Remaps - variations in expected increases

Ovlov440

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Hi all

I have a CLS 250 CDI. As stock, depending on which site you read it has 201 (or 204) bhp with 500NM torque.

I am looking at potentially having it remapped, but am finding pretty large variations in what different companies say they can achieve.

Someone who I have used in the past is quoting increases of 21bhp and 40NM torque.
Other companies are quoting 55bhp and 65NM.

Whichever way you look at it that is a pretty marge difference in figures.

What gives?

Ade
 

Spider1967

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i have same model merc and was considering chipping rather than a remap because the safety parameters are not overwritten and more than 1 tune is available, economy mode also known as valet mode limits the turbo and basically restricts the performance to gain maximum fuel economy with up to 6ish performance modes and a chip is easily removed by the user whereas a remap would need the garage to rewrite the original map. Performance of both systems are comparable with the best chip I found gave +45 bhp and +100nm of torque, worth considering maybe?
 

Gazwould

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i have same model merc and was considering chipping rather than a remap because the safety parameters are not overwritten and more than 1 tune is available, economy mode also known as valet mode limits the turbo and basically restricts the performance to gain maximum fuel economy with up to 6ish performance modes and a chip is easily removed by the user whereas a remap would need the garage to rewrite the original map. Performance of both systems are comparable with the best chip I found gave +45 bhp and +100nm of torque, worth considering maybe?

Tuning box for a 2.1 OM651 I presume.

Unfortunately they are nothing but marketing fakery that fool the ecu into seeing lower values especially fuel rail pressure then the ecu cranks up the pressure even further sometimes dangerously considering the injectors are handling this increase and the extra increase of fuel isn't seen by the fooled ecu and then so reports a false mpg gain , lol .

People sometimes get a small bump in torque and power then think they have got these magical unicorn more than remap figures !

The fuel rail pressure can be fooled just with a pennies / pounds ? resistor .

Some of these boxes have multiple connections including boost pressure and do have some software in them but I think the ecu's stock software is fighting these false signals and won't give anything like the claimed gain .

Remap average , 35 bhp , 50 Nm

Box , 45 bhp , 100 Nm , absolutely no way .
 

OneForTheRoad

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Even the V6 doesn't see 100 + nm gains . Not far off mind 🤣
 
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Ovlov440

Ovlov440

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Tuning box for a 2.1 OM651 I presume.

Unfortunately they are nothing but marketing fakery that fool the ecu into seeing lower values especially fuel rail pressure then the ecu cranks up the pressure even further sometimes dangerously considering the injectors are handling this increase and the extra increase of fuel isn't seen by the fooled ecu and then so reports a false mpg gain , lol .

People sometimes get a small bump in torque and power then think they have got these magical unicorn more than remap figures !

The fuel rail pressure can be fooled just with a pennies / pounds ? resistor .

Some of these boxes have multiple connections including boost pressure and do have some software in them but I think the ecu's stock software is fighting these false signals and won't give anything like the claimed gain .

Remap average , 35 bhp , 50 Nm

Box , 45 bhp , 100 Nm , absolutely no way .
I have been the tuning box route on a previous car (Saab 9-3) and whilst the gains were good it was very 'inelegant' in the delivery. Removed it and had it remapped and the difference in drivability was very noticable.

The tuning box made the engine feel like an 80's turbo unit, nothing, then everything at once. Also you could not use the cruise control as the system was constantly fighting with the real inputs from the car vs the modified ones from the box. This made the car kangaroo when it was trying to maintain the preset speed.

I would only ever now have a proper remap done and still plan on doing it at some point to my 250 - I was just surprised by the difference in figures being quoted as usually the figures from different tuners are broadly the same.
 

Larkone

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I was just surprised by the difference in figures being quoted as usually the figures from different tuners are broadly the same.
This has everything to do with marketing and little to do with reality - they will always quote the absolute max they have achieved on one particular car because they want to attract you to them and away from their competitors. Whether it is repeatable over all similar engined cars is another matter. Whether it creates a car that is over-stressed or has a poor power delivery is not relevant either when it comes to the 'marketing message'.
 

TeddyRuxpin

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Here's a similar thread I created: Wildly different figures/claims when remapping an E350 CDI | Performance Lounge

I've found that some places places actually quote way less than they can actually make (except for GAD!). MSL for example quote the minimum gains, rather than the maximum. They end up getting results which are just a bit lower than GAD, for an E350 at least. Maybe it's something to do with not wanting to over promise and then have angry customers, etc.

It's the 'off the shelf' maps and tuning box companies that seem to over promise, IMHO
 
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E55BOF

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My CLS 350, with an MSL remap, makes a bit more power than all four and a bit less torque than three of the examples in post #9. It could be down to small variations in the engine, or small variations in the dyno, or small variations in the tune. I've had the same engine in a 2014 with a tuning box on it, and it was a little disappointing; the remap feels much better, and faster, than the box.

Some of the more exaggerated claims from some tuners are likely either straight lies, or using 18% rather than the more conservative 14% for the correction factor.
 

