stafford1500 said:
frenchyd said:
The torque of an EV is going to be brutal under acceleration. Because unlike an internal combustion engine ( can I use ice? To describe the engine and ICE to describe frozen water). it makes peak torque at zero rpm.
That means acceleration away from corners will be equivalent to a big block at 4800rpm. Powerful cars in ice racing don't win because they quickly tear out the allotted studs.
But there are a lot of superficially damaged EV' s in Junkyards. And they sell cheap. Exactly what should be a winning car.
The advantage of massive torque from electrics is "fixed" on low grip surfaces by the use of traction control. Electric traction control is MUCH easier than internal combustion, since it only needs to control current to the drive motor. So, even though there is a lot of torque available, only what CAN be used is applied.
The only issue is that it would have to be a pretty smart traction control. Max acceleration happens at a certain level of slippage, and that level is higher on looser surfaces. It is on the order of 10% on dry pavement depending on tire construction.
If it cuts power to zero slippage then other people will walk away from you.
I still have questions with respect to the drivetrain inertia of an EV. I honestly do not know what they are. If it is like having a heavy flywheel then it makes regaining traction more difficult.
Pete. (l33t FS) said:
I still have questions with respect to the drivetrain inertia of an EV. I honestly do not know what they are. If it is like having a heavy flywheel then it makes regaining traction more difficult.
Unless you use all of the fancy capabilities you get from an inverter driven electric motor to just power the driveline to the correct speed, rather than simply reducing power and waiting for the speed to drop off.
As long as you have a good vehicle speed reference (easier to come by on a 2wd vehicle), it should be possible to have nearly perfect traction control with an EV. In other words, program it to maintain a certain percentage of wheel slip when the pedal is at full travel and you can just put your foot down and let the car do its thing. If it's set to 10% slip, the system would be driving the wheels to current vehicle speed + 10% with however much power it takes to maintain that, rather than just blindly increasing power until things slip and then cutting back. Because you'd never just spin the wheels up to an excessive speed and have to re-gain traction from that situation, drivetrain inertia starts to have a much smaller effect on managing your grip for acceleration.
Looking into the wheel slip controls on AC traction locomotives should give an idea of what can be done.
In reply to rslifkin :
That is a good analogy, thanks. Steel on steel tolerates zero slip so traction control and ABS are problems they ran into first.
Another thing I forgot to mention is that because EVs have regen braking, if you do manage to get the drivetrain spinning too fast, you can easily brake it down to a lower speed (much more quickly than you could do with engine braking from an ICE).
In reply to Pete. (l33t FS) :
To me, the driver should experiment with the various driving modes to see which one works best- the difference between the are how much slip is targeted for best traction. Modern ICE systems are really quick, and based on the time lag to torque, EVs will be quicker to react.
Still, this whole though experiment is keeping the OP from making progress on the quad turbo jag with MS control.
I'll still take a light ICE engined ice racer over a bloated pig no matter how much power it has.
Each stud can only generate a set amount of grip to do the entire friction circle so what you "might" gain in one area you are going to lose in another.
My sub 1500lb 90hp fwd tercel ice car gains many many car lenghts under braking and thru most of a long sweeper on the typicsl imprezza,only place it loses out is off the corner.
Lap times are pretty much the same.
Now my sub 1800 lb true mid engined awd geo metro was in the supercar league agaisn't the rest of the awd subarus despite only having 150hp fed thru ALOT of heavy chain for the drive setup.
Like lap them all min of once some twice in 12 short laps.
frenchyd said:
Pete. (l33t FS) said:
Note that on that certain Audi/sports drink promotional video with the electric SQ, they noted that the biggest problem they had was destroying tires, and this was with an endeavor where they were more concerned with spinning the tires on pavement than going fast on ice!
I have no answers, but I find discovering the questions to be interesting.
One of the reasons I like playing with rotaries on dirt is the low inertia makes it easy for the tires to regain grip if you want them to, with little engine braking to swing the slippage the other way. I have only driven powerful EVs (all Model 3s) in normal city operation, so I have no idea what their characteristics are when the tires slip. The other EVs I have driven were GEMs which couldn't break the skin on a pudding.
