28 mpg averaging 74 mph

Who needs a hybrid? Driving 95 miles and not "gunning it" in anyway shape or form, I got 28 mpg with my X51 C4S as shown in the pic. The trip computer stated a 74 mph average for that highway drive. Note, however, that I was driving the middle or right lane since averaging 74 mph in CT and MA on a Sunday is slow . People were blowing by me on the left lane. To see what the mpg would do if I downshifted into 3rd, it dropped to somewhere in the low 27's mpg just for that short mash on the gas.

How did you attain that mpg? My best is 24.3 mpg and I'm happy with that on the highway.

Mine will hit 30mpg (03 C4 Cab). My 03 C4S from a while ago would easily do 34 (I have pictures somewhere). I love my Econobox Porsche

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I stopped to get gas, filled it up, zero-ed out the mpg and mph, went on the highway and left it in 6th gear.

That is pretty good I got averaged about 26.5 on way from Miami to Daytona last year but there might have been several instances where "possibly" I was going much faster than 74mph

I got 26.8 on my trip from Detroit to Charlotte thru the mountains, but, admittedly, I was in the right lane doing seven over after my speeding ticket in Detroit!

I can get in the 32+ range on all-highway driving (2004 C2 Cab). I'm not a super aggressive driver, but that's averaging 75 - 80mph on the mean streets of New England.

I've been averaging 27.8 the past 3 tank fills. It is an amazing car!

You're obviously not enjoying the car enough! Stop with this fuel economy obsession!

I guess I'm doing something wrong.. i only get 20mpg going 85mph the whole way

Might try getting a rough estimate of speedometer error. Drive the hwy, zero the trip odometer at a mile marker, start your travelling watching the mile markers. Calculate the error bouncing the trip meter off the total miles travelled in mile markers. Not totally accurate but you'll get a good rough idea arriving at the first mile marker travelled. I'm registering 0.8 mile odometer at the first mile marker. This figures to calculate gas mileage divide odometer by 0.8 to get actual miles travelled. Then divide by gallon (liters) filled. Bad news is I'm one of the low 20's or 18's mpg suffer's and it's a pretty new porsche rebuild. For you guys with high mileage it might be a case of smaller than standard diameter tires registering higher miles than actually travelled.

Hi. Maybe its the petrol that you guys have in the states but my 99 c2 will give me c34.4 mpg @ 70 mph When i first got the car i wanted to see ho efficienti could drive. I drove 126 miles brighton to dartford and back with some stop and go traffic and got 36 mpg average. Jack

You're right. There is a big difference in the size of a gallon UK-US. I didn't think of that till I realized you guys are not in the states. 10 UK gallons = 12 US. In Hawaii we have super lousy ethanol.

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Not a tire issue. I think you have a heavy foot issue... Try this: Go on a long stretch of flat highway, zero out the mpg and set the cruise control at 75 mph or even 65 mph. Then see what your mpg says. If it's not in the mid to high 20's then something may be wrong.

OK I bit my tongue long enough WHAT THE H&LL is this a hyper mile - prius forum!! I want to hear, I got 6 mpg and went through a tank of gas by lunch - I mean OK we know they "can" get good milage but you are NOT helping your car - those three letters everyone hates to talk about need to be driven...spun up, worked, and your piston tops need the same thing - all this putting about at 2k rpm is killing your motors - and my spirit!! GO DRIVE THEM - red line is not an option, it is a daily event - many times - many many times - daily! try that thing between the seats...use one number closer to (0) than (6) ARG - these threads are SOOO boring!!

My 996 gets 6 MPG and I fill up on a daily basis.. you guys are lame When driving my Cayenne I need a KC-135 Tanker for support.

that's the spirit!!

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Highway, Autobahn, was ~25 MPG in spring of '01. Wife was along so TOP speed wasn't always "available". The thing that really amazed me was the number of motorcycles that blew by us even when pushing the limit.

