further to C220 CDI remap

[jepho]

Since the recent remap of my 51 plate W203 C220 CDI coupe, I have now driven more than 1500 miles. My initial thoughts appear to have been borne out with a little more mileage under the wheels. The car is now much more responsive in each of the 6 manual gears. I am really impressed by the urgency of the car going from 70mph in 6th gear onwards... ...only on a track of course, your honour.

There is a new sense of urgency about the character of my car's acceleration. I have a rather limited experience of seeing the nose of a diesel car raise significantly during acceleration in each of the gears and I have to admit that it is not an unpleasant experience.

The purposeful acceleration does not appear to suffer from any noticeable lag. There are no obviously noticeable flat spots either. The car also appears to be returning some very good mpg figures with the trip computer indications showing anywhere from between 65 ~ 74mpg at 70mph. (See attached low resolution image)

Would I recommend the service which I used? It was a resounding success, in my opinion. Remap Science only charged me £150 inc. VAT for the service, as part of their special April offer so I cannot provide any details on what the normal price would be for the service which I purchased. If you have a turbo diesel car and it is need of some tuning, then I can wholeheartedly recommend Remap Science to the membership because it has made a huge difference to the way my car drives and feels.

There are various levels of service offered at Remap Science and you can also have a custom map made for your engine. (I believe that the technician who remapped my car engine was named Adam) To find out what they can do for you you could do worse than give them a call. I went for the very cheapest service and I have been more than impressed by the changes which have been brought about by remapping the engine map.

There is a marked improvement in my general perception of how smoothly the car now moves. It certainly appears to be a little more economical than it was before the remap. I think that the claim for an additional 10 miles per gallon is very reasonable. The engine was mapped from 143 to 178bhp, which I believe is similar to the power output of the engine used in the E270. The torque was also increased from 315 to 380nm.

I was reluctant to consider such a drastic alteration to my car's engine before the remap was done because I could not find enough information to satisfy my curiosity. It now seems that I was over-thinking the issue. The remap can be reset at anytime, without charge and I believe that it is an undetectable modification. I am delighted with the performance changes and would not hesitate to recommend the modification to other drivers who are considering the pros and cons of remapping their engines.

 

[Colin_b]

My experience of having had one car remapped (not an MB) has left me a little sceptical

If is is so easy to increase the power and economy, why don't MB do it as standard, better economy would reduce VED and Co car liability at the least.

There has to be a downside, otherwise it would be standard?

 

[Dieselman]

The car also appears to be returning some very good mpg figures with the trip computer indications showing anywhere from between 65 ~ 74mpg at 70mph. (See attached low resolution image)

The trip computer calculations will now be as optimistic as the upgrade in power, so your 70mpg is probably 52mpg.

 

[ringway]

My experience of having had one car remapped (not an MB) has left me a little sceptical

If is is so easy to increase the power and economy, why don't MB do it as standard, better economy would reduce VED and Co car liability at the least.

There has to be a downside, otherwise it would be standard?

IIRC, all cars are produced to stock spec due to the difference of fuel quality in different countries. Where better fuel is available it is deemed safe/safer to remap.
MB do sell tuning boxes (and will honour the warranty for cars up to 60,000 miles) and a brabus one will cost around £1500, so it can't be said that they are against exploiting an engines capabilities (I suppose if they are making money out of it).

 

[Dieselman]

IIRC, all cars are produced to stock spec due to the difference of fuel quality in different countries. Where better fuel is available it is deemed safe/safer to remap. MB do sell tuning boxes and a brabus one will cost around £1500 so it can't be said that they are against exploiting an engines capabilities.

LOL...

Hook, line, sinker...

Octane levels MAY be an issue for petrol engines, but knock characteristics really aren't for diesels.

MB restrict the power output and the warranty if even their authorised boxes are used.

 

[ringway]

LOL...

Hook, line, sinker...

Octane levels MAY be an issue for petrol engines, but knock characteristics really aren't for diesels.

MB restrict the power output and the warranty if even their authorised boxes are used.

Ok, but the boxes provide increased power, so they are a re-map in a box, so there is an increase.

 

[jepho]

My experience of having had one car remapped (not an MB) has left me a little sceptical

If is is so easy to increase the power and economy, why don't MB do it as standard, better economy would reduce VED and Co car liability at the least.

There has to be a downside, otherwise it would be standard?

The idea that we don't get something for nothing is deeply ingrained. It is right and proper to be sceptical and then go on to ask the question, where does all the extra performance with a remapped turbo-diesel engine come from? In general terms, diesel engines could be described as being hugely over-engineered. This is most probably due to the combustion demands of the higher energy fuel (diesel) and engines which tend to run at a higher compression ratios than petrol fuelled engines.