Driving a dirt sprint car can be the same thing. Dry dusty track with visibility near zero. If you wait for traction to catch up to your tires. You'll be eating a lot of dust. So you floor it.
This is racing. No 1/2 measures.
Actually in dirt racing when it goes dry slick or black you have to learn how to drive slower to go faster. Fir some this can be difficult to master but most winning drivers do.
re: drivetrain inertia, for quick reference here are a couple random actual components to compare (TLDR: electric motor has comparable inertia to an ICE flywheel, not including crankshaft or clutch. I would assume gearbox/transmissions are going to be similar for the two).
online rotational inertia calculator
I keep using Leaf stuff for reference b/c when they first came out people did tons of teardowns and published the numbers.
Yeah I think EVs are cool, but they are not perfect esp. for race applications. Mostly I am highly allergic to myths, bad assumptions, and BS.
kevlarcorolla said:
In reply to frenchyd :
There is EVERYTHING wrong with using another car to do your braking and turning.
And believe me,the added weight helps NOTHING in ice racing same as every other motorsport.
ICE racing is impossible to prevent contact between cars. So it's not punished. ( unlike vintage racing where contact of any sort is absolutely forbidden )
Ruts in the lake are as much as 18 inches deep. ( they are filled overnight by simple drilling a hole until the lake water floods in ) But may be covered completely with snow and thus invisible.
In addition the boundaries of the track are constantly moving. A pack of cars will change the track location by 15-20 feet per lap.
Some events will change the track from Saturday to Sunday to minimize ruts ( a few hours with the snow plow is all it takes).
In reply to frenchyd :
You clearly implied it was fine to plan on using the other cars not accidental contact.
We only run street legal studs now so very low grip,yet somehow we managed to race this hard contact free.
https://youtu.be/TFIvlaxjpV0
In reply to kevlarcorolla :
Yes deliberate crashing into another car will get you black flagged for a discussion with the stewards. However rubbing is racing seems to be the common approach.
Look at NASCAR cars after Martinsville .
kevlarcorolla said:
We only run street legal studs now so very low grip,yet somehow we managed to race this hard contact free.
https://youtu.be/TFIvlaxjpV0
I'm not sure what you mean by street legal. Most states don't allow studs.
But back when they were allowed.
That might be the answer.
There would be added grip but not the tearing out studs type of grip. That the washer type of stud gives.
Do you guys have a limit as to how many studs you can run?
Any problem finding tall skinny tires for modern wheels?
I notice you guys were a lot slower than the fast groups that we run with. Are roll bars ( cages) required?
I'm not sure how I'd put a cage or even a roll bar in a Tesla. You can't rest it on the battery pack or even weld near it. Weld it to the sides? With cross bars already welded in?
MotorsportsGordon said:
frenchyd said:
Pete. (l33t FS) said:
Note that on that certain Audi/sports drink promotional video with the electric SQ, they noted that the biggest problem they had was destroying tires, and this was with an endeavor where they were more concerned with spinning the tires on pavement than going fast on ice!
I have no answers, but I find discovering the questions to be interesting.
One of the reasons I like playing with rotaries on dirt is the low inertia makes it easy for the tires to regain grip if you want them to, with little engine braking to swing the slippage the other way. I have only driven powerful EVs (all Model 3s) in normal city operation, so I have no idea what their characteristics are when the tires slip. The other EVs I have driven were GEMs which couldn't break the skin on a pudding.
Driving a dirt sprint car can be the same thing. Dry dusty track with visibility near zero. If you wait for traction to catch up to your tires. You'll be eating a lot of dust. So you floor it.
This is racing. No 1/2 measures.
Actually in dirt racing when it goes dry slick or black you have to learn how to drive slower to go faster. Fir some this can be difficult to master but most winning drivers do.
I think you are thinking of racing in the rain. There throttle control keeps the tires from blowing off what traction there is..
The track is fastest when it's rubbered in. Traction is much better rubber on rubber than rubber on dirt.
I've carried the front tires off the surface Using just the stagger to keep the car turning left. Stagger is the outside tire being much taller than the inside tire.
I'll lay that outside tire against the berm and "steer" using the throttle. More throttle it turns harder left. Lift and oops you're heading to the wall plus your front tires come down so when they contact you hope they are pointed in the right direction.
