MPG Test

[petemac]

I wanted to know what my cars MPG is so filled it to the brim did 270 miles at different speeds 50. 60.70. mph. topped it up and its average I worked out was 31.9 MPG my car is 57 reg.

so 14 years old now with nearly 60000 miles is this good or bad? I have owned the car for 6months so I was curious to know its so called true MPG. Has anyone done a similar test and if so how how well or poor did your car do? and is this a fair way to test your car? ie different speeds as you would probably drive it. Some stats state the 987 should achieve 36 mpg. I did notice how heavy the car was with a tank filled to the brim something I never normally do, so surely this must have some affect on my results. I may do another to compare. 

[phazed]

2.7?

[Boxer boy]

2.9 - 09 MY  6 speed manual 

Seen 37 doing those numbers sat on a busy speed camera ridden motorways / dual carriageways .To frightening to exceed to speed limits 

On a run slightly lower speeds 40 , 50 , never over the National speed limit ie no motorways about 36 .

Fresh air filter fitted if that’s any use ? 

[½cwt]

42 minutes ago, Boxer boy said:

2.9 - 09 MY  6 speed manual 

Seen 37 doing those numbers sat on a busy speed camera ridden motorways / dual carriageways .To frightening to exceed to speed limits 

On a run slightly lower speeds 40 , 50 , never over the National speed limit ie no motorways about 36 .

Fresh air filter fitted if that’s any use ? 

And the new generation direct injection engine, much more efficient than the M96 and M97 motors!  i average between about 5.5 (25 mpg) and 6.2 miles per litre (28mpg) in my 2000 3.2, but then again it is rarely used as a daily and often take A and B road rather than motorways so will use rather more fuel.  A long run to the gite we stay at regularly in France will see about 7 miles per litre (32 mpg) using cruise control at about 85 on the Autoroute, two up, full luggage, top down and boot bag fitted so more weight and drag.

[½cwt]

9 hours ago, petemac said:

I wanted to know what my cars MPG is so filled it to the brim did 270 miles at different speeds 50. 60.70. mph. topped it up and its average I worked out was 31.9 MPG my car is 57 reg.

so 14 years old now with nearly 60000 miles is this good or bad? I have owned the car for 6months so I was curious to know its so called true MPG. Has anyone done a similar test and if so how how well or poor did your car do? and is this a fair way to test your car? ie different speeds as you would probably drive it. Some stats state the 987 should achieve 36 mpg. I did notice how heavy the car was with a tank filled to the brim something I never normally do, so surely this must have some affect on my results. I may do another to compare. 

65 litres of fuel is about 48 kg (density approx. 750kg/m³), so you added 20 - 25 kg by topping off vs half tank.

[Boxer boy]

The base 2.9    9A1  from 09-12 was still port injection.

The “S” eq 3.4 was DI as we’re all from 2013 in the 981 .

For the 981 they de bored the base 2.9 , 255 Hp to 2.7 with DI which gave 265 Hp to maintain the “s” Hp gap mindful as always during  boxsters glittering career to resist knocking the 911 of it marketing Hp advantage perch , or put another way 0-60 time .

You can’t display handling in a show room , put it on paper .

Back on topic on a every day errand run slow mixed it’s 32 mpg .

Pleasantly surprised tbh .

Our ( wife’s ) Maccan SD does 45 on a mixed U.K. dual carriageway/ motorway keeping it legal .

The Macca SD did 42 on a 900 miler from Switzerland to Yorkshire recently of which there was a significant 80 mph French autoroute proportion . About 34 running about errands.

 

[½cwt]

Thanks for that extra info. 👍  Didn't realise the 9A1 had a port injection version.  Another school day.

[petemac]

I forgot to mention  is a 3.4 I suppose I should be fairly happy with nearly 32 mpg and it was heavy with a full tank so I assume that would have some affect with weight being a real killer when it comes to fuel consumption. I was just curious to see how it was in real time so to speak and it will help with my planned trip to sunny France (I hope its sunny I'm off camping for a week) thanks for your feed back guys.