My pre-remapped engine appeared to be in a relatively soft state of tune. It is still feels like it is a softly tuned engine but it appears to be much more responsive. The acceleration is notably different throughout the gearbox. The pulling power appears to be increased. It is difficult to see what objection can be made to increased torque and power output, where the operational parameters of the engine have not been exceeded.

I am not really a fan of the slippery slope type of argument which you have offered here... If is is so easy to increase the power and economy, why don't MB do it as standard, better economy would reduce VED and Co car liability at the least. ... because it assumes rather too much. It assumes that MB would want to offer the potential improvements to their customer base... without the increased charges one can make for re-badging the same product and creating other models from the same engine components - in this case the W203 C220 CDI engine.

MB is not a charitable organisation, it is a business with a very specific business model. That business model relies on MB selling cars across its whole range. If they offered all of the much vaunted advantages of remapping an engine across their complete range of cars, there would be no need for MB to sell any Blue Efficiency cars or any cars with more cachet (because of a more powerful engine) than the base-engined models.

 

[jepho]

The trip computer calculations will now be as optimistic as the upgrade in power, so your 70mpg is probably 52mpg.

Are you saying that remapping doesn't provide any increase in power? I am confused. I asked a question in the forum before deciding on a remap but there were no answers. I have asked around and (of course) the people providing the services would claim whatever they thought would sell the service. In the end I went with the service that was cheap (because of a special offer) and the technician I spoke to before making the decision to try a remap appeared to have a good understanding of the subject.

I don't have the benefit of expert knowledge or skills in the area of how MB cars work or can be fixed (too many electronics for my liking) but I have some well-devloped mechanical engineering skills, which give me a small insight into what is achievable and what is unreasonable in terms of engineering. I would be obliged to you for your views on the value of remapping. Is it all just an illusory gain or can any real gains be made by remapping the engine operational parameters?

 

[Dieselman]

Are you saying that remapping doesn't provide any increase in power?

Not at all. You definintely get an increase in torque but the fuel computer can no longer calculate the fuel used as it the ECU is now being fooled to deliver more fuel.

The amount of torque is proportional to the fuel consumed so a given % increase means a similar amount of additional fuel is being used, but the computer won't display that now.

As a matter of interest what are the peak EGT figures for this map and how much torque cant the gearbox stand?
I wouldn't say that modern diesels are massively over-engineered, due to cost reasons.

 

[artyman]

I think there is a valid point here, Mercedes have stated that they wanted to utilise different power outputs from the same engine, so since there would be no financial advantage in manufacturing it with different components, the extra horsepower must be in the ECU. Therefore it seems logical that there are gains to be had from remapping. Now whether it's possible for outsiders to be able to manipulate all the electronics that Mercedes obviously have access to I can't say, do they try and prevent what they would consider interference, and diminuation of an income stream for them.

 

[jepho]

Not at all. You definintely get an increase in torque but the fuel computer can no longer calculate the fuel used as it the ECU is now being fooled to deliver more fuel.

The amount of torque is proportional to the fuel consumed so a given % increase means a similar amount of additional fuel is being used, but the computer won't display that now.

As a matter of interest what are the peak EGT figures for this map and how much torque cant the gearbox stand?
I wouldn't say that modern diesels are massively over-engineered, due to cost reasons.

I see what you are saying but don't quite follow the reasoning. In purely simplistic mechanical terms, I see the crankshaft as the component that is connected to the transmission which then transfers the crankshaft output through a driveshaft and a differential gear to the wheels. My limited understanding was that the transmission reduces the engine/crankshaft speed and the result is an increase in torque which in turn makes the vehicle move at suitably slow speeds when stopping and starting.

If we accept my simplistic model of a car for the sake of the debate (and to increase my knowledge)... if torque is derived through the transmission slowing down the engine, I don't understand how more fuel is required to generate more torque.

I apologise if this seems to be a bit dumb but I really would like to know more.


After the bank holiday, I will ask the tuner for the EGT numbers. Did you make a typo here... how much torque cant the gearbox stand?

edit: I realise that you have not said things in the way I have paraphrased - I took you to be saying that an increase in fuel consumption delivers more torque but on reflection, I see that I may be wrong.

 

[jepho]

I think there is a valid point here, Mercedes have stated that they wanted to utilise different power outputs from the same engine, so since there would be no financial advantage in manufacturing it with different components, the extra horsepower must be in the ECU. Therefore it seems logical that there are gains to be had from remapping. Now whether it's possible for outsiders to be able to manipulate all the electronics that Mercedes obviously have access to I can't say, do they try and prevent what they would consider interference, and diminuation of an income stream for them.

I think that there is a considerable commercial advantage to having a single engine which can be fitted to many different purposes. I can also see why Mercedes would want to prevent people from obtaining the necessary tools with which to make sh*t out of their beautiful cars. The high price of entry keeps the casual tinkerer outside of the official tool loop.

