Cheap Way to Stiffen the Chassis

[DarkLight]

So, I’ve been running all of the Ultra Racing chassis braces for some time now, and it really transformed the car’s handling.

Which got me thinking, what other ways could I stiffen the chassis without adding too much weight or resorting to extreme/impractical measures like seam welding the chassis or adding a cage? I daily the car now so anything invasive is off the table.

What I decided to do was to seam weld the lower radiator support bracket. I noticed that it ties the ends of the subframe together, where the most flex occurs, and can unbolted from the car. Perfect place to add some stiffness, and also works on the same plane as the UR front power brace.

I went online and looked up prices for this piece. I was seeing about $80 new and as low as $27 used, so I didn’t have much to lose if something went wrong.

After removing it from the car, I noticed that it was made from two pieces of thin stamped steel only held together by about a dozen tack welds on each side. The welds aren’t the highest quality either. When I was surface prepping, the welds were rusting underneath the paint and had numerous inclusions. I highly doubt that such a crudely constructed part would be heat treated, so I proceeded.

I seam welded the entire piece end to end, using small tack welds to judge how it would handle the heat, then I made .5”-1” long beads at time, alternating from side to side, until I was finished.

I allowed ample cooling time and refinished the part by dipping it into cold blue and then put 3 coats of VHT roll bar/chassis paint on it.

Good news is no warping of the part, and there was a noticeable improvement in roll stiffness. Multiple friends who have ridden with me have commented that the ride seemed harsher and they were not informed of what was done.

I plan on doing the front/rear subframes, possibly control arms too.

Anyone else tried something like this? Any further thoughts/refinements? Thanks for reading.

 

[gtman]

DarkLight, that's really impressive work but seam welding is a bit extreme for a street driven daily driver. Weren't all those UR bars good enough?

Do you race your Civic on the track as well? How harsh does it actually ride now?

 

[typeaarrr]

Stiffer engine mounts

 

[DarkLight]

DarkLight, that's really impressive work but seam welding is a bit extreme for a street driven daily driver. Weren't all those UR bars good enough?

Do you race your Civic on the track as well? How harsh does it actually ride now?

Thanks. The UR bars work great, money well spent, and more than enough for most spirited drivers, but I have to make serious upgrades to reach my goal: which is to get the handling on par with a stock FK8. I still have a good bit more to do, and I will share with the community as I progress.

My first impression was it felt like a mild spring/damper upgrade along with a ~1mm stiffer front sway. Steering is heavier/tighter and gives better feedback. The car stays composed even when taking corners at unspeakable speeds. It’s a great mod because it can be swapped out in minutes if you don’t like it or something goes wrong.

I admit harsh is a bit subjective, but I meant that most average drivers would probably not want to spend much time riding in my car. I can feel every bump in the road, whereas before I installed any bracing, the car felt soggy even with Si springs and touring coupe dampers.

I will start racing the car some time next year, after I’ve finished a few long running projects. I work slow, and a build usually takes me about 4-5 years to finish.

Stiffer engine mounts

I’m running all 3 mounts filled with urethane.

 

[Thanks_Enjoi]

Look into beatrush

 

[Ghosted]

Keep up the good work DarkLight. Always looking for ways to stiffen up the chassis. Following.

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