No, it doesn't. nyathpppt

(anecdotally speaking, the additives used to raise octane can leave deposits on valves; google it. Empirically speaking, there is no measure of detergents other than federally mandated. The regulations apply equally to regular vs. premium. The rest is hype. The only valid measure between regular and premium is the anti-knock rating.)

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wrong. FUEL burns dirty when its low quality or if your ignition system cannot burn all the fuel up.

higher octane is HARDER to burn, hence why higher octane is required for higher performance motors. As octane level is increased, chance of detonation from higher-then-normal heat and higher cylinder pressure from say compression ratio or forced induction is reduced/decreased.

Octane level itself does not cause dirtyness. Its whether your system is capable of getting benefits.

My car did much smoother runs down the dragstrip last night with half tank of 93 octane. I got it from a gas station that is known for sampling and testing their tanks religiously every month. Never had a fuel quality issue brought to their attention in a long time. Even the 87 from them is awesome, gives me a noticable MPG difference between theirs and other stations.

My car runs smoother on 93, but performance is about the same.
It runs strange when I filled the empty tank just now with 87. I pulled the battery when I was redoing a ground wire that had pulled out of the terminal from all the wheel hop I get at the drags, and now it runs just as smooth as ever.

I think if I decide to switch octanes again I will do it at half a tank rather then empty. Our car computer knows when there is a different octane present, but fuel trims will not be correctly adjusted within minutes of tnak fillup. Takes a few miles for it to catch up enough.

 

Well that is a new one.

Tell us more.

I have one 200K Blazer, one 100K Colorado, one 140K Jimmy, and one 100K GMC motorhome. None have ever had a converter or oxygen sensor failure and pass bi-annual emissions inspections with flying colors. I'm wondering when to expect these failures to begin. I would really like to know how long until my oxygen sensors and catalytic converters are going to fail so I can preemptively order them and have on hand these failing components?

I'm obviously baiting you to back up your statements with some reputable information.

With all of the money we as an economy have spent on cleaning up gasoline and now diesel burning engines, I'm interested in where you got the idea that the anti-knock qualities or ratings of any fuel has anything to do with clean or incomplete burning of gasoline.

 

That blazer must be in perfect running condition to withstand that mileage on original O2 sensors.

Just proves if you take care of your car, less failures is pretty much guarenteed across the board

 

Well I do not not know about "perfect" running condition. It gets 6000 mile oil changes and uses about 1/2 quart of oil in 6000 miles. I have had to replace the water pump once, the AC compressor once, one idler arm, a couple of sets of tires, one battery, and one set of plugs (it is now due for another replacement). The Jimmy at 140K has had one alternator, plugs, and I'm replacing the AC compressor on Sunday. Oh yes, Blazers and Jimmys all have a leaking oil cooler line problem over time. I have replaced the lines on both at around the 100K point. I also had to replace the oil filter adapter gasket on the Blazer at around 160K.

My daughter's older 1996 Blazer has about 270K with no converter or oxygen sensor replacements. She does not drive it much any more because she would rather drive her FIT. It is probably time to retire it.

In the 1970's and 1980's through extensive lab experimentation we found that the ideal air/fuel mixture for emissions was around 14.7 to 1. We also found that even leaner mixtures were possible and practical for better fuel economy, but as we leaned above the 14.7 number, emissions actually went up. So to keep the EPA happy the industry settled on 14.7 as a standard.

For fuel economy the Voyager which flew around the world non stop and un-refueled in 1986, used a leaning technique the resulted in mixtures on the lean side of peak EGT (Exhaust Gas Temperature) resulting in F/A numbers much higher than 14.7 .

Because of this experience and Petroleum Chemical knowledge, I do not buy the argument that 87 vs. 91 or 93 R+M/2 octane fuel makes has any difference on how clean the fuel burns in a modern computer controlled engine.

As a side note, What has killed or at least reduced the gasoline additive industry is the EPA REGULATED Renewable Fuel Standard (RFS) of 2005 and 2007. On top of the existing standards for the EPA non-attainment areas, the RFS mandated fuel mixed with Ethanol be used in most markets but left actual implementation to the states.

Ethanol, and to a lesser extent other oxygenates like MTBE, which is no longer used for other reasons, have greatly reduced additive sales by chemical companies like Dow, BP, etc. In low concentrations bio-ethanol works as a decent detergent. In stronger concentrations or over time in low concentrations it is corrosive to many products like hoses, some adhesives / sealants, and aluminum (pot metal) components used in gasoline engines.

 

This is true ^^^^^

 

Like others have said, 87 is no dirtier than 93 or any other octane (given you don't buy the 93 from shell and the 87 from "Bobby-Ray's discount gas". Higher octane, as any ASE Certified Tech should know, is more resistant to pre-detonation allowing engines to run a higher compression ratio. (in return, delivering more HP, again, allowing companies to produce smaller more fuel efficient engines that produce the same amount of power as other larger more fuel-guzzling engines). Cleanliness has nothing to do with it and while the debate of 87/93 and less/more power continues (probably forever), I doubt anyone else would think that the "quality" of gas is different.

One consideration is that some gas stations do not use Ethanol in Premium which would make a difference but again, not due to the octane rating, simply due to the addition of the Ethanol.

~SB

 

As an old petroleum engineer let me emphasize that 87 octane is no dirtier than 93 octane; in fact, because the flow of gas through 87 'containers' is higher than for 93 octane it is more conceiveable that 93 is dirtier. Most 'dirt' is picked up in storage tanks than anywhere else.
Add to the fact that gasoline is not a fixed recipe; it changes by the source of the crude AND by the various legislated recipes for the green crowd thinking emissions can be reduced significantly with certain choices of crude and recipes.
The reason ethanol is not much used in some 93 octane is because ethanol has much less energy of combustion than gasoline of any common recipe and thus fails the marketing requirement that the customer should feel a difference when they pay more for gas. Not to mention they should get better mpg, or at least thats the idea.

 

Reviving this thread and bringing it back on topic...

I can see my fit leaning slightly to the drivers side consistently regardless of the slope I'm parked on. The height difference on each side isn't much, 1.5 finger gap difference at most. But I can clearly see the car tilting slightly from a distance.

I am on stock suspension.

 

I freaked out when I pulled a jack from one side to have it not fit on the other....perfectly normal. Now I adjust my coilovers for the expected driver's side sag accordingly. Don't worry, you didn't break anything

 

before i switched springs my stockers sagged also


the Fit is a light enough car that it takes even stockers awhile to settle

hell my dropzones are still settling a lil, even after 7k miles

 

LOL samething happened to me so I just adjusted my coilovers all the way down. Still have a sag o well!!

 

Good to know the sag is normal. I was on eibachs for a month or so before switching back to stock, so I was just worried that I reinstalled them incorrectly.

 

Why not pull the springs and switch sides?