How will a used rear-wheel hot hatch measure up?
The plan was to take a used hot hatch and see what we could do with it. Could we improve a BMW M135i? Or would we manage to make it decidedly worse? We decided to start with changing the standard suspension for Bilstein springs and dampers. We thought it would improve matters.
It did. Over some West Country bumpy roads the BMW responded in a way far superior to its standard reaction, making it a truly outstanding car to go rapidly cross-West-Country.
Emboldened by our apparent ability not to mess things up, we thought about adding the hand-grenade engine mapping, but then had a moment of sense and decided to sort out the transmission first.
We needed a limited-slip differential, obviously. Car makers aren’t very keen to add these, and BMW is no different. Perhaps it wants to keep those for the full-bore M Cars rather than these M Performance cars. Either way, unbothered by such niceties, we went for a Quaife differential. We teamed up with BMW specialists Birds for this, and there’s another reason BMW may not fit one as standard – it costs £2,033.
What we wanted to stop was the car’s habit of spinning up the rear inside wheel when we gave it buckets mid-corner. With an LSD it forces torque to both wheels, so all the power can’t just spin up the one that unloads first.
With the limited slip in place early signs are that the car is now much more capable of drifting the rear in a small, controllable manner that is huge fun and doesn’t set fire to the tyres and the surrounding scenery. We’ll explore it further over the coming weeks.
We’ve also fitted the short-shift kit and a modified clutch pedal, all to add some heft to the whole process. We’ll see how that goes and, while we’re about, we’re going to repair every single panel on the driver’s side of the car. Thank you to whoever decided to key the car. At least we know what to do with the old suspension damper if we find you.