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Why is Ludicrous retro-fit not available for P85?

mdemetri

Member
Jan 30, 2014
186
33
Irvine
I apologize if this topic has been addressed previously, but I would really like to know why Tesla is not offering the Ludicrous upgrade to P85 owners. It is either not technically possible or Tesla has chosen to not include the original P85 owners. While I am far from knowledgeable in this area, but is it not possible to to change the contactor in the P85 to the new ludicrous contactor? I see no obvious reason why not. This leaves me thinking that Tesla could offer this to P85 owners but has chosen not to. Can anyone illuminate this issue and whether there is a technical reason that prevents this upgrade for P85 owners.
 

mikeash

Active Member
Oct 26, 2014
1,105
703
Fairfax, VA, USA
Ludicrous Mode happened because the P85D is limited by the amount of current it can push through the contactors and fuses. Ludicrous Mode upgrades those to handle more current.

The P85 is likely not limited by the current capacity of the contactors and fuses, but by other factors like traction and inverter/motor power. Upgrading the contactors and fuses would therefore be possible, but wouldn't allow for any increase in performance.
 

mdemetri

Member
Jan 30, 2014
186
33
Irvine
Ludicrous Mode happened because the P85D is limited by the amount of current it can push through the contactors and fuses. Ludicrous Mode upgrades those to handle more current.

The P85 is likely not limited by the current capacity of the contactors and fuses, but by other factors like traction and inverter/motor power. Upgrading the contactors and fuses would therefore be possible, but wouldn't allow for any increase in performance.

Thanks for the input. In JB Straubel's blog about Dual Motor he states that "[FONT=HeiS ASC Simplified Chinese, HeiS ASC Simplified Chinese_n5, HelveticaNeue-Regular, Helvetica Neue Regular, Helvetica Neue, Helvetica]The shaft horsepower rating of the rear wheel drive single motor Model S is straightforward and roughly 360-470 hp depending on the variant (60, 85 or P85). Also, it is generally similar, but not the same, as the battery electrical "horsepower" output." The 'but not the same' suggests that there may be some benefit from changing to the ludicrous contactor. While the improvement may not be as large as with the P85D, it may still provide a performance improvement ([/FONT]I am less convinced that my P85 is limited because of traction, especially when I can improve traction with bigger tires).[FONT=HeiS ASC Simplified Chinese, HeiS ASC Simplified Chinese_n5, HelveticaNeue-Regular, Helvetica Neue Regular, Helvetica Neue, Helvetica][/FONT]
 

SmartElectric

Active Member
Jul 9, 2014
2,515
2,165
Toronto,Canada
I am less convinced that my P85 is limited because of traction, especially when I can improve traction with bigger tires

Ok. Don't be convinced. However, having read a wide variety of threads here on the subject, and driven a P85 myself (loaner), it seems completely obvious that the P85 is traction limited.
 

Olle

Member
Jul 17, 2013
787
402
Orlando, FL
The 470 hp (350kW) from the P85 is nowhere near in need for the ludicrous fuse. 350 kW/360 V=972 A. Ludicrous fuse is 1500 A.
The interesting question is if the P85 can be upgraded with the ludicrous 503 hp software from the ludicrous rear DU. Would still need less than 1100 A.
It sounds like a no brainer for Tesla to sell a SW upgrade for a couple of grand or send it as goodwill. And why not?
Anybody has any clues?

- - - Updated - - -

Yes but up to about 50km/h only then more power could be "useful"
at 70% SOC or less, the P85 is barely traction limited at any speed, with summer tires. More power would be nice :)
 

Kalud

Active Member
May 7, 2013
1,059
290
Montreal, QC
From the leaked 7.0 software, it says that:

Improved Performance

Motor control enhancements initially developed for Dual-Motor Model S have now been incorporated into Rear-Wheel Drive Model S, enabling higher acceleration at all speeds, especially near top speed.


 

SabrToothSqrl

Active Member
Dec 5, 2014
3,767
3,079
PA
More Power at any speed or battery level... would be nice ;) lol.

I had a P85 loaner, and while it certainly felt faster, the best part was the clouds of white smoke it could produce off the line :-D
 

Olle

Member
Jul 17, 2013
787
402
Orlando, FL
From the leaked 7.0 software, it says that:

Improved Performance

Motor control enhancements initially developed for Dual-Motor Model S have now been incorporated into Rear-Wheel Drive Model S, enabling higher acceleration at all speeds, especially near top speed.


Does this mean the 503 hp rear motor power of the Ludicrous in classic P85?
 

AmpedRealtor

Well-Known Member
Jun 30, 2013
6,396
3,366
Phoenix, AZ
I own a mid-2013 P85 and I received no changes to performance or driving improvements that other RWD owners received. Apparently such improvements are only limited to RWD cars produced after the Autopilot was announced.
 

Dennis87

Member
Nov 15, 2014
364
198
Norway
Improved Performance is delivered in 7.0 but only for RWD cars with autopilot hw that use a new revision Drive unit with a top speed of 140 mph. If the car did have the requirement the release note info did appear.
 

ACDriveMotor

Member
Aug 11, 2013
900
33
Seattle, WA
Well if true that only the brief overlap window is in play then that's pretty weak. The notes for 7.0 read as if all RWD will benefit when perhaps only a tiny fraction of cars receive a benefit.
 
Mar 11, 2010
4,550
1,426
Humboldt/Los Altos
Just because P85 is traction limited doesn't mean Ludicrous has no value. Let me decide how much to spin my wheels! :cool:

not always. proper tires and/or on very sticky asphalt there is 0 wheel spin. On a still >100F fresh mat of asphalt with my stock 21" wheels I got no spin. also on very sticky chipseal with AS tires, no spin.
My RE71R's on some surfaces hook up 100% too (sure they would in the sticky road cases)

not completely traction limited
 

MrJones390

Space Boat
Jun 26, 2015
246
47
Los Angeles
not always. proper tires and/or on very sticky asphalt there is 0 wheel spin. On a still >100F fresh mat of asphalt with my stock 21" wheels I got no spin. also on very sticky chipseal with AS tires, no spin.
My RE71R's on some surfaces hook up 100% too (sure they would in the sticky road cases)

not completely traction limited

You got the Ludicrous upgrade in your Classic P85 and launch with no wheel spin? That's what we're talking about here.
 

RyanT

Member
Sep 9, 2014
388
158
Portland
Improved Performance is delivered in 7.0 but only for RWD cars with autopilot hw that use a new revision Drive unit with a top speed of 140 mph. If the car did have the requirement the release note info did appear.

I got the message on my P85 with autopilot. Haven't timed any runs or top speed though.
 

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