Amazing Fuel Economy of an E46 325ci

[daveco]

Currently driving a 325ci sport '03 facelift model and I have to say the fuel economy has been superb over the last few months.

Filled the tank to the brim with 99 octane fuel (also use OW30 oil) and do mixed town and motorway driving. After 90 miles of this the tank is still more than 3/4 full.

If I was any good at maths or bothered to check the manual to see what the tank holds I'd know exact mpg but it's on a par with my '00 330ci.

6 cylinder petrol Bimmer engines

[mmm-five]

What's the capacity of the tank?

Even the e46 M3 can manage 360 miles on a tankful, so 90 miles on a quarter is nothing special - and the read-out won't necessarily be perfectly linear anyway, and as you 'brimmed' the tank to over-capacity you may have another gallon in there.

I'd expect 35mpg out of a 325 or 330, so if it's a 55l (12gal) tank, you should expect 420 out of a tank, or 105 miles per quarter.

Edited by mmm-five on Friday 9th July 13:47

[gmarks1]

mmm-five said:

I'd expect 35mpg out of a 325 or 330......

Never saw better than 28mpg mixed driving on my 330 - long term average was 24mpg according to the trip computer.

Gary

[Pablo16v]

mmm-five said:

What's the capacity of the tank?

Even the e46 M3 can manage 360 miles on a tankful, so 90 miles on a quarter is nothing special - and the read-out won't necessarily be perfectly linear anyway, and as you 'brimmed' the tank to over-capacity you may have another gallon in there.

I'd expect 35mpg out of a 325 or 330, so if it's a 55l (12gal) tank, you should expect 420 out of a tank, or 105 miles per quarter.

Edited by mmm-five on Friday 9th July 13:47

400-420 miles per tankfull is what I usually get from my E46 325i Touring with a manual 'box. That's with a good mix of driving styles. Not sure what the actual MPG figure is but the car is showing 30.1 most of the time which is probably not too far off the mark.

[mmm-five]

gmarks1 said:

mmm-five said:

I'd expect 35mpg out of a 325 or 330......

Never saw better than 28mpg mixed driving on my 330 - long term average was 24mpg according to the trip computer.

Gary

My mate's CSL is on 26mpg average since he bought it, including a long weeked trip to the 'Ring with some a fair amount of high-speed cruising (i.e. 160mph) and high-rev fun.

I suppose it will also depend heavily on the mix of driving though. I tend to do a lot of 80mph motorway trips between Liverpool & London, but it spends the rest of the time trundling around urban/sub-urban Liverpool & London.

[daveco]

gmarks1 said:

mmm-five said:

I'd expect 35mpg out of a 325 or 330......

Never saw better than 28mpg mixed driving on my 330 - long term average was 24mpg according to the trip computer.

Gary

The best I could manage was 34mpg out of the 330, but that was 80% motorway driving. Bear in mind for the current 325 my commute into work is mostly uphill and I have to go through 24 sets of traffic lights (yes I counted) so that's a lot of stop-start.

It really needs a 6th gear though for the motorway, why did BMW only add a sixth ratio on the 330??

[Oi_Oi_Savaloy]

I've got an e30 1990 325i touring with over 200,000 miles on her and have just covered 322 miles on 43 litres of 97 ron (excellium by Total). I think that equates to 34mpg.

But that was trying to drive it with real care and no thrashing on mainly A and B roads.

My usual average is more like 29-30 mpg which I think is a miracle anyway!

[bodhi]

This has been one of the mos timpressive things about my E36 328i is the fuel economy I'm getting out of it. The computer is telling me an average of 30.4 since I bought it, and I recently averaged 38mpg on a run from Staffordshire to Swindon - AND back. Considering the run back was on a Friday afternoon and I got stuck for half an hour outside Oxford, I'd say that was pretty impressive. It included a quick burn up the Midlands Raceway as well.

Brilliant engines these BMW straight sixes. Such a shame the great unwashed are buying rattly diseasals instead, all for the extra 4mpg.

[Fun Bus]

So, it would appear the 325Ci is quite an economincal engine? Seems little different to my 2.0, 318Ci (2004) - has anyone any real world experience of the difference?

[anonymous-user]

My 330ci did 450 miles on a tank and averaged 37.5mpg. Its a 63 litre tank by the way.

I did mostly motorway driving at 70mph

[Matt80M]

I did Toulouse to London last week - just over 10 hours door to door, so not hanging around - a lot of the time cruising about 100-105. Managed to get 29.5MPG average on the journey from my auto e90 330i. I was pretty impressed with that. Commuting around London it's pretty bad though - lots of speed bumps and only starting to warm up my the time I get to the office. Normally hang around the 20mpg mark.

[andy665]

daveco said:

Currently driving a 325ci sport '03 facelift model and I have to say the fuel economy has been superb over the last few months.

Filled the tank to the brim with 99 octane fuel (also use OW30 oil) and do mixed town and motorway driving. After 90 miles of this the tank is still more than 3/4 full.