Ok, I'll bite. As per my avatar speed indication, the mpg was roughly 9 mpg. And yes, that was our actual speedo shot.... my wife was driving and I took the picture... This was on the autobahn. Also, 11 mpg at Monticello track.

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ivangene, I'm with you!

On one of my most boring rides ever I managed to get more than 29mpg... 8 l/100km = 29.4 mpg (US) I won't do it again I promise!

you got that right - I didnt wait 30 years to get a Porsche so I could get 29 MPG !! (not saying it doesnt happen - just that it's embarrassing to admit)

I just completed a 6,788 mile R&D test run into Alberta Canada from Georgia. One leg of the trip we averaged 89 MPH for the majority of one tank of fuel when running hard through the plains. This was able to net us the maximum MPG for the trip @ 27 MPG and that was running a 13:1 highly modified generation 3 FSI test engine. Time and time again we see that higher speeds are conducive to higher MPG with these vehicles, even when making 100HP more than factory power.

In my 04 Gt3 I used to get 28.3 driving the 55 miles to the track at 75-85 mph and then it would drop to 8 mpg for the track driving.

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Sounds like a 40 mph tail wind to me

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That's conjecture and hearsay. Allegations of this sort will never stand up in court.

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Gasoline with no ethanol. I got 27-28mpg in my 02 C4s going about 75mpg coming back from minnesota earlier this year.

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With both of my Porsche and a few other cars while the speedo can be off -- reading optimistic from 2mph (Turbo) to 5mph (Boxster) the odometer is spot on. I have always run the OE tire sizes though but I do run the tires the rear tires especially down to the wear bars. I might note the speedo error remains consistent even as the tires wear. Fuel mileage measuring is tricky. In my Turbo -- which has an onboard computer and I can monitor fuel mileage as I drive -- even a bit of town driving before heading out on the highway can take mles to recover from compared to immediately easing my way directly out on the highway. Hills and head wind and traffic -- slowing down for slower cars and speeding up again to the limit once clear of slower traffic -- all work to affect gas mleage. I just try to pick a consistent starting from a fill up technique so my numbers are as consistant as they can be. My technique is to after filling the tank is to get in the car and start the engine and write down all the data: odometer, trip odometer, mpg, range, and average speed. Then I reset this info and head out. If I reset the fuel mileage while under way on the highway the reading can benefit to the tune of several milers per gallon easy. Also, the nozzle auto shut off can vary from nozzle to nozzle but I have found I'm able to get pretty consistent shut offs by turning the nozzle nearly upside down when filling my cars with gasoline. Sincerely, Macster.

No matter what Ed says, I think it's Perfect to have a car with the performance to get 8-13 mpg at a track event, then get 27-30 on the highway. When I bought this Porsche, I was tempted by several cars with fire-breathing, large engines....but was irritated by fuel guages that tried to race the speedometers. (Now if only the economy would turn around so the State of Washington would repair its highways so I wouldn't be considering selling my Porsche for a car with a more pliant suspension....)

LOL James - what kind of mialage you get out of that plane of yours....I bet its quite a bit more than most fuel guages that tried to race the speedometers. FUNNY!!

I'm getting about 15 in the city, 19 on the highway. Could be low because the of Super-Charger! Not sure about ethanol in my gas though. I'm in Western PA.

Since the A/C system operates 24/7 then opening the A/C clutch circuit except when actual cooling, initial cabin cooldown, is needed will improve FE. My switch for that is conveniently mounted on the back wall of the console "cubby". It spends a LOT of time in the "off" position.

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Monitoring engine load with the A/C on or off (barring having the A/C deal with a very hot cabin on a hot day) and at least with the autoclimate system which is what my cars have with its variable displacement A/C compressor the system barely causes an uptick on the percent of load when switched on and a down tick when switched off. These modern A/C systems are pretty darn efficient and do not present that much of a parasitic load. Oh, what appears to be a goodly amount of parasitic load is the electrical power required to run the cabin vent fan and the head/tail lights. Sincerely, Macster.