First post from this newbie. I'm gathering information on the XE for a purchase. Other than diesel are all the gas engines premium fuel only? Cant seem to find online information, only saw a youtube video with the V6 sport model and they mentioned premium fuel. Thanks in advance for your replies.

 

According to this:
https://www.fueleconomy.gov/feg/bymo...aguar_XE.shtml,
they all require premium gas.

 

I have the V-6 and it uses premium.. this makes sense as they need to have a fairly high compression ratio to garner horsepower, thus efficiency.
Lawrence

 

The 25T and 20T use premium as well, over here at least.

 

All petrol engines recommend premium gas. Took a look at my XE's manual and that is what it says. Here's a link to their digital manual Jaguar Owner Information

After selecting your language, country, and the XE. Look for "Fuel and Refueling" category, then "Octane Rating" sub-category.

"The vehicle manufacturer recommends the use of premium unleaded gasoline with a minimum octane rating of 91 AKI (Anti-Knock Index) to contribute to increased performance, fuel economy and driveability."

"Do not use fuels with an octane rating lower than 87 AKI, as severe engine damage may occur."

"Do not use leaded fuels, fuels with lead substitutes (e.g., manganese-based) or fuel additives, as these may adversely affect the emissions control systems and may affect warranty coverage."

From a personal experience, I find Shell's V-Power Nitro+ to be the most accommodating fuel for my XE. Not sure if it's just a placebo effect but the engine appears to agree with it more. Performance seems better compared to other fuel.

 

As others have said, Jag recommends using 91AKI. There's no evidence that using even higher grades 93, 94 etc. makes any difference. Use of fuel less than 91AKI may increase consumption and reduce performance.

As for fuel brands or the all-revered Top Tier marketing scheme, a recent study indicates that it makes little or no difference. Jags do not require the use of Top Tier unlike some other OEMs.

 

According to this recent AAA study, there is actually quite a bit of difference...

https://s3.amazonaws.com/association...rt-FINAL-1.pdf

 

That's the exact study I was referring to- and the devil is in the detail.

According to them, the difference is limited to a maximum of 4% in mileage, ie 19.2 mpg vs. 20 mpg, when using the worst of the worst gas (if such a thing exists) over an extended term vs. the best of the best over an extended term.

That's hardly 'quite a bit of difference'.

BP suggests that up to 5000 miles is required for additives to take effect.

It's likely that very few retailers 'go cheap' and specify insufficient additives for their brands.

 

There is a large difference in engine deposits though, supposedly, according to that study.

 

Again the devil is in the details. Here's the actual numbers:

"The test engine operated on a TOP TIER gasoline averaged 19 times fewer intake valve deposits than when it was operated on non- TOP TIER gasoline. (based on the ASTM D6201 test - TOP TIER gasoline averaged 34.1mg of deposits per intake valve versus non- TOP TIER average of 660.6mg)"

Yes, 660 is 19 times more than 34, but it's measured in milligrams (1,000th of a gram) so the concern is over something that weighs only 0.02 oz. worst case.

Hardly a 'large difference' as confirmed by the minor difference it makes in fuel consumption.

 

Fuel consumption is just one aspect. The study also points to a number of performance impacts:
- rough idle
- hesitation
- knocking/pinging

Granted, they have not quantified just how big that impact is, so it's anyone's guess.

 

I happen to use the top tier gas whenever possible (usually Shell 91 around here) although it seems to have slight advantage.. just a personal preference.

My recollection of the study referred does not use a direct injection engine? At least thats what I remember reading a few weeks ago when I copied it onto the Forum site. So, on a direct injection engine it may not keep the valves cleaner. Regardless, I like using the best gas I can for these cars.
Lawrence

 

And yet actual examples of cars with issues attributable to the fuel seem to be very difficult to locate, I've never seen one. The bad gas from Mom and PoP stores seems to be somewhat like seeing BigFoot.

By definition, it cannot.

 

Unless one is filling up at non-branded gas stations, one is most likely getting top tier gas.
Retailers

There is no reason to believe one top tier gas is better than another.

Now this is not about gas, but here's an engine failure that was caused by bad quality diesel from a Shell station.
Do NOt Buy A BMW Diesel Engine Car Without Understanding this Risk - Bimmerfest - BMW Forums

 

I didn't read all 25 pages of this 'he said she said' trainwreck, but apparently the car was misfueled with gasoline, not diesel.

 

It's important to read the whole thing before posting such a conclusion!

>>>
Bimmerfest - BMW Forums - View Single Post - Do NOt Buy A BMW Diesel Engine Car Without Understanding this Risk

That is a fair point and I am not intending to be evasive. Here are the facts:

- car is a 2015 328xD with 12000 miles purchased in May 2015
- Wife and I are only drivers and the three fuelings we can isolate prior to early engine symptoms are known and we have original diesel receipts from each. All fuelings were Shell but in two separate states
- we were both in the car when the three fuelings were performed and no gasoline was ever introduced into the tank
...
>>>

There's also a follow up thread:
Bimmerfest - BMW Forums - View Single Post - Diesel Fuel Contamination Thread Continued...

 

I read all that. The owner says he didn't fuel it with gasoline, the dealership says that they found proof of gas in the tank- and that this was the source of the engine issue. He said, she said. One of them is wrong obviously - but it's got nothing to do with Jaguars or gasoline or additives or Top Tier.

This thread is discussing the advantages (if any) of Top Tier. The AAA study more or less concludes (if you read past the big print) that Mom and Pop gas is just fine. Maybe this indicates why Jag makes no mention of using TopTier at all.