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McLaren 12c 2012
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Hi Bobsfurniture and others who are interested to tune,

I am going to back up what @M-Engineering is saying here, but I think there is a need for more technical info, as to be honest the forum needs it. Phh where to start, so lets get into it. As having a McLaren background and working for the company in the UK, I have seen a few things/lucky enough to learn more than the average having worked with some very experienced people who have been technical support for years on end.

There seems to be a lot of people worried about tuning their McLarens due to "reliability". From experience, I can tell you, these cars yes have their gremlins which most of the time small electrical issues, however, the engines are STRONG if maintained properly and some technical common sense being used, yes there have been some instances of cracked liners and thrown rods, but from the cases I have seen, have mainly been because of poor maintenance, abuse or poor tuning. I think its fair to say that there are some poor tuning techniques out there, which I have seen myself, and having dedicated about a year to learning how to tune this particular platform, great benefits can be found in tuning these cars if done properly.

While the stock mapping as already mentioned is good, there are some negatives within the tuning which could do with some refinement, such areas include the fueling, McLarens run far too rich with a minimum of .67 Lambda on full throttle under certain conditions (Component protection), running fueling so rich, can actually INCREASE EGTs to around 800c, so while this might cool down combustion temperatures the temperature of the exhaust gases is significantly increased putting extra heat into the turbos, manifolds (which is probably why some have cracked P13 upwards), oil, etc is obviously not a good thing, which is why tuners like me, and M-engineering fine tune this area which actually results in much lower EGTs at full load by about 50-60c. (730-740c).

The ECU strategy is mainly operated on requested load and EGT modelling, once a certain EGT is seen by the ECU, (850c) component protection will come in and you will be running .67 lambda. (9.98-10 AFR) or so, this is detrimental for power and of course EGTs, (exhaust gas temperatures). So as I said above, this is an area that is greatly improved to around .79/.80 Lambda with tuning, and from the amount of logging I have done, these cars after a few pulls will kick into component protection mode anyway, and mainly maintain this very rich operating condition. As the too rich lambda will generate the high EGTs and its a never ending cycle from there on in unless you allow the engine to cool for a significant amount of time, so tuners will opt to change this map to keep EGTs under control.

Another area that is optimized is the ignition timing, the profile as stock is as said, aggressive but well controlled knock strategy that will pull timing to protect the engine from any damage, so this isn't a problem, ignition timing is a key factor in making more power, but we have to be safe with it and use the right amount as it will be destructive on any engine.

Boost is another aspect of tuning which is cranked up a little, approx. 18-19 PSI (tuned) depending on the platform but we will use 12c/650 as an example. This is also an area that is closely monitored. The ecu has a MAP sensor limit which needs to be set correctly, once we set this limit, the boost will not exceed, and is there to protect the turbos running too much boost into the engine, if the fueling is good, then the engine can see higher boost levels/timing without any issues, the problem is when intake air temperatures get too high and boost is not limited by poor tuning (example map below), I have had a car come to me with boost vs IAT maps still requesting full load/boost to the engine at temperatures above 90c, which is totally asking for trouble and this is the point we are making here, if the tuning is done correctly, there is really nothing to worry about, I have just tuned my McLaren myself and I am really happy with the results. Its so much better, I am hitting the dyno on Friday and I will post in this thread the before and after dyno results.

Example of stupid and unsafe tuning of a Load vs IAT map.


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My advice to all McLaren owners would be to tune their cars, but, make sure it has been done by someone who knows that they are doing, just as an FYI, tuning these cars do not need to be done by a McLaren expert, they run the same ECU has some Audis and VWs. If someone knows how to tune those well, they can also tune McLaren's well.

To summaries the tuning process it consists of: Raising map limits, fueling, Boost, ignition timing, torque changes, there are various maps within these areas, but this is mainly all that is changed, tuning is like making a 5* meal, with the right amount of ingredients, its fantastic.

The engines can take the tuning if its done properly. Its really nothing to be scared about also regarding the warranty issue, the way this is checked to see if the car is tuned is by using the calibration area (map segment of the data's checksum vs McLarens) once the data within the ecu is changed, the checksum also have to change, McLaren stock calibrations all use the SAME checksum, so its easy for them to check if the data is stock or not, but if you take the car for any warranty work I don't think warranty voiding is an issue if you revert to stock via BENCH flashing and you keep the RPM limit standard, you will be fine and it will in the main go undetected, because if you exceed the RPM limit stock, that will show in diagnostics and its obvious, its pointless changing the RPM limit of these engines anyway as there is little power after 7500 with stock turbos, bigger turbos its obvs another story.

In terms of safeties, the ecu from factory have these anyway (Knock, Fuel trims and some others) but m-engineering have been smart and added more just incase for the sake of people who do not understand what is going on.

Open to any questions so please ask, I hope you found this interesting,

Mike
 

· Registered
McLaren 12c 2012
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1,183 Posts
Couldn't agree more with your statement below @mrvex. When we retune cars and see this table setup this way it is almost always a dead giveaway that the previous tuner was using a server file and has very little understanding of what they actually put on the car. It seems the "go-to" method of most tuners is to just raise all of the limits out of the way rather than calibrating the various load, torque, pressure, etc... limits to the proper setpoints.

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I would also blame this on the reason why some liners have cracked and rods thrown I literally know of 2 other tuners on the planet who write their own files apart from me, DME, and you guys.

I have also seen the turbo efficiency table totally changed with stock turbos. LOL
 

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McLaren 12c 2012
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1,183 Posts
Yes it had it perks and it was fun and a lot of horse play, but the monetary side of things wasn't great so decided to move on to something unfortunately more officey which pays better.

Yeah I think you will find this one interesting McLarens dont actually use EGT sensors, they use simulated temperatures based on Lambda, as different lambda values have different temperatures, so based on what lambda is being seen by the ecu, the ecu has a logic built into it that engineers researched using an actual EGT to measure different lambda temperatures. Very good idea actually, it works as it should.

Component protection is what is says on the tin really. Its used to cool down the engine components when things get a bit toasty by throwing fuel in, its not great for the cats though. This also what causes the flames out the back of the car when its been running on track. Its a total waste of fuel to run it that rich and yes other things get even hotter such as the exhaust/ cats and turbos.
 

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McLaren 12c 2012
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Hey,

Yes it is way too rich and this is a fact to the level that the car is not that fuel efficient. Take a look at your exhaust after having a hard drive and you will see what I mean. Black. In the world of tuning and engine, every tuner knows the optimal AFR for the engine. For example, most naturally aspirated cars run max power at 12.9-13.0 AFR, McLarens on the other hand around 11.7, most other turbocharged engines also depending on ignition timing mainly and of course a few other things.

McLarens have aggressive timing from factory but the extremely rich mixture at WOT can support that timing but suffers in terms of optimal power because of the slower burn and the unburnt fuel ends up out the back and sticks to the exhaust tips. When tuned, all of the fuel is burnt and the mix burns faster too.

Your car is running what is used by mclaren is “rest of world configuration” meaning its maxed out and optimised for 97 RON. ROW cars consist of middle east, asia and europe. What is known as FED spec is for american cars only and the mapping is slightly different for emissions purposes, but there isnt much difference in power

I hope that clears some things up :)

Any questions pls ask
 

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McLaren 12c 2012
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1,183 Posts
Yeah, most dont understand really, lol thats why tuning is only for the minority. When the car is tuned it will be optimised for whatever you ask for in basic terms.
 
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