Pete

[Codfanglers]

Mine displayed 29.5 on the indicator when I bought it. A year later it's down to 26.5. No idea what it really does to the gallon but I can say that I don't usually avoid the opportunity to enjoy wringing some performance out of the engine.

 

[BrianJ]

Nobody has mentioned whether they are using regular unleaded (95) or something better. My 986 (2.7), 987 (Gen 2 3.4) and 981 (3.4) all did/do noticeably more mpg on 98/99 fuel, especially since 95 became E10. 

[bally4563]

Because I drive mine in diving boots typically 18 mpg 😂

[Stuart21UK]

4 minutes ago, BrianJ said:

Nobody has mentioned whether they are using regular unleaded (95) or something better. My 986 (2.7), 987 (Gen 2 3.4) and 981 (3.4) all did/do noticeably more mpg on 98/99 fuel, especially since 95 became E10. 

Popcorn🍿 at the ready

[Codfanglers]

3 hours ago, BrianJ said:

Nobody has mentioned whether they are using regular unleaded (95) or something better. My 986 (2.7), 987 (Gen 2 3.4) and 981 (3.4) all did/do noticeably more mpg on 98/99 fuel, especially since 95 became E10. 

E10 from the supermarket. I run my S3 on it too. A lot of the 98 RON stuff is now E5 anyway.

[phazed]

Surely they should all run on Super, (mouthful of popcorn spluttering over the sofa)?

Just returned from a spirited Surrey Hills drive. Mpg normally around the 23-24mpg mark. Dropped to about 22mpg.

Flat out on track it returns a respectable 15mpg! Which is really good compared to my track 1.8 turbo Skoda that returns 12 mpg on track. (Previous 5.5 TVR returned less than 5mpg….)

Sounds like your mileage is very good. You must be a sensible driver!

[Codfanglers]

I started down the Momentum 99 route with my S3 but the only filling station on my normal routes that sells "premium" is Esso, and that's 25p a litre (average £12 a fill up) more than Morrissons. Tesco 99 is cheaper but it's a 10 mile round trip out of my way.

Quite honestly, when I gave up on the Tesco Momentum 99, the S3 didn't run any differently, the performance didn't suffer and it didn't seem to do any less miles between fill-ups, so I abandoned "premium" and have run on 95 for the last four years with no problems. I also run a stage 1 tune with no issues, even on E10.

My Boxster runs well enough on 95 E10 as well. 

I'm sure premium has better detergents, able to run more advance on the timing, burns in a more controlled fashion etc. but my decision is one of convenience and cost and I'm not seeing any down side.

My snack of choice is honey coated cashew nuts rather than popcorn, so I'll crack a bag open now.

[boer13]

On 5/27/2022 at 10:36 PM, petemac said:

I wanted to know what my cars MPG is so filled it to the brim did 270 miles at different speeds 50. 60.70. mph. topped it up and its average I worked out was 31.9 MPG my car is 57 reg.

so 14 years old now with nearly 60000 miles is this good or bad? I have owned the car for 6months so I was curious to know its so called true MPG. Has anyone done a similar test and if so how how well or poor did your car do? and is this a fair way to test your car? ie different speeds as you would probably drive it. Some stats state the 987 should achieve 36 mpg. I did notice how heavy the car was with a tank filled to the brim something I never normally do, so surely this must have some affect on my results. I may do another to compare. 

Depends your definition of 'so called true MPG' and how pedantic you want to be about measuring it 

Your trial covers a specific, narrow use range, and achieves a good indication of MPG under the stated circumstances. Good if this is what you wanted to measure! But then this may not represent all your driving and.

For my own interest, I want to know consumption across all actual use. Always fill up completely, always write down the odo reading.. that type of bore! Because to meet my definition I need to look at long term total fuel / mileage. But as they say, YMMV!

Here's a snap from my Excel file. Tank to tank varies, but the long term cumulative number suggests 'my consumption' is 22.5MPG.

 

 

 

 

 

[boer13]

(and don't trust the trip computer..)

