Webers Vs. MFI

(Still trying to learn as much as I can)

I know this may start a debate but I am still a little confused... I was looking through old posts as well as Anderson's book and I can't seem to find much reference regarding Webers and the 2.4L engine. I could be blind or not searching under the correct terms, but can someone clue me into the benefits of switching from an MFI to dual webers on the 2.4, if there are any?
The only two I could come up with is a slight increase in horsepower (>10?) as well as torque and possibly better throttle response. A mechanic in the area said it was common because of a lack of MFI knowledgable mechanics (for when they go bad; only a 2 or 3 mailorder types).

How far off am I and where is the proof (pg numbers or forum URLs)?

PDreams

Anderson really discusses some pros and cons when he discusses mod.s for 2.7l.I think basically when the MFI is set up correctly you have crisper throttle response and cleaner exhaust. Once set up they keep tune pretty well. The onle thing you need Gus for is to rebuild the pump. I'm not sure what the life of the pump is perhaps warren knows.

I've done this very swap on my 2.4L '73. The MFI was working properly but I could find no one who knew anything about working on these systems. I didn't want to wait for a failure so I made the swap and added a few go fast goodies in the process. The result was a much cleaner looking engine that I could work on. Power was up from the stock MFI as well. I still have this system if any purists would like it.

OK, the numbers are on p. 108-112 in Bruce's 2nd ed. 'Handbook' ... in factory engine uprades from Webers to MFI, 10 hp were gained for the 2.0 'S' and for the 906 to 906E engines.

All of the discussions in Bruces book dealing with 2.7 Weber upgrades on power were dealing with going from the CIS fuel injection, which cannot handle radical cam timing, so he was referring to cam changes as well as Weber conversions. He does not discuss replacing MFI with Webers. Likewise, with 3.0 SC engines.

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Warren Hall
1973 911S Targa

On page 142 and 143 Bruce talks about a 2.7 with "E" cams and webers, he then goes on to talk about an RS conversion of wich he says with the MFI you would get a little more power, crisper low end throttle response, better fuel economy and cleaner emissions wich may be the difference of being legal or not. This in a passing way not directly is the only comparison of webers VS MFI that I recall in the hand book. This does seem to be the diferences. You may want to E mail him through www.911handbook.com and ask him any other questions you may have.

That is all what I found as well... after reading the book more carefully today during my 'down time'. He seems to refer to the MFI and Webers together alot in the 2.7 area... again, over the CIS. Not much at all in the 2.4, and then the 10hp gain on the 2.0 mentioned above by Warren.

I'll see what he has to say...
Let ya all know...

PDreams

[This message has been edited by PDreams (edited 06-05-2000).]