Back to VIR with Two 3's - MPP BBK - Prototype Radiator

[MasterC17]

I brought the two Model 3's back to VIR last weekend. The weather was excellent, and the cars performed superbly.

I set PB's in both cars. 2:08.08 in the Black Model 3 and 2:08.8 in the Red Model 3. I left a second or two on the table in the Black car, but had a lot less open track to work with. The tires are also at the end of their life, so that is slowing me down some.

The Red Model 3 had been fitted with the MPP.R StopTech STR-60 BBK. It was paired with Raybestos ST-45 Pads and fresh Motul RBF600 brake fluid. Braking was far superior to the stock setup. The pedal was firm and consistent throughout the day, and inspired a lot more confidence. Braking was quick and linear during deceleration, no more squishy pedal or delayed responses. No overheating occurred, and they look pretty awesome too! Street manners are quite nice, they don't make any strange noises and they shouldn't require frequent rebuilds. Overall, a highly recommended upgrade for anyone seriously tracking their 3!

As some of you know, I installed a prototype radiator into the Black Model 3. It performed well - no leaks, and it did its job. It did not resolve the power current reduction issue entirely, though it helped some. When comparing the two cars back to back, drive unit inverter temperatures were roughly 8% less (peak), and the car was able to be driven ~20% longer before current was pulled. There is still work to be done, and work has begun on some more modifications to improve this. The ultimate goal would be to eliminate this problem entirely so we can enjoy full sessions like those ICE cars.

Overall, I continue to be amazed at how well the Model 3 handles. It can keep up with basically anything in the corners. You would never guess it is so heavy given how agile it is. I did find a 45/55 bias to be the sweet spot for my driving style. 50/50 resulted in a little bit of understeer, and 40/60 resulted in a little bit of oversteer. Traction is set to -10. I played around with reduced regenerative braking but it didn't seem to help the power current reduction much and did result in the battery consumption increasing even more. At 100% regen braking I am at about 1,500wh/mi, at 75% that increased to about 1,650wh/mi.

The weak spot of the Model 3 continues to be speeds over ~110mph. Up to that point, there isn't much that will pull on it, but the Corvette's, 911's, and other high horsepower cars pull away quickly as speeds increase. VIR is a high speed track where the car would benefit from a 2nd gear, but it is what it is.

Along with solving the power current issue, I am looking to put in some lightweight seats this offseason and some R-Compound tires. I believe a sub 2:05 at VIR is very achievable at that point. After that, we may need to go Plaid for some sub 2:00 laps.

Here is my 2:08.08 in the Black Model 3:

And the 2:08.8 in the Red Model 3, with some 911 Turbo overtaking included:

 

[BiffSpiff]

Love your write ups.

I hope that Tesla recognizes you value as a brand ambassador.

I’m waffling on getting a Model 3 Performance, but your vids are pushing me to just place my order.

 

[Caynan]

Awesome post/videos. I am really interested to follow your progress on cooling, this really seems to be the car’s Achilles heel. That and charging at the track, but that’s more of an infrastructure issue.

 

[Vines]

Great work there, and that is quite a fast track, seeing up to 145 is quite fast! I'm excited to go out to Laguna this coming Tuesday for a track day.

I wonder if you can start dialing back the regen to reduce heat in the pack as well? I imagine once your friction breaks are good enough the extra heat of the regen charge might not be worth it?

 

[Dolemite]

Great work there, and that is quite a fast track, seeing up to 145 is quite fast! I'm excited to go out to Laguna this coming Tuesday for a track day.

I wonder if you can start dialing back the regen to reduce heat in the pack as well? I imagine once your friction breaks are good enough the extra heat of the regen charge might not be worth it?

Sounds like he tried & it didn't help much.

Who's making the radiator? Or is this some homegrown solution? Can't wait to see what the new battery cells will do - they may resolve the cooling problem entirely. I hope we'll be able to retrofit one of those packs in the future... I don't see why we couldn't.

 

[mcbarnet007]

Good to hear that the larger radiator helped. Did you have to take off the entire front end to install it?

 

[MasterC17]

Love your write ups.

I hope that Tesla recognizes you value as a brand ambassador.

I’m waffling on getting a Model 3 Performance, but your vids are pushing me to just place my order.

I hope they do too, I could use the support haha! Go for it, you won't regret it.

Awesome post/videos. I am really interested to follow your progress on cooling, this really seems to be the car’s Achilles heel. That and charging at the track, but that’s more of an infrastructure issue.

I think the infrastructure will come up quickly as there is clear demand. As more well-known manufacturers enter the EV space that will pressure tracks, who are sometimes sponsored or affiliated with them to install fast charging. What we really need is a CCS adapter.

