I have the entire article scanned if you want a copy - just send me your email.

As a Porsche tech I owned a sweet 73.5T many years ago and with the CIS set up perfect...and with a fresh tune, mid to upper 20's (24-28) on the highway and mid to high teens (16-19) around town, depending on how the machine was driven.

Your results may vary.

The CIS "T" was easier on fuel than the MI/Carb engines, by a mile.

Today, I get almost the same mpg with my 3.2, interesting.

note that current EPA figures differ from earlier ones, due to changes in the measurement spec (last year?)

P AG is very proud of the fact that they have continually increased mileage AND hp at the same time over the years - I've heard that they will not increase hp w/o also increasing mpg

Harry - you must be driving the eff out of that CIS car to get such low mpg on it...

I have a bone stock 1973 911T MFI with 88,000 miles on it. I typically get 16-19 mpg mixed city/hwy driving. I run Chevron regular as this motor has a low compression ratio.

My 73 911S with it's 2.7 RS motor I average about 16 mpg tank to tank combined city/highway driving. 91 octane California formulated dino juice. Long freeway jaunts get me about 20 mpg.

Using 91 octane in mostly city driving, I get about 15 mpg in my stock '71 T (2.2 liter.) A couple of weekends ago, I took it up to Solvang and back, and got 23 mpg.

:)

72 E Sportomatic w/MFI, drove from the UK to Le Mans last summer, 23mpg (UK), so about 19mpg US. All types of driving all seems to end up about that figure.

I have gotten just over 30 mpg in my 73.5 CIS targa, with the top on in warm weather in steady highway driving. I always get over 20 mpg, but just barely if it's around town driving and I let my right foot get heavy. I get almost as good mileage in my 71 coupe with a 3.0 liter, but it's more fun to drive.

Tom brings up a very important point: the ‘right-foot’ effect.

When henry959 has completed his data collection, he should post how the data is being analyzed and used.
He should not post that now as the knowledge of the goal may influence the data reported.

Even if the goal is to simply compare the differences among ‘T’, ‘E’ and ‘S’, the ‘how is the 911 used’ effect may be greater than the more subtle differences.
It could take a huge sample (larger than likely here) to detect the difference with confidence.

So … everyone should report mileages with as much detail as is available.
That could include everything from averages over months to specific ‘economy-runs’, race events and ‘land-speed-record attempts’.
Leave it to the data analyst to sort through the details.


Mileage is notoriously driver and driving style dependent.
My little ‘daily’ (GT3CUP) got 20-26 mpg with my son driving in HS.
With me driving in approximately similar conditions, it gets 26-36 mpg.
The wider difference is due to weather, A/C and short/long trips.
I have been able to extend the mileage with ONLY driving technique to above 53 mpg on the highway.
The highest measured was 65 mpg but suspect (I couldn’t repeat).
I will speculate that the car would get in the teens or even single-digit mileage at-speed on the racetrack (something I’m not going to try with an ’85 Camry).

My point is that there can be a measured 3:1 difference in mileage with the same car but with different drivers and driving situations.


To add another data point.
My street hotrod is a ‘73 MFI 911S engine, 2808 cc, 10.5:1 CR in a sub-2000# 914-6.
My street driving is probably rated ‘conservative’ by Porsche-owner-standards.
Yes, I get to full throttle regularly but I am a ‘gentle’ driver.
My mileage is typically 12-17 mpg on the street.
I use 100+ octane race gasoline, usually VP 112.
Mileage is single-digit on track at DE events (at $7/gal, I don’t need to know).

For reference, our (Rahal, Redman, Garretson) Daytona winning effort in 1981 was about 3.7 mpg for 24 hours (my lame recollection) in the MFI 935K3.
This was ‘good’ and we eked out at least one less fuel stop than others.

Best,
Grady

My 1972 stock MFI 2.4S would get 24MPG on the highway on the way to SCCA nationals from CT to KS, exact same mileage as the 100hp less Mazda RX7 would get.

http://www.analogman.com/911/72sback.jpg

Great point with the Right Foot theory. When I switched out the 2.2 w/ zeniths and replaced w/ the 2.4 and 46 Webers...on the German Autobahn #7 from Wuerzburg to Schweinfurt, I averaged 8-10 MPG.
But it was fun!
Vr,

I've been getting 16 mpg, however I'm well aware of my "right foot" :) I've recently put a taller 5th in, so I'm interested to see if that makes much of a difference on the highway.

Wow! I've suspected my 2.4S ran rich, but not as rich as would be indicated by comparable fuel economies. Last road trip my wife (read easy driver) got 14mpg with it: targa top off, cruising down I-5 at 60mph.

Since then I hooked up the LM-1 and leaned out the MFI pump some, but a cruise it wasn't way off.

results
 

This is a small sample, but I did take the time to be accurate.

motor is a '70 2.2T
Weber 40 IDA 3C1
MSD, Pertronix, Magnecors
.045 plug gap
Idle STE reading: 4.75 per cyl

I lost the exact miles vs. gal numbers, but it was approx 74mi in 3.6 gal

exact mpg was 20.89

The car was filled with 92 octane premium from a station in VA called Wawa. The initial and second fill were done on the same pump, and both times filled until the 1st click. Driving was mixed city and hwy. I was not afraid to put my foot into it. Most acceleration was at WOT. :D

If you need more I can provide you with an end of tank report.

Good Luck!
-Dan

How is that the 911 E takes down the 911 S in C & D's test results even though the S has better p-2-w ratio with same gearing? The almost equal trap speeds indicate the E's hp ratings are a little low, no? Just squinting so I could be wrong...

Oh, sorry City MPG is 17 and Hwy MPG is 24 with 91 RON fuel.

Don't know what C&D was doing. They came up with different MPH / 1k RPM on the E and S as well. The only difference I can see is the brand of tires. Perhaps they shifted them both at the same RPM. That would likely be closer to ideal on the E. Don't know.

Back in the day with my 69 911S I got about 16 mpg in L.A. mostly freeway driving. If memory serves me correctly the MFI could slightly best 20 mpg on a trip. My driving style was Italian allegro con brio.

Diverdan