Intercoolers are not there to save a Turbo Diesel engine. They are there to allow further safe power increases on top of a turbo system. A Turbo charger compresses air to the engine and during this process adds some heat to the air. This heat isn’t an issue to a Diesel engine as it uses super compressed-heated air to ignite the Diesel fuel anyway. Think of the last time you pumped up a tire with a compressor, it gets hot as its compressing air. Intercooling is a much misunderstood story that leads to all sorts of wonderful sales pitches and stories.
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