This Is How Much Power Is Lost When A VW TDI Is Running Clean

Photo Credit: Screenshot of The Fast Lane Car Youtube
Photo Credit: Screenshot of The Fast Lane Car Youtube /

The Fast Lane Car went ahead and dynoed a VW Jetta TDI with and without its cheater software running and this is what they found.

Now that dieselgate and Volkswagen’s cheater software scandal is all but common knowledge, a few people are wondering how much less power would a TDI engine make with its suite of emissions running. The Fast Lane Car just found that out earlier yesterday (Oct. 1, 2015) and the results are surprising. Basically, if a TDI equipped car like a diesel VW Jetta knew it was running under emissions testing procedures, it would turn on its full suite of emissions testing software which included a detuning of the engine, and the TDI-equipped engine would pass emissions testing. But when the car was driven on normal roads, the suite of emissions testing was turned off and power returned to normal as advertised when you first bought the car. Check out the full video below!

By strapping their VW Jetta onto a four wheel dyno, The Fast Lane Car was able to replicate real-world driving conditions and were able to keep the emissions testing software at bay. From the factory, a TDI Jetta makes 140 HP and 236 lb-ft of torque. Acceptable. After the first dyno run TFL confirmed that a TDI equipped Jetta made 138 HP and 260 lb-ft of torque to the wheels, better than advertised! When they switched the dyno to 2WD mode and simulated test conditions max HP and torque measured at 136 HP and 228 lb-ft, a sizeable drop, but on some parts of the power curve there was a difference of 15 HP and 32 lb-ft of torque!

And therein lies the rub to the whole scandal. Many owners love the MPG and power they can squeeze out of their TDI’s. Unfortunately after a reflash to correct this software, they’ll lose a bit of HP and torque if they want a clean conscience.

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