Home Forums Hunting & Shooting Hunter's Campfire Cars that require premium gas

The "non-ethanol" is getting harder and harder to locate.
Won't run that alcohol crap in any of my gasoline engines!
I can go further on non-ethanol than on the 10% ethanol.
Dollar for dollar, the mileage is about the same "price/mile", I just get more miles and better performance with the non-ethanol.

Non-al is too expensive here. I run it in all my small engines. I've tried it in the car but the increase in mileage doesn't even come close to offsetting the high price.

I just bought a 2022 big motor SUV that weighs around 6500 # , it has a 6.4 hemi that has 475 horsepower, this thing is nothing but a computer on wheels, with a price tag I never dreamed about spending, so why would I hurt motor or sensor’s running cheap gas and pay much more later in repair cost after high dollar warranty runs out.

My Summer Car is a 2010 Jaguar, it also required 91 octane,
I would always run off the top half of the tank, so I'd fill it with 94 then the next time 89, rounds out to be 91.5.
Never once did I run into any engine knock or poor performance.

High octane gas is 2400. Low octane gas is Unique. High octane gas is required for high compression engines because it give a slower, smoother burn than low octane gas. Low octane gas burns quicker but it hammers a high compression engine around when it ignites.

The info I see on the Lexus IS250 says that it's running 12:1 compression. Back in the old small block Chevy days if you ran 12:1 pistons a standard starter would hardly crank it over.

I don't know the answer for sure. But I would guess that 87 octane gas would be hard on a 12:1 compression engine.

It would be like pushing a 250 grain bullet to 1400 fps with Unique in a .44 mag.

THIS
I have run the gas mileage test many times.
Engines that call for 91 octane get better mileage on 91 octane.

I have an Infiniti I30 that requires high octane.
I sometimes will run a tank of regular, can't tell much difference. But 95 percent of the time I do use the high octane.

Didn't you crash your lawnmower? This might not be the ride for you.

This is a car myth. The reason why engine manufacturers specify high octane is ONLY due to EPA emissions and mileage mandates and nothing more. Modern ECUs can instantaneously retard timing to keep an engine out of detonation.

There are a brazillion YouTube engine dyno tests to prove the point.

A forced induction engine (turbo or supercharger) is another animal all together. Due to high pressure combustion, they need a higher octane. But for an naturally aspirated engine, as long as you don't need that extra 5 horsepower at 5,000 rpm, you nor your engine will notice any difference between 87 and 93 octane. But your wallet will notice the $0.30/gallon difference.

Now, if you compare 87 vs E-85, then there is a lot of performance lost/gained between the two.

I see about a 16% improvement on my 2.0 Ecoboost with premium, but that is confounded by the fact that around here premium is ethanol free. Well worth the $0.20 premium at Costco.

So, 10K for a lexus with 125,000 seems like a really good deal. Interior torn up or not; if maintained, they run for ever. But, lets run the numbers. An engine repair of $1,500 is 2.5 years of gas price difference. Keep in mind, Lexus are notoriously expensive to repair.

Assuming the $0.40 a gallon less expensive and the $50 a month variance, the annual mileage be between 10,000 - 13,000. So, for purposes of the thread, at 12,000 miles a year and MPG at 25 for premium and 20mpg for regular, the ANNUAL cost variance is less than $40. IF we use the previous comments of 16% as a baseline, yo are looking at less than $100 a year.

I feel certain that there will be $40 in increase damage to the engine.

Sometime back in the 90's, my brother had just bought an Audi A-4 or A-6 or some such, don't remember exactly. Soon afterward, he and I went on a road trip to Florida. He hadn't, at this point, driven the car extended distances at high speed. At some point, when I was driving, I noticed the temp gage climbing up there. Also, when we went to shut down, it would start dieseling a bit. He asked me what the problem was (my brother knows nothing about such things.) I asked what fuel he was buying. Answer was, "regular." I told him I don't claim to be an expert at this stuff, but I suspected that, in order to run on the regular, his engine system was retarding the timing a lot and, for some reason, ignition at that part of the cycle generated more heat than the cooling system could handle, thus the overheating and, with the overheating, the dieseling. Next fill up, he got hi test and the problem was solved. He later told me he went to his mechanic when we got home. I asked what he told him. "Some of that same stuff you said, about the timing and stuff."

I've also seen inboard/outboard boat engines that you couldn't get to shut down after running them hard until after they'd cooled down a little. Problem would go away with higher octane.

You can count on the engine ta detect and stop detonation.

*After* there's been detonation.

Ain't no "this things bout ta knock" sensor.

Just use E20, increased octane and performance and cheaper.

If it ain't available premixed, mix it at the pump.

2 gallons of E85 ta 14 gallons of 87, and ya got your 91, and cheaper.

wrong guy, I bought the hunnert dollar lawnmower, but never crashed one

Elevation vs octane

Here...GX 460 'requires' 91 oct

Rural Utah is at 6K' and up from here

Clear (eth free..readily available) 88 octane

Reg is 85

88 runs the GX great & delivers 20-21 mpg

Clear was $4.35/gallon last purchase

Oh yea......FJB

https://www.mikeshawsubaru.com/service/information/gas-octane-at-altitude.htm

You'd have to lower the compression ratio, but that would change engine performance, and defeat the purpose.

If an extra $5 a tank is a big deal to you don’t buy it.

Is Costco non-al everywhere? I'd love to pay their prices for my small engine gas instead of the high priced other game in town.