Ferrari Power Unit Hardware & Software

[gruntguru]

I don’t know how it is across the pond but in the states engines use 5 sensors to adjust afr. Uses a mass air flow sensor after air filter and left and right bank upstream and downstream o2 sensors(upstream and downstream of the catalytic converter). . . . .

. . and often a flex-fuel sensor in the fuel line.

[johnny comelately]

So, it was three Ferrari PU failures this weekend, right?

From the sound, Leclercs PU had a turbo failure, and it didn't sound sudden, so I'm guessing MGU-H.... The other ones, don't know.

Was wondering about this too from the whistle it made, maybe a shaft breakage on the turbo?

[holeindalip]

I don’t know how it is across the pond but in the states engines use 5 sensors to adjust afr. Uses a mass air flow sensor after air filter and left and right bank upstream and downstream o2 sensors(upstream and downstream of the catalytic converter). . . . .

. . and often a flex-fuel sensor in the fuel line.

If they do it’s not needed….

[gruntguru]

If they do its because - for the particular vehicle in question, the design brief and the regulatory framework - it is needed. OEM's are not in the habit of spending one cent on un-needed, unappealing additions.

[holeindalip]

If they do its because - for the particular vehicle in question, the design brief and the regulatory framework - it is needed. OEM's are not in the habit of spending one cent on un-needed, unappealing additions.

I don’t want to get in a debate by why would they need a sensor there. They pcm calculates mass air going in and the o2 out and adjusts fuel rate accordingly.

[gruntguru]

The problem is a sudden change in AFR requirements eg a car is running on E0 and then gets a full tank of E85. Chances are it won't even start. Longer term, the EMS has to re-learn the entire 3D fuel map - sure - the first time the car drives at cruise (and the lambda sensor is up to temperature etc) the EMS thinks "OK we need 40% extra fuel at cruise so lets jack up the entire map by 40%". That works well enough to make the car driveable thereafter but what about exhaust emissions in the meantime - whoops - GM you failed the certification test.

[holeindalip]

The problem is a sudden change in AFR requirements eg a car is running on E0 and then gets a full tank of E85. Chances are it won't even start. Longer term, the EMS has to re-learn the entire 3D fuel map - sure - the first time the car drives at cruise (and the lambda sensor is up to temperature etc) the EMS thinks "OK we need 40% extra fuel at cruise so lets jack up the entire map by 40%". That works well enough to make the car driveable thereafter but what about exhaust emissions in the meantime - whoops - GM you failed the certification test.

Gotcha, what exactly is the flex fuel sensor reading? The density of the fuel?

[gruntguru]

Had to look it up https://cecas.clemson.edu/cvel/auto/sen ... ensor.html. Apparently it measures the permittivity of the fuel by using fuel as the dielectric in a capacitor. Seems permittivity varies with ethanol %.
Permittivity: https://www.engineeringtoolbox.com/liqu ... _1263.html
Gasolene 2
Ethanol 25

[glenntws]

So, it was three Ferrari PU failures this weekend, right?

From the sound, Leclercs PU had a turbo failure, and it didn't sound sudden, so I'm guessing MGU-H.... The other ones, don't know.

Was wondering about this too from the whistle it made, maybe a shaft breakage on the turbo?

The turbo didn't slow down very fast, I think a real mechanical problem on the shaft would result in more abrupt stopping. My guess is that windings on the MGU-H failed since MGU-H cooling was insufficient for this long duration and high heat.

A dead shaft would certainly result in Charles stopping immediately since all kinds of stuff could get into the ICE and make things worse veeeeery quickly.

[Airshifter]

The sound was really strange, but hard to say what went boom, or crunch, or whatever. And hard to know if Ferrari will fill us in on what it really was. Either way, I hope it's not a long term issue.

But both failures during the race sounded almost exactly the same.






And to those involved.... all the street car fuel blend crap is way off topic in the thread. I'm surprised you aren't getting down voted by now for spamming up the thread with low tech road car basics.

[ryaan2904]

From the sound, Leclercs PU had a turbo failure, and it didn't sound sudden, so I'm guessing MGU-H.... The other ones, don't know.

Was wondering about this too from the whistle it made, maybe a shaft breakage on the turbo?

The turbo didn't slow down very fast, I think a real mechanical problem on the shaft would result in more abrupt stopping. My guess is that windings on the MGU-H failed since MGU-H cooling was insufficient for this long duration and high heat.

A dead shaft would certainly result in Charles stopping immediately since all kinds of stuff could get into the ICE and make things worse veeeeery quickly.

This is a good thing (if true), since they can improve on it with a new ERS upgrade. I thought the turbo failed. That would be a big thing

[enzo75]

Just read that turbo and Mgu-h are damaged but ICE and Mgu-k are ok.

[Drift4794]

Any guesses what was the reason then?

[PlatinumZealot]

I have seen discoloration in 3.5cc radio control cars racing engines (1/8 category) that hit 40000rpm with 25-30% nitro.
It happens after 2-3 hours of racing and it's normal. This engines last at best 50 hours before you need to rebuild them.

Can I see photos of this?

[PlatinumZealot]

Had to look it up https://cecas.clemson.edu/cvel/auto/sen ... ensor.html. Apparently it measures the permittivity of the fuel by using fuel as the dielectric in a capacitor. Seems permittivity varies with ethanol %.
Permittivity: https://www.engineeringtoolbox.com/liqu ... _1263.html
Gasolene 2
Ethanol 25

Used similar technology when I was in food production. Capacitance sensors. Can tell the defference between air water and whatever food you're pumping to protect the pumps or whatever you want it to trigger. Nifty sensors.