Have always used high test for anything that uses gasoline.
Lawn mowers, garder tiller, weed whacker everything

 

Well, that's a waste of money. If the engine doesn't need it, premium fuel doesn't add anything. It's not "better" fuel, it's simply higher octane, which makes it appropriate for engines with higher compression or forced induction. It adds zero benefit to an engine that runs on regular fuel. ZERO.

 

Your entitled to your opinion wfooshe.
Regular gas will often plug the carb on a lawn mower, or chainsaw if left in oner the winter.
Ask anyone that repairs small engines for a living about it.

 

That's what Sta-Bil is for, and costs a fraction of what months and months of an extra 30 cents a gallon costs. And it's not just regular that does that.

 

Choice as always is yours to make.
Old Neighbor i purchased my first car from told me about high test gas.
His first car was a six cilinder, & what he found out about high test gas was.
You will not have near the carb issues as others.
Better car starting in the winter, & better gas milage as well .
Found out he was right, been using high test ever since.
Don't need or use any sta-bil in my fuel

 

Might depend on what additives they put in the gas at the station. I know that Amoco, for one (or was it Chevron?) used to advertise the detergents they put in their supreme gas, but those additives are not in all brands. I still say that for the most part, premium fuel is simply higher octane, and not "better" or "cleaner" gasoline. If the brand you buy has stuff in it that the regular gas doesn't have, then by all means, go for it. Adding stuff to regular gas yourself is still significantly cheaper.

 

There's "high test" or "premium" based on octane rating, but the icing on the fuel cake at standard name brand stations is what is known as "top tier" gas. It has more "detergent" in it. Here is an AI-generated definition, followed by a link to the Top Tier program: "Top Tier gasoline is a fuel standard, not a grade of gasoline. It's a program where fuel retailers voluntarily agree to supply gasoline that meets a higher detergent standard than the EPA minimum.These fuels are specifically designed to help prevent and remove carbon deposits from engine components."

https://www.toptiergas.com

Unless I desperately need a few gallons of fuel and I'm in the middle of nowhere, I won't use off-brand fuel. I personally stick to Shell, largely because I am surrounded by stations with that brand, it's part of the Top Tier program and they are part of a discount program that ties in with grocery store purchases in my area (Fuel Rewards). I just bought 17.5 gallons with a $1.10 per gallon discount off a posted price of $3.80. I get the best there is at a substantial discount. Costco fuel also is Top Tier and for 93 octane in our area is it generally about 20-30 cents a gallon cheaper than name brands like Shell. I just don't use Costco regularly because of the distance from my home and the number of Shell stations very close to me.

 

Not a lot of Shell, or Amaco stations around here anymore.
But there is a Cosco not too far away from me.
Anyone remember Sunoco's leaded 260 octaine?

 

As the story goes, Jaguars are not cheap cars and in a lot of cases the cost of ownership is not either.

 

I was always under the impression that if one requires 93 and you run a motor on 87 instead of 93 the computer will adjust the timing to offset the lower octane? It will cost you about 20-30 HP depending on the motor size and type but it will avoid detonation-burnt valves, pining etc. On my American muscle this was always the case and I if went el-cheapo on gas it never hurt the motor. This is my first Vanden Plas.

 

Octane is fuel's resistance to igniting under compression. As you noted, modern engines can adjust timing to limit preignition, at the cost of efficiency. I think you have to weigh the fuel cost against the loss of power and fuel efficiency. The manufacturer tells you the octane level the engine is optimized for, so using a lower octane rating means you are not fully realizing the potential of the engine, but the impact to performance may not justify the difference in fuel price. Most people don't record mileage/performance data to such a degree that they can measure the strength of the relationship with octane rating. For me, the extra HP is worth the extra cost.

 

32 bit is 95 RON (90 AKI) max anything else is a waste, either 50/50 mix or just fill it with 89. early XJRs are slow as molasses anyways

06+ panpag will take advantage of premium fuel