MPG - How many are you Getting?

It doesn't matter, but it IS interesting....and if you're getting something completely different to everyone else, then you know there's a problem

 

With the change in modern fuel, the variations between each of these cars in jetting alone will create a substantial difference especially in comparison to when new.

 

My 328 averaged 21MPG on a trip across the US at interstate speeds - around 70-75MPH most of the time...at least once I left NV/AZ. Speeds were MUCH higher in those states...

 

My odometer reads about 6% high based on measured miles in my area. Other vehicles of mine over the years including MB's, a BMW, a Porsche, and an Acura all agreed with the measured miles. The same result is also verified with a stop watch and mile markers on an interstate highway.

 

I have a 1982 Mondial 8....my fuel gauge doesn't work (just reads empty, full, or dances, at random). At some point my car starts to "hiccup" like at curves or hard acceleration and I think it is because there is not enough fuel in tank and the pump cannot feed the engine. If I put say 5 gallons in, problem is gone. Maybe I am getting 5-10 MPG in city under spirited driving.

questions: do others get this behavior when gas is low (what is low? I don't know --- maybe 1-8 gallons in tank?) Today I am going to try filling it up until gas just spills out...

questions: isn't 5-10 a bit low.... lines are fine and I am in the process of mixture adjustment but it is generally set ok...

thoughts?

 

I have a euro 85qv. As I recall the owners manual states something along the lines of 15 or 16 in town and 34 on the highway!

 

Sticker says something like 8 city, 15 hwy. I honestly have no idea at all what sort of MPG I get. I just refill the tank when it's 1/4 full.

 

I've been monitoring mine more closely over the past 12 months and it works out around 13l/100km or 21.73 Imp gal or 18.09 gUS across all driving street, highway, track, motorkhana, events etc. The smiles per miles values are much higher though

PS what on earth constitutes 'spirited city driving'?

 

I think I am getting 8-12 MPG is spirited city driving... I guess ok....

 

I record my fuel consumption since 20 years with the help of an Excel chart. Just to notice early enough if something doesn't work o.k.
Average are 15.5 mpg.
City or track driving close to 11mpg. And longer drives on speed limited highways close to 20mpg.
(carb car)

Best Regards from Germany
Martin

 

Hey Guys, I've tested this twice with my 328 and I got around 25/26 mpg on a full tank from full to empty and again full to empty which is around 10.5 - to 11 km/L (euro - kilometers per liter )

regards
Johnny

 

It matches with my two '89 328s.
About 9 to 10 l for 100 kms when at 125kph stabilised speed on highways.
About 11 to 12 l for 100 kms when driving on country roads and not exceeding the 80kph speed limit (50 mph).
Spirited driving? Forget it. Cops and radars everywhere, 50 mph speed limit. Your biggest risk is to fall asleep.
Rgds

 

Poor french

Best Regards
Martin

 

Take care when you cross the Rhine, Martin. 80kph (50mph) is REALLY slow.
I tried this again this morning with my GTB when the outside temperatures were still cool ("à la fraiche", in old colloquial french)...what a bore!
Rgds

 

Taking the risk, that our US buddies laugh at us. But even the 90kph before 1st July were annoying.

Best Regards
Martin

 

11-12mpg city and 20-22mpg highway.

 

oh yes forgot to mention my tests were for highway driving cruising 125-130 kph and I tried not to "rev " the car too high - pulling away..

cheers

 

This is some serious **** right here. I need to sleep on this very important information. And never return to this absurd thread.

 

Yes you'd think and you will not believe how many of those are around !

 

How and what’s the most accurate to calculate mpg?

 

Hi Mike T.,

To answer your question, my approach has always been to log odometer number (and/or zero out the 'trip counter'), 'fill until full', drive until re-fuel needed, log new odometer reading and number of litres/gallons used to 'fill until full'. Then calculate MPG or Litres per 100Km (typical European methodology). I have done this with every car I have owned, including my '84 US QV (owned for over 25 years now). Obviously notating the manner of driving is always a good thing and monitoring fuel consumption can oft-times give you an early warning of something out of kilter.

Note: 1 U.S. Gallon is equal to 3.78541 litres and 1.60934 Km per Mile. Imperial Gallon is 8 x 20 fl. oz. pints (as opposed to 8 x 16 fl. oz. pints in the US). Anyone that frequents British Pubs and American Bars should know that!

Error: For calibrating the odometer, best to use a GPS to log miles traveled and then compare to odometer readings (or for MPG calculation, simply use the GPS trip miles to calculate). The uncertainty in 'fill until full' may not yield accurate numbers, however the degree of accuracy improves as the sample size increases, I.e., averaging over many tanks of gas (although there will likely be a mix of driving and climactic conditions, so this would tend toward an overall average MPG).

My experience (and an anecdote): My QV has a turbo and engine management system (care of Bob Norwood)... Fuel economy went up when going from original to 'Emtech F-3' then yet more when migrating to a 'Haltech E-6' (both dinosaurs today, so likely in desperate need of an upgrade!). I do not have data to-hand, but 18 MPG overall was typical if memory serves. That said, ~doubling the BHP of the stock 308 rarely led to 'normal' driving (evidenced by frequent tire changes!)... Many years ago I drove from North Dallas to Fredericksburg on back roads (67, 281, etc.): The distance (odometer, as this was in the days before GPS) was exactly 300 miles and I made it in precisely three hours, including stopping once for gas (the tank was not on empty at the end of the drive). So we are talking an average speed of more than 100mph.