The probable concomitant to explicitly permitting remapping is that MB's hard-won reputation, for high quality cars, could be completely destroyed because of the indiscriminate modification of Mercedes engines by an army of ignorant numpties. Repurposing is the apposite neologism.

Presumably this is the main reason for the high price of MB analytical tools which are designed to identify issues with any MB car... nevertheless, anything which is coded within software can be hacked just as easily as it was coded.

 

[markjay]

I don't see the issue, really... surely this is an empirical question? If the mpg on the car's computer is better than it was before the remap, then the remap saves fuel... even if the figures are not accurate? If the car feels better to drive, smoother, accelerates better, etc, then surely it was worth it, even if the actual BHP increase is unknown? On that premise, I am happy to go by other members' experiences before deciding on a remap for my own car.

 

[Stratman]

...........

If we accept my simplistic model of a car for the sake of the debate (and to increase my knowledge)... if torque is derived through the transmission slowing down the engine, I don't understand how more fuel is required to generate more torque...............

Torque isn't derived through the transmission 'slowing down the engine'.

Picture a big rock that you want to move. You can use a scaffold pole as a lever. The nearer to the rock you put the pivot point the more force you can put under the rock, but the smaller the distance you can move it. What you will find is that the applied torque (force times distance) is the same both sides of the pivot.
If the pole is ten feet long and you put the pivot one foot from the rock while pushing down with a force of one hundred pounds, the torque produced is one hundred pounds multiplied by nine feet, or nine hundred foot pounds. The same torque is applied the other side of the pivot, but as the length of pole pushing on the rock is only one foot, the force acting on it is nine hundred pounds. You've traded distance for force. Every nine inches you push down on the lever will only move the rock one inch. This is what the gearbox does, and when you change gear you move the pivot point.
The only way to increase the torque is for you to eat more Weetabix or the engine to burn more fuel.

Incidentally, the 'force' and 'distance' in the engine is the expansion of the burning fuel pushing down on the piston and the distance between the centres of the main bearing and big end, which is half the engine stroke.
The stroke is fixed, only the force can be changed by altering the amount of fuel burned.

 

[Colin_b]

IIRC, all cars are produced to stock spec due to the difference of fuel quality in different countries. Where better fuel is available it is deemed safe/safer to remap.
MB do sell tuning boxes (and will honour the warranty for cars up to 60,000 miles) and a brabus one will cost around £1500, so it can't be said that they are against exploiting an engines capabilities (I suppose if they are making money out of it).

MB produce cars very specifically for different markets, LHD/RHD, different indicators, mirors, warning labels and the like.

Trivial to have dataset A,B or C in the ECU as well. Are you really saying MB are content to have BMW selling more economical and cheaper to tax cars in the UK market because the right ECU software is too difficult?

 

[markjay]

I must admit this is an aspect of car marketing I don't fully understand.

I often read in car magazines that a new model has a 'detuned version of ... this and that engine'. Why detune an engine in the first place?

I can understand MB not activating the Tyre Pressure Monitoring or the Cornering Fog Lights functions because they want to charge for it. But they don't seem to offer ECU-mapping to different tune level as an optional item anyway? (Other than Brabus etc.)

 

[Stratman]

I often read in car magazines that a new model has a 'detuned version of ... this and that engine'. Why detune an engine in the first place?

To reduce fuel consumption figures and hence emissions, thereby placing it in a lower tax band is one reason I can think of.

I can understand MB not activating the Tyre Pressure Monitoring or the Cornering Fog Lights functions because they want to charge for it. But they don't seem to offer ECU-mapping to different tune level as an optional item anyway? (Other than Brabus etc.)

The C200 and 220 CDI both have the same 2148cc engine in different states of tune.

 

[artyman]

Presumably you could take the ECU from a C220cdi and put it in a C200cdi for an instant tune

 

[markjay]

The C200 and 220 CDI both have the same 2148cc engine in different states of tune.

So are the W203 180K, 200K, and 230K - but in all these cases the differences are more than just an ECU re-map... the differences are in having lower compression ratios and larger kompressors.

I suspect that the same is true for the C200CDI/C220CDI - surely you can't just re-map a C200CDI into a C220CDI?

 

[jepho]

I don't see the issue, really... surely this is an empirical question? If the mpg on the car's computer is better than it was before the remap, then the remap saves fuel... even if the figures are not accurate? If the car feels better to drive, smoother, accelerates better, etc, then surely it was worth it, even if the actual BHP increase is unknown? On that premise, I am happy to go by other members' experiences before deciding on a remap for my own car.

It is true that the car now feels better in every respect and in that sense, I agree with you; that the question about whether or not a person should consider a remap is simply answered and empirical. What is less clear to me is the technical advantage to the remapping process and, of course, some of the subsidiary questions raised by lack of knowledge and various members expressing their viewpoint.