Great work there, and that is quite a fast track, seeing up to 145 is quite fast! I'm excited to go out to Laguna this coming Tuesday for a track day.

I wonder if you can start dialing back the regen to reduce heat in the pack as well? I imagine once your friction breaks are good enough the extra heat of the regen charge might not be worth it?

It's a double edged sword. While lowering regen helps with heat slightly, it also results in more energy consumption. It's not a good solution.

Sounds like he tried & it didn't help much.

Who's making the radiator? Or is this some homegrown solution? Can't wait to see what the new battery cells will do - they may resolve the cooling problem entirely. I hope we'll be able to retrofit one of those packs in the future... I don't see why we couldn't.

It's homegrown. I would wait for a "real" solution from one of our vendors. It sounds like it will be several years before the new cells will come to the Model 3. The cooling issue also is not in the battery, it's due to the drive units. The battery indicator goes red only to indicate that the amount of power the drive unit can draw from the pack is limited. The battery is nowhere near as hot on-track as it gets Supercharging. The drive unit temperatures on the other hand are off the charts (comparably).

Good to hear that the larger radiator helped. Did you have to take off the entire front end to install it?

Yes, but it is easy to do. Planning to do a video showing how to DIY install a new radiator.

 

[Mash]

Interesting, so you believe battery indicator is BS and it actually shows drive units temperature? But there is a drive unit indicators and they don't look that red... Also, I'm not sure that charging at high.temps is same as discharging atuch higher rates at high temps...

 

[MasterC17]

Interesting, so you believe battery indicator is BS and it actually shows drive units temperature? But there is a drive unit indicators and they don't look that red... Also, I'm not sure that charging at high.temps is same as discharging atuch higher rates at high temps...

It's not showing drive unit temperatures, it is showing that the current the drive units are able to draw from the battery are limited. That is why the battery shows red, it is indicating limited discharge rates, but it is due to the drive unit. It's confusing, I admit.

 

[Dolemite]

It's not showing drive unit temperatures, it is showing that the current the drive units are able to draw from the battery are limited. That is why the battery shows red, it is indicating limited discharge rates, but it is due to the drive unit. It's confusing, I admit.

That’s more in-line with what I’d learned earlier - I thought I’d been mistaken. I recall a post on here where someone was saying that specifically the inverters are the problem - everything else is whatever. The inverters are cooled directly by the coolant loop so beefing up the system is the right approach.

 

[MasterC17]

That’s more in-line with what I’d learned earlier - I thought I’d been mistaken. I recall a post on here where someone was saying that specifically the inverters are the problem - everything else is whatever. The inverters are cooled directly by the coolant loop so beefing up the system is the right approach.

I don't believe the inverters are the real problem. It appears to be the rotor/stator which are cooled by the oil. The oil and coolant go through a heat exchanger though, so improving the radiator cooling will help reduce overall drive unit temperature.

We're venturing into uncharted territory here. I don't think there's too many people who have tried to resolve motor cooling in an EV lol. I am sure soon enough we will find a viable solution(s).

 

[Daniel in SD]

I don't believe the inverters are the real problem. It appears to be the rotor/stator which are cooled by the oil. The oil and coolant go through a heat exchanger though, so improving the radiator cooling will help reduce overall drive unit temperature.

We're venturing into uncharted territory here. I don't think there's too many people who have tried to resolve motor cooling in an EV lol. I am sure soon enough we will find a viable solution(s).

If it's the oil the obvious thing to try is adding an oil cooler. I guess the question is, even if you cool the oil down to ambient is there enough thermal transfer to keep the motor cool?
I remember a post from MPP saying they had looked at it and they did not think the limiting factor was the radiator. I interpreted that to mean that the coolant coming out of radiator was already pretty close to ambient temperature. Nice to see you got an improvement, I wonder if they felt it wasn't quite enough for a marketable product.
Have you thought about CO2 cooling?

 

[Dolemite]

If it's the oil the obvious thing to try is adding an oil cooler. I guess the question is, even if you cool the oil down to ambient is there enough thermal transfer to keep the motor cool?
I remember a post from MPP saying they had looked at it and they did not think the limiting factor was the radiator. I interpreted that to mean that the coolant coming out of radiator was already pretty close to ambient temperature. Nice to see you got an improvement, I wonder if they felt it wasn't quite enough for a marketable product.
Have you thought about CO2 cooling?

