I hate you guys. I recently fell down the MFI rabbit hole after deciding $5k+ for a set of PMO's wasn't worth it to me and if I was going to start with a blank slate rebuild there may be another way. This thread is making me want to go this direction even more.

I've been reading all of Jeff Higgins old posts and started to put together a spreadsheet of things I need to start accumulating. Henry Schmidt's builds are the stuff dreams are made of and also provide a lot of inspiration.

For me EFI isn't even remotely a consideration. One of the things I love most about my car is the lack of computers, having to tune it with a laptop would ruin the experience, I'd rather sell the car.

That is one clean running machine! What spark plugs are you using?

Bosch W3DPO, spec for all MFI cars except 911T. Also for 930.

Works in winter or summer, city or highway.

Thanks Jeff, I'll try that spark plug on my 70 911S

And here I was starting to worry about you... ;) I haven't given up on vinyl yet, though...

Yup, I check all of those boxes. And yes, I readily acknowledge all of MFI's shortcomings, and still prefer it.

At the end of the day, this is all about having fun. Some of us enjoy discovering how archaic old systems work and trying to make them work for us. I think one thing our little community has learned in these modern times is that MFI is not the mystery some had thought it was. With the benefit of modern instrumentation and test equipment, we can now make these systems run far better than when they were new. To me, that has been the challenge, and the enjoyment. I can see the same satisfaction in getting modern EFI/ITB systems working on these old motors.

I find it interesting that those work so well in your application. Every time I stray away from plain old single fat electrode style plugs, the really primitive bargain basement ones, I run into trouble. My car lives on NGK BP6ES's, while my son'e likes the BP7ES's. Any of the multi electrode plugs, or the ones with the really fine electrodes like the one you show, simply foul. Of course neither of our motors are any kind of original Porsche factory spec, and are running custom space cams, so they do run a bit dirtier in spots.

Which ignition are you running? My car uses the old Electromotive crank fire with six split coils, my son's uses the stock distributer (recurved by Barry Hershon) with a Pertronix Ignitor and a Bosch 6AL. Plenty hot spark from both, but they still foul the "fancy" spark plugs.

Ignition is Bosch 3 pin and Bosch coil from, I think 74-75. I’ve also used the original Permatune blue box and blue coil that Porsche used on 74 CIS 911s when they ran out of Bosch parts in late 73. They seem to perform equally well on this car with no discernible difference.

Yeah, vinyl, to sound great, needs to be real clean and cared for well. Plus, it is getting super expensive to obtain quality vinyl. I spent a bunch of time finding the best masterings of the albums I have on CD and SACD. Then, I rip these and play them through Roon. Roon integrated wonderfully with Qobuz so I can explore music I don't own. I don't have to get out of my listening chair to change albums.

I am all for people using MFI if that is what they want to do. If I were to pick up a pre 1974 911, I would want one with MFI and I would be happy to deal with the system. If I were building a restomod on a 1974 or later chassis, I would be using EFI.....there is no way I would try to make MFI with the modern engine build I would use.

Let's keep in mind that my only point of contention in this thread has been the idea that MFI has superior throttle response to a modern and well setup EFI ITB setup.

Wait, you use MFI because you enjoy the old systems yet you use Electromotive crank fire with six split coils?

Twisted....

The Electromotive crank fire stuff sucks.....

Yes, indeed. Quite the contradiction, I know. The problem was, about 15 years ago when I built the thing, twin plug distributers were virtual unobtanium. Originals would have set me back the cost of the entire rest of the motor build. Cap and rotor sets were in the neighborhood of $1,500 each. Just not a viable option at the time, for a street car that was meant to be driven. A lot.

My real world experience says otherwise. 15 years of absolutely trouble-free operation. It will roll over on its first 100,000 miles before the end of this year. It has averaged 10-12 DE events per year. The motor regularly sees in excess of 7,000 rpm with nary a misfire or bobble of any kind. The system is eminently tunable, with individual control over idle, mid range, and high RPM advance, with a high RPM retard available as well. I literally set this thing and forgot it 15 years ago, although I do check it once a year with a timing light.

So, yeah, 15 years of real world, hands-on experience with the Electromotive crank fire ignition system, and over 20 with MFI. My opinions are based upon actual experience. There are, of course, other ways to form opinions, some more valid than others.

I guess it works for street cars....I see failures at the race track way more often than I should considering the limited number of people running them.

That speaks more to the quality of people running them than the quality of the components themselves.

If anything, these components lead a much harder life on a street/DE car than on any race car. They see a lot more mileage, a lot more duty cycles, a far broader range of climatic conditions (my car regularly sees, with the changing seasons, anything from bone dry 110 degree Eastern Washington high desert to the snow and ice in single digit temperatures of our Cascade Range to our infamous Pacific Northwest rain).

Beyond that, this car gets driven every bit as hard on our local race tracks as any race car. My lap times would put me out in front of our local SOVREN (Society of Vintage Racing Enthusiasts) C/Stock class, wherein our local vintage 911 continent runs. Alas, I am "cheating" - my 3.0 displaces too much for the class (2.4 limit), has newer aluminum cases, and is twin plugged. Oh, and I run "Wide A" calipers on the front, also illegal for the class. Even though it is purely my equipment advantages speaking, I do lap faster than they do...

So, I guess I'm unclear on how Electromotive "sucks" (but only on race cars...). Race cars are prissy, pampered pussies compared to cars used on the street. Race cars typically get far more love and attention, they get far, far fewer miles (hours), and get to operate under far more controlled conditions. If someone cannot get Electromotive to work under these conditions, he must be rather inattentive or incompetent. It's a fantastic system.

Maybe. The competent race engine designers and builders I know recommend against it.....of course these are people mostly using MoTec with EFI. I guess their combined 100+ years of experience pales in comparison to your experience...and what I have seen.

Yeah, you are so fast I tremble in my racing shoes....jeez. Oh, doing a few laps at a time at race pace is not the same as running 40 minutes to 90 minutes at race pace.....

Here is my crappy MoTec setup not using Electromotive:

http://forums.pelicanparts.com/uploa...1605733094.jpg

Interesting. You began this little sidebar by flatly exclaiming that "Electromotive sucks". I responded by saying I have had great luck with it. You responded by saying "I guess it works for street cars....I see failures at the race track way more often than I should considering the limited number of people running them".

I went on to explain why I believe these systems lead a harder life in street car, particularly street/DE cars that do double duty. Essentially, they are faced with the harsher environment of street use, plus the same duty on track as any race car.

I guess I'm not sure why you would respond to that with a simple argument from (others') authority, a childish insult, and a flash of your wallet. Do you honestly believe any of that furthered your argument, or answered any of mine? :confused:

Again, why is it some people on this forum are always trying to pick a fight? It’s tiresome.

Come on, Jeff. Your argument is more fallacious than mine. Just because you have had success with Electromotive does not negate what I have seen at the track or heard from high performance engine designers and builders. Also, my photo was not a flash of my wallet anymore than your lap time comment was a flash of your ego.

I am glad you have Electromotive working for you. But don’t try to suggest that one positive case cancels any and all negative cases. Street engines see a different kind of environment than race engines. Race engines won’t last 100,000 miles….so that argument is flawed too.

Please post that same comment a few more times as I might have missed the last two in this thread.

The behavior continues and yet still no answer to my question.

Oh, you mean the part where someone has an opinion that is contrary to another person’s opinion? Oh, you want a forum where no opinions or statements are challenged. Boring….and not at all educational.

Is it really (more fallacious than yours)? Do you honestly believe my experiences represent an "example of one", or some kind of an anomaly? There are literally thousands of these systems in daily use in everything from our 911's to American muscle cars. A great number of "high performance engine designers and builders" use it as their first choice. My first hand experience is merely representative of their outstanding reputation.


Hardly. I took pains to point out that the only reason for my lap times is the fact that I'm "cheating" and have a distinct equipment (mainly power, some braking) advantage over what is allowed under class rules, thereby ruling out any possibility it is my "skill". Hardly any sort of a display of "ego". My only intent was to illustrate that the car is operated under the exact same conditions as "race cars", in addition to leading a much more demanding life when not on the track. Instead of just sitting in a garage, awaiting the next race day.

Again, do you honestly believe I'm suggesting my "one positive case cancels any and all negative cases"? There are thousands of these on the road. Thousands.

Race engines do, indeed, see a different kind of an environment. An environment that is much harder on some mechanical components - rod bearings, valve springs, and that kind of thing. Reciprocating, moving parts. These modern ignitions systems have no moving parts. All they "see" is how many times they are asked to provide a spark. In a race motor, they see no RPM induced loads nor stresses that they do not see in a street motor. In a race motor, they are not exposed to the extreme environmental conditions I noted earlier. Coupled with a fraction of the number of duty cycles on a race vs. street motor, these electrical components actually lead a much easier life on a race car than they do on a street car. They are simply not experiencing systems failure due to the added stresses of racing - there aren't any with these kinds of components.

These are all points I made earlier, none of which you were able to address - hence your response. I think you must have some image of everything on a race motor (or race car as a whole) somehow leading a much tougher life, somehow being much more highly stressed, than a similar component on a street car. While that is absolutely true for some components (tires, brakes come to mind) it is absolutely not true for others. Electrical components come to mind, including ignition components.

So, yeah, if they are seeing failures on race cars, it's due to faulty installation, neglected maintenance, inattention, or incompetence. And I'll bet the truly competent have chosen not to run it because other systems give them other advantages, like full engine management integration with the EFI system. Not because Electromotive is failure prone.