Why is there smoke that smells like rubber coming from the driver's side wheel well of my Mazda RX-7 FD?

A rubbery smell most likely means failed rubber components near the turbos are letting oil mist from the turbos or the crankcase ventilation system drip onto the hot side of the turbos, producing smoke that can drift back toward the wheel well — assuming the smoke is originating in the engine bay rather than the wheel well itself ³.

Here is a breakdown of potential causes based on the components in that area, organized by the smell you're noticing:

• Failed Rubber Components: Inspect the area around the turbos. Failed rubber components can allow oil mist from the turbos or the crankcase ventilation system to drop onto the hot side of the turbos, causing smoke ³.
• Coolant Leak (Sweet Smell): If the smoke has a sweet smell rather than rubber, it is likely coolant. For 1993–1994 models, there was a recall for a bad turbo coolant hose that could leak onto the hot turbos and cause a fire ³.
• Oil Leak (Burning Oil Smell): If the smell is burning oil, you may have an oil leak around the turbo ². Another common culprit is the o-ring sealing the y-pipe to the small pipe connecting the secondary turbo compressor; when this fails, it allows oil to drip onto the exhaust ³.
• Exhaust Leak (Exhaust Smell): If the smoke smells like raw exhaust, it indicates a leak near the manifold, turbo, or downpipe ².