Quick way to convert from E85 to 98RON (efficiency table?)

[CraigComet]

Hi

I'm wondering if it is possible to change an E85 tune so that it can get me home on 98RON in an emergency? This is on a supercharged 2017 Mustang with a M150 (plug and play GPR to suit the Mustang).

For example, if the engine is running perfectly on the E85 tune and I absolutely needed to run a couple of tanks of 98RON petrol, could I jump into the Efficiency Table and adjust fuel type/fuel density, molar mass, stoich ratio. Save those changes and will the system then hit the new lambda targets for petrol without further changes?

Why am I asking such a question?

I am buying a car this week. The seller had the Motec installed and has only ever run the car on E85. He doesn't believe that it has a flex fuel sensor, or that it has been tuned for 98RON, although I won't know until I connect a laptop and have a look. I will be flying 900km to the car and driving it home. There SHOULD be service stations selling E85 along the way, but if two particular service stations have any supply issues, I will be about two tanks of fuel short to get home. I'd prefer not to carry a spare 120 litres of E85 in the car with me, so was hoping that at a pinch, I could make the changes to the fuel type / settings so that I could run 98 octane petrol. I will just be cruising at light load, not getting into any boost at all, so I don't have any concerns that the ignition table will be too aggressive for the 98 fuel as I'm cruising down the road.

Thanks for any guidance.

I will definitely be setting up a flex sensor as a priority and I have a feeling that there will be countless features of this M150 GPR install that the seller didn't know about, or forgot. I can't wait to connect a laptop and find out all about it. First step is to make it home.

Thank you

[David Ferguson]

The Efficiency table won't change, but it likely the ignition table might need adjustment if it has been optimized.

I would simply change the fuel properties (M1 Tune->Initial Setup->Engine Details worksheet), and remove a few degrees of ignition timing (M1 Tune->Tuning->Ignition Trims) with the overall trim (i.e. set it to say -4). if you avoid full throttle / high loads on your drive, you should be fine.

[Stephen Dean]

If the Knock Control has been configured properly, and it has enough of a window for taking timing out, then even some load on the engine with the 98 should be ok. The bigger issue is not short bursts of acceleration, such as passing a slower car, but long times with the engine under load and building heat, like climbing a mountain range. If this can be avoided with 98 in the tank, then it shouldn't be an issue*.

*Assuming that the engine has been tuned correctly and all of the safeties are in place.

[CraigComet]

Thank you both for your replies. Unfortunately today, I found out that the workshop that tuned the car put a password protection on the M150, so I won't have access to anything.

I will need to do some research to find out what that actually means as the "soon to be" owner of the vehicle. I assume that datalogging, engine protection, diagnositics, warnings and inputs/outputs are still accessible, with probably no access to modify tune functions such as the fuel, ignition and cam timing tables. Does that sound about right?

[David Ferguson]

You should get access to the ECU, or compensation in the price you pay for the vehicle.

The security system in the M1 is extremely flexible (and complicated). It's hard to say what level of password locking they did.

But as the owner, I would demand access or at least understand the cost of licensing and recalibrating from scratch.

[CraigComet]

Good point David.

As it turned out, the workshop was unwilling to unlock the ECU and wouldn't clarify over the phone what level of password protection they had put onto it, just that "it is locked, because these things aren't easy to use".

I had to assume the worst case scenario of the ECU being significantly restricted, and that's just not an option for me.
With the expected cost to wipe the M150 and start again, the sale didn't go ahead. The seller is disappointed in the sale falling over at the last minute, I'm devastated at having to walk away, and I'd booked a flight and two days off work to make it happen.

All because a workshop thinks that what they've done to a mass-produced engine in a mass-produced car that only sees street duty...is so special and secretive that they see it necessary to lock down the M150.

I've had numerous Motec and Haltech powered cars tuned over the years and the workshops have never considered locking down anything. Their rationale is that the customer has paid for the tune and modifications, so the customer should have full access. Seems pretty simple to me...