Bought a C250CDi and it feels slow

[NISFAN]

A remap works by altering the base reference table, not the calculation tables.
Once the base reference table is altered the ECU can no longer accurately calculate the volume of fuel used per injection pulse because it no longer has the standard reference to work to.
The injection pressure will have been altered and maybe the pulse duration, but as the ECU is calculating off standard values it will always give and over-read situation because the injectors are now injecting more fuel than they were, but the ECU doesn't know that.

Brim to brim figures are the only way to accurately tell how much fuel is being used.

Isn't that being a little presumptuous? Whilst I would agree that 'some' re-maps are performed this way, it doesn't mean that they all are.

As for Fuelly, whilst I am drawn to the data collected, it is seriously flawed in the fact that it fails to distinguish the ability of the driver to drive economically, conditions, or the type of use of the vehicle (city/motorway?) (50mph on motorway or 90mph?). It makes a great log for a particular driver to compare his/her own cars too though.

So in the case of the OP, would not point to how accurate his fuel computer is. For what it is worth, the average fuel computer read out on my C220CDi BE is seriously flawed, so I wouldn't trust it in an un-mapped condition to start with.

 

[Dieselman]

Isn't that being a little presumptuous? Whilst I would agree that 'some' re-maps are performed this way, it doesn't mean that they all are.

I can't wait for you to enlighten us on another method.

It makes a great log for a particular driver to compare his/her own cars too though.

Which is what we want, isn't it?

 

[NISFAN]

I can't wait for you to enlighten us on another method.

Look up ECUTEK, it cracks straight into the mapping tables, this is one of many, but used by professionals like Prodrive.

As I feel I need to add a disclaimer when answering your questions: *ECUTEK is not an MB mapping tool, but an example that as it can be done on other marques, no reason that such a method has not been used on an MB ECU. Prices may go down as well as up, Your home is at risk if payments are not made, other views are available*

Which is what we want, isn't it?

Is it? A hard charging, mate racing, ECU re-mapping, former M3 driver is not necessarily likely to be too fussed with long term economy. So what would an individual persons figures prove? If the OP did a month of logging prior to re-map then a month after you 'might' be able to draw comparisons. GizzE has provided his findings.

 

[Dieselman]

So what would an individual persons figures prove?

That their OBD was not accurate.

Surely, what we do want is a single person to give us both figures to compare.

 

[Dieselman]

Look up ECUTEK, it cracks straight into the mapping tables, this is one of many, but used by professionals like Prodrive.

As I feel I need to add a disclaimer

Probably a good thing, as I can't see anything to suggest it is anything other than a custom map lookup table programming tool.

If the lookup tables are altered the OBD goes out.

 

[rothbury]

Some so called experts on here seem to confuse a proper ecu remap with a plug in device designed to fool the ecu. Then a wave of false ridicule builds up that could be regarded as cyber bullying.

It is true that posts should be treated as opinions and not fact. But when they come from members with thousands of posts they can be treated with more respect than they actually deserve.

Like wolves they pack together

Well it doesn't take long to work out the most opinionated and unpleasant member on this forum. The sort of vindictive rubbish he and his sidekicks put on Khamen's thread about his C63 was despicable and now he's at it again. You know who you are ,and just a suggestion- a lot of us don't want your dreary chip- on -shoulder, mealy- mouthed posts thank you very much.

 

[BigSilverEstate]

So to recap:

DM: you should rely on brim to brim fuel economy calculations rather than the OBD in assessing the impact of a remap because the procedure inherently tends to make the OBD over read
GIZZE and others: this is correct but there are genuine fuel economy gains in many cases and the amount of over reading varies between cars
NISFAN: some remapping companies use an alternative procedure which is less prone to this OBD over reading issue, it is not clear whether the OP used such a company
OP: you are all so mean and have impugned my good name by branding me a liar. Here is an irrelevant picture I took today (exit left)
Rothbury: DM now look what you've done. You are a fiend and thanks to you another valiant man has been lost.

