Home 4x4 Preparation Jeep Sinister Kid

Jeep Sinister Kid

jeep spidertrax sinister kid
jeep spidertrax sinister kid

Saying that Sylvain is a real offroad enthusiast is an under-statement. In fact, he must have been fed with motor oil as a child, his first child book must have been a moped FSM, and his first holidays must have been spent wrenching in a garage.

Lets study the profile of our friend :
 aged 7 he tore down and rebuilt a Caddy moped
 aged 14 he started offroad wheeling with a Dodge WC51 and bought a “junky” Jeep Willys in order to rebuild it with the help of his father. The project lasted for 3 years.
 aged 18, once he got his driving license, he bought a Range Rover V8
 then he built an AMC 360ci powered Jeep CJ8 which was super reliable, he never had any problem with it
 in parallel, he followed mechanical studies and graduated several degrees in engine tuning, electrical and injection systems, etc…
 in 2012 he built the Sinister Kid (the name comes from a song performed by The Black Keys band)

A nice Jeep Preparation

So Sylvain acquired a strong practical and theoretical knowledge, both in the familial circle and at school. You can feel his passion and even some kind of fascination when he starts talking about his work. Note another important thing :besides having an impeccable vehicle, his main interest is the process and the gameplan that comes with such a project.

The project of building this buggy came as an idea after several participations to the “Chambon sur Jeep” meeting. It’s a big Jeep meeting where the first American rockcrawling buggy has been revealed in Europe (the Currie Fire Ant project).
His good friend Fabien already having a Juggy, and Sylvain having helped him to build it, this idea makes even more sense.

This project is also like a challenge, a defy he swore to tackle. This will also be, at 36 y.o. some kind of evaluation of his know-how and competences. And, as you will see, he managed to pass it high-hand.

You can recognize a good craftsman at its tools
Before starting actual work on his buggy, Sylvain wanted to have a proper shop to build in the best possible conditions. He proceeded at the work with a specific idea in mind :
 a welding/grinding
 a bench zone in order to assemble parts
 a central zone to hold two cars and still having enough space to move around.

He spent about 18 months building it, while making it work with his budget and family schedule. As he said, he took time and didn’t rush this part.

Twisted Customs inspiration

At first the idea was to make a copy of his buddy Juggy, but the more he thought about it, the more the idea of starting a tubular chassis from scratch appealed to him. The challenge would become more interesting and at that time, in France, a full tubular chassis was really innovative.

First step : Spend hours thinking, working out and analyzing what was going on the other side of the Atlantic ocean.

He finally felt in love with the “Geodynamic” chassis from Twisted Customs (http://www.twistedcustoms.biz), build by Jason PAULE (a famous american RockCrawling champion) and his crew. Sylvain e-mailed him to ask permission to copy the chassis and have some advice. Jason agreed to the idea and, while not sending plans, he helped Sylvain with pictures and dimensions. “He has been fabulous with me !” said Sylvain. Now, as the build is done, Jason doesn’t hesitate to make suggestions and advices on the Facebook wall of our Frenchy.

Next comes up the design phase, with drawings and listing the parts. Sylvain wanted to have all the parts before starting to build. He chose to let Nicolas from 4Krawl Products handle this task.

And soon, some goods showed up in the shop :
 Twisted Customs Jeep TJ front clip
 Spidertrax axles
 LY5 Chevrolet Vortec Engine (5.3l and 300hp).

Finally, in September 2012, he starteds to bend the first tube. His wife had been very supportive, allowing him a complete autonomy, the only condition being that the whole build wouldn’t exceed a reasonable time limit. Sylvain choose to build the buggy in 9 months, no more, no less. He planned and followed a regular schedule : from 8pm to 1am from Monday to Thursday and from 8 pm to 4am every Friday and Saturday. That’s a real commitment, but as you noticed, Sylvain is a man of challenge.

He started by setting up the powerplan combo in order to build the bottom half of the chassis. It supports the front clip, radiator and seats. Then the upper tubes are put together in order to have the searched look. His buddy Fabien has been a great help in this step.

Then, as the axles are shipped unfinished, he cut, assembled and welded them. Each step was carefully planned and he didn’t have to tinker and improvise here.

1000 hours later the buggy was done and on display at the 2012 Pirate4x4 annual meeting.

The Ohlins suspension choice

For suspensions, he chose the same setup his buddy Fabien has been using on his Juggy. He chose to stay with trail-proven parts, meaning 4 Ohlins coilovers, with 14” of travel and integrated bumpstops. As he planned some high speed use (with an upcoming participation in the next European Ultra4 series), airshocks were completely out of the question.

The Ohlins Company is located really close to Sylvain’s place, at Aurillac. They brought their vast competition experience and knowledge to build the best shocks for this car. They engineered and calculated the spring rate and tuning of the shocks after the car sprung and unsprung weights. The found compromise is awesome, you just have to look at this buggy running to be amazed by the quality of the suspensions on it.

Build Year2012
NameSinister Kid
Build lenght9 months
Chassisinspired from Twisted Customs JASON PAULE’s Geodynamic chassis
TypeFully Tubular with 51“ width
Tube materialTU37B
Lenght360 cm
Ext Cage Width130cm
Othersfully TIGed chassis
engine makerCHEVROLET
displacement325 cubic inch 5.3 L VORTEC LY5 found on a Chevrolet Avalanche
Power / Torque300 HP – 454 Nm at 4000 rpm
BatteryRed OPTIMA
RadiatorGriffin aluminum radiator with 1 SPAL fan / PS and transmission Derale twin radiator
Air filtrationK&N Filter
ExhaustHome made
AdaptaterAdvance adapter
ShifterWinters Sidewinder
Transfer CaseAtlas II 4.3 to 1
Fuel cell12 Gal
Front clipJeep TJ Twisted Custom
GaugesAutometer : Tach, Water temp, Transmission temp, Oil pressure, Voltmeter
DirectionFull hydraulic with PSC pump and ram
BrakesWillwood pedal with 2 master cylinders
Harnesses – seatsMastercraft – CROW
ElectronicsTurn key engine ECU and wire harness
Security1 fire extinguisher
Winches front and rearUsed for suspension suck-down : Warn 9.0 RC and Tmax ATW4500
Front Suspension/ type / materials4 Aluminum links with uniball heat treated joints
Front shocksOhlins Coilovers with integrated bumpstops and 14” of travel
Front axleSpidertrax 9”
Diff / LockerCurrie 9” + Detroit Locker
R&P4.88 Ratio
Axleshafts300M 35 splines
JointsCTM U-Joints
Drive flanges / HubsSpidertrax
Front brakesSlotted rotor and Wilwood 4 pistons caliper
Front and Rear DriveshaftsDumas et Colinot
OthersFront pillow block
Rear Suspension / type / material4 Aluminum links with uniball heat treated joints – Currie antirock sway bar with aluminum arms
Rear shocksOhlins Coilovers with integrated bumpstops and 14” of travel
Rear axleSpidertrax 9”
Diff / LockerCurrie 9” + Detroit Locker
R&P4.88 Ratio
Axleshafts300M 35 splines
Drive flanges / HubsSpidertrax
Rear brakesSlotted rotor and Wilwood 4 pistons caliper
Cutting brakesCNC
TiresGoodyear MTR Kevlar 40/13.5/17
Wheels17 x 8 Walker Evans Racing Beadlocks


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