome, but where is the dizzy?

[RSTarga]

He doen't need a Dizzy because it is crank fired.
My question: is the throttle response as good as when it was MFI? I think this is the reason so many of us prefer MFI.
Very clean installation.

[Tiago/Tecnomec]

Hi guys, thanks for the positive feedback! I´ll try to show some more:

jpnovak, to mount the EFI injectors, we made some threaded adapters on a lathe:



Scott R, there is a Electronic Control Module that receives the crankshaft speed and position signal from the trigger wheel and sensor you saw above. The module then fires the coils on a "wasted spark" mode, like all modern engines. The dwell and advance curves can be programmed by the user (us)



(I still have to make a moulding for it)

tobluforu, the distributor and its parts (cap, rotor, points and cables) are very problematic parts that although work well, they are a source of losses, imprecision and frequente maintenance on any engine. So, I opted to eliminate all those parts and mount a Coil On Plug system, wich is way more precise and less prone to wear, losses and so. Check ou the cap and lock we made for the dizzy´s hole on the crankcase (the threaded hole is to aid in future removal):



RSTarga, the ECM is fully programmable, I can make up any spark and fuel curves I want, in relation to RPM, throttle position, engine oil temperature, Intake air temperature, and more... The engine is running already, and even though it´s not fully dialed in yet, it is already very responsive and starts very quickly even when cold. So, the system capabilities are there, if I don´t get as good as, or even better throttle response, power and consumption than before, than SHAME ON ME!!! haha

I´ll be back with more infos and with a little clip of it running. Please feel free to post any questions, comments or criticism, it´s all welcome!

[pjh69911]

What injector did you use, and can you provide further details about your custom adaptor. Very nice work, BTW!

[timmy2]

Nice work on your adapters, knurled so you can turn them in to the threads of the original injector fitting and I'd guess they are line and taper bored for the injectors to fit snugly with an o-ring.

[tobluforu]

Geez, doesn't anyone understand what a wink means? I know the reason why there isn't a dizzy as I have a saab viggen that untiizes the same concept which I can map myself due to open source. But, it amazes me that you were able to do this on an old mfi based motor, If this works out you might want to market this. Super clean motor and car, nice job.

[Tiago/Tecnomec]

pjh6991, the injectors are from a Brazilian version of the Opel Astra, but had it´s flow enlarged for the 911 engine´s needs. These are very affordable and reliable injectors.

About the adapters, we made it from stainless steel, no problems so far, I have my drawing (like a blueprint) for it, if you want PM me and I´ll send it to you. We also designed and fabricated the crank pulley for the trigger wheel and it´s sensor mount, a mount for the TPS (throttle position sensor) and a few other bits. Will be glad to share any details.

timmy2, you are correct, I thought about making it with a hexagon to use a wrench, but there is no space available. Since I did not want to cut and enlarge the engine cover, I made it knurled Inside the adaptor hole it is a very smooth and a snug fit for the o-ring to seal, but not tapered, it´s parallel (like the OEM ones). The fuel rail and its mounts holds everything in place against the fuel pressure.

tobluforu, I am sorry for that, I did not catch the irony So far the engine is running perfectly, still have to do the full load calibration, but the engine is behaving flawlessly on start-up, idle and part-throttle, cold and hot. I have no intention of marketing any of this, I am just doing it for the love I have for mechanical work and my Porsche 911. Being so, I will be glad to share any details to all of those who shares the love!

One more thing I forgot to say that favored this conversion is the Gas available here in Brazil. All pump gas has a MINIMUM content of 20-25% ethanol by federal law, and the Ethanol corrodes the MFI fuel lines and injectors. These EFI injectors installed are ethanol friendly, and can I can service them with the normal EFI equipment I already own, wich is a big factor for me.

See you all later, and thanks a lot for the compliments!

[Grady Clay]

Taigo,
Welcome to the Forum
You will find a lot of help and support here.


Congratulations on your very clean and clever conversion.
As an MFI affectionato, I appreciate your diligence with a ‘reversible’ conversion from MFI to EFI. Nicely done.
Please document your conversion with (VW and other) part numbers and similar information.
Many (worldwide) are in your situation.
Here on Pelican is the worthwhile exchange of information.


