Mileage Report 1978 911SC

[tgomer]

I finally used up my first tank in the 911. I got 14MPG. I am starting to change the plugs. They look good but tired. What kind of gas mileage can I expect from a stock 1978 911SC Targa?

Is there any thing I can do to improve it? The car has 135K on it.


Tom Gomer
1978 911SC Targa
1976 914 2.0

[makaio]

You don't say if that is around town or freeway driving. But I'm going to assume that's around town. The only thing I know of to maybe help improve your mileage, is to have the mixture checked, to ensure your not running to rich.

But I get about the same mileage just driving mine around town. 18-20 down the freeway @ 70-75.

And welcome to SC ownership!

[pbs911]

A well turned and maintained 3.0 will go much further than 135K and get gas mileage comprable to modern sports cars. Since it was your first tank of gas I imagine you tested out the acceleration of the motor more than once. I did. Considering you were probably WFO and stop and go driving around town, 14 mpg I pretty good. The best I ever get is about 23 -24 on the highway cruzing at about 85. But only on highways marked for 85.

Welcome to world of Porsche and don't forget your membership in the SCWDP.

[Superman]

Yes, I find that at about 85-90 mph, I can get mayber 24.5 mpg (only on roadways marked with 90 mph speed limits of course). I find that the engine is perhaps not operating quite as efficiently below 3500 rpm as above it, so I don't get much better than 22-23 mpg on roadways marked in the 60 mph neighborhood.

After two years, I still cannot resist the temptation to steer this car around town with the gas pedal. It's really fun. And I get about 16-18 mpg.

[tgomer]

Yes,
I have been testing the acceleration of my car. Maybe the tune up and oil change the improve things a bit. The car sat up for 2 years before I owned it. By the way, what is WFO?

[gblumenstock]

I get between 13 & 15 for mostly shorts trips. My commute is quite short so this seems pretty consistent. I have 170K miles.

Sounds like you are fine.

GB

[pbs911]

Originally posted by tgomer
By the way, what is WFO?

Its the alternative version of "Wide Open Throttle" - "Wide Frigin' Open"

[stormcrow]

I am surprised at the all over the place MPG. I can average 18 - 24 depending on how I drive. The highways I drive on have slow - medium - high speed lanes.

Slow speed which is about 55 -65 I can average 18 because of stop and go traffic.

Medium speed which is about 70 - 75 I can average about about 20 - 22 because traffic flow is a little better.

High speed which is 80+ I can average about 24 because traffic flow is a lot better and you better not slow down.

Now, there are some lanes here that are super slow but we won't talk about them. Those are for commuters.

Steve

[speeder]

This is a great thread because I have been wondering this myself. I get about 14 in town, (112k miles, plenty of right-foot), never checked on long trip, (haven't taken any yet), but have heard stories of great gas milage on SC's at speed. All I know is that every car has a favorite cruising speed, for my SC it is about 100mph. I've heard about instability at higher speeds,(125+), but at 100 car is glued to road, quiet, still steers really well, it's like a dream. What a great car, can't wait to take a road-trip in it.

[Jim T]

I get around 14.

But my car is not used for commuting, only for fun.

So, lots of shifting, braking, accelerating, etc.

[Clark Griswald]

I normally don't pay attention to mileage. But last weekend I measured and got about 7 mpg.

Now I wasn't in an SC, but a Carrera so that may contribute. And I was lapping the track at Buttonwillow at the time, largely at WFO.

YMMV

[Jdub]

Tom:

Ouch! First thing you need to do is dump that oil, and change the oil filter and gas filter. Drop the sump plate and clean that up, replacing the gaskets (x2) you will find there.

Then I would put about 500 miles on the oil you put in and dump that. You don't know the history so you want to purge the oil system of any impurities. During that 500 miles I would go ahead and perform two Techron runs, where you put 20oz in an empty tank, fill it, and drive the heck out of it (I mean like for over an hour, so that the engine gets hot to the core). When youl've done both runs, dump the oil when it is nice and hot.

I would also consider new plugs, rotor, cap, and wires if they look old. An air filter is cheap insurance. Now you can have your CO2 checked with the system baselined; you don't want to spend the money having a car refined with old or worn air/gas/oil.

Welcome to the SC world!

John

[tgomer]

I'll be doing the tuneup and oil change this weekend. I'll post another update after the next tank.

Thanks,
Tom