Mech Injection

With a recently rebuilt MI pump and system which is in good shape do I reinstall it or do I bite the bullet and take the carb route. Having had previous experience with carbs on a 914/6 I am aware of the work required to get them set up. Am I fooling myself into believing that the MI system offers better throttle response with improved drive ability.


Chris Nielsen
72 Targa

Well you may have ignited another wild debate about FI vs. carbs here...IMHO a *properly working* FI system does offer as-good as or better performance compared to carbs, plus huge gains in starting, drivability and throttle response. My opinion is also for *stock engines* -- when you go well beyond stock the balance may shift towards properly set up carbs.


OK maybe I'm biased as my 70 911E has newly rebuilt MFI and my 73 914 2.0 also has original FI.


The smog police are also a big factor depending where you live.

MFI is coming around again as the choice to take IF all the parts are in spec.Horsepower and response are superior. If not the carbs are a lot easier for the novice to work on and in PMO's case, they are smog legal as well.

There are two specific cases where factory engineers gained an additional 10 hp on 2 liter engines converting from Webers to MFI. In the first case, racing engineers did it on the 906 engine, though this early application used the single-row pump without the 'space-cam' ... from 210 hp DIN to 220 hp ... the gain might have been even more with a double-row pump! In 1969 the 2 liter 'S' engine gained 10 hp over the '67-'68 version with Webers, from 160 to 170 hp DIN, using the production double-row pump with 'space-cam'!!!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 02-20-2000).]

It seems to me that you've answered your own question, by saying that you have everything rebuilt and ready to go.

To this enthusiast, an early E or S with a properly set up and running mechanical injection system is a really special car, one that I really enjoy looking at, riding in, and if given the chance, driving!

If carbs have been stuck on it, it loses alot of its specialness, to me. To me, its an indication that somewhere over the decades, shortcuts have been inflicted upon the car.

Thanks for the input and yes I did answer my own question the MFI is going back on.


Chris Nielsen
72 E Targa

I am considering removing the MFI on my '72T only because I like to do my own work. I have had one heck of a time finding any docs or people who know about the system. When it works it works well, but if anything goes wrong, look out. Warren told me about docs but I can't find anybody who can get them as they are out of print. Good Luck

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John Birkett
73'T Targa

A RennList member named John Hunt used to have a site with a fair amount of MFI info. There was also talk about somebody scanning the Bosch/Porsche MFI service manual(s). Anybody know what happened with John and/or the scanning project? I would be glad to host the MFI pages if John H. is not anymore.

I have a copy of the "blue book" available from Gus at Pacific fuel injection for 25$.

Bruce