Rumbles: Thinking about Converting to RWD

I’ve been thinking about this for a while, however, my reason is probably not what you are thinking. I don’t plan to go drifting or to do burnouts. I’ve done plenty of burnouts back in my Fox chassis days. Tires are expensive, haha.

The biggest reason is tires. I am running 265/35/18s summer tires with plans to go even wider once I complete my widebody setup (at least 275s or wider). These tires already grip well so the need for AWD grip has diminished. The EJ207 just doesn’t make the low-end torque to make traction an issue.

My power goals are pretty modest as well. I think somewhere in the 300-350hp range is plenty for me, especially if I get the weight of this car down to around 2800 lbs. That would give me a weight-to-power ratio (or pounds per hp) of around 8.XX, which puts us in the Camaro SS/Mustang GT territory. It’s crazy to think about how the WRX/STi was either equal to or better than the pony cars in the 2000s. Now, they are not even close.

The only times I lose grip is during a touge run when the center diff starts to bind up and/or I give the front wheels too much angle. I’ve thought about gutting the center diff of the vLSD parts, except I already know how an open center diff works on the Subaru. I owned a 2005 STi for a couple of years and I would set the center diff to open in the tight turns. The car rotated much easier.

So, instead of running an open diff, I think I am going to convert the center diff into a spool. There are several videos out there that show what’s needed to convert the Subaru 5MT into a spool. Basically, you remove the vLSD parts, the center diff spider gears, and weld the rest together.

My main fear is that I will break the R160 or the rear axles. However, the EJ207 makes boost pretty smoothly and very low cars seem to break axles more frequently regardless of power level. And I can turn the power down with my hybrid boost controller.

And I hope that the 207 will be happier just spinning up two wheels versus four, and I can get a bit more angle in tight turns. And if I like the RWD setup, then long-term plans would be to swap rear diffs for something more durable like an r180 with a 1.5 way LSD along with a 6MT with a RWD spool.

Even longer-term plans would be to try and push the engine back approximately 9-inches or so. There are 12-inches between the heads and the firewall, but then the steering rack has to go somewhere. Moving the engine back 1-inch is supposed to be great for handling

And if I hate it, I will just buy a replacement center diff or maybe just do the 6MT trans swap and forget it ever happened.

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