further to C220 CDI remap

[jepho]

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.

This was a very lucid explanation and I now understand a little more of the physics involved in the generation of torque. Thank you. I did manage to find a useful explanation and a clip that illustrated the generation of torque very well and, unsurprisingly, it underpinned the explanations given by you and Dieselman.

p.s. I had a bowl of Weetabix this morning but I did not find that there was any increase in torque. Should I have used full cream milk?

 

[ringway]

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?

Not so much, Colin, no.

I was lead to believe (from a thread on this very forum), that all engines are stock for whichever country they go to (due to fuel being of poorer quality in certain countries) and that cars running in countries that have better quality fuel at their disposal were safe/safer to re-map.

I'll have a dig and see if I can find the thread. IIRC two of the contributors on that thread who subscribed to the above theory were a re-mapper and a fuel company employee.

 

[Dieselman]

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?

Not necessarily and possibly not at all, it could even be using more fuel but register less.
The computer works on there being a set volume of fuel injected per injection actuation of a given length and system pressure. The pressure has now been altered so more fuel is injected per unit of time, but the computer doesn't see that as it has been fooled to increase pressure.

 

[Dieselman]

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

It's not that simple as the turbo and other components are specified for the different power outputs.

 

[ringway]

I recall a thread where a guy had bought a used Sprinter van. Van ran okay to a point, but would die at 75/80mph.

I remember the thread. He seemed to know his stuff, but was pulling his hair out after spending a lot of time and money swapping, changing and cleaning just about everything.

His engine was 129bhp. It transpired that a second hand ECU was fitted by the previous owner which was from a 89 or 109bhp model.

After fitting the correct ECU and the van was spot-on.

 

[effbee584]

Recently had my 2003 E320cdi re-mapped by Clive Atthowe in Norwich. Initial impressions are greater smoothness, much more torque, acceleration significantly better. Not done enough miles yet to see if mpg increases but local mileage only figures suggest a 4/8 mpg improvement. Time will tell.

 

[Flash]

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.

I have contacted Remap Science and am getting them to remap my ECU on my W203 C220 CDI saloon - I have opted for the mobile service they offer and that is £200 ALL IN and they will be sending someone out to me rather them me go all the way up to Bradford. They claim I will get an exra 30BHP and an additional 55NM of torque and will iron out the turblo lag on flatspots and will be working off my existing ECU settings and not a generic file and that my original ECU settings will be stored with them on a database should I need to revert back for any reason FOC.