Dai Yoshihara’s 2018 Formula Drift Rebuild Continued!

Dai Yoshihara's 2018 Formula Drift Rebuild Continued!

by Mike Kojima


So the rush to freshen Dai's car for 2018 by Eimer Engineering continues. In our last story, the chassis had gotten acid dipped, and the cage along with a few other things had gotten some working over for improved stiffness and increased simplicity. 

Now the car is getting reassembled for a quick shakedown run at Irwindale and some more extensive testing at Willow Springs this week. So let's take a look! There are a lot of right ways to build a car here and anyone can benefit from looking at how our car is put together. 


The front suspension is basically unchanged from previous years, with the steering switched from rear steer to front steer. The roll center, bump steer, camber curve and anti-dive have all been tuned over the years to deliver a package that works really well. 

The Akerman angle and curve on the car can be highly tuned via adjustments in the knuckle and steering rack position. This is a useful tuning tool for controlling how the car behaves at angle. One of the tweaks for 2018 is simplifying the Ackerman adjustment so it can be done faster. With the new 2018 rules limiting practice before qualifying to only12 passes, having the ability to make the most out of adjustments quickly is more important than ever. 

Note that all pivot points in the front suspension are double shear for strength and that all the spherical bearings are larger than typical for durability. The knuckle itself is made of 4130 chromoly plate that is laser cut and tig welded. Being hollow, it is a lot lighter than the stock cast iron part.


The rear suspension is identical for 2018, except for some very minor geometry tweaks to improve rear traction and to increase driveability.

Note that everything is in double shear and that the rear knuckles, like the front, are fabricated from 4130 plate. KW Suspension 3-Way Motorsports dampers are the coilovers of choice. Driveshaft shop axles with 930 type CV's and 300M axles are used.


A mid-mounted Fuel Safe Fuel cell with a Holly Hydromat is tasked with holding the fuel.  The Hydromat ensures continuous pickup of fuel until the tank is completely empty without the need for a surge tank, saving weight and adding simplicity. 

The pictured Aeromotive Pro Series fuel pump will be replaced with a new Brushless Eliminator pump before the season starts. The brushless pump can flow more, is lighter, cooler running and draws much less power. It can flow a massive 1000 lbs of fuel per hour!


Here is a view upwards into the rear bay where you can see the rear mounted radiator. The differential is a Winters quick change with a spool and some internal trick stuff for durability by RTS. A custom Progress Group 3-way anti-sway bar is used. There are 3 different diameters of of sway bars to select for varying conditions as well. 


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