How many MPG are you getting from your Boxster?

[efedor]

I recently made a trip to L.A. and got 500miles using cruise control of course. This is an 04 boxster(2.7) with 28k miles and stock plugs. Are you getting more or less?

[rsfeller]

boy I hate to be the guy who yells b*%$^#@t but seriously, 35mpg...was it downhill the entire way or were you driving 50mph?

I have a flat drive 50 miles to work I drive daily in three different cars I rotate. When I take the 2.5L Boxster 26-27mpg is the best I've ever seen and that is driving 65mph.

I get a bit frustrated on the BB I frequent when some guy selling (or not) is telling us he gets 32mpg out of his vanagon or eurovan when the rest of us are getting 18mpg. I've seen it on the Saab boards too with values 10+ mpg then the rest of us. I have new plugs ever year along and plug wires when they apply to the vehicle.

I feel they are doing bad math, have bad data or are just BS'ing.

How sure are you of your data? Unless you ran the car bone dry I'm assuming you still left a gallon in the tank or am I wrong here and there was a tank larger then 15.3 gallons in the US cars?

Edited March 24, 2008 by rsfeller

[White987S]

I get about 22-24 MPG with my 2006 987S. Top down, mostly spirited highway. I use a calculator, not the on-board computer.

[White987S]

am I wrong here and there was a tank larger then 15.3 gallons in the US cars?

I think the 987 tank is 16.4 gallons.

[rsfeller]

If so we are still looking at 32.5mpg if we assume he left some gas in the tank.

Feds say different, I think he has a bad odometer or forgot to reset something!

[White987S]

Gotta luv a good tail wind!! :D

[efedor]

Ok haters, the manual for the 04 says it has a 17 gallon tank so redo your math. I have a de snorkeled and KandN airfilter as well as NO cats. 5 speed,Top up,windows up with an occasional A/C here and there but not more than 15-20 minutes worth of use. No passengers, gas needle was slightly above the orange/red empty line. no luggage I even took a dump prior to that!

[White987S]

Only #2? No #1's? :P

[wxseed]

maybe the tank is imperial gallons, they are 20% higher in volume than a US gallon. i.e an imperial quart is 40 ounces a US quart is 32 ounces .....

[koendp]

The best I ever had myself was 8,5 liters/ 100 km. Which is about 31 miles a gallon. (No cruise control, airco on)

I drove to Koln airport in Germany for 300 km nonstop, a lot of traffic but no queuing so I did about 120 km/hour all the time.

The same on the way back and I got 630 km before reserve sign came on.

I think the numbers told by rsfeller are believable. Most petrol consumption is by stop and go and speed changes.

[efedor]

Porsche Boxster 04 manual states on page 243: Fuel tank Refill volume approx 16.9 US GALLONS/64 liters, including approx 2.6 US gallons/10 liters reserve. So if you do the math thas approx 29 miles per gallon what the manufacturers window sticker states. I know it's hard to beleive bit the boxster IS an economical car.

[Lcv]

I must be driving mine too hard :o, the most I have ever got was 470 Km on a full tank and generally I average between 300 and 400Km.(180-250 miles) on a 97 boxster

[grover]

I must be driving mine too hard :o, the most I have ever got was 470 Km on a full tank and generally I average between 300 and 400Km.(180-250 miles) on a 97 boxster

Your Boxster only has a 15 gallon tank, and how long do you drive after the fuel warning light comes on? Sounds like you're right there in the 17-27mpg sticker range for your car. Edited March 25, 2008 by grover

[roadracer311]

I recently made a trip to L.A. and got 500miles using cruise control of course. This is an 04 boxster(2.7) with 28k miles and stock plugs. Are you getting more or less?

I drove to Oregon and back (from SF) over Thanksgiving. I averaged about 29.7 mpg in my 2003 Boxster S. I was averaging about 75 mph. Around town I get about 20 mpg. The whole trip was >1,000 miles (I stopped a few times for fuel. I don't like to run lower than 1/4 tank if I can help it.)

