[Dr_O]

I have a 328i F31 and love it so far! Fuel economy is not quite what I would like though - averaging 31 MPG over the last 6 tanks (which, annoyingly, is what those with 340i's seem to be getting!).

I haven't been able to find much info about people getting 328i's remapped and the impact it has on fuel and components - I plan on keeping the car for a good 6-7 years.

Has anyone here tried it?

[Tengocity]

In my experience... nope, quite the opposite! No remap I've had (3 cars though all diesel) has led to improved economy, all led to worse economy as they had greater performance potential, which I utilised regularly. Even looking at my wife's fuel consumption with the cars (she'll drive them pretty consistently) I couldn't detect any improvement.

[Soul_Glo]

Some tuners sell economy remaps and power remaps though...

I am going to say yes but with the caveat of utilising added performance you won't see many or any gains.

It depends on the car, the driver... some cars are already near maximum tune and there is little to be squeezed out. The remap could be used to improve drivability though.

My old E92 325 was 218ps and gained 12 after the map. I didn't feel it in my butt dyno.. the car drove a lot smoother though. Felt more linear than before.

The 328i sounds like the no mans land the 325i was in. It had less economy than the 320i but no more power than the 330i and sometimes closer to the economy.

I drove one last year as a courtesy car it was quite nice. I don't think it needed anything bar ditching run flats.

Having said that. Ditching run flats made a big difference to the 325i. Less rotational mass saw a jump of 2-3 mpg.

[ahero4eternity]

I'd kill for 31 mpg.

[225]

Originally Posted by Tengocity

In my experience... nope, quite the opposite! No remap I've had (3 cars though all diesel) has led to improved economy, all led to worse economy as they had greater performance potential, which I utilised regularly. Even looking at my wife's fuel consumption with the cars (she'll drive them pretty consistently) I couldn't detect any improvement.

This. I have had a few with a remap and others with boxes. In theory it does as you can use the additional torque on motorways etc
However the temptation to use it all the time is too great most of the time. Lumps like the b58 respond
so well to a box/remap that its very difficult not to use the oomph....

[Richtw]

I had the same engine in a 428 GC, it was not the most economical no matter how I drove it could not get better than 32mpg. I feel your pain!

Currently driving a C43 with 3l bi turbo generating huge bhp by comparison, in a much heavier car I seem to be getting 28mpg! Not a million miles away from the 428..... i don't understand either!

[GEP77]

Originally Posted by Richtw

I had the same engine in a 428 GC, it was not the most economical no matter how I drove it could not get better than 32mpg. I feel your pain!

Currently driving a C43 with 3l bi turbo generating huge bhp by comparison, in a much heavier car I seem to be getting 28mpg! Not a million miles away from the 428..... i don't understand either!

It's just the awesomeness of having 6 cylinders!

But in all seriousness during normal driving you need the same amount of power and torque regardless of the engine. To maintain 40mph you only need a few HP all the rest are spares. The difference in mpg largely reflects the different weight and frictional loses of different sized engines.

[HighlandPete]

Originally Posted by 225

This. I have had a few with a remap and others with boxes. In theory it does as you can use the additional torque on motorways etc
However the temptation to use it all the time is too great most of the time. Lumps like the b58 respond
so well to a box/remap that its very difficult not to use the oomph....

It is in how the torque is used.

It can only be more economical if you can use the torque to reduce rpm, (higher gear for the same speed). Extra torque in itself uses more fuel, doesn't come for free.

An example would be in tuning a farm tractor, more torque at lower rpm. It allows for engine down speeding/up gearing, to do the same job... cutting engine/drivetrain losses saves fuel.

[HighlandPete]

Originally Posted by GEP77

It's just the awesomeness of having 6 cylinders!

But in all seriousness during normal driving you need the same amount of power and torque regardless of the engine. To maintain 40mph you only need a few HP all the rest are spares. The difference in mpg largely reflects the different weight and frictional loses of different sized engines.

Add that the bigger engines normally pull higher ratios, (even if it is only the diff ratio), hence why virtually as economical as the smaller engines in similar driving.

