Strengthening and Improving the Geometry of the S13 Subframe With GKTech and ZSM Custom

This is how the original fit of the part is.  This is not a problem with the GKTech part, the OEM subframe has a lot of variation and GKTech has to have enough tolerance to be able to fit all of the subframes.  We found this issue when we were modding subframes on our Formula Drift cars for Quick Change rear ends.  Our cad designed parts didn’t fit too well and had to be fitted to each subframe individually.

Zac used an angle grinder and bench grinder to fit the reinforcement to the subframes.

Zac also used the angle grinder to clean weld boogers off of the subframe that was interfering with the fit.

Booger gone!

Ah, now the fit is a lot tighter!


  1. Thats some awesome attention to detail. I can only see myself crashing the car on its maiden voyage with all these nice parts. Love the photo documentation as well.

    1. You guys always do it right. Kinda of rare. If I ever need or one of my friends needed some work done or just good advice I would reccommed your outfit 100% Mike. Thanks.

  2. i’ve installed quite a few of the s13 and s14 gktech weld in reinforcement kits (haven’t done the s13 roll center correction one yet) and i HIGHLY recommend this for ALL 240 owners. if you’re dropping the subframe to install solid bushings, its a great time to have the whole thing sandblasted and the gktech kit welded in.

    Personally, i mig weld them, but if someone wanted to pay for the additional time to tig weld (most of the time is spent getting super tight fitment for all parts prior to welding) i don’t see any downside to it in this application.

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