I am considering a 2008 Nissan Altima 3.5 Coupe. The recomended fuel is Premium.That factor these days is a turn off to me. Is it possible to run these cars on regular fuel and if so what are the disadvantages?
I'm not sure about the V6 in the Altima, but the cpu in my Z will reduce the performance of the engine when it senses the lower grade fuel. It will also cause pinging. It's only a few extra bucks per fill up. I would use what it recommends to get the full performance out of the car, but its up to you.
Here's how it breaks down: any car made in the last two decades or so that requires premium fuel has a knock sensor in it. Thus, when people put regular in it, it retards the timing and runs just fine. Those individuals then mistake "runs fine" for "runs great".
What is really happening is this: when you put lower octane in, you probably won't experience any knocking and pinging, but please do not mistake this for thinking it doesn't really need premium. The retarded timing which is keeping the cheapo fuel from hurting the engine is also costing you horsepower, or fuel economy, or (more likely) both. So when you put lower octane in there, suddenly you're not making 265 horsepower, you might only be making 250, or maybe less. And suddenly you're not getting 30mpg, instead you might be getting 26.
Now this is where the math kicks in: my ride recommends the use of 91 octane fuel. I get 24mpg running 91 octane. For the sake of quantifying the loss, I ran a few tanks of 87, and promptly dipped down to 17mpg. At $4.25 for premium and $3.95 for regular, let's figure out my cost per mile, shall we? Running premium, it costs me 18 cents a mile for fuel, whereas running regular, it costs me 23 cents per mile. It is, in fact, cheaper for me to use premium. Not to mention that I did a before & after dyno run (had some spare time on the dyno when I got it tuned) and noted that 87 octane fuel cost me 17 wheel horsepower.
Is it worth it? You decide. Quite frankly, if you don't want to be buying premium, don't buy a car that uses it. Even though it is only recommended, that still means the engine was engineered for use with premium fuel and straying from that recommendation means it won't be running the way it was designed to run. Save yourself the premium cost for the V6 engine, opt for the 2.5 and put the difference into a savings account. You will be better off in the long run.
most cars dont need premium fuel even if the manufacturer recomends it. I would use regular if it drives ok. I know a lot of people who have cars that recomend premium and none of them use premium fuel.