Can an Oil Change Affect Horsepower?


For our fresh oil, we chose Royal Purple HPS High-Performance Street oil. Royal Purple HPS is a synthetic oil fortified with high levels of zinc diphosphate and phosphorus for extreme pressure protection in addition to their proprietary Synerlec additive technology.

Unlike more racing oriented oil blends, Royal Purple HPS also has additives to help reduce deposits, keeping the engine clean for long term daily driving use as well as providing protection from wear under extreme conditions. It also has anti-oxidants for a long service life.


We completely drained our old oil and changed the oil filter and added 5 quarts of the Royal Purple HPS.

5 quarts of HPS exactly matched the oil level we had previously on our dipstick.  Now we could feel confident that windage would also be about the same as our previous dyno test.

Once again, we let our mighty bone stock K20A3 rip on the dyno. The differences between regular dino oil and Royal Purple were immediately felt when starting the car. The car had a smoother idle and less perceived vibration.

We ran the car many times on the dyno to let the car’s temperatures stabilize on both the original oil and the Royal Purple.

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