Gas Mileage Experiences?

[986sport]

I just bought an 03 Boxster with 18" wheels. I put all-season tires on it. 5 speed.

On my first trip to the mountains in Eastern PA, I got 35 mpg going up and 36.5 mpg return. That's mostly highway top up, top down/windows up on the side roads, some AC on returning, highway speeds to 75, mostly 55-65.
Around town, short trip suburban driving, I'm getting 26-27 mpg. I use 92 & 93 octane gas.

The car is EPA rated at 20/29 mpg. I seem to be doing much better, especially on the highway--so the numbers look to be very conservative.

Any other experiences out there? I'm surprised at these numbers, which I verified in several fillups.

[Spy4cia]

Running AC all the time, top up, average speed 75 mph...

I was pretty happy...

[dmenn]

Those numbers seem on the high side, however in this case that's a good thing.

Are you calculating the MPG based on miles driven/gas filled up, or is this the number you're reading off the OBC?

[rick3000]

I recently returned from a 750 mile one way roadtrip. So I put 1600 miles on the car total. I averaged around 20-24 around town doing mostly 40mph and some bumper to bumper. On the freeway doing 80mph I got up to 32mpg but the average was around 29mpg. I was even shocked when the OBC told me I had a 500 mile range until I started driving and it dropped to 450 mile range. So it was right around the EPA milage with the air on medium the entire time, and in a 2.5L.

Did you mod anything on the car, I would love to get that kind of milage? Or are your numbers possibly wrong, did you calculate from range or with the OBC?

[986sport]

Originally Posted by dmenn

Those numbers seem on the high side, however in this case that's a good thing.

Are you calculating the MPG based on miles driven/gas filled up, or is this the number you're reading off the OBC?

I'm reading the miles driven since last fillup off the on-board computer, and the gallons on fillup. The on-board mpg indicator which measures avg mpg since the last fillup agrees with the total miles driven/gallons pumped. I set the miles back to zero after each fillup.

[OldBlevins]

I just got back from a 2500 mile road trip between Seattle and central California, and pretty uniformly got 26 mpg. It didn't seem to matter whether we were on curvy mountain roads or the straight-shot of I-5, or if we had the a/c compressor on or off. With a 3.2, I was pretty happy with that mileage.

[FrayAdjacent]

Driving from Austin, TX to Phoenix AZ... a little local driving, then back to Austin... I averaged 31mpg. I was quite impressed.

This was mostly on I10 at ~80mph both ways.

[pauldee]

Funny, when I first drove my car home from the dealer (about a 200 mile drive), I got well over 30 mpg. But, I was new to the car, the car was new to me, and I drove very carefully and conservatively. Now that I drive the car the way it should be driven - keeping the RPM in the 3-4,000 range, rev matching on down shifts, etc. - I get 25-26 combo and 29 highway. Maybe you need to drive a little more spiritedly! I'm sure that you will grow more aggressive over time, and the mileage will adjust accordingly. But, for a car like that to get that kind of mileage is amazing.

[986sport]

Originally Posted by FrayAdjacent

Driving from Austin, TX to Phoenix AZ... a little local driving, then back to Austin... I averaged 31mpg. I was quite impressed.

This was mostly on I10 at ~80mph both ways.

Sounds like the same ballpark as me. I drove mainly 55-65 without AC. And I don't accelerate much over 3K rpm. I used to go to 4K with my SC, as recommended, but the Boxsters don't require the higher revs. You can drive them every way.

I guess this is conservative driving. Probably the regular 20/29 numbers are for more aggressive driving. I'm still breaking new tires in.

Anybody watch Live Earth the other night? Save gas. LOL.

[986sport]

Originally Posted by 986sport

I'm reading the miles driven since last fillup off the on-board computer, and the gallons on fillup. The on-board mpg indicator which measures avg mpg since the last fillup agrees with the total miles driven/gallons pumped. I set the miles back to zero after each fillup.

miles driven on odometer/gas filled up.

agrees with the mpg on the computer.

wonder what I can do on cruise control. maybe 40 mpg.

[BoxsterBob - CA]

Originally Posted by rick3000

I recently returned from a 750 mile one way roadtrip. So I put 1600 miles on the car total. I averaged around 20-24 around town doing mostly 40mph and some bumper to bumper. On the freeway doing 80mph I got up to 32mpg but the average was around 29mpg. I was even shocked when the OBC told me I had a 500 mile range until I started driving and it dropped to 450 mile range. So it was right around the EPA milage with the air on medium the entire time, and in a 2.5L.

Did you mod anything on the car, I would love to get that kind of milage? Or are your numbers possibly wrong, did you calculate from range or with the OBC?

Wow. 32 MPG? The best I ever did in my '99 Ocean Blue Boxster (you have great taste in cars, BTW) was 27 MPG coming home from Lake Tahoe, all down hill. I typically get 20 mpg with 70/30 Highway/City

[pteam]

They say a K&N air filter increases gas economy 5%. Even more if your replacing a pretty dirty filter then going to the K&N. 5% = 1mpg on a 20mpg avg. Who knows if its really true or maybe its really 2% or up to 5% but some is better than none, and its much better than a dirty filter.

Does the boxster S get less gas milage than a Non S?

[JCL12]

I drive an 01 regular boxster with tiptronic.

It is rated for 18/25 (city/highway)

I can get a little over 27.1 MPG on pure highway driving - typical speeds high 70's with a good bunch of 80's and high 60's mixed in with occasional 90-99+.

I am guessing with consistent 68-72mph, I could crack 28 MPG. I think porsche lies about the mpg (or assumes more aggressive diving styles)

[986sport]

I looked up Boxster gas mileage on google, and got a British consumer review on what appears to be the 07 Boxster, 2.7L, 5 speed. They listed 20.9 mpg city, 40. mpg highway, 29 mpg average. I wonder if the Euro Boxsters are more fuel efficient? Mine is a US model from the VIN, made in Finland.

Another factor is the on board computer, which constantly reads mpg since last fillup. That could make you drive more fuel efficiently as you are monitoring it continuously.

[wanna986]

Originally Posted by 986sport

I looked up Boxster gas mileage on google, and got a British consumer review on what appears to be the 07 Boxster, 2.7L, 5 speed. They listed 20.9 mpg city, 40. mpg highway, 29 mpg average. I wonder if the Euro Boxsters are more fuel efficient? Mine is a US model from the VIN, made in Finland.

Another factor is the on board computer, which constantly reads mpg since last fillup. That could make you drive more fuel efficiently as you are monitoring it continuously.

U.K. would be a bigger gallon- approx 4.5 litres- U.S. is 3.8

[abacusnw]

When I fill the tank and drive on the highway at consistant speeds via the cruise control, I get 32 MPH. BUT - when my tank goes down to less then half, the milage drops to 26-28. If I fill up before the tank goes below 1/2 I can get 32 MPH for as long as I keep the gauge over 1/2.

I am reading the milage off of my trip odom and using the fuel pump to meter a full tank until the nozzle goes auto off.

This is a consistant and repeatable event. Confuses the hell out of me.

[cvhs18472]

Brucelee, As long as you don't say it is road racing it is OK to do 99+ on the highway without being called childish?