[MolarBear]

So with the recent snow and stormy weather in the UK, I have made a few observations about the drive train, which I feel is poorly understood / misunderstood or documented (re: 4WD). Here are a few of my observations about the behaviour / quirks of the drive train during the winter and my ownership - for reference, my car is a 2018 LCI coupe with nearly new Michelin Pilot Sport 4S. Unsure if this applies to all model years (probably), I've owned the car for about 15 months now.

1. The electric drive train is extremely temperature dependent - and I'm not referring to range. Low temperatures will limit the top speed of the 'e-drive' only mode. After driving with the ICE for a good 30 minutes (so sufficient time to warm up) at 70 mph, I thought I'd try and use up some battery before my destination. Activating e-drive at 70mph would start it for a few seconds then immediately present 'drivetrain not available' (or something similar) before reverting to ICE. Dropping speed to 60mph and activating e-drive worked fine. So this is clearly speed dependent and probably a safety mechanism.

1B. The ICE is temperature dependent too. After a good 30 minutes of using largely just the ICE in sports mode (temperature yesterday was 0.5 C) - I reached the motorway after some country lanes. Normally 1st goes from 0-25mph ish, and 2nd goes from 15-55mph, 3rd onwards from this. 2nd refused to go any higher than 47mph, when I tried to manually override it in sports mode with the paddles. Perhaps not warmed up enough, but this surprised me of how long it would take...

2. There seems to be a lot of conflicting views on what activates 4WD mode. A lot of people seem to be under the impression 'hold state of charge' and sport mode activate 4WD mode and all wheels at the same time. I am under the impression that you cannot engage and powder all 4 wheels permanently (but would love to see this proven with a car driven on dyno/ramp).

From what I gather the 4 wheel drive system is not active unless in boost mode or slipping is detected (regardless of sport or comfort) and I don't think that at low speeds/low power all 4 wheels receive power. I think the front wheels only kick in during comfort/sport when the inner ring glows blue with boost.

In the snow yesterday, doing a sharp right turn immediately flicked out the back end with a ton of oversteer. Not especially reassuring in the snow (for those that feel reassured by 4WD). My observation is keeping it in sports mode means that the electric motor can kick in when there is some slip detected but I'm not convinced of how effective this in snowy conditions, it feels still largely rear wheel driven and not that grippy. Then again I have summer tyres on and have no professional training.

3. There is an advantage to still being in sport/hold state of charge, and that is that at speeds < 63mph (where it resorts to EV mode), it keeps the engine on, which means that in the chance of slipping, the electric motor can provide some power to front wheels.

If you use only comfort mode and no hold state of charge, the ICE appears to activate on slippage (although I have limited observation of this).

4. There is no reverse gear for the ICE. Reverse comes only from the electric motor. If you drive into heavy snow, and try to reverse, you could get stuck (like I nearly did) as power only comes from the front wheels.

5. Comfort mode goes to 63mph under normal conditions, but it is not a hard limit, rather dependent on engine load. Going down hill, I have seen this go as far as 66/67mph without activating the ICE.

6. Comfort mode provides a higher gear ratio than the e-drive in electric only. E-drive uses 1st gear, whereas comfort uses 2nd gear. Those that are cruising at steady speeds (such as a roads/motorway) and want to use electric only, will increase range quite a lot by not activating e-drive and using only comfort mode. Fine for commuting, not great if you need to go above 63mph..

There are several videos of the i8 playing in snow - winter tyres probably help a lot!

[Nachbar]

You are driving in snow, without winter tyres? Hoooly cow. This is even illegal over here.
With winter tyres, the i8 is doing great in the snow. And even better in Sports mode.

I live in Switzerland and daily mine all year round since 5 years.

[stressdoc]

I find the reverse issue problematic. It would be good to find a work-around to keep the rear axle engaged.

[thesubmitter]

in Quebec, winter tires are mandated. I think its logical to put winter tires on an expensive car. At the end all the safety features in the world don't matter if your car's tires are bad.

