911MSN

when i used my c4 cab as a commuter car (17 miles each way, highway, local street and hills), i had about 18 MPG...

Mike J

Try a Turbo - I would LOVE to get 15 mpg average - its more like 10.

But WHAT a 10!

Cheers,

Mike

Kika

My average is right around 19mpg which includes both city and hwy. best I ever did was right after a tune up, got 24 mostly hwy driving.

looked at 02 sensors for a 993, ???? why are they so expensive? are the Volvo ones direct replacement?
for $100 I'd replace all of them but $450 for a set! I don't think so.

IXLR8

Kika, check out the Bosch Oxygen Sensor PDF I've attached.

It cross references Bosch direct fit to Bosch universal fit. Page A28 shows how to go about the connections.

Kika

Alex,

Thanks! Have you used the universal fit sensors and changed the plugs to adapt to your 993? a good way to save $300

IXLR8

I haven't needed to and the fact that I only have one O2 sensor, I'll just shop around for the best price from Porsche...probably Sunset.

NineMeister

Leading question folks:

How much would you be prepared to pay to improve performance by 10%, gas mileage by 20% and at the same time reduce engine wear by a factor of 5?

$1,000 or $10,000?

IXLR8

Sounds like one of those late night infomercials.

My next daily driver will be a diesel; problem solved.

abiazis

Mixed driving - 17.2 MPG averaging 31 mph...............25 plus mpg highway on long trips keeping under 70 mph.................rev close to 4500 rpm most shifts......

Mizuno

Thank you all for the great input. I just bought a scangauge II (vs e because of a better trip calculator) to help me better understand how to influence my mpg.

The SG can be calibrated by changing the speed measurements. As I was trying to calibrate the settings using my odometer by measuring the time it takes to complete a certain distance and compare this with my SG reading, it hit me.

Would all my measurements be wrong because my rims are 18' vs the original stock rims (98 993 cab)? If so is my odometer underrepresenting the distance travelled, And have my prior mpg calculations done the old fashioned way (distance travelled divided by gas amount to refill tank), been underestimated too.

Is that the case? What would the adjustment have to be?

I can still calibrate my SG with external distance markers and measuring time, but question is puzzling me. Has anyone gone through a similar calibration and can share the sg adjustments?

Thank you

ca993twin

Worry less about the diameter of the wheels, and more about the overall diameter of the tires. That is what can affect the accuracy of your odometer.

IXLR8

The aspect ratio of the tire will usually keep the overall diameter the same.

Get/borrow a GPS, find a flat straight road, maintain a steady speed using your cruise control and calibrate your speedometer...and odometer. Go from there.

dsmyth

In terms of your engines influence on fuel economy the largest losses are caused by carbon deposit build up in the engine squish area, valves , pistons, cat and o2 sensors. It absorbs your fuel and tricks your o2 sensor into sending a lean condition to your cars computer which turns around and increases your injectors pulse width and adjusts timing. This creates a vicious cycle as the fuel trapped in the carbon does not thoroughly burn and created more carbon.
This is greatly increased by the reformulated gasoline we have been burning in our cars for the last 20 years. The next generation of direct injection engines is turning out to be a headache for manufacturers as they suffer even more from this issue.
Fuel trim on a car with 40k can be out as much as 7-12% without setting off a code.
Get rid of the carbon and improve performance and fuel economy.