Cadillac SRX Second Generation Forum - 2010+ Discussion, 2010 2.8 turbo-- gas in Cadillac SRX Forums; Can I use regular gas in this SUV? Or should I stay with super? Please list some reasons why and ...
If the vehicle has the 2.8L V6 engine (VIN Code 4), use premium unleaded gasoline with a posted octane rating of 91 or higher. For best performance, use premium unleaded gasoline with a posted octane rating of 93. In an emergency, you can use regular unleaded gasoline with an octane rating of 87 or higher. If 87 octane fuel is used, do not perform any aggressive driving maneuvers such as wide open throttle applications. You might also hear audible spark knock during acceleration. Refill the tank with premium fuel as soon as possible to avoid damaging the engine. If heavy knocking is heard when using gasoline rated at 91octane or higher, the engine needs service.
Need premium (as Rippy said) with the higher compression of the turbo. If you dont, you'll have detonation which can cause motor damage. The octane rating has nothing to do with anything other than resisting detonation/knocking. However any higher compression motor will generally have detonation problems without it. Its not so much for performance as it is to stop the knock. Yes, the knock will reduce performance, but its the damage to the motor you would be more concerned with.
Most everything out there says "use only recommended gasoline grades". Higher octane doesnt really increase power (a gallon of gas has the same energy, no matter octane) so if the book says regular, use regular; if it says premium, use premium.
Kinda rambling, but hopefully you get the point. Just trying to explain 'why'.
the short version is that if you use 87 it will spontaneously combust due to compression instead of combusting by spark
the exact timing of the combustion events is crucial to operating correctly and the premature combustion causes knock
severe knock can cause serious engine damage
I agree with both Turbo and zinner.
What I sometimes THINK tho is that the knock sensors 'should' fix most detonation situations, retarding the timing some to cut down on it... Perhaps my understanding of the system is over-simplified (or wrong) but I always kinda thought that one might be able to coax the computer to more power with high octane, assuming the computer 'should' just keep advancing the timing until it heard a knock...
Like I said, in theory, that might work. Reality is surely something different...
how about middle grade fuel...gas is expensive here in Canada
You can use regular or middle grade gas for the short term and your computer will adjust the engine's timing and performance automatically. However, you will notice there will be some loss of HP and your gas mileage will also be affected too. I see hundreds of Canadians come to the US for shopping savings and gas savings. They fill up as many as 3 and 4 Five gal. gas cans all the time to take back with them.
IMO I would try not to use mid grade or regular gass for more than a couple of tanks full.