Winter tires apparently are better because they are softer and are malleable in cold weather and obviously the tread is better suited to getting rid of the snow.

Also considering that it doesn't actually cost you much more than 2x tire changes per year because you are basically splitting your wear and tear between 2 sets of tires instead of 1 its a good tradeoff. Bonus points is to just get an entirely new set of wheels with winters and another set for summers (the annual changes are cheaper)

[ericsi]

Originally Posted by MolarBear

So with the recent snow and stormy weather in the UK, I have made a few observations about the drive train, which I feel is poorly understood / misunderstood or documented (re: 4WD). Here are a few of my observations about the behaviour / quirks of the drive train during the winter and my ownership - for reference, my car is a 2018 LCI coupe with nearly new Michelin Pilot Sport 4S. Unsure if this applies to all model years (probably), I've owned the car for about 15 months now.

1. The electric drive train is extremely temperature dependent - and I'm not referring to range. Low temperatures will limit the top speed of the 'e-drive' only mode. After driving with the ICE for a good 30 minutes (so sufficient time to warm up) at 70 mph, I thought I'd try and use up some battery before my destination. Activating e-drive at 70mph would start it for a few seconds then immediately present 'drivetrain not available' (or something similar) before reverting to ICE. Dropping speed to 60mph and activating e-drive worked fine. So this is clearly speed dependent and probably a safety mechanism.

1B. The ICE is temperature dependent too. After a good 30 minutes of using largely just the ICE in sports mode (temperature yesterday was 0.5 C) - I reached the motorway after some country lanes. Normally 1st goes from 0-25mph ish, and 2nd goes from 15-55mph, 3rd onwards from this. 2nd refused to go any higher than 47mph, when I tried to manually override it in sports mode with the paddles. Perhaps not warmed up enough, but this surprised me of how long it would take...

2. There seems to be a lot of conflicting views on what activates 4WD mode. A lot of people seem to be under the impression 'hold state of charge' and sport mode activate 4WD mode and all wheels at the same time. I am under the impression that you cannot engage and powder all 4 wheels permanently (but would love to see this proven with a car driven on dyno/ramp).

From what I gather the 4 wheel drive system is not active unless in boost mode or slipping is detected (regardless of sport or comfort) and I don't think that at low speeds/low power all 4 wheels receive power. I think the front wheels only kick in during comfort/sport when the inner ring glows blue with boost.

In the snow yesterday, doing a sharp right turn immediately flicked out the back end with a ton of oversteer. Not especially reassuring in the snow (for those that feel reassured by 4WD). My observation is keeping it in sports mode means that the electric motor can kick in when there is some slip detected but I'm not convinced of how effective this in snowy conditions, it feels still largely rear wheel driven and not that grippy. Then again I have summer tyres on and have no professional training.

3. There is an advantage to still being in sport/hold state of charge, and that is that at speeds < 63mph (where it resorts to EV mode), it keeps the engine on, which means that in the chance of slipping, the electric motor can provide some power to front wheels.

If you use only comfort mode and no hold state of charge, the ICE appears to activate on slippage (although I have limited observation of this).

4. There is no reverse gear for the ICE. Reverse comes only from the electric motor. If you drive into heavy snow, and try to reverse, you could get stuck (like I nearly did) as power only comes from the front wheels.

5. Comfort mode goes to 63mph under normal conditions, but it is not a hard limit, rather dependent on engine load. Going down hill, I have seen this go as far as 66/67mph without activating the ICE.

6. Comfort mode provides a higher gear ratio than the e-drive in electric only. E-drive uses 1st gear, whereas comfort uses 2nd gear. Those that are cruising at steady speeds (such as a roads/motorway) and want to use electric only, will increase range quite a lot by not activating e-drive and using only comfort mode. Fine for commuting, not great if you need to go above 63mph..