From what I recall, the car already has a de facto oil cooler. Someone else can correct me if I’m wrong, but I think that the motor & gearbox are swimming in their own oil & have their own dedicated electric pump providing circulation. This goes through a stacked plate heat exchanger (or whatever the hell its called) that transfers heat into the coolant loop. I think preheating in the winter works the same way - the car stalls the motors and heats the drive units and then that heat gets transferred into the coolant loop. It’s just that in one scenario (high-performance driving) the main goal is to take heat out of the drive units, while during winter, it’s to put heat into the coolant. Same principle, two different use cases, one system.

I think.

 

[Daniel in SD]

From what I recall, the car already has a de facto oil cooler. Someone else can correct me if I’m wrong, but I think that the motor & gearbox are swimming in their own oil & have their own dedicated electric pump providing circulation. This goes through a stacked plate heat exchanger (or whatever the hell its called) that transfers heat into the coolant loop. I think preheating in the winter works the same way - the car stalls the motors and heats the drive units and then that heat gets transferred into the coolant loop. It’s just that in one scenario (high-performance driving) the main goal is to take heat out of the drive units, while during winter, it’s to put heat into the coolant. Same principle, two different use cases, one system.

I think.

Yep. But how hot is the coolant when it reaches the heat exchanger? How hot is the oil when it leaves the heat exchanger?
Many ICE vehicles have coolant/oil heat exchangers to warm the oil more quickly on startup but for track use people install larger oil/air coolers (on a separate thermostat).

 

[MasterC17]

If it's the oil the obvious thing to try is adding an oil cooler. I guess the question is, even if you cool the oil down to ambient is there enough thermal transfer to keep the motor cool?
I remember a post from MPP saying they had looked at it and they did not think the limiting factor was the radiator. I interpreted that to mean that the coolant coming out of radiator was already pretty close to ambient temperature. Nice to see you got an improvement, I wonder if they felt it wasn't quite enough for a marketable product.
Have you thought about CO2 cooling?

Well, we don't need to keep the oil cool forever, we just need to keep it cool long enough for another 10-15 minutes or so. Realistically, even from a full charge you will get down to 20% SOC in ~25 minutes on track. So we need it to work that long at a maximum. Even then, most people are probably not going to run more than 20 minutes in a session (95%-30%).

I have not considered C02 cooling given the complexity and amount of hardware that would need to be added. Not interested in bringing a giant tank of C02 with me to an event. It's good to know it works, but there has to be a better solution.

From what I recall, the car already has a de facto oil cooler. Someone else can correct me if I’m wrong, but I think that the motor & gearbox are swimming in their own oil & have their own dedicated electric pump providing circulation. This goes through a stacked plate heat exchanger (or whatever the hell its called) that transfers heat into the coolant loop. I think preheating in the winter works the same way - the car stalls the motors and heats the drive units and then that heat gets transferred into the coolant loop. It’s just that in one scenario (high-performance driving) the main goal is to take heat out of the drive units, while during winter, it’s to put heat into the coolant. Same principle, two different use cases, one system.

I think.

You are correct. The next step is to cool the oil more effectively.

 

[dfwatt]

I brought the two Model 3's back to VIR last weekend. The weather was excellent, and the cars performed superbly.

I set PB's in both cars. 2:08.08 in the Black Model 3 and 2:08.8 in the Red Model 3. I left a second or two on the table in the Black car, but had a lot less open track to work with. The tires are also at the end of their life, so that is slowing me down some.

The Red Model 3 had been fitted with the MPP.R StopTech STR-60 BBK. It was paired with Raybestos ST-45 Pads and fresh Motul RBF600 brake fluid. Braking was far superior to the stock setup. The pedal was firm and consistent throughout the day, and inspired a lot more confidence. Braking was quick and linear during deceleration, no more squishy pedal or delayed responses. No overheating occurred, and they look pretty awesome too! Street manners are quite nice, they don't make any strange noises and they shouldn't require frequent rebuilds. Overall, a highly recommended upgrade for anyone seriously tracking their 3!

View attachment 592423

As some of you know, I installed a prototype radiator into the Black Model 3. It performed well - no leaks, and it did its job. It did not resolve the power current reduction issue entirely, though it helped some. When comparing the two cars back to back, drive unit inverter temperatures were roughly 8% less (peak), and the car was able to be driven ~20% longer before current was pulled. There is still work to be done, and work has begun on some more modifications to improve this. The ultimate goal would be to eliminate this problem entirely so we can enjoy full sessions like those ICE cars.

View attachment 592421 View attachment 592422

Overall, I continue to be amazed at how well the Model 3 handles. It can keep up with basically anything in the corners. You would never guess it is so heavy given how agile it is. I did find a 45/55 bias to be the sweet spot for my driving style. 50/50 resulted in a little bit of understeer, and 40/60 resulted in a little bit of oversteer. Traction is set to -10. I played around with reduced regenerative braking but it didn't seem to help the power current reduction much and did result in the battery consumption increasing even more. At 100% regen braking I am at about 1,500wh/mi, at 75% that increased to about 1,650wh/mi.

