[Jeroen]

Originally Posted by dracul

MB OM 501 engines are available at different tunes from 310-460 HP. Not much mechanical difference and even the ECU (MR) is same. It's a 12L v6 truck engine.

Do you know what the mechanical differences are? Would be interesting to understand what can be achieved by parameters only and wheren/when mechanical (or other) measures are necessary. Do they all use the same transmission and brakes too?

Jeroen

[Myth_sx]

Taking a guess at what might be the logic behind the single parameter based tuning and larger range of output gains.

Originally Posted by Jeroen

One parameter changes the output by that much?

Its just a key value pair in the ECU, like a hash map. All (major) components might be querying this table to verify the state of tune and then applying the corresponding matching value for that parameter from a specific metric table. And i expect there must be loads of reference tables for every function.

Originally Posted by Jeroen

To be honest, I find it very hard to believe that engines and powertrains would be over dimensioned by this much.

Try to imagine the other way round. Option 3 might be the normal working/optimum output for that hardware. Option 1 and 2 are just under-powered specs for lower variants/models. In future, they just spike those with next higher parameter and push it back to the market at a higher pricing.

E.g. The 2.2mhawk runs at 120bhp in scorpio and 140bhp in xuv. They increase the parameter after a few years and now make engines run at 140 and 170bhp respectively. In reality, the engine might be actually capable of 170bhp since the beginning or maybe more.

[Sutripta]

Originally Posted by Myth_sx

Its just a key value pair in the ECU, like a hash map.

I would guess a jump table index/ vector. If so, calling it a parameter would be misleading.

Regards
Sutripta

[SPIKE ARRESTOR]

Originally Posted by AMG Power

True. Happens with VW's 2.0 TDI which has several states of tune - 110 Bhp / 140 Bhp / 150Bhp / 170 BHP and 190 Bhp.

Most of their engines including petrols have varying states of tune.

Proof 1

Originally Posted by dracul

MB OM 501 engines are available at different tunes from 310-460 HP. Not much mechanical difference and even the ECU (MR) is same. It's a 12L v6 truck engine.

Proof 2

Originally Posted by im_srini

While I share Jeroen's scepticism, I guess you're the expert !

Could you at least state if it's a gasoline or diesel engine, & whether it's NA or turbo ?

If it was a gasoline NA engine, I would, frankly, be flabbergasted !

I'm not an expert, I happen to work in this field.

The engine I mentioned is Petrol, TC. But the concept is applicable to NA engines as well. However, there is a limit to what can be achieved with a NA engine.

Perhaps a lame question, why doesn't someone simply replace that variant coding say at a dealership or how hard will it be for someone to replace ECU from a higher output engine variant to a lower?

The difference is, dealerships just flash the software to the control unit, they don't manipulate it or alter it, unlike tuning maps where the software is modified / bypassed.

Originally Posted by Jeroen

No he hasn’t. He just says:

I think he has, that's how it works, and this post pretty much as well.

Originally Posted by Myth_sx

Its just a key value pair in the ECU, like a hash map. All (major) components might be querying this table to verify the state of tune and then applying the corresponding matching value for that parameter from a specific metric table. And i expect there must be loads of reference tables for every function.

Do you have a dyno available?

I don't have one, the company I work for has. But I'm not involved in Dyno testing.

Originally Posted by Jeroen

Agree. Yes there are ECU's that store multiple maps. A single parameter allows you to choose which map. Nothing new about this.

I still think this is a case where the ECU is used for multiple (different)versions of an engine. You choose the parameter for the respective engine version. Different engines with different output require a different ECU paramter setting.

I don't understand where your problem lies? If it is with over/under dimensioning, that's true. It's also the manufacturer's strategy how they look at it. BMW might have different mechanicals for different engine outputs, but looking at the examples shared by other members, this is not something new.

A question to you, what happens when :

a) A car is used in a country where the fuel quality is poor?
b) Engine operates at high altitudes?

How does it work?

Spike

[tsk1979]

Originally Posted by Akshay1234

I too find it hard to believe that such a huge change can happen from just variant coding, without any internal changes. I know that the 328i and the 320i engines are the same, except for the pistons due to which the compression ratio is also different. Even for BMWs which use the basic N57 engine in the 258, 313 and 380bhp tunes there are a single, twin and tri turbos respectively.

Originally Posted by Jeroen

Agree. Yes there are ECU's that store multiple maps. A single parameter allows you to choose which map. Nothing new about this.

I still think this is a case where the ECU is used for multiple (different)versions of an engine. You choose the parameter for the respective engine version. Different engines with different output require a different ECU paramter setting.

Jeroen

This reminds be about the USA spec Triump V8 and the British spec. The British was 140bhp, and USA was 120bhp. I believe this was for emissions. However, the changes were mechanical too, with 140bhp one having different pistons. So a lot of people who restore Triumphs in USA, try to do the 140bhp one.

A friend is restoring one in his garage, and he says its not worth it. For a typical classic cruiser like the Triumph, that 20bhp is not going to take you anywhere.

