I understand where you are coming from, but can tell you from experience building race cars that even when the external unit design is not there to shed heat flowing air vs stagnant air makes a big difference in overall heat soak
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MASTER THREAD: Comprehensive Road-Course Modification Guide — Optimizing the 3 for the track
- Thread starter MasterC17
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We will be at the track tomorrow doing logging for you all to geek out
The only thing that matters is the data and results, so I look forward to seeing them!
Data, data, data!We will be at the track tomorrow doing logging for you all to geek out
The nerds in all of us are chanting. Thanks MPP, keep the info coming.
Hello guys, let me introduce myself, I'm Luca and I organize races in Europe.
We are working on a project with the Tesla Model 3 and, at the moment, the only doubt we have is precisely this of overheating and falling performance.
I ask you some questions, it can help our study of the problem (we are obviously also doing some tests on the track and we will share the results with you).
I state that we already know that SOC causes a drop in performance when it il low, but this does not worry us, because it will be standard for each driver and constant during the race.
1- Is it clear from your data that the problem is exclusively the overheating of the rotors? Have you precisely seen that the power changes at the same SOC with different rotor temperatures?
2- Does anyone have a clear table of the temperatures reached after a session on the track? For example: battery cells 50 °, 95 ° rotor F, 120 ° rotor R etc.
3- Can anyone tell me how much is the loss in lap times at 50% of the battery (without overheating, therefore with "green" battery in track mode)?
4- I saw that an oil cooler was tested ... do you know the results?
5- Considering that the main coolant remains under control, Could it be a good idea and perhaps decisive to change the stock oil-water heat exchanger to a Racing one? Has anyone tried?
We are working on a project with the Tesla Model 3 and, at the moment, the only doubt we have is precisely this of overheating and falling performance.
I ask you some questions, it can help our study of the problem (we are obviously also doing some tests on the track and we will share the results with you).
I state that we already know that SOC causes a drop in performance when it il low, but this does not worry us, because it will be standard for each driver and constant during the race.
1- Is it clear from your data that the problem is exclusively the overheating of the rotors? Have you precisely seen that the power changes at the same SOC with different rotor temperatures?
2- Does anyone have a clear table of the temperatures reached after a session on the track? For example: battery cells 50 °, 95 ° rotor F, 120 ° rotor R etc.
3- Can anyone tell me how much is the loss in lap times at 50% of the battery (without overheating, therefore with "green" battery in track mode)?
4- I saw that an oil cooler was tested ... do you know the results?
5- Considering that the main coolant remains under control, Could it be a good idea and perhaps decisive to change the stock oil-water heat exchanger to a Racing one? Has anyone tried?
I'm hoping MPP are going to give us some data from their tests, but meanwhile here's a some from a track day I did yesterday. I thought there wasn't oil temperature data from the CANbus, but having looked again it appears there is an oil temperature reading from either the oil itself or the pumps. Maybe someone can verify where the sensor is in the drive unit?
Anyway, this is an 8 lap session showing the stator temperatures and oil temperatures from the front & rear drive unit. These are relatively short laps (1.2 miles) but I'm on full throttle about 50% of the time so 6 or 7 laps in I usually see the battery graphic turning orange and feel the power drop. What I was interested in here was how quickly the stator temps drop relative to the oil temps and also whether the oil lookd like it's doing a good job of keeping the stators from getting too hot.
Anyway, this is an 8 lap session showing the stator temperatures and oil temperatures from the front & rear drive unit. These are relatively short laps (1.2 miles) but I'm on full throttle about 50% of the time so 6 or 7 laps in I usually see the battery graphic turning orange and feel the power drop. What I was interested in here was how quickly the stator temps drop relative to the oil temps and also whether the oil lookd like it's doing a good job of keeping the stators from getting too hot.
Interesting .. but honestly I don't find them good data. The oil temperature (if it is really this) is really very low, it means that the problem is not overheating of the liquid (which can be solved) but probably due to "stress" of use, so I'm afraid it could be a technical limit .
Can you make a graph for each engine (one front and one rear) with this data:
- Battery cell temperature
- Rotor temperature
- Oil temperature
- Water temperature (although I think it's not essential)
- Power absorbed by the rotor
With this in my opinion it is possible to identify exactly the threshold and what the limiting factor is. Of course, if it is the rotor temperature with the oil already at 40 ° I think nothing can be done ...
Between lap 1 and lap 7, so BEFORE overheating, what is the drop in performance and the drop in SOC?
Can you make a graph for each engine (one front and one rear) with this data:
- Battery cell temperature
- Rotor temperature
- Oil temperature
- Water temperature (although I think it's not essential)
- Power absorbed by the rotor
With this in my opinion it is possible to identify exactly the threshold and what the limiting factor is. Of course, if it is the rotor temperature with the oil already at 40 ° I think nothing can be done ...
Between lap 1 and lap 7, so BEFORE overheating, what is the drop in performance and the drop in SOC?
