Engines are more susceptible to pinging as the temperature increases. It’s not surprising that you need higher octane fuel during the summer. We have a 1960s car that needs 91 octane premium all the time. During the hottest summer weather, it still pings at full throttle.
I have an 02 VW Passat with a 2.8L V6. A minimum of 91 octane is recommended for this car. I have experimented systematically with regular, midgrade, premium, as well as blends of these. Here’s what I have discovered: If I buy a tank of anything less than a 66%/33% blend of 93/89 octane fuel my check engine light will come on within a few days. For my next tank, if I put in all 93 octane the check engine light will eventually go off; again this usually take a few days of routine driving. When running on a lower octane mix I get a noticeable lag when trying to accelerate in 1st gear (manual trans) but this is the only noticeable performance difference. Mileage is about the same in mixed in-town & highway driving. On a long highway trip I do save a little money by using all mid-grade (89 octane). The unanticipated dilema I have encountered is this: If I should decide to regularly use a lower octane mix and run around with the check engine light on all the time the car will not be able to alert me if another, different “check-engine” problem should develop. So, I guess I will go with at least a 91 octane blend for the time being. Can anyone confirm for me that the octane difference is likely responsible for the check-engine light coming on and going off?
my new 3200mi suv would not start due to engine flooding per the service dept at the dealership. they told me this happened because i was not using 91 octane gas, is this possible?
Just as a sidebar, have you ever seen, firsthand, the damage that using 87 octane fuel does to an engine that recommends 91 octane? You hear stories but I’d like to talk with someone with first hand knowledge.
Also, when there is spark knock, there is some loss of performance even if the timing does not retard as in my 1993 Ford 5.0 ltr. My question is, is there real damage or just wive’s tales.
I’ve always thought that your current advice is right. But to be on the safe side when I bought my 2001 Honda Prelude I asked you (car) guys and you told me that while the spark advance allows the engine to run on regular without pinging, when the spark is advanced the engine runs hotter, and it can run enough hotter to do serious damage. Why did you change your mind(s)?
Here’s the way I look at it! If you are nuts about cars and you have spent alot of money on your car/truck or in my case car’s/truck’s. What’s an extra 20/30 or 50 cents a gallon for the good stuff.
Now i’m not saying go crazy and put 93 in your rusty 85 Yogo ETC but if you just spent $2000 dollars for some hi-po tires for your sweet ride, get ya some hi-test. If you are the type of person who hasn’t washed your econo box in 6 months and has french fries under the floormats then by all means drive in around all day looking for the cheapest gas you pour into the thing! But if you are like me and can’t drive your car until the windows are cleaned or if you have ever waxed the underside of a trunk lid on your 71 buick, go ahead ,put that super stuff in there and call it a day.
I will also ad this if you have cars that sit alot put hi-test and some fuel stabil in it, you will thank me when August comes around again!
Agreed; my 2002 Cooper lost power, knocked, and generally complained the one time I thought I’d see if BMW/Mini were serious about needing 91 octane. They sure were!
Can someone help me with my case? I drive a '97 Mazda 626 with a V6 (LX model). My wife and my father-in-law are always making cracks at me about insisting on premium gas in it. They have firmly bought the myth that it makes no difference for ANY car. I keep telling them that the manual says it is required, therefor that is what it gets. Is there any stronger evidence than that? I love this car and it has very good power (especially for having 110,000 miles on it). Help!
My own experience with both cars and motorcycles is that performance and gas mileage suffer when switch from premium to regular grades of gasoline where the vehicle calls for premium gasoline. My current car, a Lexus LS400, shows a 10% decrease in mileage (I check the mileage at every fill up). With premium in California now at $3.30 per gallon, this equates to a $0.33 per gallon loss in value which exceeds the $0.20 per gallon price difference between premium and regular grades of gasoline.
The only comment that I have in the discussion of PREMIUM vs regular is this. The people who own Mini Coopers equipped with a 116 hp engine requiring PREMIUM gas have bought(literally)into what BMW and other PREMIUM (there’s that word again) car companies want them to believe in. They bought a PREMIUM vehicle with PREMIUM dollars, therefore they must fill it with PREMIUM gas!Really, give me a break, a 116 hp engine? I dont give a crap about high, medium or low compression! It’s all nonsense.That’s my PREMIUM response on this subject.
We have always driven old Japanese cars. One Toyota sedan–I forget the model–as well as our Toyota Sienna–both ran much more smoothly with the highest premium gasoline. Most or all of our cars seemed to have gotten slightly better mileage with premium fuel too. So, I tend to believe there’s a worthwhile difference.
Tattian, I’m not sure what you are saying here? That smaller engines never require premium? What bull! It’s strictly a function of compression ratio. Why is compression nonsense? Our cars won’t run, wouldn’t exist without compression!
MazdaJohn: You are 100% correct. You might post this as a new question, you would get more responses. Although I don’t know of any responses that would help. Doesn’t seem like any facts will change the opinions of wife and father-in-law.
mws: Prevalent opinion is that their older advice is correct. They are trying to generalize too much in their current stand. If the owner’s manual says premium required, than it is required.
The people who own Mini Coopers equipped with a 116 hp engine requiring PREMIUM gas have bought(literally)into what BMW and other PREMIUM (there’s that word again) car companies want them to believe in. They bought a PREMIUM vehicle with PREMIUM dollars, therefore they must fill it with PREMIUM gas
Clearly you don’t understand what premium gas is nor do you understand why it is needed. Premium (not really a good name) means high octane. Higher octane burns slower so it does not burn too fast in a high compression engine. Many modern engines have a sensor that detects the fast burn of regular and retard the spark.
Funny thing, diesel fuel is rated on the cetane scale and there a higher number means it burns easier/faster.
So here is my question. Is Premium gas better for the environment?
Sandy
Read through the thread. If the manual says it MUST have it, then it MUST have it or you risk damage. If it says it should have it, then you don’t risk any damage, but you will loose some power and some mileage. It may even end up costing your more to use regular.
So here is my question. Is Premium gas better for the environment?
It is about the same. It really is a little complex. It takes a little more resources to make premium so if you car does not call for it, then it is bad for the environment to use it. But not very bad.
If your car says it must use it, then you likely will loose mileage and possible damage to the engine so that is bad.
What comes out of the tailpipe is not really different.
I have an 03 passat with the same engine. While I always run 91 or 93, I have never seen a CEL. The salesman said I could run regular with no problem, which advice I ignored.
The previous owner of my 1990 Cadillac Fleetwood told me he got good performance with 89 octane gas instead of 91, so that’s what I use and never have had a problem. However, my mechanic did tell me that I must use only gas with Techron in it and when I didn’t, it ran very rough. Since then, I’ve used mostly Chevron 89 octane.