Does anyone know if a rear McPherson strut conversion been performed on any Honda hatches? Think stage rally suspension WRC style.

WRC Rear Suspension

 

But there's no suspension in your picture! J/K, I think I can see some external reservoirs hiding down there.

WRC are generally required to keep the same configuration as the road car they are based on. I can't really dream up a good reason to switch to a Mac strut except for maybe the front of a drift car, which uses some pretty unorthodox geometry to achieve what it does.

Hondas generally (except for maybe the 01-05 chassis) have really effective rear suspension configurations. Converting to Mac struts would completely change the load paths, requiring a total rethink of the body/frame structure, all to achieve what? Reduced dynamic geometry and dampers that have to be built to live in high bending stress modes, less control over roll centers and anti squat/dive options, I really only see negatives. A front wheel drive car really needs dynamic geo in the rear to work well.

TLDR: Mac struts are really only an upgrade if you're starting with a live axle or swing arm suspension.

 

All WRC and pretty much any competitive rally car uses a rear Mac strut setup. I think it's primarily for durability and ease of service. They also tend to use really long control arms to minimize geometry issues. I did a conversion on a Ford Focus awhile back. Was just curious if anyone tackled one in the Honda scene, Here is a pic from from the 2022 Toyota Yaris WRC car. They don't even use road cars anymore. The chassis is now all tubular with body panels that resemble a road car. I think WRC went this way for safety reasons.

 

Have to confess, I don’t really follow WRC anymore so I’m pretty unaware of the current formula. Seems everything is converging to homologated cars on spec tubs with some oem profiled bodywork. It’s part safety, partly that it’s easier to scrutineer, and partly that it makes it easier for sanctioning bodies to balance performance and keep all cars competitive with each other if they’re all basically the same. You also theoretically get cars that are a global spec and can plug into multiple series around the world… think GT4, GT3, TCR, etc.

I guess the only thing you really lose with the struts is control over camber. Still, I don’t think you’d move away from a Honda’s usually great rear suspension designs unless the rules require it for some reason.