isFiend

Is it Ok to feed an '09 IS 350 91 octane gas or should I actively pursue 93 octane only?

Which brands are recommended?

If Chevron and Shell are among the recommended brands, which brand would you guys recommend between Chevron and Shell (I ask this because I readily have access to Chevron and Shell)

jhill20

iTrader: (1)

You should you use whichever is recommended for the vehicle. Only reason I word it this way, is that I don't know what octane is recommended for your IS.

Gasolines octane rating is ONLY for detonation resistance. Any other by-product of using a higher octane fuel is purely that just a by product. So if your vehicle is engineered to run on 91 octane fuel then that is the lowest octane you should use. Using a higher octane is only helping the situation...

I'd say Chevron.

isFiend

Thanks for the input.

To be honest I've been trying to sift through hundreds and hundreds of topics via searching "gas" "octane" "gas brand" both here and at my.is

Finally after 45 min. of looking I found some great threads on gas brands, etc. at my.is

Many people have been giving high praise to shell's V-power. Going to read some more, I'll report back summaries if I find anything useful.

jhill20

iTrader: (1)

I'd be interested in what you find for sure.

panda327

iTrader: (3)

i find i get less mileage from shell V-power and more on chevron and petro

2slow

iTrader: (5)

There is already a thread dealing with gas and octanes.

isFiend

I've been persuing through the miata forums for a while now, and the genreal consensus over there is that Chevron is the higher quality fuel over Shell. Here are the posts that discuss this issue -


"Chevron is rated as a top tier gasoline. Shell is not. I have FI and when I use Shell I have to advance spark to stop ping. With Chevron no ping.
Just my experience."

The part where he says Shell is not top tier gasoline is incorrect. It is considered "top tier" right now.

Here is a caranddriver article discussing what it means to be "top tier":

http://www.caranddriver.com/features..._stuff.-column

Later on he does correct himself

"I was wrong!
I put foot in mouth, I don't advance spark I retard it to stop ping.
The last time, maybe 6 months ago, that I looked at www.toptiergas.com SHELL was not on the list.
It still doesn't change the fact that Shell gas still makes my car ping and Chevron doesn't.
Sorry for the misinformation."


"I rotate through different gas brands since they all offer different detergents and additives...avoid the cheapo brands like Arco, Rotten Robbie, etc. Chevron is widely regarded as the highest quality fuel you can buy in my neck of the woods, predominantly due to Techron, but I would not balk at Shell, 76, Texaco, Mobil, Valero, etc."


"Our '04 requires Premium and I had been getting a slight ping on Exxon/Mobil. The local Mazda dealer advised switching to Chevron. Sure enough, the Miata is happier on the Chevron. No more ping. Both claim to be 91 octane, so I don't know what the diff is."


"Chevron premium in Arizona is 91 octane. In fact all premium in Arizona is 91.
While in Texas I tried some Shell 93 octane and still got ping. With Chevron at 91 or 93, not a sign of detonation."


"I stick to Chevron exclusively - and Shell stations are much more available here! I've used Shell on 5 occasions in the last few years, when I had to (nothing else close enough). On 4 of those occasions, my vehicle ran so bad I had to either add several bottles of gas line antifreeze to clear the water out of the tank so it would run. And in my motorcycle, on two occasions I had to drain the tank manually to clear the mess. The last time, I drained the tank into a large container, and found that I'd been sold over 1 liter of water in the 4 liters of gas I bought

All my attempts at going after Shell to at least refund the price of the gas fell on deaf ears. They basically said "So what? If you don't like it, sue the company." They didn't deny that they were pumping water with the fuel.

On the other hand, after testing the fuels available, Porsche recommends Chevron exclusively in their FI cars. I use it in everything I have, and I'm happy with it."

The first part sounds a big exaggerated but the bolded part is of great interest to me.


" In the early 90's, I think it was, Porsche issued a TNL to their dealers that Chevron's Techron was what they recommended for cleaning fuel system and intake valves."

on one porsche forum


"Fuel pumps can get hot before they die. Porsche recommends using Chevron fuel injector cleaner with Techron as a preventative maintenance on the fuel system; this will help keep the fuel injection components from clogging up, and keep them lubricated."

source: http://www.924.org/techsection/3fuel.htm



Renntech porsche sub-forum responses:


"Use Chevron, has one of the best additives for keeping fuel system clean with techron .I don't have any association with CHEVRON, but have never had a fuel problem with their gas ever in any car I drive. here in california I undersatand they use only their refined fuel vs the independents who buy their fuel from the "less expensive" source."