From Taigo’s website, the Portuguese-to-English (Google) translation is:

“We offer specialized courses, and research services and technical development of the internal combustion engine cycle "Otto / 4 time" of the light line.
Our courses in motor mechanics are directed to those who have the desire or need to improve their knowledge in this area.
They are efficient and flexible courses that allow a rapid maturation and secure progress in the understanding, assembly, maintenance and preparation of four-stroke engines. Whether at beginner, intermediate or advanced, the Tecnomec have content you are looking for.
We emphasize both the technical understanding of the physical phenomena involved in the processes of the engine, as the practice of working procedures used in the workshop. The methods applied in our courses are adopted worldwide by major engine manufacturers and recognized competition teams, and rely on more than 20 years of experience Tecnomec founder and tutor of the course, James Jorge.
The classes cover the basics from the run up to the advanced metrology required in the assembly, maintenance and preparation of Otto cycle engines, popularly known as "four times." We discuss principles and techniques that allow work to understand and work with new and existing engines, domestic and imported, equipped with carburetor, fuel injection, ignition distributor or static.
The module system provides the advantage of flexibility, enabling students to make (s) module (s) most appropriate (s) to your current technical level and the specific objectives of their work.
Click for more courses.
The Tecnomec also offers the following services:
Preparation / restoration technique printheads and motors; measurements and development bank flow, rental, measurements and technical advice on the dynamometer, consultancy / development engine configuration, modified or unmodified.
Click on the tabs at the top of the page to learn more."


Clearly, we have another world-wide skilled Pelican promoting the ‘cause’ (of Porsche & MFI).
Taigo, WELCOME again.

Best,
Grady

[fanaudical]

Very clean! Your Porsche is not only "not ruined", but I would argue is also "greatly improved". Please post dyno results when you get them.

[Tiago/Tecnomec]

Hello Grady, thank you, I can always use all the help and support I can get!

I just got to know the forum (although I did buy from Pelican Parts before), and I am already drooling over some of the cars here.

I also love the factory MFI setup and had a great time with it, including a 1st and 2nd place at a local hillclimb on my category. But the problem we have here is mostly with the fuel, wich deteriorates the pump, hard lines and injectors. Since there is the need for special equipment to rebuild the pump (wich I don´t have) and we pay over 60% import dutyes for any parts imported, it is a VERY expensive system to maintain properly over here.

This ECM I used "Pandoo" is made in Brazil, and you can (and should) make your setup as per your needs, there are numerous options, you can use it with the distributor or not, with turbos, any kind of fuel etc. it can also use different sensors and components from various manufacturers like Delphi, Bosch, Hitachi, VW, Porsche etc etc, the combination just have to be properly matched. Here is what I used:

Coils: VW/Audi 06B905115E (similar to Hitachi CM 201).
RPM/Crank Trigger Sensor (CKP): VW 041906433
Intake air temperature sensor (IAT): MTE 5053 (IG901)
Engine Temperature Sensor (ECT): MTE 4053 (IG 802)

I used a TPS (throttle position sensor) from a brazillian VW car its from Magnetti Marelli I will get the number, don´t have it here.

The injectors were calculated for the engine I am using six injectors with 27 pounds/hr of flow measured open at 45 psi.

Glad to share, would hope to help anyone having problems with MFi or carbs have their Porsches happy and strong again!

fanaudical, thanks a lot, will do!

See ya!

[Lukesportsman]

This has been approached a couple times on this site, but you have taken a fresh approach. Many of us will watch this with anticipation. If only it sounds more like a 2.7MFI than a 3.2EFI its worth the effort.

[al lkosmal]

Tiago,
That is an excellent approach and very nicely done.

regards,
al

PS: I also like to play with adapting EFI/ITBs to the 911 engine.

[Tiago/Tecnomec]

Hello everyone, been very busy here at the shop, but finally got the chance to do a little bit of tuning on the 2.2.

Lukesporstsman, the car sounds just the same as before (with MFI), it just starts faster now - especially when cold -, and the sound is a little "cleaner", probably because of the 6 coils and the better AFR control of the electronic injectors... The intake tracts and exhaust system are the same as before, so it roars loudly as before when wide open

al ikosmal, thanks for that, I just want to maintain my beloved 911 running the best I can. Are there any of your EFI projects around the forum? I would love to see them!

Here is a quick clip of the engine running, just cold starting and a little revving to about 4000 rpm standing still:



Soon I will post some power pulls. C ya all!

[island911]

Is fuel metered by throttle position only -- or is their some hotwire / mass Air flow sensor as well?

Originally Posted by tobluforu

Geez, doesn't anyone understand what a wink means? I know the reason why there isn't a dizzy ....

I'm surprised that he knew "Dizzy" translated to "distributor" and not --read: there is no need to add confusion for the guy to translate.

[Lukesportsman]

With ITB's I'd think a MAP sensor would certainly be easier than Mass Air. Most of the EFI's I've played with use a correlation between rpm, throttle angle and MAP to determine fuel needs along with feed back from a wideband AF.

[kenikh]

Someone finally DOCUMENTED this - there was one other thread long ago that died before anyone could get answer as to whether this would work.

Tiago, you've completed exactly what I've long wanted to do, but have never had the time to execute. Kudos to you for blazing the trail (and capturing it).