What does everyone put into their XJRs? I'm approaching half a tank for the first time and am wondering if i could use regular or have to use something better. I know a lot of turbo cars require premium, but i dont see it asking for anything like that on the gauge. Plus the dealership i got it from filled it up with regular and it seems fine. The car is a 2004 XJR btw, Thanks guys!

 

been discussed many times. premium gas is required for the car for a number of reasons. yes it might run OK on regular but expect premature wear of the parts, reduced performance, and worse gas mileage.

in any car designed for premium that runs OK on regular you usually get such worse gas mileage you spend more in gas then just buying premium to begin with before taking into account any of the other points above.

bottom line: BUY PREMIUM, if you cant afford the difference you should be driving an economy car. also, that dealer is a fool to put regular in it, id probably tell you to never buy there again. im a dealer also, they should be the first people to know better but half of them are stupid and/or just want to be cheap at your expense.

hope this helps!

 

I will never buy from that dealer again, they just had my dream car at a dream price haha. A 2 hour drive away though. And i can afford premium, i just was not sure. Plus this half tank seems to have gone by very fast, so i know what you mean when you say it gets worse gas mileage. Thanks for the heads up! I want this car to last me a very long time!

EDIT-- Also, when i asked the dealer specifically "does this car require premium, plus, or regular fuel?" The salesman said "well i have no idea! I'm sure regular would work fine, but if you want to be safe you could always try plus!" this is why i asked you guys before my first fill up =)

 

I get to half a tank pretty fast too, and I only use premium in mine. I'm sure it has nothing to do with my driving style.

 

haha, i expect the first few to go fast, but i plan on taking my foot out of it after a while. I have a 79 camaro z28 that has roughly the same HP, but is heavier and a tad slower. So i didnt get this car for pure speed, just speed when i want it and comfort the rest of the time

 

This subject is probably #2 or #3 on the most frequently asked list and just as frequently all the old myths and misconceptions get dragged out for yet another

Do a search on octane on this forum and most often you'll see me wading into the ring for few spirited rounds of myth buster. Knowledge is power.

What does your owner's manual say on the subject?

 

i did a forum search for "regular gas" but i'll check out octane lol. And i'm not sure, my dad took it for reading material while he rides the train to work bc i told him he cannot drive it until he knows it inside and out...i didnt think he would take me seriously haha

 

The owner's manual will tell you that 95 octane is best. Good luck finding that in the U.S.

93 is as good as I ever see.

 

From a practical perspective, the salesman was right. Absolutely right.

 

I ran a mileage test a few years back with my XJR. It got 2 more mpg on the best high test available over regular. This was at freeway speeds and using a complete tank full of each.

When you do the math, a cost savings is still present using regular. However, when you multiply the cost savings per gal times the miles you drive in a year the saved amount was not that much. Plus you lose the performance fun of the car and gain increased ware and tare.

 

Was that rating 95RON by any chance? If the corresponding PON number is around 91, then that's the equivalent to 93 AKI gasoline as sold in N. Am.

 

the dealer did not know if to premium in the tank. if you open the fuel door it states it there...

 

he wasnt the most competent of dealers lol

 

I have spoken to people who not buy a car that required premium gas.
The think that it is a waste of money. Then I do the math for them.
If premium cost 15 cents more per gallon and they are an ave driver and use 1 tank a week. then they are spending all 3 dollar more per week on a luxery or performance are for gas. I am sure everyone waste more than that a week. To no buy a car just because of a gas requirement is foolish. They we going to spend the extra money on the car then not on the gas..

 

Interesting. That's exactly what the rating is. Guess I have some reading to do.

 

i agree on the 'not buying a car for premium gas' statement. Sure regular is cheaper, but if our cars call for premium, i can go ahead and not get that dollar menu food and use it for gas lol

 

And 93 is rare too as many stations only offer 91 as their highest (87, 89, 91).

 

OK, I'll bite :-)

Which parts wear out faster if a lower octane fuel is used ?

Cheers
DD

 

89 + 93 / 2 = 91 octane

91 octane = 1/2 tank of regular and 1/2 tank of premium for the price of midgrade

 

sorry if mine or anyone elses comments seemed to be kinda harsh at first, we are genuinely glad you showed up to actually ask and learn then to just assume and have 1 more XJ treated bad lol

i fell bad for all the bruised horses out there though.