I have to cross reference data from track mode to tell you that, which I will do a bit later. I only recorded temps in SMT yesterday. I'm sure MPP will have much more comprehensive data they can share....
OK thanks.
Is the feeling when the battery turns "red" a sudden drop in power or is it gradual as it warms up?
It is gradual power loss, both with the SoC running down and the temperatures getting higher.
If you are thinking of running 10-lap sprint races, I believe it could work with the cars in their standard state. The drivers would learn how to manage the power loss and with more driving skill could carry more speed and use less throttle, leading to lower temps and less power drop. It could become a strategic part of racing these cars.
I also don't think spectators would notice so much the cars losing power. The racing would still be good and the lap times might be a few seconds slower, but it wouldn't be like the cars had all gone into limp home mode. Longer races would need more thought and probably some mods to help with cooling.
In fact, SOC is not a problem, the loss is constant and will be the same for all participants. Overheating, as far as I understand, causes a much more significant drop in performance and is difficult to manage with the strategy (accelerating slightly less is not enough to lower the temperatures it seems, but you start to lose many seconds per lap). Also there are more variables for overheating.
It is not a problem to make changes to the car (they will not be standard cars
..) the problem is if the solution does not exist because the overheating is due to stress and not caused by the increase in oil temperature.
Overheating isn't an issue in all situations. It's going to depend a lot on the length and type of circuit you plan to race on and how many laps duration the races are.
Quite a few owners here track their cars on long, fast circuits and in high ambient temperatures, so you'll see the battery graphic turning orange after just a couple of laps, but even then the loss is only affecting straight line speed, not speed through the corners.
Yesterday, I drove a 7 or 8 lap session and my last lap time was still very close to my first, even though the battery graphic was red at the end. If you were to stick to short circuits to begin with you can then put on some good races and gradually develop the cars to cope with the longer, faster circuits. 10 lap races are well within the capability of the stock cooling system IMO.
Quite a few owners here track their cars on long, fast circuits and in high ambient temperatures, so you'll see the battery graphic turning orange after just a couple of laps, but even then the loss is only affecting straight line speed, not speed through the corners.
Yesterday, I drove a 7 or 8 lap session and my last lap time was still very close to my first, even though the battery graphic was red at the end. If you were to stick to short circuits to begin with you can then put on some good races and gradually develop the cars to cope with the longer, faster circuits. 10 lap races are well within the capability of the stock cooling system IMO.
If you are running a spec series, it doesn't really matter given everyone will likely be in the situation.
Sorry to burst your bubbles, but there is no way you can lap close to what you can do lap 1 on a lap 5 unless you blew lap 1 or 2 in a stock car. Maybe it is possible in a tiny <1 mile track, but the power is down every lap. You can make up the few tenths with your driving on lap 2, but there is no way to make up a deficit of 50HP+ by lap 3 or 4. I did two hot laps, 1 cool down, 1 hot, 1 cool and 1 hot. The power simply wasn't there.
If you add all the numbers, you will see 3.5-4.5 miles is what you really get out of the car before the power comes down and turns it into a normal sedan.
I did leave time on the table as I gave up after feeling the loss of power, but I wasn't making up 4 seconds.
Sorry to burst your bubbles, but there is no way you can lap close to what you can do lap 1 on a lap 5 unless you blew lap 1 or 2 in a stock car. Maybe it is possible in a tiny <1 mile track, but the power is down every lap. You can make up the few tenths with your driving on lap 2, but there is no way to make up a deficit of 50HP+ by lap 3 or 4. I did two hot laps, 1 cool down, 1 hot, 1 cool and 1 hot. The power simply wasn't there.
If you add all the numbers, you will see 3.5-4.5 miles is what you really get out of the car before the power comes down and turns it into a normal sedan.
I did leave time on the table as I gave up after feeling the loss of power, but I wasn't making up 4 seconds.
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You need to realise not everywhere is the same as America. As I said above, if an event is run at a short circuit, it is absolutely possible to run 10 laps and still be putting in decent lap times at the end.
Not if you run at an F1 circuit, I agree.
If I was organising a race series for Model 3s in Europe, I would stick to the shorter circuits first and build it from there. It will get better as the technology and aftermarket mods improve, but right now it could be done if you select the venues carefully.
I confirm, they will be short circuits and without long straights, and I confirm that the performance degradation given by the SOC is not a problem. Also because, honestly, a Model 3 with the modifications we want will be faster than almost all touring cars even when the lap time is 3/4 seconds slower.
The real problem, as I said, is to understand how much of this loss of performance is given by the temperature and how much by the SOC, to understand what the real potential will be once the overheating is resolved (with racing components).
Mattak, for example, laps 1, 2, 4 and 6 were all done with the "green" battery in the track mode?
If you can tell, what track were you on?
Exactly. Even when the drive units are hot and power is reduced, these cars still lap faster than most other cars on any track day I've been to and the spectators won't see much of a difference either.
We can look at numbers all day long and complain about not having as much power on lap 10 as lap 1, but as long as there is some sort of equivalency the racing will still be good.
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