High Octane Fuel vs. Low Octane Fuel : Facts and Myths (2 Viewers)

[Beowulf]

OK, I was right before I was wrong.


I recalled a thread a while back (~18 months) where Bear80 stated the Lexus OM specified premium fuel (it does not.)

Then I recalled that Doug had stated that Lexus specified premium across all their products. (See above link by Curtis)

I was somehow convinced that the LX450 OM also specified premium.

Soooo.... Nevermind. :sheepishgrin:

-B-

 

[CJF]

I’ve noticed a very subtle, pinging on hard accelerations. Either I didn’t notice it before or something is out of adjustment.

Or you have Harmful Engine Deposits from using Low Grade Fuel with the Weaker Additive Package.



(Just messin...)

 

[LX_TREME]

I’ve had the LX since new (10 years ago), and I've been filling with premium for the past 10 yrs. About 3 weeks ago when I did complete engine overhaul (1FZ), took all the 6 injectors to RC Engineering to get them clean, bluerprinted also balance. The results,

Only # 4 injector dripping (the one I marked with red X) but the rest of them were good, excellent condition.

 

[BrettinSanAntonio]

Did they say this was due to using premium unleaded?

It would be interesting to see a control in the form of a similar truck with similar mileage that used regular unleaded.

I’ve had the LX since new (10 years ago), and I've been filling with premium for the past 10 yrs. About 3 weeks ago when I did complete engine overhaul (1FZ), took all the 6 injectors to RC Engineering to get them clean, bluerprinted also balance. The results,

Only # 4 injector dripping (the one I marked with red X) but the rest of them were good, excellent condition.

 

[BrettinSanAntonio]

Heh, yep, could be.

Of course I use Exxon or Valero unleaded and BG additives. No bottom of the barrel here!

Did they say this was due to using premium unleaded?

It would be interesting to see a control in the form of a similar truck with similar mileage that used regular unleaded.

 

[BrettinSanAntonio]

Interesting. This "Top Tier" standard; is this an indusrty standard or an EPA standard? I'd be a bit more sceptical if this is something that came out of the marketing departments of two or three large oil companies.

From Shell's site:

Shell Regular and Plus gasolines, which meet the “TOP TIER” standard, also contain more than two times the amount of cleaning agents required by the EPA. Shell V-Power goes even further – it has more than five times the minimum amount of cleaning agents required by government standards and twice the cleaning agents required by the “TOP TIER” standard.

 

[BrettinSanAntonio]

LOL....this came right out of Chevron's marketing department, didn't it.

The Shell and Exxon site is very similar. They probably got together during a sales meeting in Cancun and wrote this stuff.

Techron is a very good product. No doubt about it. I just think buying premium unleaded to get more of it is more expensive than adding a profesional cleaning agent like BG44K. Or, you can buy the Techron cleaning agent at nearly any parts stores and add to your fuel as needed.

From Chevron's site:

5. I have seen your advertisements that say your Supreme gasoline has "more Techron®." What does the higher dose of Techron® do for Supreme customers? The higher dose of the Techron® additive in Chevron Supreme can clean up dirty carburetors, fuel injectors, and intake valves even faster than our Regular and Plus grades. This attribute can be important for customers who occasionally purchase a lower quality gasoline, or who own a vehicle that is particularly sensitive to deposits.

 

[CJF]

Interesting. This "Top Tier" standard; is this an indusrty standard or an EPA standard?

The Shell site claims it's an auto industry (BMW, GM, Toyota, and Honda if I'm remembering correctly) initiative to get oil companies to put more additives/detergents in their fuels than the minimum mandated by the EPA. I have no idea if that's true; I've personally never heard of it before.

Curtis

 

[Bear80]

I still swear the LX450 I had for a while, had it printed for 93 octane and I know I didn't confuse the Research Octane with the Ocatne rating. Maybe it was something printed by Lexus or the dealer along the lines of what Doug pointed out.

I run whatever I feel like, 87, 89 or 93, not the latter so much with prices as they are.

 

[motorsargeT]

The Shell site claims it's an auto industry (BMW, GM, Toyota, and Honda if I'm remembering correctly) initiative to get oil companies to put more additives/detergents in their fuels than the minimum mandated by the EPA. I have no idea if that's true; I've personally never heard of it before.

Curtis

I work for one of the manufacturers that is pushing the top tier fuel stuff. We regularly get documentation from Subaru on what they consider "fuel" and which oil companies havae the best product out there. On a side note 90% of all wierd drivability issues I have seen that appear "all of a sudden" come down to a fresh tank of cheapo gas! After running a battery of tests on it(Reid vapor pressure and Ethanol content to name a few) and seeing what is in some of these stations tanks it is incredible that some cars will even run on it.

For what it's worth I run the cheapest gas I can find!

 

[Bear80]

You know it's kinda off topic here but one thing I've noticed is all the stations are going to a single hose pump. I hate the damn things, if I select mid or premium I can hear it pump about 1/2 a gallon of somthing else, ie what's left in the lines, before the selected grade comes out. I don't want to pay for somthing I'm not getting. I only pump 87 at those but it's harder and harder to find a mutli-hose pump station.

 

[CJF]

We regularly get documentation from Subaru on what they consider "fuel" and which oil companies havae the best product out there.

Share-sies??

 

[motorsargeT]

I'm not at work now with the list in front of me but I remember Chevron, Shell, and Mobil as being the top 3.

 

[CJF]

T'anks!

 

[motorsargeT]

Figured I should say that is for the northeast. Those companies will have the same gas all over, but there may be others in other parts of the country.

 

[kraeji]

I had an rx8 that required premium but I always ran regular without any pinging/knocking. I say run the lowest octane that you can get away with. My gas mileage was better with the regular too.

 

[Romer]

The one thing that concerns me is these computers adjust for a lot and you don't even know there are issues inside your motor. When Robbie did my headgasket as PM the truck was running great. The head and pistons were covered in carbon. Way more carbon buildup then Robbie could remember seeing. Probably due to a combination of cheap gas and cheap oil (Penzoil) with not frequent enough changes.

 

[motorsargeT]

Good point Romer. When I rebuilt my engine the head and rings were so full of carbon I couldn't believe the thing actually ran. I wish I had pictures of it but the sides of the intake ports on the heads had about 3/8's of an inch of buildup in them. It looked like there was only half the available space for air to get through. Before the overheat that pre-empted my rebuild there was no indication that there was anything wrong carbon build up wise. The truck ran great with plenty of power( for a 3f-e).

 

[BrettinSanAntonio]

Thanks; good to know!

I'm not at work now with the list in front of me but I remember Chevron, Shell, and Mobil as being the top 3.