"I use Shell Gasoline. Why, because with the Shell VISA card we get 5% off all gas purchases. At $3.00/gal that is $.15, and gas is only going up. Sometimes I see other brands for less that Shell, but seldom 5% less."

"+1 more for Chevron. Everyone always says "gas is gas". I've noticed I don't get as good mileage with some other brands (Mobil) compared to Chevron. When I cleaned my throttle body at 51K miles, it wasn't nearly as gunked up as I expected it would be based on all the pictures I've seen. Not sure how much the Techron added to Chevron gas had to do with that, but I'm not complaining "



Then you have this:

"I've been using the cheapest gas at whatever station, for years now.
Never had any fuel related problems yet with any one of my vehicles..."




Honestly, I don't think I can conclude anything from any of these responses. The sources are not reputable by any means. The only truly reputable source suggested top tier gasoline, and both Chevron and Shell fall under that category.


But, my thinking is - "well we do have all of these people on the miata forums, porsche forums praising Chevron so much with some even talking about subpar experiences while using Shell"...

I think I'm going to just go ahead with Chevron even though really I'm not entirely convinced that Shell is "worse" in any way. If I had to use Shell I really wouldn't mind right now. Maybe it might irk me just a tad bit based on all of these positive reviews of Chevron.


Over at my.is forums there is one individual with an '05 IS 300 who says he uses Shell V power.

In general, I only found bad reviews about Shell and positive reviews of Chevron, but none of this came form reputable sources. Just people citing their personal experience.



2slow can you direct me to the topic on gas/octanes here? I swear I've been searching for a while. I'm not entirely sure what search words to put in, I've tried "gas" "gas brand" "octane" and unfortunately it brings up hundreds of topics where those words were used in some post.

isFiend

Wow that was silly. Never mind man I finally found these topics. I wasn't aware that with advanced search I could search for topic titles only and not entire posts.

Initial G

iTrader: (38)

I use 91 Shell or Chevron. Whichever one is cheaper at the time.

Koz

Shell is a "Top Tier" gas, here is the list;

QuikTrip
Chevron
Texaco
MFA Oil Co.
Conoco
Phillips 66
76
Entec Stations
Shell
The Somerset Refinery, Inc.
Kwik Trip / Kwik Star
Aloha Petroleum
Tri-Par Oil Co.
Turkey Hill Minit Markets
Mileage Stations
Chevron Canada
Shell Canada
Petro-Canada
Sunoco Canada

Also, any octane gas OVER 91 is a waste of money! The best octane gas is the lowest octane that will not cause knocking.

Koz

Kurtz

iTrader: (1)

"top tier" remains largely a marketing gimmick.

All fuel sold in the US must meet certain minimum federal requirements, and as long as they're the appropriate octane will be just fine in your car.

You'll on very very rare occasion find a bad station or a bad batch, but it's no less likely to happen because the station has one national-brand franchise name above it than any other.



The previous poster is correct in that you should always use the lowest octane that causes no knocking/pinging... for a 2IS that is 91. Using anything lower is a bad idea, using anything higher is a complete 100% waste of money.

Koz

Not to get in (another) pissing match but, there is absolutely a difference between Top Tier and the others (Top Tier is BETTER). Top Tier gas has different/amounts (higher) of detergent additives in their fuel. Depending on where the gas station gets their gas, you may be able to get Top Tier gas at a non Top Tier station.

Koz

Evitzee

TOP TIER was developed by the industry as a marketing vehicle, so that should tell you something about where the focus lies. It's a marketing program, pure and simple. To each their own.

Lets Drive

iTrader: (3)

Interesting that you have that option. Around here, we get 87, 89, and 93 octane fuels, while 94 got pulled from Sunoco stations some years ago.

panda327

iTrader: (3)

Shells here in Vancouver only go up to 91 and usually gas station only sells up to 91
when ever i run across a gas station with 93or 94 .. i fill it up with it ...its only a few bucks more ... and i like having that peace of mind that i am feeding the car good gas
will it make a difference ?" .. probably not ...