1973 T - MFI or CIS?

David Bahr · 03-06-2002, 10:56 AM

I just acquired a 1973 911T targa. How do I determine if this is a MFI or CIS car (1973 versus 1973.5 model year)? It has been converted to Weber 40/IDA 3C carbs so it is not readily apparent. VIN# 911 311 0438.

Also, any thoughts on the effects of the carb conversion, in horsepower, torque, mileage, etc.? It has been stored and not started for 2.5 years so I don't know how it will run.

Thanks for your insight! http://www.pelicanparts.com/support/smileys/s1b.gif[/img]

BK911 · BK911's Garage

According to:
http://www.us.porsche.com/english/excitement/classic/911/1973.htm

it was an MFI car. To verify check the engine type.

Have fun!
BK

Early_S_Man · 03-06-2002, 11:23 AM

Yes, per the spec book ... that is an MFI 'T' car built before 1 Jan 1973! The Webers cost 10 hp, meaning it is equivalent to the ROW 'TV' engine with 130 DIN hp with carbs!

David Bahr · 03-06-2002, 07:25 PM

Thanks, guys!

I'm somewhat surprised that the TV carb version made less power than the TE MFI version. I'm hoping that the Webers will make more power than the Zeniths used on the TV engines.

campbellcj · 09:30 PM

Quote:

Originally posted by David Bahr
Thanks, guys!

I'm somewhat surprised that the TV carb version made less power than the TE MFI version. I'm hoping that the Webers will make more power than the Zeniths used on the TV engines.

In the late 60's / early 70's, the factory used MFI on virtually all of its highest performance street and race cars because it did make more power than carbs.

I really doubt that Weber carbs would make any more power than Zeniths, all other things being equal, i.e. both in great condition & properly sized, tuned and jetted. IIRC the Zeniths were made by the same company who made Solex carbs and were essentially a Weber clone. They are good carbs.

BTW You do know what the "E" in the TE designation means, right?

David Bahr · 03-08-2002, 03:23 PM

E = einspritzen = fuel injection.

Yeah, FI generally offers better combustion hence more power.

Since Porsche did CIS over MFI for emissions reasons, and CIS required particularly mild cams, I had hope. However, the CIS cars had 8.0:1 compression versus 7.5:1 in the MFI.

It was just a hope...

Honestly, as the car will be a daily driver, torque is more important the horsepower and I think the car will perform admirably as it is.

Thanks for your comments!