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

You can see how much tighter the fit is compared to the first pictures. GKTech in their how-to videos shows that you can also do the installation welding with a Mig welder without fitting.  This sort of welding is actually better than the gloppy OEM welds on the cross member so it is not detrimental but Zac is a perfectionist craftsman.

Now that is a nice, tight-fitting part!

To hold the reinforcement in place for welding, it is bolted in place via the differential mounting holes.

Here is a final look at how much tighter the gaps are after fitting, compare this to the first photos before fitting and see.


  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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