Hmmmmmm whats the octane of your gas????
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Mid grade is a blend of the 2. Another dirty little secret is that if your car is not high compression (such as in a performance of turbocharged engine) you might have less performance and mileage with higher octane gas. Octane rating is the fuel's resistance to detonation.
High compression is only in small high-performance engines. Turbocharged usually have lower compression ratio than normal, their enhanced over normal engenes power comes from more air-fuel mix pushed into same volume cylinder by turbocharger, so no need to rise compression ratio.
We have АИ-92 (Regular) and АИ-95 (Premium) gas here, rarely АИ-98 or АИ-102. If engine could run on both 92 and 95 then there is no any profit in one or another. Engine consume slightly less 95 than 92, and 95 sliglty more expensive than 92. So, there is no any point to use 95 instead of 92. But if engine is designed for 95, then there could be excess detonation if you will use 92, so more wear and lower power output, because ECU will lower power to avoid detonation. You could save some money, but will lose both in mpg and service.
Seems that big american engines don't care about gas octane at all. At least those with more than 3 liter volume made up to 2010. They could actually run on АИ-80, but it is nearly impossible to find one today on the market, it produced in limited amount mostly for old agriculture machines without diesel.
Also, LPG have octane number around 110 (104 by US standard), and most engines have no problems running on it. Installing LPG fuel system could save a lot of money because LPG is around twice cheaper than gasoline,
So, if your engine can run on low octane, then you could use any grade you want, the higher price will be compensated by higher mpg.
For modern small Japaneese, Korean and European engines better use highest grade available. They screwed reliability in exchange to higher efficiency, (HP per volume) so even little detonation could lead to faster wear.
I tuned engines for racing on cars with carburetors back in the 80's. We would use visual observation of the spark plugs to look for signs of detonation, fuel mixture optimization and spark timing. It was part of the fun with racing. The ECU handles that now. Sometimes we would blend toluene or methanol into our fuel when we could get away with it. Combustion chamber design could help reduce detonation and empower you to tune in more power. It was fun.
I bet you could still smell the mtbe lol.
Ah!!! Thanks. I new it was in the controller
Hi and mid grade gas is typically not optimal for most vehicles. If your engine is not tuned for it, you will get less power and lower gas mileage
Good life pro tip