So does anyone actually know what real fuel economy and performance gains can be achieved with this engine by remapping, within the mechanical limits of its components or should we all just stick to the threads about old cars we are never going to drive if we prefer to read discussions that reach conclusions rather than sending everyone into swoons?

 

[V12]

I vote big silver estate for pm.

Sent from my GT-I9300 using MBClub UK

 

[redbaron]

Im unsure what the fuss is about?


FACT ODB can and does talk ******
FACT Cheap remaps may not be ideal for the engine.
FACT Decent remaps give better performance and can show economy gains.
FACT the EU test is nothing more than a comparator between vehicles and is not a real world figure - what amazes me is that even the press / motoring magazines still fail to understand this.

 

[HumberMart]

I can see the day when the memory function will not only set the seat, mirrors and wheel to suit the driver, but also select the optimum engine map.

 

[developer]

My electronically enhanced car goes rather quickly when I gas it.

Does it also give better fuel consumption - I don't know, nor do I care - it's a performance chip - the clue is in the name and I drive it accordingly (where permitted, of course ).

Simples .

 

[st4]

I can see the day when the memory function will not only set the seat, mirrors and wheel to suit the driver, but also select the optimum engine map.

Why, the seat position for one driver will remain constant but they may like using different maps for different situations.

Anyway, the car needs to default to the most Eco friendly one as that's the settings used to attain the figures quoted in the MPG tests

 

[NISFAN]

That their OBD was not accurate.

Surely, what we do want is a single person to give us both figures to compare.

Erm, my car is stock standard and the OBD is NOT accurate, or maybe all the random fuel stations I use are conning me?

 

[Dieselman]

Erm, my car is stock standard and the OBD is NOT accurate, or maybe all the random fuel stations I use are conning me?

What is that going to prove for the O/p's car? We want his figures, not yours.

As an aside, I back worked the 59mpg less 30% and it came out to 41mpg, which isn't too far away from the original report he gave of 37mpg.

How big is the tank on a C coupe, 60 litres?

I would love to see the O/p try to go for 800 miles between fills...

 

[Paul/]

Why, the seat position for one driver will remain constant but they may like using different maps for different situations.

It's been a while since I tuned in to the technology, but around 10yrs ago there was a chip available for the Integrale that was switchable from the dash, with Economy/Road Performance/Track Performance optimised settings. Nowadays I expect there's also MOT mode and MaxPower Afterburner options.

Snag though with your friend 7Gtronic, is it really needs shift points to be reconfigured to properly exploit any changed torque profile.

 

[HumberMart]

Why, the seat position for one driver will remain constant but they may like using different maps for different situations.

Anyway, the car needs to default to the most Eco friendly one as that's the settings used to attain the figures quoted in the MPG tests

I don't agree, surprise surprise!

IMHO progress and the quest for maximum efficiency will move the manufactures away from standard one size fits all maps to smart learning maps that adjust to driver style and the environment.

Of course legislation and codes will need to evolve to permit this development but why not?

 

[NISFAN]

What is that going to prove for the O/p's car? We want his figures, not yours.

As an aside, I back worked the 59mpg less 30% and it came out to 41mpg, which isn't too far away from the original report he gave of 37mpg.

How big is the tank on a C coupe, 60 litres?

I would love to see the O/p try to go for 800 miles between fills...

If re-mapped properly, low boost cruising will return stock figures

 

[Dieselman]

If re-mapped properly, low boost cruising will return stock figures

It always will on a diesel as the air volume is unregulated, so is self adjusting.

As I already said some pages ago...

but in reality the same amount of fuel is being injected on cruise and more on acceleration.

Tip:

If trying to prove me wrong, don't say the same thing I have already said much earlier.

 

[NISFAN]

I was trying to prove you wrong? ....more like you just jumping to conclusions again

 

[Dieselman]

However, if the O/p is only cruising, he isn't using the additional torque the remap has offered, which is how people still manage decent mpg figures after a remap.

It doesn't take a detective to work it out.

To make more torque a diesel engine needs more fuel.
Adding more fuel isn't going to save fuel.
Using more fuel means lower mpg.


Not really hard, is it?