Yes...Rub it in, my boy

+1

gonna start adding in as recommended

I've used Costco gas in my C32 for about 4 months and haven't had any problems so far...

I haven't tried octane booster for fear of it turning the spark plugs orange. I hear it's not a big deal if the spark plugs change color, but I just don't want to do it.

Obviously octane booster works because you find giant drums of the stuff at some performance shops.

Commercially available Octane boosters are a waste of money. If you read the bottle on them, they'll tell you that it raises the octane in your tank by "4-7 points". Then when you read the back of the bottle it deines 1 'point' as being 1/10 of the R+M Octane rating. So you would need two bottles of this crap at $5 each to go from 91 to 92 Octane. A waste of money if you ask me.

Here's a link to a scientific test done that proves NOS "off road" (i.e., not street legal) octane booster raises pump 91 octane to over 93 octane with just one bottle of octane booster added to a 16 gallon tank:

http://www.europeancarweb.com/tech/0...ted/index.html

The charts at the bottom hold the results.

The ratio of octane booster to pump gas is .8 fl oz to 1 gallon of 91 octane gas. And one bottle of octane booster is 12 fl oz.

IIRC the pink/orange color is a hallmark of MMT-based octane boosters. I've tried this type before in my M3 and when I pulled the plugs one look was all it took...that was the last time I have used an octane booster. I always wondered what other deposits were being left in the combustion chamber. IMO one is far better off just blending in a few gallons of 100 octane gas.

I agree completely.

I only put Shell in my cls forget that, mycar seems to drive way better v-power

there are way too many factors if someone wanted to test that theory.

I have no issue with filling up my car at costco. I haven't had any issues with pinging or reduction in MPG's.

Which octane do you fill up with?

I'm on the same page... I've actually seen an increase in mpg recently with all the cars in our family.. 91 octane for the C, S and lexus gs-
Even 87 octane in my dd 2000 nissan maxima has seen better mpg

In NY/NJ, we have 93 octane everywhere. 94 at sunoco.

I would fill up at Costco if it was 93 octane. I'm sure the C63 runs great at that octane, even if Costco isn't top tier gas. Your car likely runs better than mine on Shell 91 octane.

Why wouldn't Costco gas be considered top tier when they are purchasing their gasoline from top tier producers? They buy from whoever is cheapest. Cheapest in price doesn't necessarily mean cheap quality.

Costco is extremely demanding. If industry-standard products are 12% meat Costco might ask you for 18% meat. It wouldn't surprise me in the slightest that they hold their gasoline suppliers to top-tier standards. They have that kind of purchasing power and they use that clout all the time in search of higher quality.

Costco gas is NOT Top Tier. Check the Top Tier website for the list of stations - Costco isn't there.

Top Tier gas is all about the fuel additive. Costco's suppliers simply put a different additive into their own gasoline than they do Costco's.

Costco is not a gas brand. Costco buys from different suppliers. Duh.

And you know this how? I say BS.

Let me point out that I (your friendly op) am questioning possible ping due to lower octane available in California. Top tier or not, if 156 p31 pings on California premium (91), that is a problem for the health of this engine.
I of course wondered if this might be due to the quality of the gas my local Costco sells versus other brands available here.
I am sure if this is a true ping issue, even a low tier 95 octane will eliminate the ping.

I've been using 76 for a while now since they advertise they don't add ethanol/methanol. I know shell and chevron, at least here in WA, are mixing up to 10% ethanol/methanol.

I work in the industry, for a major gasoline producer, in the department that wholesales to other gasoline retailers. In a previous role I worked closely with our product quality guys and am very familiar with fuel additive treat rates.

Those are my credentials, what are yours to make you so sure I'm wrong.

Costco gas IS a brand. If you claim its not, then what brand does Costco sell? It certainly is not the brand of their supplier as they are not licensed to use those brands, and are selling different fuel than is sold at the majors' own branded stations.

Yeah, and I invented gasoline. It's the Internet, I can say what I want. So, you have specific information relating to Costco? If so I'm not seeing it here. But tell you what, I went to B-school with a friend whose brother is a Costco VP. I'll try to find out one thing - whether Cosctco's gas is Top Tier if they buy it from a producer whose own labeled brand of gasoline is Top Tier...I'll revive this thread when/if I find out.

Just filled up at costco... I was talking with the attendant while I was there and he said that 80% of the 87 octane was from conoco phillips, 90% of the 91 from exxon, and sometimes from Valero... And that they add the 10% of ethanol at the station... He also said that he isn't aware of any other additives, there's no "v power" or "techron" type additives.... So until there's more clarity I won't be filling up the C at costco anymore... that's looking to be a 15-20 cent /gallon difference at the moment

Hey man, believe what you want. I'm just trying to help others here make informed decisions on what they're buying for their car.
I don't benefit either way. I haven't advertised for any particular brand of gasoline. I just want the group to be aware that there IS a difference in quality between the majors and the 'others'. As I said, if you're not keeping your car for long, save your money and buy cheaper gas, because valve deposits won't have time to build up and affect performance. For me, I'd rather spend a few extra bucks a year so that my car will run better, longer.