Some (hopefully unanswered) LDU Board Questions

[Zeus Wayne]

Hi guys,

New to the forum and after talking to a number of USA based outfits, thought it would be better to chat with those who have a true passion for this rather than those who only want to sell me packages they currently have to offer, and not discuss what I actually want and need...and COVID hasn’t helped!

I’ve done a lot of research, but still have some unanswered questions that I could use a few pointers on, as I have not seen it specifically talked about (or at least found it) here on the forum.

1) With regards to the available LDU boards (Damien - BTW, You DA Man!) is there an option to select the ultimate power level on the fly? IE – can one switch to/engage a “ludicrous” type mode temporarily, and revert back to just (stock) performance mode, given a sport+ LDU is being used? Or are the boards programmed to be maximized for the given LDU and one must modulate their right foot accordingly?

2) Has anyone built an AWD using 2 rear LDUs, one in back, and one up front? Given the size and weight of my project car, I am shooting for around 1200HP to put me where I want to be.

3) Has anyone used more than 16 (P100) cells to support a high horsepower dual LDU install? Attempting to design in some range with that heavy right foot…

4) Assuming a dual LDU setup is feasible, from either 1 or 2 boards, is there the capability to adjust for a significant tire diameter stagger to prevent tire scrubbing? For instance, my car is designed with 28” dia tires up front and 33” tires out back.

Thanks in advance!

Zeus

[Isaac96]

1 - you can set a throttle maximum using the BMS input (just tell the board that your battery is low, and it can limit throttle). A few users are working on tuning for absolute maximum power - Jon Volk is getting 3.2 seconds 0-60 with a single LDU last I checked.
2 - not yet, but that sounds awesome.
3 - for maximum power, you want a multiple of 16 - so 16, 32, 48. 16 should still give you up to 300 miles, any more than that is rather difficult to fit in most vehicles; maybe check out different batteries if you want more flexibility.
4 - you don't set speed, you set torque; there are speed limitations but all that does is cut power until speed drops again, so your stagger is not an issue.

What car is this going into? It sounds like a monster!

-Isaac

[P.S.Mangelsdorf]

Welcome! I've answered what I can below, but I advise you to explore the forums heavily. The answers to several of these are either in or implied by other posts.

1) With regards to the available LDU boards (Damien - BTW, You DA Man!) is there an option to select the ultimate power level on the fly? IE – can one switch to/engage a “ludicrous” type mode temporarily, and revert back to just (stock) performance mode, given a sport+ LDU is being used? Or are the boards programmed to be maximized for the given LDU and one must modulate their right foot accordingly?

You've got to tune it yourself. There isn't necessarily one parameter that changes power levels. To do that, you'd need to develop 2+ tunes, and a controller that would change all of the needed parameters over CAN when you hit a switch. Sort of a variation on Jon Volk's current project working on some live parameter tuning.

2) Has anyone built an AWD using 2 rear LDUs, one in back, and one up front? Given the size and weight of my project car, I am shooting for around 1200HP to put me where I want to be.

Are any done? Not that I'm aware of, but there are some in progress. Yes you can control both, send the throttle to one, have it output throttle over CAN, and tell the other to take throttle from CAN. See at least 2 threads asking about this in the software/hardware forums.

3) Has anyone used more than 16 (P100) cells to support a high horsepower dual LDU install? Attempting to design in some range with that heavy right foot…

You can set up all sorts of batteries to support these units. Several of us are or are planning to use multiple Chevy Volt batteries. See the recent thread re: what batteries for Tesla drive units.

4) Assuming a dual LDU setup is feasible, from either 1 or 2 boards, is there the capability to adjust for a significant tire diameter stagger to prevent tire scrubbing? For instance, my car is designed with 28” dia tires up front and 33” tires out back.

That may give you issues (mostly that the units may want the same speed if they are using the same throttle), but it probably depends on tuning. Anyone else have insight or more expirence? EDIT: See Issac's more informed answer above.

[jon volk]

All the parameters can be set over CAN. With minimal added hardware you can set multiple tune ups to switch on the fly.

Im working on dynamically changing parameters, but have had a switch to go between a lower power mindlessly mash the throttle tune and another tire shredding tune. That works really well and also allows my to do A-B comparisons of the dynamic mapping.

[Zeus Wayne]

Thanks for the quick responses guys! One of my concerns with the awd was torque split, given The different overall HP capabilities front (P85) vs rear (P100) motors coupled with different revs per mile with different height tires.

Isaac - it’s big (22’ long, 8’ wide), black, has .30 machine guns, a turbine, and was once owned by some eccentric billionaire who liked to dress up as a flying rat at night. I can’t call it what he did due to copyright/trademark concerns, but I can call it a big black car with optional machine guns...

[P.S.Mangelsdorf]

given The different overall HP capabilities front (P85) vs rear (P100) motors

If you are using the rear (large) drive unit from a P85 and a P100, they are the same thing.

There are only 2 versions of the LDU (Base and Sport) and the internet is still arguing over whether there is actually a hardware difference between the two anyways.

Isaac - it’s big (22’ long, 8’ wide), black, has .30 machine guns, a turbine, and was once owned by some eccentric billionaire who liked to dress up as a flying rat at night. I can’t call it what he did due to copyright/trademark concerns, but I can call it a big black car with optional machine guns...

Ok now I have to ask; where are you located? and please dear lord start a build thread, the world needs to see this.

[Zeus Wayne]

Yes, lots on controversy based on PNs... ment to say S85. Rear will certainly be a sport, front might be a sport, but could be a base as not as much power is needed up front, though I certainly wouldn’t rule it out. Grabbing complete cars outta Copart so, it’s luck of the draw on what’s avail in my region.

Located in Sarasota, FL

I might start a build thread, but only for the chassis, as DC/WB can be a little temperamental when it comes to showing the body which they believe could be interpreted as an IP infringement if one prints the wrong word...

[Jack Bauer]

Sounds like a very interesting project:)

[MuskTang]

Sounds like a perfect project to utilize Model 3 Battery modules.

[P.S.Mangelsdorf]

Located in Sarasota, FL

Awesome, some more southeast builds!

I might start a build thread, but only for the chassis, as DC/WB can be a little temperamental when it comes to showing the body which they believe could be interpreted as an IP infringement if one prints the wrong word...

Yeah that can get tricky. I know Rob Kibbe from The Muscle Car Place and Kibbe & Friends Show podcasts has said that he reach out to WB regarding his uhhhh... General-ly awesome orange Charger (since he uses it to promote the podcasts) and they didn't respond; though that may be because they are trying to pretend they don't own that property.

[slow67]

There is a road race Cobra that has dual LDUs. I think they will eventually move to the model 3 magnet motors though, as they cant keep rotor heat under control when road racing (after 4-5 laps).

[Zeus Wayne]

Yeah, their IP attorney is a real lazy LA type lawyer - can't answer the phone, can't respond to emails, unavailable for appointments, etc. How he remains on the payroll is a mystery...

[P.S.Mangelsdorf]

Yeah, their IP attorney is a real lazy LA type lawyer - can't answer the phone, can't respond to emails, unavailable for appointments, etc. How he remains on the payroll is a mystery...

That may be why he remains on the payroll...