[Sankar]

Originally Posted by SPIKE ARRESTOR

Proof 1

Proof 2

3. Toyota 1GD Diesel. Innova 360NM, Fortuner 450NM. 90NM leap, same hardware.

[Akshay1234]

Originally Posted by AMG Power

True. Happens with VW's 2.0 TDI which has several states of tune - 110 Bhp / 140 Bhp / 150Bhp / 170 BHP and 190 Bhp.

Most of their engines including petrols have varying states of tune.

Agreed but these engines have different parts too, and are not exactly the same. Now I know for sure the turbos are different, but I'm not sure what else is.

[Dr.Naren]

ECU has thousands of maps. I have got DAMOS for S-Cross 1.6 ECU. I think there are more than 20,000 maps and all these won't be related to engine. A tuner would be dealing only with maps related to engine.

Maps have X and Y axis and the values are mentioned in the table. I have posted the pic of Injection duration opening map in tabular view earlier on this thread. Please see that pic to understand what a map is, what parameters / values are in a map

SPIKE ARRESTOR has spoken about variant coding by single parameter change. Don't get it wrong by thinking it's just a single map or single value. Manufacturers have state of the art calibration softwares and it is nothing like the hack methods / tricks used by aftermarket tuners. The way an calibration engineer looks at ECU maps and the way how aftermarket tuner looks at it won't be the same. But as I said before usually many maps are repeated in ECU. I assumed that manufacturers would be code the ECU in such a way that by selecting single parameter / code : couple of maps would be changed and SPIKE ARRESTOR has also confirmed it

[Sankar]

Originally Posted by Akshay1234

Agreed but these engines have different parts too, and are not exactly the same. Now I know for sure the turbos are different, but I'm not sure what else is.

If i remember correctly 110 upto 150 had the same turbo and associated hardware. 170 and higher had a different turbo and I am not sure about other hardware changes if any.

As I understand variant coding helps in manufacturing efficiency.

An aftermarket tuner getting more power out of the engine by changing "only" variant coding is like activating a cheat code and releasing more factory tuned horses out of the motor. Its not tuning. But sometimes its best to change a code and get some more factory horses out rather than risk being part of tuner's R&D team without even knowing it

[Dr.Naren]

Originally Posted by Sankar

An aftermarket tuner getting more power out of the engine by changing "only" variant coding is like activating a cheat code and releasing more factory tuned horses out of the motor. Its not tuning. But sometimes its best to change a code and get some more factory horses out rather than risk being part of tuner's R&D team without even knowing it

Hahaha!!

Don't even dream of aftermarket tuners doing it. 99 percent of the tuners identity few performance related maps and just increase it by certain percentage : Trial & Error method, guess work and what not.. That's the R & D of tuners. Very few tuners were able to crack the ECU at code level, for example switchable maps by APR for few VAG cars and Wolf Moto for Fiat, Renault, old VRS and few Suzuki cars

[Jeroen]

Originally Posted by SPIKE ARRESTOR

I don't understand where your problem lies? .

A question to you, what happens when :

a) A car is used in a country where the fuel quality is poor?
b) Engine operates at high altitudes?

How does it work?

Spike

I don't have a problem. I find it remarkable that an engine is manufactured that can produce such a vast range of power output. We had a discussion on a different thread around this although it was more pertaining to manufacturing efficiency. Obviously, overdimensioning is a cost increase per unit, but from producing an overall range of engines, standardisation might still bring the overall cost down. (Actually, if you find that thread (I can't for some reason, you will see that I was very much on the track of standardisation rather then to produce many slightly different parts for different power outputs).

Your proof is just people repeating the same mantra about a certain engine producing so much power and so much power. Still various members are also saying:

these engines have different parts too, and are not exactly the same

110 upto 150 had the same turbo and associated hardware. 170 and higher had a different turbo

I'm just interested to undertand the difference, if any, between the 'same'engines producing a vast range of output. I would think that many of the big component are identical (i.e. crankshaft, cylinderblock, cylinder head, piston (?). But there are likely to be some differences on things perhaps such as turbo's, injectors, gaskets etc. Other members post suggest the same.

So I think the statement that such a vast range of power output comes from one and the same engine is a bit too generic. It could be, but I think in many cases there could be differences in certain parts.

To your other questions; you have to be more specific what poor fuel is. (diesel, petrol, dirt/water ingress, octane incorrect, problems with the dopes etc)

Contrary to popular belief an engine doesn't know at what altitude it operates. So it's performance isn't altitude depended as such. It is however dependent on atmosferic pressure and that varies. Higher altitudes have lower pressure as a rule compared to the ground below, but not necessarily in an absolute sense. (Anorak fact: It's why pilots must adjust their (barometric) altitude meter all the time to the local atmospheric pressure.

Even the very basic Bosch L-tronic system on my 1980s Alfa Romeo has a barometric pressure sensor that feeds into the ECU to adjust for variations in atmosferic pressure. Whether that is due to a high / low pressure zone, or a high altitude doesnt matter.

