High Octane premium fuel = smoother ride?

[edgarhighmen]

Its 3AM, i'm exhausted, sorry if this thread is a ramble; bear with me here, some pics included. Just been wanting to ask/share whats happened but wondering why/how 93 octane made a difference.

So I changed my oil the other day, normal stuff, 5.2 qts Mobil 1 Full Synthetic extended mileage and 1 quart Lucas Synthetic Oil Stabilizer.

Car usually runs a little smoother, a little quicker, just slightly freshened up really after an oil change every 5k.

But within a couple days of doing so, I also filled up with 16.5 gallons 93 octane at Sunoco and realized a noticeable smoothness and slightly smoother/quicker acceleration than normal (especially above 2k rpm). Lately accelerating for me has felt like pushing your hand through water (resistance), but after the oil change and 93 octane fill-up I feel like the cars riding on top of it. (lame analogy, but whatever)

Whether its placebo effect or not - I filled up on 93 just because I was able (discount), and I did not expect or assume anything to come from it. Also I'm halfway through the tank and its still driving better than normal. Normally I'd notice a difference in driving if I wore Boots vs Shoes because I'd realize I was pushing harder w/ boots, but I've had shoes all week.

Whether its a combination of the gas and oil change, or maybe the higher octane fuel is better for cars, IDK. But it has been a noticeable change. I drove 3 days on the new oil before I filled up. After I filled up I noticed it.

I'm at 136k on OEM plugs, I only do air, cabin, oil filters/oil changes on my own, recently replaced starter/alternator and need new front shocks (they died around 70-100k... been ridin on struts(springs?) too poor)

Sunoco A+ got me 20-30$ (actual cash saved) off gas + gives you refreshments if you totally buyout your gas cost with their Sweet Leaf tea 10¢ off per can/per gallon deal hehe. (You actually buy your gas in "tea" purchases as opposed to paying for your gas; But the discount from the tea covers more than the cost of the tea purchase, in effect saving about 32$ on 20 gallons if you completely cover your fuel cost in the discount, and giving you alot of tea (raspberry flavor is best and I like it IMO, peach is good, sweet is ok, but beware- the mint tea sucks/undrinkable) If the sunoco thing helps anyone - SORRY I didn't share it sooner =/

Totally off topic, but that's how i've got my last 3 tanks of gas; started filling a 5gal gas can after my car was full for the full 20 gallons to make the most out of the discount. Working on my 4th tank now, and probably gonna do the 93 octane again. I've heard that going higher octane will do nothing for a car meant to run on regular. Could it be cleaning my plugs or something? If it could, I wouldn't expect it to be able to clean something practically immediately w/ these results. Unless I had something gunked up and the fuel cleared it? Is this possible? What would happen if I added a can of seafoam or some fuel additive to a full tank of 93 octane? hehe

Some pics attached.

First pic is the 93 octane, 2nd/3rd pic is regular 87 octane (3rd pic shows what I paid for gas+goodies "48.97" while if i bought that much gas w/o discount i'd have paid "67.20")

Its $45.42 for 36 teas which = $3.60 off per gallon for 20 gallons. Gas prices above $3.60, you can do the math

Fourth pic is a recent wash.

[rjg202]

I noticed a smoother acceleration and idle as well with 93 octane. I was running it for 2 tanks while and switched back to regular and my idle is rougher and acceleration is a little smoother. I have been playing with 89 with no noticable difference with the 87 octane. Interested to see what replies you get. I hope/dream to make 100,000 miles just turned 60,000 today and had a second rack replaced last week, trans week before. Now I have an oil leak from rack area, hoping it is residual.

[edgarhighmen]

Wow man, Seems our car gets a variety of random problems. Different for everyone too. I think I've had minor oil leaking out of the engine block onto the alternator and maybe a leak on the opposite side too... I'll ask my mechanic to look at it next time I go, but probably can't afford a repair =/

Maybe I'll try using 93 from now on if I can get decent discounts on the gas.

[riceR]

Depends... did you fill up with Ethanol free gas? MN usually has 10% Ethanol. Pure gasoline is usually gets better mileage and the engines usually like them more. Anyways, probably a placebo. Higher octane is mainly used to prevent detonation. Although you should probably change your plugs if they are the originals.

[edgarhighmen]

Placebo or not, car is driving differently on 93 compared to 87. :P Yes its 10% ethanol, gas prices are in the $3.60's right now for 87, and I think there's a Mobil or some station bout 15-20 miles away that has ethanol free gas but its like $4-6 a gallon. Maybe the 93 octane cleaned a fuel injector or something? SCIENCE please explain! haha ... local shop wanted $337 to replace spark plugs/intake manifold gasket + coils (boots? w/e)

Figured I'd try it myself. I'd like to buy the azera intake manifold+ parts that are in the performance thread/sticky if I could.

[riceR]

nah, you don't need all that extra crap included when just replacing the plugs. DIY and save a ton of money. Iridium IX plugs will run you less than $50 for all 6.

well, if you feel it, you feel it.

[edgarhighmen]

I'm back down to quarter tank and it feels sluggish again. Maybe its just from running low on gas lol....

[V6 Sonata]

Mine has always gotten sluggish quarter tank and below, fill her up and she will be running tip top again. BTW I've always ran 91and my car just feels better runs smoother some say it doesn't make a difference but to each his own and after all what's another $3 to fill up for me at least.

[v33sonata]

the oil change is most likely why the car feels better. i have gone thru 87,89,93, 94 and 105(or 110 i dont remember) i've also gone thru a bunch of octane additives and the ONLY difference i got for my troubles were bad o2 sensors.....lol.

[sbr711]

Ok,, the smoother drive feel and posssible small bit better mileage comes from the added knock resistance of the fuel.. thus the knock sensors not picking up knock or decreased knock over the 87.. with the decreased knock, we can effectively add a little more timing, thus the slight smoother feel and little more zip..

Knock sensor is a PIEZO generator, 1 bolted to each bank in the center valley of the block.. it is listening for a small frequency (hertz) of knock, the PIEZO generates a small voltage wave and input to the PCM for timing correction..

Knocking, we going to cut ignition timing lead to point knock is reduced to acceptable level or eliminated.. No knocking, we will allow for more ignition lead till knock detect, then trim back from there.

Have seen cases where rod knock will drive a knock sensor crazy, and set a knock code.. but who cares,, loud hammering knock,, time for engine.