[SteveChester]

I'm of the opinion that more power just encourages you to drive it harder..... So less MPG

[Sasquartch]

I've averaged 39.2mpg in my 328i over the last 9 months

So they can be economical if driven carefully and you have good conditions

Best ever on a hypermiling exercise on my 24 mile route home was 53mpg !! But you don't buy a nice car like a 328i to drive like that :-)

Personally I wouldn't touch a tuning box, if you're only doing it for economy then how many miles would you have to do to recoup the cost of the box ?

[JOHNBMWM5]

Originally Posted by Tengocity

In my experience... nope, quite the opposite! No remap I've had (3 cars though all diesel) has led to improved economy, all led to worse economy as they had greater performance potential, which I utilised regularly. Even looking at my wife's fuel consumption with the cars (she'll drive them pretty consistently) I couldn't detect any improvement.

I second this, all the Diesel cars I have had remapped , none have improved MPG.

[UKF30]

i don't think ONE can ever have speed and economy same time.

why would you want economy when you can have POWWWWWERRRRRRR

[Lorcan]

It really does depend on the vehicle and how it's driven. I regularly sell tuning boxes to farmers as they save them thousands of litres of fuel a year. They are happy to pay £1200 for a box that saves them £8000 pa!

Anecdotally some road car customers sometimes tell me they get a 2-3mpg saving, I've even heard 7mpg, but just as many use the performance often so these customers see consumption increase. My advice for cars is buy for the performance, and if you get a fuel saving regard it as a bonus.

[AlanYoro35i]

if u cant resist not hooning it then you will!

[Dr_O]

Originally Posted by Sasquartch

I've averaged 39.2mpg in my 328i over the last 9 months

So they can be economical if driven carefully and you have good conditions

Best ever on a hypermiling exercise on my 24 mile route home was 53mpg !! But you don't buy a nice car like a 328i to drive like that :-)

Personally I wouldn't touch a tuning box, if you're only doing it for economy then how many miles would you have to do to recoup the cost of the box ?

Wow... 39mpg - I don't see how you can achieve that... it slowly creeps up to the late 30's when on a single carriageway, but as soon as you get to a roundabout it just drops again.

Plus I like to boot it every now and then if it did increase the performance I don't think I would be able to resist using it.

[Dr_O]

Originally Posted by HighlandPete

Add that the bigger engines normally pull higher ratios, (even if it is only the diff ratio), hence why virtually as economical as the smaller engines in similar driving.

I just wish there were more second hand 340i F31's around in my budget when I was looking... I would have snapped one up in an instant!

[AlanYoro35i]

The fun factor is well worth the additional few hundred quid + few mpg less! when i had my N54 335i the tunning box was the best thing ever!

The Dinan sport tuner for 435ini had was really good, can change setting via mobile app and you wont be able to resist hooning it as it change the car from a slewping beast to beast mode!

[2CRO4TV]

Originally Posted by Dr_O

Wow... 39mpg - I don't see how you can achieve that... it slowly creeps up to the late 30's when on a single carriageway, but as soon as you get to a roundabout it just drops again.

Plus I like to boot it every now and then if it did increase the performance I don't think I would be able to resist using it.

Eco pro will achieve that mpg easily but is so boring.
My car's at 27.1 mpg so 31mpg is quite good imho.

[Ajs_435d]

Originally Posted by HighlandPete

It is in how the torque is used.

It can only be more economical if you can use the torque to reduce rpm, (higher gear for the same speed). Extra torque in itself uses more fuel, doesn't come for free.

An example would be in tuning a farm tractor, more torque at lower rpm. It allows for engine down speeding/up gearing, to do the same job... cutting engine/drivetrain losses saves fuel.

This.

No magical tune will improve it.

[CazuaLLUK]

Yeah no way will it improve MPG.

[NISFAN]

Tuning boxes or remaps for economy.......it's one of those legacy notions. Yes 15 years ago it was possible to tune a standard car for more economy, but as Lobb mentions, modern cars are tuned to the nth degree to squeeze as much economy out of them as possible.
It is also achievable to have very high power and good economy on the same tuning map, because the load cells are completely different ones, so can be optimised for whatever the situation demands.