by "chaozbandit" (chaozbandit)
Published 01/23/2017 at 08:30
by "chaozbandit" (chaozbandit)
Published 01/23/2017 at 08:30
Tags: Onpointdyno
; Toronto
; Lotus
; Tesla
STARS: 5
Sasha’s done it again, and this time its another project that won’t disappoint.
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Unsurprisingly Speed Academy (Dave and Pete) always get the inside scoop on Onpoint Dyno’s latest projects, from the Z33 racecar that’s been tuned to match GT1 speeds of yesteryear to the plethora of other motorsports applications that roll through Sasha’s shop. This Lotus is no exception, and is an excellent showcase of what’s possible at this shop.
Of course if you want more up to date information on the build, Sasha has his own thread over on Lotus Talk that goes over much of the same points.
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Sasha’s goal for the project? To create a capable EV car that carries on the spirit of the original Tesla Roadster with modern components, driven by brand new MoTeC hardware. It goes without saying that some outside help was required when it comes to reverse engineering some of Tesla’s first party control systems, but there are undoubtably several key players within the community that can provide those final clues.
The base car itself is a 2014 Lotus Evora, chassis #514, which was purchased in November 2016 and projected to complete in Spring 2017. The decision to use an Evora chassis should be pretty obvious: a MR platform provides much more room to place the EV hardware compared to a FR platform. Additionally Lotus uses lightweight aluminum in the construction of the frame and substructures, which are modular, making it significantly easier to modify for axle and suspension geometry.
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To drive the Evora, a Tesla 85 motor (rated at roughly 360hp, compared to the Lotus’ 250hp) will be paired with two Chevrolet Volt battery packs (rated at 16kW each for a total 32kW). The reasoning for using the Volt packs over the Tesla packs include cheaper raw cost (each cell is $2K USD), lower voltage drop at load, watercooled cells, and built in battery management that helps ensure even wear across individual cells by monitoring charge levels.
It’s hard to say at this point in the build exactly how much extra weight the chassis gains over the OEM configuration. A safe estimate would be 500lbs, but the increased torque should be more than enough to offset the slightly less lightweight sports car. As many Model S owners have experienced, there is an obvious concern regarding the longevity of the drivetrain especially with respect to heat management and limp modes. One could argue that an Evora is much lighter than a Model S so the motor/battery will be at load for less of the time to get up to speed.
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Nonetheless, I look forward to seeing where OnPoint Dyno takes this project. Sasha has already tested the Evora on track (Toronto Motorsports Park, Cayuga) and the goal is to reduce the lap time by five seconds with the EV swap, which means a time of 1:16 around the 3km road course. For reference, his 350Z laps the track in 1:21 on full slicks.
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Here’s to hoping I get to see the car in person sometime in 2017 and best of luck Sasha on completing the project! Also, congratulations to you and your wife on the upcoming baby!!
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UPDATES:
After reading through the forum, there’s a few additional pieces of information I feel would be useful:
- First off, the Tesla motor is out of a 85 non-performance and is rated at 360hp, not the P85. The article has been changed to reflect that.
- The Chevrolet Volt battery packs weigh roughly 320 lbs each, and will be placed in front of the motor unit, in the fuel tank, and in a new section of floor. Ontop of the 290 lb drive unit weight, Sasha is aiming for a curb weight of around 3,050 lbs when completed (maximum 64% rear weight bias)
- The car will feature level 1, level 2, and level 3 charging modules to facilitate the different charging stations in and around the GTA. The level 3 hardware, a Sendyne unit, has the capability of providing a 80% charge in 30 minutes. The Sendyne is able to provide very precise charge calculations thanks to incredibly accurate internal coulomb counting.
- A MoTeC M130 controls the components of the charging system, with a MoTec M1 handling most of the driving duties. It is all sent to a fully programmable C1212 LCD.
- With the advent of motor regeneration, Sasha has also elected to remove the brake booster for a more mechanical feel. Additionally, the clutch and all related hardware have been removed.
- The motor control unit remains undisclosed, as is the module that sends data to the drive unit itself (which remains Tesla OEM)
A very brief schedule of whats to come from Sasha himself:
Feb will be spent on minor systems mounting and fabrication, as well as the final electrical systems design, and March will be electrical systems building and final plumbing and fabrication, with April being the final re-assembly and bodywork updates. We’ve ordered some cool bodyparts from Hethel Sport
"SidewaysOnDirt still misses Bowie" (sidewaysondirt)
01/23/2017 at 08:51, STARS: 1
That is neither simplifying or adding lightness.
"chaozbandit" (chaozbandit)
01/23/2017 at 08:54, STARS: 1
One could argue a motor+battery unit consists of less moving parts than a Camry engine and gearbox, ergo simpler.
"diplodicus" (diplodicus)
01/23/2017 at 10:58, STARS: 0
What do they use as a controller for the motor?
"chaozbandit" (chaozbandit)
01/23/2017 at 11:11, STARS: 0
Motec standalone ecu, data logger and reverse engineered canbus data. Somebody in Switzerland (CERN) helped him decode the basic functions.