Octane Adjust Ratio and msd map

[JohnD]

Before you datalog, switch units to metric.

JohnD

[Tyrefitter]

@JohnD enlighten me.

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Andy.

 

Red Edition.

[JohnD]

The list of parameters that Stewart recommends to be datalogged are shown in metric units  eg boost in kPa, AFR as Lambda, charge temp in degC  etc

The list contains 32 parameters!  Most of which I understand and a few I don’t!   It should be on the Email you received containing the map.   It’s also on the MSD website under Cobb tuning?

 

JohnD

 

[Tyrefitter]

@JohnD Thanks,i bought the handset secondhand but stuart did send me a email with the peramiters i need to check.

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Andy.

 

Red Edition.

[JohnD]

Just an update on the datalogging on my MSD420

Having flashed the revised map after the first datalog  I’ve found a definite improvement in mid range response with the boost coming in earlier and it’s livelier off boost.  Along with this, my average fuel consumption over similar driving to before, has gone from 26/27mpg to 30!

I’ve done the second datalog run and flashed the (very) slightly adjusted map and have to say that although I was not originally convinced of tangible improvements over the Mountune M400R, after the revisions following datalogging, I’ve now stuck the MSD420 badges on the car!

So, for all those with any of the MSD maps installed via the Cobb Accessport and with the option of two datalogs available (E-tune) do it! 

[richard31337]

@JohnD

All agreed from me 🙂 definite improvement over m400r, and I’m also on my first revised map from Stu. MSD all the way.

 

Thanks

[evolutionstu]

Hi Guys,
Just stumbled across this as I dont use forums much but thought that a few words about your OAR system here may help folk to understand how Fords Octane Adjust Ratio (OAR) works.

A little background:
First of all, you need to understand that this is a FORD octane prediction strategy. It has nothing to do with COBB or any other tuner. The PCM running ALL the Ecoboost engines with a Ford HDFX Strategy is at all times listening closely to the noise that the engine makes. It is programmed to be able to know the difference between an engine running well and one with poorly combusting fuel running into knock and it can adjust its spark and load allowance accordingly in order to combat it happening constantly due to the current fuel octane.

All manufacturers cars now do this to some extent, but Fords recent strategies use this proprietary and patented system as their octane monitoring solution. The calibrations differ across models, early calibrations use OAR, later ones use the KOM strategy, but all essentiall do the same thing.

Which is wht you might ask?
Well, the ECU needs to be able to detect poor fuel and react accordingly by dropping advance and cylinder load (years ago it was advance only) but a system like this is also required because a modern ECU is constantly looking to add a small allowance of extra spark advance in order to improve efficiency, and so long as the engine seems to respond positively to that advance, with little to no knock, the strategy will assume decent octane fuel and move towards its high octane tables which, importantly, also allow additional cylinder load.

If the engine is knocking badly it will move the other way, towards its low octane tables. It’s position between these blending tables is indicated by the OAR Figure which will be somewhere between a best of -1.00 and a worst of +1.00 (Or +1.00 – -1.00 on the KOM system)

This is a constant process and one which allows the ECU to react to poor octane fuel quickly and take steps to combat the damage that can result from knocking fuel. Incidentally, the Ecoboost 2.3 strategy is significantly better at it than the earlier 2013 2litre ECU’s, but they all do it and some tuners like ourselves have incorporated some of the later strategies into the older ECU calibrations.

Where do we start?
The factory strategy starts the process off in the middle at 0.00 upon ECU programming, and it remembers its current progress between key cycles. Because an ECU reflash typically sets you to zero again, this feature is one of the reasons you have will all have heard things like…
“She made 270ps on the dyno mate, but after you have driven it for a while it will make the 280”

Indeed, a strategy utilising the load and spark blending tables properly really WILL gain power as you drive. (On good fuel only of course… so yes, that should call an end to the the age old argument that the engine seems more powerful on good fuel. It should, because working properly the engine will gain a little power on high octane fuel. )

Should I care?
If you are not running a handset that allows you to monitor this process and receive custom tuning, your interest in this strategy really ends here, just stick decent fuel in at ALL times and enjoy the fact that your ECU has this capability. It is very impressive and tuners who understand Fords HDFX strategies should (Although sadly don’t) retain it.

But what if I am running a COBB Accessport:
These devices (and others) allow you to monitor this parameter live. Unfortunately, people get really hung up on it, to the point of panic at times! They shouldn’t, but they do, and they tend to get upset when it doesn’t advance up to -1.00. Yet if they didn’t have an Accessport, it still wouldn’t have done so… but they wouldn’t have known! Too much information can be a bad thing and leads people to calling them an “Anxiety Port”. LOL

However,
I must take SOME blame as I know some customers get frustrated when I tell them I won’t remote tune their calibration until the OAR is at max because there is already power left on the table not being utilised by my base calibration… and that has led to this little article because I see lots of misinformation online about this. So, if the octane adjust ratio is proving resistant to change it is probably just your driving style is too relaxed, or too hard, so see if you can find a long road that is slightly uphill and will allow you to use a medium gear from quite low rpm and low boost levels, maybe around 3 psi in 4th gear.

Why?
Because the key thing to know is that the ECU only adjusts the OAR during times the engine is LIKELY to knock but shouldn’t when using good fuel, so it doesn’t respond much, if at all to cruising along a motorway, it also responds very little under WOT as that is deemed as likely to knock anyway.
Those are the kind of conditions the ECU will try and optimise its spark table in as it actively tries to reach the advance figures indicated in its MBT table so that it is running at optimum efficiency. (The minimum amount of fuel with the maximum amount of ignition it can get away with without knock = maximum efficiency)

If that scenario above doesn’t work then we may be looking at the knock sensor recording either real or ghost knock. That will then require further investigation of course.

I hope this clears up some of the confusion around OAR and my waffling hasnt just added to it!

**Disclaimer**
The above advice relates to FACTORY and MSD tunes only as many tuners disable all the LSPI limiters and octane adjust strategy and just poke max load figures in them all, effectively neutering the strategy so it runs the same load and advance no matter where the OAR is positioned.

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Best Regards,
Stu

[evolutionstu]

Blimey…
And that, right there, is why I tend not to get too involved in forums anymore.

Once I start waffling, I cant stop!!

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Best Regards,
Stu

• This reply was modified 3 years, 3 months ago by evolutionstu.

[9designs]

Stu, as always, insightful, informative and very well written so it can be understood. Also why I moved to an MSD map on mine.  Though I still haven’t got around to logging and sending you the results.

Thanks for taking the time.

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Magnetic Grey with all the best bits

FPM375/COBB/MSD-  Quaife LSD,  DSC+Tractive  Suspension,  HJS200 cell sports cat and MT Cooler. Sync3 upgrade.

Was UK seller for DSC & Tractive  Active suspension !!!

    

[robroy]

Top guy 👏

[richard31337]

Nice one Stewart 🙂 good to see you on here! Car is running great thanks to your work buddy 😁

[1234enough]

Good to hear from a tuner, excellent information 👍👍

[JohnD]

Feel free to waffle!

 

JohnD

[Author]

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