What if I told you 1mm could mean 14 more horsepower for your diesel?...

 Well, the latter was the case for the '02 Jetta we've been playing with the past few weeks. In upgrading from the factory turbo to an S7 BorgWarner unit from Kerma TDI, the little oil burner went from 142 hp to 156 hp at the front wheels. It's also cranking out an impressive (for a little 1.9L) 328 lb-ft of torque now! Peak boost is 30 psi on the street, and we've seen 1,500 degrees on the Pyrometer for short instances.

 The stock turbo's inducer measurement on the compressor wheel measured a tiny 33mm, while the new turbo's inducer came in at the pictured 34.4mm. Still, all else being equal, a 14-15 hp gain from a 1.9L engine is very respectable. By comparison, we've seen a 5.9L Cummins gain 14-rwhp on the dyno upgrading to a larger turbo and leaving the fueling and tuning the same, so we're pretty happy with these results.

 Once off the rollers, the car's owner jokingly said he wanted to go out and find some Mustangs...or at the very least, some '80s Corvettes, to play with.