MASTER THREAD: Comprehensive Road-Course Modification Guide — Optimizing the 3 for the track

[MasterC17]

@NA&CH I feel like an LR RWD might be a great starting point for a track focused build. With an MPP Party Box of course. I've zero experience to back this up, it's just a thought. I also don't know if Tesla still made LR RWD in 2020.

Of course if you're after outright speed then just get a Performance.

2021+ refinements and heat pump are worth getting for daily driving in my opinion (since older cars aren't even priced much lower right now), but for a track focused build save money by starting with an older car (whichever trim you choose).

The point about the LR RWD is a good one. You put an oil cooler and Partybox on it, and it's good for a twenty minute session, whereas a Performance is as bad as seven minutes.

This all depends on your goals. If you are going for fastest lap, such as Time Attack, a Performance makes sense.

If you're just going to have fun, learn, and enjoy an HPDE, the LR RWD is the better car. It's also phenomenally fun as a DD with the Partybox; and cheaper.

 

[Captain Ahab]

I am mentally ill. Disregard my bad behavior when it occurs. It's not an excuse, just an explunation.

First, this is a hardware modification. Second, this is applicable to pretty much anything with wheels. Third, this DOES NOT change the actual peak output potential of the motors - just like this same change on any other vehicle would not change an ICE's output potential.

If it has not been widely discussed - anyone can change their tire sizes to achieve an effective gear change.

If you have a separate set of track wheels and tires. It may be worth considering a change to the rolling diameter of your tires.

Smaller rolling diameter will result in higher wheel torque - this means a potential for increased accleration - provided you have the grip, and possibly only an advantage over certain speed ranges. The increased wheel torque will come at the expense of reducing the potential top speed.

I have driven on 3 different profile tires on my M3P.

With a larger rolling diameter (5 up on profile), accleration is decreased - I was unable to break traction in a straight line.

With a smaller rolling diameter (5 down on profile), accleration is increased - ONLY when I can achieve grip. The tire set I had easily broke traction at 60% SOC.

By changing the tire profile:
The speedometer will be inaccurate.
Efficency drops as you lower the profile. It cam be signifigant. Yes, I accounted for the differences in rolling diameter in my calculations.

During my limited testing, I was unable to capture meaningful data via Dragy. This was in part due to traction limitations of my setup with the lower profile tire. The accleration plot in Dragy is incorrect - accleration is the mathematical derivative of the velocity over time plot at any given point - NOT whatever data it displays. A line with a constant slope? Accleration is a horizontal line across the y-axis.

I would love to see 60 foot, 0-60, 0-100, and 1/4 mile data under ideal conditions for the lower profile tire. Dyno would be nice.

I am currently running OEM 18, I switched back due to efficency.

Want to try my 245/35/18's? I am in Gainesville.

I have them ready. If you can't get them to grip, a back-to-back dyno run with tire swap would be neat.

Attached are calculations of some OEM wheel options - compared to some different 18 inch tire options.

 

[Mash]

Model 3 is intentionally keeping torque Vs speed lower than tire traction limit, so I won't be surprised if significantly smaller wheels would make strong advantage at low and medium speeds. Limitations though is not with the top speed of gearbox, but with the lowered HP at the same high speed point. There is also the question about how small you can go before it will throw esp errors.

 

[superflyrolla]

I love that you have data. Are these all different tire compounds though? Seems like that will make a significant difference in efficiency.

Did you get any errors when running 24" diameter tires? I'm curious where the limit is. People are autocrossing on 25" tires without error, but maybe not driving down the highway on autopilot?

 

[Captain Ahab]

I did not do extensive tesing, nothing more than lots of road driving, and spirited bits when safe to do so.

The only *nag warnings* I encountered was engaging traction management frequently with the lower profile tires.

I am *not* a subject matter expert qualified to confirm this with certainty: I do not suspect there is any mechanical reason not to opt for a tire size that matches your HPDE intentions.

People have been running different tire and wheel sizes on cars for about as long as the automobile has been around. See any lifted truck, jeep, or donk. - Yes, a mechanical parts change like this will ultimately change the operational forces experienced by some mechanical parts. You may very well be putting hardware at risk - it is 100% certain that our software is not yet able to have non-OEM wheel & tire sizes accounted for. Regardless, whatever the effects may be, my M3P operated on the road for a couple hundred miles without any unexpected consequences. Auto-pilot and all, just fine.

