Even on turbo engines, with modern engine electronics, detonation is a thing of the past. Of course, it might reduce the power slightly due to the extra timing retardation, but you can easily run a "premium fuel only" vehicle on regular fuel without worrying about engine damage.
Yousuf Khan
Wade is absolutely right. Automotive engineers who don't work for any automotive or oil companies will tell you this all of the time. The premium fuel is only a recommendation in modern engines, and modern engine management systems will compensate for all fuel types easily,
100's of times per second.The only time a high octane fuel would be needed is if you have an old high-performance car from the 1970's or earlier which didn't have electronic engine controls.
If you have a high performance car, and you want to go racing with it on a track day or something, then by all means fill up with high-octane that day. If you're driving around town or on public highways with speed limits, you'll never need that level of performance.
Yousuf Khan
It is NOT a thing of the past. If the manufacturer says "premium fuel recommended" you can get away withr regular, with reduced performance. If it says premium fuel REQUIRED you may get away with regular fuel if you drive conservatively, but if you run it hard you WILL damage the engine. The engine being referenced by the original poster is definitely a "premium fuel only" engine. 2 years newer you can squeak by on regular.(premium fuel recommended)
Or the early models of the EJ25Turbo. AnEJ255 V1 requires premium fuel. The EJ255 V2 dies not because the compression was lowered with larger "dishes" in the pistons. The EJ257 is a premium fuel engine (300 and 305HP WRX) The series 2 EJ255 uses different camshafts than the series 1 and the EJ257 as well. The EJ251 was also a premium fuel engine, although normally aspirated- It required premium fuel due to a cooling problem. Run on regular gas they lost their head gaskets while on Premium they usually lasted - apparently due to low level detonation on regular fuel.
Unless you are drivinf an outback with 5 adults or 4 adults and a full load of luggage on a hot day in hilly country. If it is a "premium fuel only" engine, use regular fuel at your own risk, and drive with an egg-shell taped to your right foot. If it is a "premium fuel reccomended" engine, know your performance and economy will suffer on regular fuel, and avoid "spiritted" driving or heavy loads. With a standard transmission make sure you keep the revs up - don't lug the engine. Low speed lugging is where detonation is most likely on a high compression motor due to inferior fuel.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.