Rally Discussion and Bar Talk Thread

[WRCStan]

The big question is whether you need to have artificial gears like that mode in Ioniq 5N. If so it could again be set in the rules.

The bigger question is who's buying them, and are we likely to be seeing these at all at the end of this decade.

[saco0o]

another thought I had reading the dirt fish article with msport about the non hybrid car. he said that evs went on a high (sells? perception?) and now are declining and hybrids are going up. at the same time is super normal to find daily articles on how much evs are growing (in sells and perception) passing hybrids for new cars. u'know? we can find both arguments nowadays. its such a mess. we probably can find data showing how both evs and hybrids are outselling each other on the same journal. everything is so weird and contradictory nowadays, all the time.

[Mirek]

Why do you keep repeating this when it is clearly wrong?

Current technology EVs can do the current WRC stages just fine. Refueling zones are set up completely arbitrary and have no effect on spectator experience.

At the extreme you could do 10 min charges at the end of each stage. With current gaps that would mean 4 cars charging at the same time. Lets say they charge at 360 kw which is mainstream tech today and you get 60 kwh charged. That is enough for 150 km road section minimum or a normal stage and some 50 km road section.

If you have 10 cars total in top class the charging station would need some 700 kwh capacity total, should be roughly 2-3t. So the charging station could be on a small truck, no need for trailer.

I say again why do you keep repeating that this is impossible?

I have never said an EV rally car can not do a rally loop distance. The problem is that it can not be competitive to WRC cars at the same time.

Let's say you take a car with 60 kWh battery. That is about 250 kg without cooling. What percentage of the energy can be recuperated in rallying? Formula-E does about 40% but that is impossible in rallying, especially on gravel. Let's say it can be 20%. That means you have realistically 1,2 * 60 =72 kWh. How far can WRC go with 72 kWh (I count the powertrain to have 100% efficiency for simplification)? Hard to say but we can simplify the question by setting the loop as long as a petrol tank allows. Just for comparison.

If we go by the petrol Rally2 cars (to avoid the effect of hybrid which is too complex to estimate) we can count that 80 litres equals 60 kg of petrol which is 780 kWh of energy. The petrol engine has much lower efficiency. How much? An average turbocharged petrol engine has about 40%. WRC engine will have probably less due to the use of anti-lag and also the mechanical drivetrain is less efficient. Let's say that it's total 25% which might be too low. That means the Rally2 car in my example has 195 kWh of usable energy available. How much does en empty rally fuel tank weight? I don't know but it's a soft bag. Let's put it filled at 100 kg which might even be too much. The racing battery needs massive cooling otherwise it can not discharge and recharge high power. In formula-E the battery alone creates about 60% of the battery pack total weight, that makes our battery pack about 400 kg heavy and it contains about 1/3 of usable energy compared to the fuel tank of the Rally2 car which is 4x lighter.


If we use the same average power with both cars (I counted the effect of recuperation into usable energy value already) we need in theory more than 3x total battery capacity for one fuel tank. What C-rate is used for race battery charging? I don't know. Normally the very best batteries allow 4C not to damage the battery but that applies only for 20-80% of the charge level, not for 0-100%. That would destroy the battery. It means we can use only 60% of the battery capacity for the fastest charging. That is only 36 kWh available for the fastest charging. The good thing is that with 4C you can recharge that in 9 minutes which looks great. The bad thing is that 3x quick recharging is not enough to finish the loop a fully-filled petrol rally2 car can finish.

But that's not all. As we saw our EV has 300 kg extra weight for the 60kWh battery. It will definitely need to deliver more power than the Rally2 to be as fast. In fact it will need a lot more because its weight will punish it badly in cornering speed and maybe even in braking (the recuperation will help here but I don't know if enough). This hypothetical example fits with the reality where an EV Rally2 car with similar battery to my example was clearly slower than the Rally2 cars.

But the worst thing is that this example compared with Rally2 not with WRC. WRC cars are about 2 s/km faster than Rally2 which means that among other things they need a lot more power. The equation to give them enough energy onboard in batteries to allow them to be so powerfull to overcome the weight punishment coming with the larger battery is unsolvable at the current tech level, at least at some realistic price tag.