For what it's worth, some vehicle drivetrains are vulnerable to damage from changing the wheel mass and tire rotational diameter. For instance, eletronically controlled single- and multi-clutch automated-transmissions; nototious for frying transmissions on some supercars when equipped with oversized and heavy aftermarket wheels, popular among certain enthuiasts.

 

[mattack4000]

Tire load rating is only a suggestion

 

[drew.cleaver]

If one was to get into the Tesla racing/AutoX world what platform would one jump into. I would assume an M3P but curious to hear thoughts.

After running a M3P for a couple years, I'm really enjoying the first impressions with the SR+ RWD. A lot TBD, but it's fast enough, so much lighter, and the charging logistics are a bit less complicated.

I might try and get in a MYP 4680 later this year though. The 4680 SR+3 should be a real track weapon.

 

[tm1v2]

@drew.cleaver Just checking - is your SR+ RWD the older, lighter NCA battery version, or the newer, heavier LFP battery? (Which yes later got renamed to just "RWD" but I believe Tesla was selling "SR+" cars with LFP for a couple months.)

 

[drew.cleaver]

@drew.cleaver Just checking - is your SR+ RWD the older, lighter NCA battery version, or the newer, heavier LFP battery? (Which yes later got renamed to just "RWD" but I believe Tesla was selling "SR+" cars with LFP for a couple months.)

It's a 2021 NCA. It's fun but I anticipate the 4680 being a massive leap forward in making track use way more simple and enjoyable.

 

[Captain Ahab]

It's my understanding that a Tesla powertrain on a Model S has been mechanically upgraded to a different Model S drivetrain. I think single motor to dual motor.

In the same vein:
Is it possible to transplant hardware from a Model S Plaid - and make any custom necessary hardware solutions - to upgrade a Model 3?

My initial thoughts are that this would be achievable with enough time, skill, and budget.

Thoughts?

 

[MasterC17]

It's my understanding that a Tesla powertrain on a Model S has been mechanically upgraded to a different Model S drivetrain. I think single motor to dual motor.

In the same vein:
Is it possible to transplant hardware from a Model S Plaid - and make any custom necessary hardware solutions - to upgrade a Model 3?

My initial thoughts are that this would be achievable with enough time, skill, and budget.

Thoughts?

Well the problem is that no one can alter Tesla Firmware. A Model S that has a motor added already has Tesla Firmware for a Dual Motor configuration. There is no Firmware for a Plaid motor in a Model 3. It's not necessarily impossible, but would require incredible amounts of work and a custom battery pack with a custom BMS. It would be impossible to use the factory battery pack both from a software and hardware perspective. So, I just don't think it would make any sense at all to be honest.

 

[EVolv3d]

It's my understanding that a Tesla powertrain on a Model S has been mechanically upgraded to a different Model S drivetrain. I think single motor to dual motor.

In the same vein:
Is it possible to transplant hardware from a Model S Plaid - and make any custom necessary hardware solutions - to upgrade a Model 3?

My initial thoughts are that this would be achievable with enough time, skill, and budget.

Thoughts?

Of course it could be done.. but not recommended for the amount of custom fabrication and programming required. Say goodbye to OTA software/firmware updates and a lot of the OEM functionality. Like @MasterC17 said, it wouldn't make sense to do it in a street driven Tesla. It would cost a ton of money and you would lose a lot of convenience and reliability. Maybe someday if there's a racing class specifically for EVs with modified powertrains. Otherwise, it would make more sense to do the swap in a project car with an AEM VCU standalone like Rywire's 500hp Tesla-powered RWD S2000.

Rywire's build playlist:

https://www.youtube.com/playlist?list=PLXb18XTfHf6fxHvQWzXr-5WVBM5FBDRvz

 

[Captain Ahab]

Excellent points. Sky is the limit with powertrain swaps. From a lawnmower engine to a rocket.

 

[RedMax]

Hi everyone, I am tracking my M3P 2020, after few heavy track events my Drive shafts CV joints started to make weird clicking noise during turns. Tesla has replaced them once with new. Now after another GP track event i have experienced same issue with brand new drive shaft.

CV joints drive shaft noise
Getting CV oil in the hub, clicking noise under side load from both front hub or drive shaft CV bearings.
Running:
275/35R19 Michelin Cup2
MPP FUCA and Camber Arms, sealed bearings for lower control and trailing arms.
Eibach Lowered springs and Swaybars.
GyroDisk brakes on Carbotech XP10 pads.
Car runs solid but appeared excessive noise from DriveShafts made it uncomfortable to push to the limit.
Anyone faced with this issue?

