Rodger did as what was called for by MWB. You can do that and all good, or do what I did...
View attachment 19173 View attachment 19174
This first photo shows what I did instead of the heavy stock: a somewhat thick 14G (0.0747") sheet welded across.
The MWB team recommends cutting out the entire lower area for exhaust or something. I agree but wanted to be able to transfer load from that lower crossmember to the upper crossmember, so I built this:
View attachment 19171
Here's what it looks like all installed.
View attachment 19172 View attachment 19168 View attachment 19169 View attachment 19170
Here's my (hillbilly) thinking... The primary reason to reinforce the rear crossmember with the K20 kit is that the subframe takes ALL the torque from the engine at the suspension points. Nice, but now you need to reinforce. The primary torque under full throttle will be to twist the powertrain "back" (that is clockwise when looking at the driver from the left side of the vehicle) to power the vehicle forward. As I've said before - imagine the X trying to "pop a wheelie", then you get it.
So all the force on the subframe, this the crossmember, is down. My goal was twofold: beef up the cross member lightly with nice tall/wide plates then look at how that transferred load to the rest of the chassis.
I am trying to make it strong but keep the extra weight as low as possible. No idea if I have succeeded, but I have to go with my gut. It's my money so I'm doing my build my way. Hope this helps. Keep posting what you're doing to your build Hussein.