Hence why I repeat my stance that the only way how to make EV competitive in rallying at the currect tech level is to give them an energy source with far greater density - in serial hybrid it's the petrol which carries about 50x more energy per kg than the best batteries. Anyway Audi won Dakar while the pure EVs have achieved exactly nothing in rallying.

PS I am well aware that there is a lot of guessing in my post but a mistake in the range of 10-20% doesn't change the resume.

[becher]

I don't see why recuperation would be a performance benefit, the limiting factor under braking is grip not power of the brakes no?

[Mirek]

I don't see why recuperation would be a performance benefit, the limiting factor under braking is grip not power of the brakes no?

There are more factors but the most important one (especially whe you count the whole stage) is the power you can take away from the brakes, i.e with normal brakes the heat you can dissipate. Recuperation takes away huge amount of heat.

[mknight]

Direct quote:

Serial hybrid is the only way an EV can do a WRC event on the current technological level but nobody seems to be interested in it.

"Can do" - is able to run or finish.

Nothing about speed.

You know that 1990 group A car would get beaten by 1986 group B car. 2013 Fiesta WRC would get beaten by 2008 Focus WRC on most rallies etc.

Ironically the epic looking and sounding group B car would also get beaten by even WRC car from 2003 on most rallies due to much better suspension and traction.

Speed does only matter inside own class, spectacle matters more. In terms of EVs the car could be more spectacular out of corners especially slow corners but will obviously lose time in faster corners and braking. (Kinda exact opposite of an S2000).

If EV rally car can deliver more spectacle than current Rally2 it won't matter if its only marginally faster. Some 0,5-1s/km faster than current Rally2 should be possible even by your rough numbers.

To make Rally EV spectacular it needs to have much more power even at the expense of much more weight. Not be "similar" to petrol cars. So more like the NitroRX cars than the 360 hp RX2e cars.


With regards to the numbers you don't seem to take away the extra weight of the petrol engine as well as some related bits like center diff and much bigger gearbox. But if we instead assume a bigger battery the weight difference would likely be about the same.

For comparison current Taycan and Ioniq 5N will do over 50 km (over 2 laps) at Nurburgring at max push before the batteries overheat with battery capacity to spare. In a racing car cooling could obviously be increased.

[mknight]

The bigger question is who's buying them, and are we likely to be seeing these at all at the end of this decade.

another thought I had reading the dirt fish article with msport about the non hybrid car. he said that evs went on a high (sells? perception?) and now are declining and hybrids are going up. at the same time is super normal to find daily articles on how much evs are growing (in sells and perception) passing hybrids for new cars. u'know? we can find both arguments nowadays. its such a mess. we probably can find data showing how both evs and hybrids are outselling each other on the same journal. everything is so weird and contradictory nowadays, all the time.

Manufacturers as well as public try to extrapolate what people will buy and manus will make in 10 years based on a few months of sales differences.

That can bring totally crazy results both ways. Some people (often outside of automotive) predicted that everyone will only buy EVs in 5-10 years. Similarly some people (often those that have 0 EV experience) predict that there won't be any EVs in 5-10 years.

The result will be somewhere in between. If regulations stay about the same I expect something like 50/50 for BEV vs others (incl Hybrids) in Europe in 10 years. Here in Norway it's 80/20 for quite some time now and I don't see it changing more than 5-10 percent either way.

What is mentioned in the Dirtfish article is that right now (last 3 months) EV sales globally have slowed down, so some manus found out that they might not have anything (new) to offer outside of EVs in the very near future and are re-routing some money to other drivetrains. Whether that is temporary fix or permanent is close to impossible to predict at the moment.

[Rallyper]

Within 10 years there´s not much EV´s sold at all.

Hydrogen engines will rather rule.

[Fast Eddie WRC]

Capito's against pure EV in rallying (mostly due to no noise)...

https://dirtfish.com/rally/wrc/capit...electric-cars/

[skarderud]

Within 10 years there´s not much EV´s sold at all.

Hydrogen engines will rather rule.

Well, in a climate that it is in norway and sweden, i doubt hydrogen is the solution.
Its steam that comes out, you don't need much fantasy to understand how 20.000 cars in the morning and the temperature is below 0 will "adjust" the griplevel on the road.

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