There are several videos of the i8 playing in snow - winter tyres probably help a lot!

funny you write that. I drove my Roadster for the 1st time in a while yesterday. Was VERY cold. Struggled to engage pure electric mode.

Stayed in 'comfort' for a while and petrol engine kept running all along which is not common.

My original 2015 never did that. Only cold temp downside was reduced range. LCI seems to be a lot more sensitive in its modus operandi

[MolarBear]

In the UK it's not mandated to use winter tyres, and we only get really bad snow a few days in the year! Might have to get a spare set of wheels though with winters on, sounds like a good idea!

[thesubmitter]

seems like 7 degrees celsius is the point where the tires are less grippy

https://driving.ca/auto-news/news/ho...s-winter-tires

[stressdoc]

Snow tires are a no-brainer. But get high speed rated ones or you risk crashing in good weather or rain. E.g., Pirelli Sottozero 3 in square 245/35/21

[stressdoc]

Also, in regard to algorithm for transmission at different temperatures, safety/control factors limit shift points -- it is not just engine warm-up.

Excellent OP.

[MolarBear]

Originally Posted by stressdoc

Also, in regard to algorithm for transmission at different temperatures, safety/control factors limit shift points -- it is not just engine warm-up.

Excellent OP.

Thanks! Another quirk I have noted a few times now - if going for it in first gear (manual override, sports mode) it will sometimes skip second gear and jump straight to third, and you cannot change back down unless you take your foot off the accelerator and slow down. Not sure if anyone else has this?

[F5506m]

I have winter tires on my i8 and a very steep hill exiting my driveway. If there is snow on the ground and I keep car in comfort mode the car will lose traction/slip (I can feel the front wheels slipping), the ICE will kick in and the car will make it up safely. I assume the ICE is used to sen power to rear wheels, as by default in comfort mode the front wheels only have power under electric. If i engage sports mode before climbing the hill the car will not skid and make it up safely. This leads me to believe the at least at lower speed sports mode activates 4WD. Electric power front wheels and ICE rear wheels.

[tommyb13662]

Originally Posted by MolarBear

5. Comfort mode goes to 63mph under normal conditions, but it is not a hard limit, rather dependent on engine load. Going down hill, I have seen this go as far as 66/67mph without activating the ICE.

6. Comfort mode provides a higher gear ratio than the e-drive in electric only. E-drive uses 1st gear, whereas comfort uses 2nd gear. Those that are cruising at steady speeds (such as a roads/motorway) and want to use electric only, will increase range quite a lot by not activating e-drive and using only comfort mode. Fine for commuting, not great if you need to go above 63mph..

There are several videos of the i8 playing in snow - winter tyres probably help a lot!

Here in the USA my 2016 i8 in e-drive hits a 75mph cut off (no matter the weather or snow). In e-drive only at I have seen it display 77mph on flats. It will accel only to 75 it seems. You feel a cut off of in power when it hits 75mph. I know the electric motors are limited to 115-120ish Horsepower but it can accel just as fast as most other cars on the road from a stop. As long as the front tires don't slip. When they do slip the power cut is very harsh and not well tuned IMHO. The cut and then return to power is much more jerky and not nearly as smooth as most EV I have tried.

[dfer]

Originally Posted by MolarBear

4. There is no reverse gear for the ICE. Reverse comes only from the electric motor. If you drive into heavy snow, and try to reverse, you could get stuck (like I nearly did) as power only comes from the front wheels.

My experience differs. While reversing in to my garage with the front wheels spinning on the icy surface outside, after a while the ICE started and pulled the car in nicely. Not sure why it didn’t start as soon as the fronts started spinning though.

[stressdoc]

Originally Posted by dfer

My experience differs. While reversing in to my garage with the front wheels spinning on the icy surface outside, after a while the ICE started and pulled the car in nicely. Not sure why it didn’t start as soon as the fronts started spinning though.

Interesting! We need more examples/experiments to sort this out.