The weak spot of the Model 3 continues to be speeds over ~110mph. Up to that point, there isn't much that will pull on it, but the Corvette's, 911's, and other high horsepower cars pull away quickly as speeds increase. VIR is a high speed track where the car would benefit from a 2nd gear, but it is what it is.

Along with solving the power current issue, I am looking to put in some lightweight seats this offseason and some R-Compound tires. I believe a sub 2:05 at VIR is very achievable at that point. After that, we may need to go Plaid for some sub 2:00 laps.

Here is my 2:08.08 in the Black Model 3:

And the 2:08.8 in the Red Model 3, with some 911 Turbo overtaking included:

View attachment 592425

Yes I can only echo the sentiments of many others on the website. Your write-ups and insights are terrific.

Have you thought about the possibility of using a spritzer on the front-end underneath side of the radiator? With one gallon of water spritzed 2 ml every second you have enough supply for a half hour of spritzing, and during that half-hour you will dispose of roughly 2 million calories of heat. It isn't just heating the water up it's also vaporizing it that takes so much energy. Water not only has the highest specific heat of any liquid to my knowledge it also requires an enormous amount of energy to turn it from 100 degrees Centigrade liquid to water vapor. Seems like a really easy way to improve the yield of the existing radiator system. You just have to rig up a spritzer with a small pump and a 1 gallon water tank. Some of the electricians on the website might be able to even figure out how to turn that on automatically when track mode is activated. Parts would be less than $100 you wouldn't have to modify anything else, and as long as you use distilled water you wouldn't have to worry about mineral deposition on the radiator fins.

 

[Daniel in SD]

Well, we don't need to keep the oil cool forever, we just need to keep it cool long enough for another 10-15 minutes or so. Realistically, even from a full charge you will get down to 20% SOC in ~25 minutes on track. So we need it to work that long at a maximum. Even then, most people are probably not going to run more than 20 minutes in a session (95%-30%).

I have not considered C02 cooling given the complexity and amount of hardware that would need to be added. Not interested in bringing a giant tank of C02 with me to an event. It's good to know it works, but there has to be a better solution.

Yeah, really need to log all the temperatures to see what's going on. Doesn't track mode already use the battery and coolant as thermal mass, pre-cooling them below ambient temperature?
A sandwich plate inline with the oil filter to a heat exchanger in an ice bath in the trunk might work.

 

[MasterC17]

Yes I can only echo the sentiments of many others on the website. Your write-ups and insights are terrific.

Have you thought about the possibility of using a spritzer on the front-end underneath side of the radiator? With one gallon of water spritzed 2 ml every second you have enough supply for a half hour of spritzing, and during that half-hour you will dispose of roughly 2 million calories of heat. It isn't just heating the water up it's also vaporizing it that takes so much energy. Water not only has the highest specific heat of any liquid to my knowledge it also requires an enormous amount of energy to turn it from 100 degrees Centigrade liquid to water vapor. Seems like a really easy way to improve the yield of the existing radiator system. You just have to rig up a spritzer with a small pump and a 1 gallon water tank. Some of the electricians on the website might be able to even figure out how to turn that on automatically when track mode is activated. Parts would be less than $100 you wouldn't have to modify anything else, and as long as you use distilled water you wouldn't have to worry about mineral deposition on the radiator fins.

Actually, I already am working on this! It is turning out to be very cheap and easy to install. I'll have more details soon once I have time to finalize the system. It can be done with like $20 in parts off of Amazon. I tried to get it installed before my last even but ran out of time.

Yeah, really need to log all the temperatures to see what's going on. Doesn't track mode already use the battery and coolant as thermal mass, pre-cooling them below ambient temperature?
A sandwich plate inline with the oil filter to a heat exchanger in an ice bath in the trunk might work.

It does, but it cools down only to ambient, not below (unless it is really hot out (80f+)).

An air-cooled (finned) oil cooler ducted into the underbody is looking like the most appropriate solution at this point in time.

 

[Dolemite]

An air-cooled (finned) oil cooler ducted into the underbody is looking like the most appropriate solution at this point in time.

I had the same thought but wondered whether that would make it even tougher to keep things warm during winter...

 

[Daniel in SD]

I had the same thought but wondered whether that would make it even tougher to keep things warm during winter...

You can get sandwich plates with thermostats. Of course they're set at 180F so you'd have to figure out how to get one with a more appropriate switching point. You can also get inline thermostats like this: Mishimoto Inline Oil Thermostat