Chassis Prep on Scotty's 2011 STI Race Car - Seam-welding and Spot-welding

Chassis Prep on Scotty's 2011 STI Race Car - Seam-welding and Spot-welding

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At the end of last season, Scotty was able to set yet another personal best of 1:59.05 at High Plains Raceway. His plan for the 2019 season is to run a full season of NASA Time Trials, so in the off-season, the top priority is to put a cage in his car.


The prep work is almost done, and we wanted to take a look at the work that Scotty has done so far.


The main priority now is to increase chassis stiffness through the design of the cage, but also through spot-welding and seam-welding as much of the original unibody as possible. The factory unibody is already spot welded but the spacing can be as much as 3 inches between welds. Scotty is trying to put a spot-weld in at least every inch. And where there is room to work, Scotty is seam-welding the unibody. This involves running a full bead down the seam of the chassis.

B-Pillar Spot weld

engine bay seam weld


Once the cage is installed, the design of the cage with all of these improvements to the unibody should make the car significantly stiffer and more responsive.


At the same time, Scotty is taking out any non-essential pieces of sheet-metal which will also save weight. A lot of other things are also being done to reduce weight, so we will focus on those in a later installment.


The last thing that is worth mentioning is that Scotty is completely re-working the rear strut mounts on his car. The GR STI's have a known issue with lack of suspension travel in the rear due to the multi-link suspension design. There are some lower arms that can help with this (such as the Voodoo Thirteen lower arms), but since everything else is being re-worked, this is the perfect time to modify those rear suspension mounts. By moving them up 1" and reinforcing them, the function of the rear suspension should be improved significantly.

GR Rear Suspension Modification


Thanks for reading, and stay tuned for the next installment!


- Jon Cooley