[petemac]

2 hours ago, boer13 said:

Depends your definition of 'so called true MPG' and how pedantic you want to be about measuring it 

Your trial covers a specific, narrow use range, and achieves a good indication of MPG under the stated circumstances. Good if this is what you wanted to measure! But then this may not represent all your driving and.

For my own interest, I want to know consumption across all actual use. Always fill up completely, always write down the odo reading.. that type of bore! Because to meet my definition I need to look at long term total fuel / mileage. But as they say, YMMV!

Here's a snap from my Excel file. Tank to tank varies, but the long term cumulative number suggests 'my consumption' is 22.5MPG.

 

 

 

 

 

22.5 MPG really that bad ? I would not be happy with this one little bit and would start to wonder why it's so poor or change my driving style you don't say how you normally drive are you one for spirited driving often ? I thought mine was bad at 32 MPG I have now done 2 runs with very similar results I think there may be very different styles of driving between us but very interesting all the same thank you for sending it, I will do one more run see how that compares I'm up north tomorrow so that will be another good run for me. I do not like the OBC one little bit it lies alot!!

Regards

Pete

[bally4563]

1 hour ago, petemac said:

22.5 MPG really that bad ? I would not be happy with this one little bit and would start to wonder why it's so poor or change my driving style you don't say how you normally drive are you one for spirited driving often ? I thought mine was bad at 32 MPG I have now done 2 runs with very similar results I think there may be very different styles of driving between us but very interesting all the same thank you for sending it, I will do one more run see how that compares I'm up north tomorrow so that will be another good run for me. I do not like the OBC one little bit it lies alot!!

Regards

Pete

Most of us drive these motors for a reason and consumption is not worth considering? If I was that concerned I would replace the engine with a lawn mower motor!!

[boer13]

Surely didnt buy a 3.4L Porsche to try beat the neighbour's fuel consumption. I pay for fuel, he pays a car loan and suffers depreciation. Guess who's having more fun  

I do have records of all the 30 odd cars I've owned to date, worst had been a Nissan Patrol 4.8L followed by some V8 Disco's. So 22.5 is a relative number!   

[Jimbo1998]

I Daily Drive mine.  2003 2.7 On a motorway at around 70 mph I can get 36.5 out of her. 

Enjoying myself its between 20-25 mpg  

[petemac]

1 hour ago, bally4563 said:

Most of us drive these motors for a reason and consumption is not worth considering? If I was that concerned I would replace the engine with a lawn mower motor!!

very good point it was not a dig just an observation, having read what the Porsche 987 "should do" I was a little surprised, I have also had cars that would do less than 18 MPG in fact one of my cars was shown on Top Gear many years ago so please don't take it heart this is my first 987 and I was hoping for better results.

Regards

Pete

[petemac]

1 hour ago, boer13 said:

Surely didnt buy a 3.4L Porsche to try beat the neighbour's fuel consumption. I pay for fuel, he pays a car loan and suffers depreciation. Guess who's having more fun  

I do have records of all the 30 odd cars I've owned to date, worst had been a Nissan Patrol 4.8L followed by some V8 Disco's. So 22.5 is a relative number!   

What I did was purely a test for my own curiosity nothing more this is my first 987 and Porsche states they are good for 36 MPG so I thought I would put mine to the test that is all pure and simple if I have rocked the boat a little it was not my intention.

Regards

Pete

[And.rs1800]

I don’t dare think about the fuel consumption-I put fuel in and use it.

 I wasn’t expecting it to be a frugal car regards fuel .

 That said it’s not much different to my supercharged cooper s,although the Porsche can to some extent be driven gently too eek it out(but what’s the point of that!-I bought it to enjoy it)

whereas the mini uses lots of fuel all the time,but who doesn’t love a supercharger!!

 Either of these cars would ruin me if I had to commute in them

[½cwt]

My classic Impreza Turbo, up to to 36mpg on a long motorway run, 8 mpg on tack...  Real world average was in 28-30mpg range.  Worse on UL, better on SUL which at the time made the price difference, so as it ran better on SUL that's what I chose as the cost was effectively the same but the fun quotient higher.  Can't comment on the comparison in the Boxster as it has run SUL all the time I've had it as that's what Porsche recommends.