On carburator cars (or my 1975 RE Bullet) I carry a screw driver so I can adjust the timing on the go. NIether a low pressure zone or a mountain is going to stop me from enjoying my drive

Jeroen

[Sankar]

Originally Posted by Dr.Naren

Hahaha!!

Don't even dream of aftermarket tuners doing it. 99 percent of the tuners identity few performance related maps and just increase it by certain percentage : Trial & Error method, guess work and what not.. That's the R & D of tuners. Very few tuners were able to crack the ECU at code level, for example switchable maps by APR for few VAG cars and Wolf Moto for Fiat, Renault, old VRS and few Suzuki cars

I shouldn't have used the term R&D it gives out the wrong picture. Only a very few number third party aftermarket guys in the world would have access to an R&D facility like Banks, APR and few others. For the rest it best can be called T,D&D*

*Trial, Destruction and Development

[Jeroen]

I just found the thread I was referring to earlier. We discussed the topic about how much power you can get from a unique engine by altering ECU settings only, and production efficiency in some detail;

Some members did some extensive research trying to figure out which parts are different on seemingly similar engines with different output:

Here some proof that although basically the same engine, there are quite a few parts that are different. So just changing one parameter in the ECU would not get you such a vast range of power output

Have a look at the table on the well known VAG TDI engine. Engine output ranges from 110->170 BHP. From the outside these engines look identical. But to get them to deliver these different outputs, various parts are different. And no doubt a few settings in the ECUas well. In addition if you read the below thread you will also notice that the transmission bolted onto the engine with different outputs differs as well.

http://www.team-bhp.com/forum/techni...ml#post4174346

There is no doubt that through the ECU alone vast differences in power can be obtained. But the question is how much and where do you need to start changing some parts? My gut feeling is that anything up to 30-40% on top of the lowest power output is probably possible. You want to increase more, you are likely to have start changing bits and pieces. But it also depends heavilly on how the engine was designed in the first place and what makes economic sense. I don't see why it can't be done technically, but I haven't seen much real evidence (i.e. identical part list between different variations of the same engine). But as we discussed in the above thread, that is probably more an economic/manufacturing issue then a technical one.

Jeroen

[Dr.Naren]

Originally Posted by Jeroen

Here some proof that although basically the same engine, there are quite a few parts that are different. So just changing one parameter in the ECU would not get you such a vast range of power output

I guess you are confused. BHPian SPIKE ARRESTOR was taking about calibration at manufacturer level. It's not just single value / parameter change in engine maps. Variant coding is something like you can switch a set of maps for different power outputs by single parameter change by coding. No aftermarket tuner would have the expertise to do it and it's a herculean task to reverse engineer the codes.

Same engine can have different power outputs. In some cases the hardware is different. There are few threads related to that in our forum. Let's not go off topic here. Thanks

[Jeroen]

Originally Posted by Dr.Naren

I guess you are confused. BHPian SPIKE ARRESTOR was taking about calibration at manufacturer level. It's not just single value / parameter change in engine maps. Variant coding is something like you can switch a set of maps for different power outputs by single parameter change by coding. No aftermarket tuner would have the expertise to do it and it's a herculean task to reverse engineer the codes.

Same engine can have different power outputs. In some cases the hardware is different. There are few threads related to that in our forum. Let's not go off topic here. Thanks

Sure the suggestion in his text:

Though many people talk about maps etc. what many people (including so called tuners) don't know is "Variant coding". Because manufacturers mostly use the same powertrain in different combinations, most often they have for this either a parameter or a characteristic line. This means, just by changing this one parameter, you could get different outputs at the wheel.

For example, the manufacturer I work for, just by changing the variant coding of 1 parameter, I can get following outputs.

Option 1 : Parameter = 0 --> 200kW
Option 2 : Parameter = 1 --> 245kW
Option 3 : Parameter = 2 --> 270kW
Option 4 : Parameter = 3 --> 320kW

Is that by variant coding you can get huge power variations out of one and the same engine. Whereas I fully agree you can get different power outputs, I have some doubts as to how much you can get out of the same engine without having to change some hardware bits

Let's leave it at that.

Back on topic; Variant coding has been around in (car) manufacturing for at least 10-15 years. It's essentially a process that enables manufacturers to program a car (ECU et all) with particular variations.

As far as I know it looks at all relevant variations on a model, so not necessarily engine stuff alone. So it's a very efficienct way of dealing with all the different models, variants, keep spare parts to a minimum, ensure interoperatibility etc.

But it doesn't prevent a tuner to remap an ECU. Or otherwise. For instance, I replaced an airbag on a friends Jaguar not too long ago. (First time ever I replaced one). We got a SRSCM variant code error. But on the net we found a procedure and a guy with a little tool and we fixed it. It was a bit cumbersome and hooking it up to the Dealer's electronics suite would have been much quicker, but also much more expensive.

So when we say tuners don't have the capability/tools this is probably true. But for what tuners like to do, does it really matter?

Jeroen