Gasoline consumption for 1972 911 T MFI 2.4

opass · 04-29-2004, 08:39 AM

ODO reading is 97000 miles. Do not know the ODO rolled back or not?

My car is running about 17.80 miles per gallon with 50-50 local and freeway drive. 23.00 miles per gallon with 100% freeway drive.

Is it good, bad or average? Thanks!

Az911 · 04-29-2004, 08:42 AM

When I had the 2.4 in my car I was getting around the same. Most of the time it was around 18-19

Tim Walsh · Tim Walsh's Garage

my untuned 73 2.4T with MFI was getting something like 10mpg.. count yourself lucky

zotman72 · 04-29-2004, 09:15 AM

When I had a 2.4T MFI motor, in tune, it was within your range. Now with the motor a 2.4S MFI, in town I get about 10 and highway about 20 with a tailwind! On the track, 6-8 mpg is max. Stepping on the go button does have a profound effect of course! But that sound is worth it. Cleaning your plugs every 1000 miles or less is a noticeable improvement. HTH

opass · 09:51 AM

Since my car eating habbit is better than average, could I use this mpg data to determine my car is still possible have the org. 97,000 miles instead of 197K, 297K, 397K...etc? (of course, assuming without rebuild)

I would like to know your car odo's reading as reference.

Evans, Marv · 04-29-2004, 09:41 AM

My '72 E got around 14 - 15 MPG with Webers. The ODO said around 53K, & I never knew if it was 153K, 253K or what.

Grady Clay · 04-29-2004, 09:57 AM

Guys,

From my perspective fuel economy with a MFI 911 has three components:

Your driving style/technique.
The road/traffic conditions.
The condition and adjustment of your MFI.

We all know that if you keep your foot in it you are pouring the fuel to it. That is where the high performance is. Consequently poor fuel economy. It depends on what you want. You can drive carefully and perhaps get 25 MPG and more. You can scoot the tires and get 10 MPG and less. Your choice. You can actually get worse mileage on the street with poor driving techniques than on the track.

There is not much you can do about traffic other than choose alternate times of day or routes.

There is a lot you can do with your MFI. Yes, you can have performance, drivability, and fuel economy. The most important issue is that EVERYTHING must be working properly. A single mis-adjusted or mal-functioning part of the engine-MFI system will throw the entire system out of spec.

Read all the posts, study the workshop and other manuals, and follow CMA.

opass, your mileage is probably typical for a normal, street driven 911 that is in reasonably good condition. Yes, you can improve it without giving up anything that we own Porsches for.

Anyone who gets 10 MPG on the street needs to see a good mechanic.

Everyone has heard the expression “We lean to perfection.” What that indicates is that the engines run best at the lean limit. Slightly leaner causes surging, backfiring, and worse. Too rich masks a world of sins but also causes many problems. Poor fuel economy, fowled plugs, oil dilution, high ware on P&Cs. The art of MFI tuning is to find that proper balance.

Best,
Grady

opass · 04-29-2004, 10:09 AM

Thanks!

I did drive easy on the car to have such as good result.

Any tips for me to distinguish from 97000 miles to 197K or 297K?

MAS · MAS's Garage

That's pretty good.

My 2.7 actually got 21.4 mpg average (hwy and city) which is higher than I expected... considering the way I drive. Although we've finally had some decent weather, so my car has been running at its proper operating temperature. All of last winter (and we have mild winters), it hardly ever got close to operating temperature. (it was usually around 80C max)

-MAS

Zeke · 04-29-2004, 11:33 AM

Quote:

Originally posted by opass
Thanks!

I did drive easy on the car to have such as good result.

Any tips for me to distinguish from 97000 miles to 197K or 297K?

As I told you before, I know that car and emailed you with useful info to get some history. I can say one thing in public: The car was driven very little for the last 10 years. Once a month or less and was completely serviced every year. The mileage is very believeable. What makes you doubt it?

opass · 04-29-2004, 09:26 PM

Zeke,

The car runs great. I am glad someone like you know my car's history and support it's condition. Can you PM me more details about it? I have not receive your email.

For me as newbie, 97K miles on the odo is just too good to be truth for 32 years old car. Again, this is my first classic ride. And used to drive 15K per year or 60K per year when I was 17-21 years old. I bought the car based on the condition inside out. Bill, the seller, owned the car only for 2 weeks and could not confirm the mileage. Therefore, at that time, I already assumed the odo reading may not be accurate.

I would appreciate if you can tell me what I have in hands. Either PM or reply to this thread. Did you own this car before?

Thank you!

speeder · 04-30-2004, 04:39 PM

Quote:

Originally posted by opass
Thanks!

I did drive easy on the car to have such as good result.

Any tips for me to distinguish from 97000 miles to 197K or 297K?

There are plenty of ways to tell the difference between 97k and 197k miles on a car besides the odometer. If you would like me to look at it for you and show you where to look, drop me a PM or email. I'm in L.A.

Obviously, complete records are the best way to verify miles. Just as a point of reference, a 911 w/ under 100k actual miles will have very light to moderate wear on original, (not replaced), seats, pedals, steering wheel, etc... Just think of, "everything that the driver touches"......

Here is a picture of my newer 911's interior w/ approx. 120k miles: