Meet Kels:
Kels is our beloved 2003 Nissan 350z racecar that we have been racing for over a decade. The car has seen years of continuous development, has set and re-set lap records a number of times and has won a fair number of races – from endurance races to sprint and more recently Time Attack. In terms of speed, it now rivals IMSA GTD cars in terms of lap time.
The car has all of the professional motorsport features you might expect of a modern GT3 Car: traction control, 12″ wide racing slicks, motorsport ABS, 4-way adjustable dampers, and nothing but motorsport electronics throughout.
In 2019 we finally achieved the lifelong dream of doing a 1:18 at Mosport – our local international racing circuit. A famous track, known to some as a mini Nurburgring for its massive elevation changes and high-speed corners, it is one of the fastest tracks in North America and has been our home since we started racing. A 1:18 is the equivalent lap time to what GT2 cars would run in the heyday of ALMS.
After achieving our goal, we made the decision to turn Kels into a mobile development platform where we could develop and test ideas we had for motorsport electrification. The plan was to add 200 horsepower through a small motor and battery while adding less than 200lbs.
This goal is relatively conservative when compared to the current state of the art in Formula 1 and prototypes, but is a very large challenge when working with a budget ~1/100th that of professional outfits.
As of summer 2023, the hybrid system has been performing exceptionally well and we are now working on further upgrades and enhancements to increase the power output and length of time the system can run at peak power. In addition, upgrades to the aerodynamics and suspension have turned Kels into a real GT contender.
The History
2003 - The Original Build
2008 - We Purchase Kels - 1:33.7
After going through multiple owners and getting it’s fair share of abuse, Kels is purchased by SG-Motorsport in an effort to bring it back to Koni Challenge.
Unfortunately, the car proves to be underpowered and uncompetitive, although the team learn a lot by running two Koni Challenge races. Both races are finished, finishing 13th in the second race and beating a number of extremely well-funded teams.
2009 - Aerodynamic Development
Kels wins various regional races after we develop a wing and splitter for the car, among other various improvements.
2010 - Endurance Racing Win
Kels runs a 3hr Endurance Race with Sasha Anis and Yukinouri Taniguchi behind the wheel. We win our class and are very close to catching the 1st place overall Dodge Viper.
You can read the entire story here:
http://www.superstreetonline.com/features/modp-1006-2003-nissan-350-z
Kels then goes on to set a new RWD Lap Record at CSCS later in the season, along with some wins in regional racing. Further development is done to the car, with the addition of 18″ wheels and used racing slicks.
We then build a high compression engine aspiring for more power.
2011 - Minor Updates
Mosport Lap Time: 1:27.02
2012 - Individual Throttle Bodies, Blue
Kels turns blue, we install individual throttle bodies, along with a number of other suspension and weight reduction upgrades. With better used tires we finally get a time closer to inline with our goal.
2013 - 3.7L Engine Upgrade
We change to an upgraded engine, and with fairly factory internals it produces the same power as the previous engine. There is now significantly more potential, but the results haven’t shown on the track yet.
2014 - Global Time Attack
We add a dry-sump oiling system to the car, along with some weight reduction upgrades and head to Road Atlanta, a track we’ve dreamed of visiting for a long time to compete in Global Time Attack.
We place 2nd in Unlimited RWD beaten only by an insane Corvette, and are one of the fastest cars at the event despite having half of the horsepower and far less aero than many of the other cars. Kels has the highest cornering speed at the event.
Watch a video from that event here:
2015 - Wind Tunnel Testing
2016 - Widebody And Green
We do a major race at Mont Tremblant and crash on oil in qualifying. After repairing the car and starting from the back, we hang with most factory-built racecars but eventually have an incident with a clown in a Porsche GT3 Cup Car. Watch that very exciting action here.
We also set a new lap record at CSCS in Unlimited RWD.
Kels never runs at Mosport with a proper setup but does a 1:25 with ease during testing. The car proves that it has the pace to keep up with GT3 Cup cars, however, it is seriously underpowered.
2017 - Kels Blows Up
We finally get back to Mosport to test the speed of the car with the widebody. Unfortunately, the tires we use aren’t that great, and the car only does a 1:21.9 – that’s only about 1 second faster than we had done without the widebody and sequential gearbox.
Kels’ engine throws a connecting rod late in the season, and the engine is destroyed. You can watch a video about that sad day here.
2018 - 4.2L Engine Development
2019 - Flat Floor, 500whp, 1:18.1, Hybrid build.
Our new 4.2L engine is incredible and makes over 100 horsepower to the wheels more than our previous engine. We design and build a full carbon fibre flat floor and diffuser.
There is a massive step-change in lap time, showing that the time we ran in 2017 was sub-optimal, most likely due to using used tires.
We achieve our 14-year goal of doing a 1:18 at Mosport. There are tears. Watch the video here.
Lap records are set at CSCS (video here), and we are the fastest RWD car at GridLife (video here).
The hybrid development is started and before the end of the year we have the hybrid system on the dyno. Unfortunately a shaft breaks, but luckily we have ample time before the 2020 season starts.
Watch the overview of the hybrid system here.
2020 - Hybrid Build First Season, 1:16.9
Mosport Lap Time: 1:16.9
The hybrid system is working, and we finished off the season beating our 2019 Time by 1.3 seconds at Mosport, an impressive feat considering the car was far from optimized!
In 2020 a paddle-shift system was added, in addition to the Hybrid system. In late 2020 the motor was also rebuilt in-house at MPP with reduced turn stators to improve the power output at high RPM. The motor now gives the engine over 150 horsepower.
Kels also turns Silver.
Dyno video HERE
First Track test video HERE
Final Mosport video HERE
The Motor
We’re using an axial flux Phi-Power motor that has been custom designed for our application. Using a custom mounting plate we’ve designed in house, the motor directly couples to the engine inside the transmission’s bellhousing. The motor’s power capability is directly related to the battery’s voltage, so our goal is to raise the voltage to achieve more output from the motor.
Cooling is a limitiation of such a small compact motor, so further cooling upgrades will be developed in house by MPP to improve the peak power duration of this motor.
As there is no clutch, the motor is directly coupled to the engine. This means that to start the car driving, the motor must overcome both the weight of the car and the 15:1 compression engine. It’s quite a challenge for this little motor!
The Battery
The battery was one of the largest challenges for the design of this build, because we needed something that was capable of extremely high power, with a quality cooling interface, and while being as light as possible. In the original build we used a BMW i8 battery, which is very power dense and relatively lightweight.
However, in 2023 we developed our own high power high voltage battery, increasing the voltage from 400V to 500V to increase power. We’ve also improved the cooling and made a number of other novel improvements that are uncommon in high voltage battery design.
The battery is just over 10kWh and is capable of supporting 160kW of power. We look forward to continuing development of our custom battery and trying to get more power out of it!
The Power Electronics
Kels uses a Cascadia Motion CM200 inverter to convert the 400-800 volts coming out of the battery to the AC voltage the motor needs to party. The inverter is capable of supporting 200kW of power, and we’ve recently upgraded to this inverter as it will allow us to upgrade to an 800V battery in the future.
A Brightloop DCDC converter is installed above of the inverter, and it weighs just over 1kg. The unit is a work of art and the same exact device used in modern Formula 1 cars. The small converter takes the high voltage from the 400V battery and powers the low voltage systems. This has allowed us to remove the alternator which both saved weight, and moved it rearwards.
We have designed our own power distribution box which houses the contactor and fuses for the off-board charger and DCDC, along with isolation measurement. This module communicates with our MoTeC M150EV via CAN to let the system know if high voltage is leaking into the chassis of the vehicle, so that appropriate steps may be taken.
The Brain
We have used a MoTeC M150EV as the main control unit and ECU for Kels. Using the M1 Build environment, we were able to develop our own software that runs on the same unit as the main engine control. So one controller runs the engine, the traction control, paddle shift – and also manages the battery, inverter and high voltages systems.
The ECU is programmed with a number of different strategies to limit power into and out of the battery, based on things you’d expect such as state of charge, motor/inverter/battery temperature, and coolant temperature.
There are multiple different drive maps and driving modes, allowing the vehicle to operate in a full gasoline mode, hybrid mode, or EV mode. In hybrid mode, there are driver-controlled trim knobs that adjust the power output of the motor, as well as the charging and regen strategies for the motor.
In addition, the ECU also controls the newly added four wheel steering, allowing us to dynamically change the alignment. Multiple maps and modes allow dynamic changes based on speed, corner phase, driver inputs, and torque at the axle.
The Installation
The main design goals for this project were to get as much weight moved back as possible and to add as little weight as possible. We didn’t want to cheat and hang too much behind the rear wheels, as excessive polar-moment is never fun.
The heat exchanger, water pump, swirl pot, 12V battery, high voltage battery, and power distribution box are all located behind the driver over or just behind the drive tires. The inverter and air shift compressor are mounted just beside the driver, close to the transmission tunnel.
The removal of the clutch, flywheel, starter, alternator, and clutch pedal hydraulics along with the switch to a magnesium cased X-trac gearbox has resulted in a net weight gain of just under 200lbs, keeping within our goals there. That is a big achievement considering the battery itself is 175lbs, which is significantly heavier than a Formula 1 battery for example, which supports 160 horsepower and weighs only 44lbs!
Chassis & Safety
- 2003 Nissan 350z, ex Koni-Challenge car
- Structural roll-cage tying in suspension load points
- Rear firewall
- High voltage isolation detection
- OMP racing harnesses
- Recaro racing seat
- 2860lbs dry, 3025lbs with driver and fuel. 51.5% front weight biased
Engine
- Jim Wolf Technology built VQ35HR
- 530whp, 8300rpm rev limit
- 4.2L Displacement
- 15:1 Comprression
- 2-ring pistons for reduced friction
- Bryant racing forged crankshaft
- Significant head porting
- In-house developed large long-tube headers
- In-house developed billet individual throttle body kit, with Jenvey throttles and drive-by-wire
- Carbon inlet airboxes
- Variable intake-cam timing deleted to allow for higher compression
- Titanium exhaust using Vibrant performance tubing
Drivetrain & Brakes
- Xtrac sequential gearbox
- Magnisum case
- Paddle shifted 6spd
- High efficiency Xtrac differential with plated limited slip
- Custom shafts designed by MPP to utilize OEM axles and to mate hybrid motor to gearbox and engine
- No clutch, no flywheel
- Tilton 800-series pedal box
- Stoptech ST60 front calipers with MPP/Girodisc 368x35mm rotors
- Stoptech ST22 rear big brake kit
- Pagid brake pads
Electronics
- MoTeC M150 ECU, all software developed in-house at MPP
- Seamless integration of gasoline engine (torque model) and hybrid system.
- Multiple system drive modes and power deployment strategies including lap distance
- Rear-steer system with multiple maps and target system based on corner phase, driver inputs, axle torque
- MoTeC PDM30 that monitors and provides solid state switched power to all electronic devices on board
- MoTeC C187 display and datalogger.
- IZZE racing tire temperature and IR TPMS pressure sensors
- Display in real-time of rear wheel steering system, tire surface and core temperatures, and map switch settings
- MoTeC 15 position keypad
- Bosch motorsport ABS
- Multi-level fault detection and error handling
High Voltage System
- 10kWh MPP developed custom high voltage battery (500V)
- 130kW peak power output
- Cascadia CM200 Inverter
- Phi-power 271.R motor with custom mounting and shafts by MPP
- Brightloop DCDC converter
- MPP Designed super lightweight power distribution box with HV isolation detection, CAN controlled
- BMS control by MPP programmed MoTeC ECU
- MPP High-Voltage indicator lights
Aerodynamics / Bodywork
- DJ Engineering dual element wing
- Motorsport carbon bodywork, with 3d fender louvers built by Spage Sport
- Motorsport front underwing/splitter built by Spage Sport
- Carbon full flat floor and diffuser, built by Spage Sport
- Polycarbonate windows
- Carbon doors
- Wrap by C17 Media
Suspension / Wheels / Tires
- KW Competition 4-way dampers
- Rear anti-roll bar deleted to make room for hybrid system and flat floor
- Solid bearings throughout
- Unitech racing upper control arms
- SPL rear multi-link arms
- Independent rear wheel steering actuators, powered by MoTeC DHB drivers
- Suspension geometry updated to adjust roll center and bump steer
- 18×12″ Volk Racing ZE40 wheels
- 325/660/18 Pirelli racing slicks Front, 325/710/18 rear
We’re fortune to be working with some of the best companies in the world to bring KERS Kels to life. Kels wouldn’t be what she is without the incredible products our partners produce.
Jim Wolf Technology put together the incredible engine which powers Kels, and the MoteC electronics provide the foundation upon which all of the wild integrations can happen in a seamless, easy-to-manipulate way.
Thanks to those two companies, Kels is able to exist. And thanks to the rest of our partners for putting together complementary parts which allow Kels to be at the level of a manufacturer built GT3 car (+hybrid)
KERS Kels For Assetto Corsa:
After literally years of development we’re very proud to share the virtual version of KERS Kels with you!
Kels has been modelled with precision, both aesthetically and physically. Using data captured from real-life Kels at tracks like Mosport and Lime Rock, we’ve been able to match up Kels almost exactly.
Using Assetto Corsa’s ERS system, you can experience the same hybrid feeling as real-life Kels offers, with various different maps to alter the power deployment. The amount of power changes based on speed, wheel slip and lateral forces – some of the same inputs we use in real life!
NOTE: Content Manager and Custom Shaders Patch is required for this mod to work! Simply copy the “mpp_kels” folder into your assettocorsa/content/cars folder. Please share your feedback of the car with us on instagram by tagging @MountainPassPerformance!
Please send your positive comments to us on IG. For feedback or negative comments, please email: noonecares@itwasfreesodontcomplain.com
We ask that you please refer anyone interested to this link, rather than sharing the car files directly. Please do NOT duplicate or modify without our permission. Thanks for understanding 🙂
Huge thanks to Mamiya Motors for the 3d modelling, and Mark Oosting for the sounds. Without these guys, there would be no virtual Kels!
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