[efedor]

Finally someone that can back up what I said before. Thank you roadracer311

[geoff]

With some stop and go, highway and canyon driving, I usually get 23 to 24 MPG per the onboard computer (reset at every fill-up). On the highway, cruising at 75 MPH with cruise control, I often see 29 to 31 with the top up (but hills really hurt). Top down at higher speeds hurts mileage. I noticed the mileage got a little worse when I had the ROW M030 suspension installed (ballpark of 0.3 to 0.5 MPG per OBC observation). Interestingly, twisty canyon driving (2nd gear, 20 to 45 MPH) seems to still give around 22 MPG, whereas stop and go commute driving drops down to 18 to 19. I once got 32 MPG on a full tank with passenger, full trunks including 2 sets of golf clubs, cruising at 80 while driving back from Palm Springs. Unfortunately it didn't stay that high once we hit really bad LA traffic on Sunday evening. 18" wheels, tires properly inflated. YMMV

[John V]

I get 22MPG in mixed city / hwy driving in my 2000 Boxster S 6-speed. I have seen 28MPG on extended freeway trips, cruising at 65-70MPH. Top up, A/C off. Top down, I get about 25-26MPG on the highway.

[rzucchet]

My 2003 986 is my DD, so with mixed highway and city driving, it's usually right around 23.5 MPG with no A/C.

-Roger

Edited March 27, 2008 by rzucchet

[geoff]

One other variable - I've noticed different brands of gas (premium 91 octane in CA) can also vary up to 1 or 1.5 MPG. Despite all the "gas is gas" discussion, many of the experiences and folklore in a post here on gas brands recently indicate there are some differences (I'm assuming a somewhat intelligent community here with analytical skills).

Edited March 27, 2008 by geoff

[savowood]

When I first got my 2k 986, I could get 28 on a good day coming back from the track, four lane divided highway, running 65 or so. I've swapped out the original motor for a 3.4 and am now getting, as of just the other day to my buddy's house, 32-33 for most of the trip, then when we hit the stop lights by his house, it dropped pretty quickly to 31.

Right after the swap, going from Atlanta to Washington, DC, I got about 30 the whole trip.

-Michael

[12rayne]

I've had my 99 boxster 2.5 from coast to coast the last few years and have gotten as high as 30mpg, but 80-90 mph highway usually gives me 25-27mpg. Around town/some highway, gives me low 20's. I have noticed that I get better mpg back east (93 octane sometimes), possibly altitude, or fuel. I get the worst mpg in California (91 octane) and I think it has to do with the road surface, or mabe the fuel itself. In any case there is a real differance from one part of the country to another, my driving habits are pretty consistant. I have gotten the same results from my Audi so I know it's no fluke. Anyone think the fuel alone could be responsible? Temp., road surface, octane, whatever, I see a noticeable differance.

[rick3000]

The fuel could have something to do with it, especially different octane's. Wind, roads surface, altitude, and temp. could also play a small role in fuel economy, but I don't think it will make a huge difference. I also get noticeable worst milage in California too, and I think it is due to all the extra additives that are required there.

I have a 2.5L and my driving style is spirited, and I average about 20-22mpg when it is about 50/50. When I am doing about 80 highway / 20 city I get up to about 25-26mpg, and on road trips with the cruise control I have gotten up to about 30-34mpg.

[rsfeller]

The fuel could have something to do with it, especially different octane's. Wind, roads surface, altitude, and temp. could also play a small role in fuel economy, but I don't think it will make a huge difference. I also get noticeable worst milage in California too, and I think it is due to all the extra additives that are required there.

I have a 2.5L and my driving style is spirited, and I average about 20-22mpg when it is about 50/50. When I am doing about 80 highway / 20 city I get up to about 25-26mpg, and on road trips with the cruise control I have gotten up to about 30-34mpg.

You would have to have really low octane and serious "pinging" going on before efficiency would be affected. Changes (especially going up) in octane affecting fuel economy are considered a myth by most experts.

http://www.co.suffolk.ny.us/webtemp3.cfm?dept=3&id=2049

[dave944]

That makes sense for a v-6 that weighs around 3000lbs. Even with taller gears the mileage probably wouldn't improve much as the computer keeps the mixture optimized for the amount of air entering the combustion chamber. It would be nice if there was a warp drive that got 40mpg though!

most likely the biggest variable affecting mpg is air temperature. laws of physics are in your favor with higher temperatures. the air is less dense requiring less fuel to meet designated mixture pre-programmed into computer. also lubes thin out more and cause less friction. and air expands in tires providing slightly taller gearing. but keep the A/C off for best results.

Also much better to state the computed mpg (miles driven since filling up divided by number gallons to refill) than the miles between fillups when comparing fuel economy since some run it down to empty and others fill up at 1/8 or 1/4 tank.

[Delusionary]

FWIW, I've been keeping a running total on my 2001 2.7 whenever I fill up, and I've gotten between 20 and 22.8 MPG each time. Of course, most of my mileage is either city or, uh, enthusiastic. :D

Edited May 4, 2008 by Delusionary