As crazy as that sounds it becomes second nature to you.
In reply to frenchyd :
The majority of states allow studs these days. Many didn't for a while, then started allowing them again. NY is 10/16 through 4/30 for studs on public roads, for example.
There's a full list here: https://www.autotrader.com/car-tips/studded-tires
In reply to frenchyd :
I'm in Ontario,we build our track in a field so with the lack of real winters the last decade or so we've had to make changes to preserve the track.
We have a max of 19 studs per foot with max of 2 mill projection.
Before that we allowed Menards,before that homebuilt tires using purpose built ice race studs.
They went thru the tire with a fender washer and nut on the inside,only way they came out is if the stud broke...very very rare.
Keeping the street studs in the tire is a big challenge,I can get about 3 seasons from a pair on the front before the rubber tears and the studs start to go missing.
Technically we don't use "street legal" studs as we use 12m long rally studs from the people that build the world rally ice tires.
I have a light car and drive it with compassion for the studs,most awd guys go full Ken Block and complain about stud loss every weekend.
My tercel has a win ratio over 95% across 5 seasons so its a good benchmark of what works.
In reply to frenchyd :
I believe AMEC in upstate NY has a strict no contact policy. Touch and you're done. Not too hard to do if you know what you're doing. There's no need for contact to race, even on ice. Poor excuse for lack of car control skills.
frenchyd said:
MotorsportsGordon said:
frenchyd said:
Pete. (l33t FS) said:
Note that on that certain Audi/sports drink promotional video with the electric SQ, they noted that the biggest problem they had was destroying tires, and this was with an endeavor where they were more concerned with spinning the tires on pavement than going fast on ice!
I have no answers, but I find discovering the questions to be interesting.
One of the reasons I like playing with rotaries on dirt is the low inertia makes it easy for the tires to regain grip if you want them to, with little engine braking to swing the slippage the other way. I have only driven powerful EVs (all Model 3s) in normal city operation, so I have no idea what their characteristics are when the tires slip. The other EVs I have driven were GEMs which couldn't break the skin on a pudding.
Driving a dirt sprint car can be the same thing. Dry dusty track with visibility near zero. If you wait for traction to catch up to your tires. You'll be eating a lot of dust. So you floor it.
This is racing. No 1/2 measures.
Actually in dirt racing when it goes dry slick or black you have to learn how to drive slower to go faster. Fir some this can be difficult to master but most winning drivers do.
I think you are thinking of racing in the rain. There throttle control keeps the tires from blowing off what traction there is..
The track is fastest when it's rubbered in. Traction is much better rubber on rubber than rubber on dirt.
I've carried the front tires off the surface Using just the stagger to keep the car turning left. Stagger is the outside tire being much taller than the inside tire.
I'll lay that outside tire against the berm and "steer" using the throttle. More throttle it turns harder left. Lift and oops you're heading to the wall plus your front tires come down so when they contact you hope they are pointed in the right direction.
As crazy as that sounds it becomes second nature to you.
In dirt racing the track is fastest when it's tacky and there is moisture in the track. When it goes dry slick you have less traction and can be like driving on ice depending on how rubberd in it gets.
frenchyd said:
....
I'm not sure how I'd put a cage or even a roll bar in a Tesla. You can't rest it on the battery pack or even weld near it. Weld it to the sides? With cross bars already welded in?
Putting a cage in a Tesla is absolutely impossible, and no Tesla has ever been entered in any race. 
edit to add something maybe actually useful:
Model Y's do have the battery cover as the structural floor of the interior ( teardown vid1, vid2), but all the other Teslas (and EVs in general) still have a sheetmetal floor with door sills etc. like any other unibody. Anyway, I think typically a roll cage is not attached to the middle of the floor? Teslas with aluminum front/ rear gigacastings will have more difficulty with mounting points for a cage, but that is true for any aluminum unibody or composite monocoque and has nothing to do with electric vs. combustion.
weld-in installation of a cage in a Model 3
one company selling weld-in or bolt-in cages
DIY cage: Design and fab
Putting a cage in a body-on-frame vehicle is going to be pretty much the same, whether it is a car from the 60's or an EV with 'rollerskate' construction.