P.S checked hub nut and suspension with motor brackets , all torqued within specs.

 

[MasterC17]

Hi everyone, I am tracking my M3P 2020, after few heavy track events my Drive shafts CV joints started to make weird clicking noise during turns. Tesla has replaced them once with new. Now after another GP track event i have experienced same issue with brand new drive shaft.

CV joints drive shaft noise
Getting CV oil in the hub, clicking noise under side load from both front hub or drive shaft CV bearings.
Running:
275/35R19 Michelin Cup2
MPP FUCA and Camber Arms, sealed bearings for lower control and trailing arms.
Eibach Lowered springs and Swaybars.
GyroDisk brakes on Carbotech XP10 pads.
Car runs solid but appeared excessive noise from DriveShafts made it uncomfortable to push to the limit.
Anyone faced with this issue?

P.S checked hub nut and suspension with motor brackets , all torqued within specs.

Can you upload a video of the noise? My guess is inadequate lubrication on the axle splines.

 

[mattack4000]

Have you also replaced the actual bearing? Both of mine failed at like 12k miles

 

[DFW_MVP]

Hi everyone, I am tracking my M3P 2020, after few heavy track events my Drive shafts CV joints started to make weird clicking noise during turns. Tesla has replaced them once with new. Now after another GP track event i have experienced same issue with brand new drive shaft.

CV joints drive shaft noise
Getting CV oil in the hub, clicking noise under side load from both front hub or drive shaft CV bearings.
Running:
275/35R19 Michelin Cup2
MPP FUCA and Camber Arms, sealed bearings for lower control and trailing arms.
Eibach Lowered springs and Swaybars.
GyroDisk brakes on Carbotech XP10 pads.
Car runs solid but appeared excessive noise from DriveShafts made it uncomfortable to push to the limit.
Anyone faced with this issue?

P.S checked hub nut and suspension with motor brackets , all torqued within specs.

Did you have to pay Tesla to look at your car, since you have aftermarket parts on?

I have axle-clicking when first moving forward or backwards from a stop; Tesla Mobile Tech tightened axle nuts, and that helped for ~20 minutes.

I greased the outer axle splines after that, and that helped for an hour.

Took car to Tesla Service Center, and they said it'd be $80 to look at the car (due to aftermarket parts), and that they couldn't hear a noise after a test drive.

My next plan is to follow this thread's instructions while I have the hubs out for lug stud replacements: Rear Axle Click: Ultimate DIY Fix

 

[tm1v2]

Did you have to pay Tesla to look at your car, since you have aftermarket parts on?

I have axle-clicking when first moving forward or backwards from a stop; Tesla Mobile Tech tightened axle nuts, and that helped for ~20 minutes.

I greased the outer axle splines after that, and that helped for an hour.

Took car to Tesla Service Center, and they said it'd be $80 to look at the car (due to aftermarket parts), and that they couldn't hear a noise after a test drive.

My next plan is to follow this thread's instructions while I have the hubs out for lug stud replacements: Rear Axle Click: Ultimate DIY Fix

Which aftermarket parts did they cite? Or is your car modded enough that sort of went without saying?

To be fair I think some warranties have clauses against competitive use or sometimes any track use (independent of mods), but I haven't looked into Tesla's for that.

 

[DFW_MVP]

Which aftermarket parts did they cite? Or is your car modded enough that sort of went without saying?

To be fair I think some warranties have clauses against competitive use or sometimes any track use (independent of mods), but I haven't looked into Tesla's for that.

They didn't cite any specific aftermarket parts this time, nor the previous time. Just tried to look for the invoice where I paid the fee, but not seeing history prior to December 2019 (which is when I was charged an "aftermarket fee" of $80 while trying to get an alignment at Tesla while in for the FSD computer install). I didn't pay them the $80 this most recent time (November - December 2021), and they resolved the service request without doing anything besides the test drive.

I have the UP aero, MPP suspension/brake components, and wheels/tires, so you can tell it is modded, but don't think that should prevent them from investigating a known issue with axles/hubs.

 

[Theadonnan]

I just bled my brakes in this order: RR - LR - RF - LF (used almost 2L of ATE200) - pedal feels firm, but should I go back and bleed them in the opposite direction? LF - RF - LR - RR? Used a pressure bleeder system around 15-20 psi.

Installed stainless lines and unplugged pads. 2021 Model 3 Performance.