If I was any good at maths or bothered to check the manual to see what the tank holds I'd know exact mpg but it's on a par with my '00 330ci.

6 cylinder petrol Bimmer engines

Have you actually calculated the actual fuel consumption, seems your thinking is a bit hit and miss. I never judge a cars economy by where the needle is or what the trip computer says. Tank has to be brimmed, trip set to zero, when refilled divide the mileage by fuel put in to brimmed again - its the only way to do it

[to3m]

andy665 said:

Have you actually calculated the actual fuel consumption, seems your thinking is a bit hit and miss. I never judge a cars economy by where the needle is or what the trip computer says. Tank has to be brimmed, trip set to zero, when refilled divide the mileage by fuel put in to brimmed again - its the only way to do it

I quite agree - even if the fuel tank needle is accurate (I have never seen this myself), my experience has been that the bmw computer will spin you all manner of lies. I don't know how it's possible for it to get any of it wrong, but it does. Maybe it is not quite measuring the right thing? Perhaps it's using some kind of algorithm that is more complicated than it needs to be? Who knows. Whatever the reason, the answers it gives you aren't the same as the ones you get if you just divide distance driven by fuel consumed.

So much not the same, in fact, that you can check rough figures with google and see they're wrong with your own eyes.

(Google is really good for this kind of conversion, by the way. It has an amazing stock of measurements and is pretty good at working out what you want.)

For example,

bmw535i said:

My 330ci did 450 miles on a tank and averaged 37.5mpg. Its a 63 litre tank by the way.

Search in google for "450 miles per 63 litres in miles per imperial gallon" - it will tell you 32.47 mpg

Perhaps exclude the reserve tank?

"450 miles per 60 litres in miles per imperial gallon" - 34.10 mpg

What would 37.5 mpg give you?

"37.5 miles per imperial gallon in miles per 63 litres" - 520 miles

And so on. The computer's figures are consistently inaccurate, and I wouldn't trust it one jot. You're better off just looking at the odometer. No less accurate, and you get bigger numbers.

[anonymous-user]

to3m said:

Search in google for "450 miles per 63 litres in miles per imperial gallon" - it will tell you 32.47 mpg

Perhaps exclude the reserve tank?

"450 miles per 60 litres in miles per imperial gallon" - 34.10 mpg

What would 37.5 mpg give you?

"37.5 miles per imperial gallon in miles per 63 litres" - 520 miles

And so on. The computer's figures are consistently inaccurate, and I wouldn't trust it one jot. You're better off just looking at the odometer. No less accurate, and you get bigger numbers.

My apologies - I wasn't very clear in my original post. The 37.5mpg average was over a 10,000 mile period. It's also worth noting that when I did achieve 450 miles from a tank and then filled it up it would only take 55 litres........

The only way to calculate fuel economy to get a 100% accurate reading is to brim the tank and then drive till it runs out of fuel.

I would agree that the on board computers aren't as accurate as some people would like to believe though.

[Patrick Bateman]

Given the official combined cycle for a 330i is 31mpg you won't be seeing much more, if any, than that.

[ASR1]

38 mpg over a 500 mile mainly motorway round trip recently - N52 engine, auto.

[croyde]

I check mine by brimming, an E36 323 with a 2.5L engine.

Consistently get 18 round London and 29 on a run. Once drove a whole tank at mainly 50 miles an hour and got about 40 mpg.

[AOK]

croyde said:

I check mine by brimming, an E36 323 with a 2.5L engine.

Consistently get 18 round London and 29 on a run. Once drove a whole tank at mainly 50 miles an hour and got about 40 mpg.

I got almost exactly the same figures as croyde for what is essentially the same block in a manual E46 325Ci

[4rephill]

bodhi said:

This has been one of the mos timpressive things about my E36 328i is the fuel economy I'm getting out of it. The computer is telling me an average of 30.4 since I bought it, and I recently averaged 38mpg on a run from Staffordshire to Swindon - AND back. Considering the run back was on a Friday afternoon and I got stuck for half an hour outside Oxford, I'd say that was pretty impressive. It included a quick burn up the Midlands Raceway as well.

Brilliant engines these BMW straight sixes. Such a shame the great unwashed are buying rattly diseasals instead, all for the extra 4mpg.

Just be aware that the accuracy of the E36's OBC fuel consumption can vary from being spot on accurate to being a fair bit out, it varies from car to car.
If you do a search on the net you can find a procedure to reset the OBC's compensation factor for fuel consumption measurements to make it more accurate.
To check the accuracy of the OBC you need to do brim to brim checks to work out your actual consumption and then you compare it to the OBC's readings.

[billzeebub]

Beemer 6 cylinder engines can be as economical as you want to drive them. When Im trying they can be very frugal. I brimmed my tank on my 323 before setting off from mid-Surrey for St Ives-Cornwall recently and still had well over quarter of a tank remaining upon arrival because I just pootled down on a sunny day with the roof down..

Edited by billzeebub on Monday 29th August 15:56