Martyn_n

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A quick question; why is an "off the shelf" remap less valid than one that is "custom"? As long as the "off the shelf" map has been developed on a dyno / rolling road and the engine is the same spec as the one it is originally developed for why is this not as good as one done just for your car? After all isn't that what happens when the car came off the production line? They grab an ecu off the shelf and away you go and we all seem happy to quote standard power outputs as gospel and universal across all cars delivered new.
I accept where other modifications have been carried out, larger turbo or different flow injectors etc, there is a benefit to a custom map done live on a dyno but I am not convinced that it is otherwise essential. (other than the printouts for use in the pub)
 

E55BOF

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A custom remap can be tailored to the actual engine the ECU controls, and no two engines are exactly the same, as any tuner will tell you. Think of the engine as a suit; as standard it comes 'off the peg', and may or may not be a very good fit; with a generic remap or tuning box it is 'made to measure' and should fit well; with a custom map it is 'bespoke', and should fit almost perfectly.

You may be lucky, and get a generic remap or tuning box that is as good as 'bespoke' on your car, but there's no guarantee it would be quite the same on any other with the same engine. It will generally be to some degree better than standard, though in the case of £20 Shenzhen Specials off eBay, I'd not want one anywhere near any car that I owned.

That's why Saville Row tailors, and top tuning houses, are more expensive than Moss Bros. and TDI Tuning boxes respectively. You really do get what you pay for in this respect.
 
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TeddyRuxpin

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Thing is, they aren't really. In my opinion the idea that there's some kind of 'custom tune' is a fallacy for a stage 1 (which is what we're talking about). You can't do 'live rolling road remaps' with the majority of cars. You just do a before rolling road, flash the ECU, then another rolling road run to check for problems and to have proof of all the extra power. It also helps to check the torque and power curves look as they should (no weird dips or flat spots). Plus you get to show this 'after' graph to your mates.

If it's a car that's a few years old, the maps have already been worked out during development. People like GAD, Big Fish Tuning and MSL simply have a lot more experience than a generic mappers that have done a couple of days R&D tested their map on a Jeep OM642 engine (e.g. Celtic) and called it a day, and are now selling them to any 'remap company' that has an ECU flashing device. GAD/MSL maps are clearly 'better' than these generic maps that just adjust a few tables and ups the boost and fuel pressure, and that's what you're paying for.

For example, on my E350, you have to physically remove the ECU from behind the wheel arch and attach a computer to the pins, flash the ECU, put it back in the car, and then test. You used to have to actually heat up the ECU box and get the glue to melt and physically adjust the soldering and so on before it was possible to do it via the pin sockets. How many times do you think they're going to do this to 'customise the remap to your car'?

What you can do is have a 'before' rolling road, chuck a highly-tested and tweaked map on there and see how it performs. If there's no problem and the gain is good, that's it, it's done. I've read this from GAD themselves over on the 'other' MB forum.

Even with cars that can be remapped via OBD, they're not 'live tweaking' anything, but it's a lot easier than physically removing the ECU. If there's a problem or the customer has some kind of 'weird' request (perhaps they really want to push the power or wants the torque or power curve tweaked in a specific way), they might get the maps adjusted to cater for that, but most people are happy with the tried and tested 'standard' map.

So, the idea that every 200bhp E250 is getting some kind of bespoke map is not really true - if you have a E63 with a different turbo or intercooler, and uprated air filters and exhaust then sure - but even then, if it's a standard stage 2 or 3 kit, usually the remapper has already worked out the best map for that combination of mods, unless you're the first!

I'm no expert though and happy to hear info to suggest otherwise.
 
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E55BOF

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GAD/MSL maps are clearly 'better' than these generic maps that just adjust a few tables and ups the boost and fuel pressure, and that's what you're paying for.

That would be like standard (off the peg), made to measure (generic) and GAD/MSL (bespoke) maps, then? The comparison isn't exact, but as I said, you get what you pay for.

Sometimes the generic tuning box maps can be excellent. My first diesel MB - an old IL6 S211 E320 CDI - had a TDI tuning box on it, and I was mightily impressed. Mind you, with the old five-speed box it was a bit like a two-stroke: Wait for it (as the turbo spools up), wait for it...Waaaheyyyyyy!....(box changes up, turbo spools down)... Wait for it...wait for it...Waaaheyyyyy! again, and so on.
 
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TeddyRuxpin

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Well sure, but a tuning box isn't a remap. I thought we were talking about the difference between actual remaps/remap companies - otherwise @Gazwould would have posted his favourite Darkside Developments "Tuning boxes vs remaps" video in this thread by now!!!! :p
 

E55BOF

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I'd put tuning boxes and 'generic' remaps in the same category, more or less.
 

Aidroos

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I have been the tuning box route on a previous car (Saab 9-3) and whilst the gains were good it was very 'inelegant' in the delivery. Removed it and had it remapped and the difference in drivability was very noticable.

The tuning box made the engine feel like an 80's turbo unit, nothing, then everything at once. Also you could not use the cruise control as the system was constantly fighting with the real inputs from the car vs the modified ones from the box. This made the car kangaroo when it was trying to maintain the preset speed.

I would only ever now have a proper remap done and still plan on doing it at some point to my 250 - I was just surprised by the difference in figures being quoted as usually the figures from different tuners are broadly the same.
How much did you pay for the saab remap?
 

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