Best gas for 991
05-22-2013, 05:18 PM
#31
Burning Brakes
I too once thought the same thing... but then I saw the result in black and gunk.
Take a look at the black barbeque-like gunk on the top of the intake value in the attached photo. That's Costco gas gunk. Gunk from not adding valve cleaning detergents. That valve should be as clean as a whistle with a slight yellow-gold tint.
That's what Costco cost savings is doing to the intake valves on your magnificent motor. That reduces airflow into the cylinder... and air IS power.
Save now, pay later.
Take a look at the black barbeque-like gunk on the top of the intake value in the attached photo. That's Costco gas gunk. Gunk from not adding valve cleaning detergents. That valve should be as clean as a whistle with a slight yellow-gold tint.
That's what Costco cost savings is doing to the intake valves on your magnificent motor. That reduces airflow into the cylinder... and air IS power.
Save now, pay later.
Here's Costco's side of the story:
http://www.costco.com/gasoline-clean-power.html
05-22-2013, 10:03 PM
#32
Rennlist Member
[quote=Hothonda;10482878]Thanks for taking the time to post + photos!
Here's Costco's side of the story:
Translation:
To be fair, with direct injection, your intake valves shouldn't much care about the gas additives. If you have a lot of combustion residue on your intake valve stems and seats, you have bigger problems.
Here's Costco's side of the story:
... Costco has closely studied fuel additives and engine deposits, and conducted extensive fuel tests at nationally-recognized laboratories. As a result, we decided to increase the detergent additives in our fuel to provide a better value to our members.
Our gas used to suck. Now, it sucks a little less. Happy motoring!
05-23-2013, 09:00 AM
#33
Burning Brakes
[quote=Noah Fect;10483558]
When it comes to "who do you trust he most" - the oil companies or a company like Costco ?
So far I never been screwed by Costco on anything.
Thanks for taking the time to post + photos!
Here's Costco's side of the story:
Translation:
To be fair, with direct injection, your intake valves shouldn't much care about the gas additives. If you have a lot of combustion residue on your intake valve stems and seats, you have bigger problems.
Here's Costco's side of the story:
Translation:
To be fair, with direct injection, your intake valves shouldn't much care about the gas additives. If you have a lot of combustion residue on your intake valve stems and seats, you have bigger problems.
So far I never been screwed by Costco on anything.
05-23-2013, 10:43 AM
#35
Burning Brakes
Yesterday....and I guess since 1973 when they decided gas was too cheap.
The debate about Costco's gas quality can go on forever....it works for me & the price is always fair (relatively speaking).
In closing I will say that Costco gas is not available everywhere I go, but when it is that's where I purchase. The facilities are spotless, handles on the pumps are clean & I get 3% back.
My Porsche seems to agree w/the gas along w/ 5 prior NSX's + who knows how many other vehicles over the years.
Done
The debate about Costco's gas quality can go on forever....it works for me & the price is always fair (relatively speaking).
In closing I will say that Costco gas is not available everywhere I go, but when it is that's where I purchase. The facilities are spotless, handles on the pumps are clean & I get 3% back.
My Porsche seems to agree w/the gas along w/ 5 prior NSX's + who knows how many other vehicles over the years.
Done
05-23-2013, 11:55 AM
#36
Race Director
this thread, especially the part about BIg oil and Costco, should be moved to an off topic thread.
Kes7u, which oil comp do you work for?
Hothonda, i like costco, and I agree w/ you. Their customer service is excellent. A hot dog and coke for $1.50- how can you beat that?! I used to use their super gas, but my car started knocking, so i stopped and the knocking went away. Another friend had a similar issue. So I havent been back to their pumps in a while. I just basically use the gas recommended by the manufacturers, tho I'm sure theres some behind the scenes happening there. Having said that, even "premium" brands can have problems. Ask my friend that. Last year his BMW has problems after filling up at a SHell station. Turned out that station was in a remote part of town and didnt get a lot of traffic and there was an unusal amount of water in the gas. Go figure. I guess gas is like a box of chocolate- you never know what youre gonna get.
Kes7u, which oil comp do you work for?
Hothonda, i like costco, and I agree w/ you. Their customer service is excellent. A hot dog and coke for $1.50- how can you beat that?! I used to use their super gas, but my car started knocking, so i stopped and the knocking went away. Another friend had a similar issue. So I havent been back to their pumps in a while. I just basically use the gas recommended by the manufacturers, tho I'm sure theres some behind the scenes happening there. Having said that, even "premium" brands can have problems. Ask my friend that. Last year his BMW has problems after filling up at a SHell station. Turned out that station was in a remote part of town and didnt get a lot of traffic and there was an unusal amount of water in the gas. Go figure. I guess gas is like a box of chocolate- you never know what youre gonna get.
05-23-2013, 07:38 PM
#39
Damn, missed it
But JohnnyBahamas, where did you get those pictures from? I don't know if I would consider one set of photos proof of anything, unless they were done after a series of tests in a carefully controlled environment. And even then, I'd want to compare them to valves that were exposed to top tier gas, everything being identicle except for the fuel used.
I always assumed the additives claims were just marketing BS. Have there been any scientific studies comparing the different fuel brands? That Costco web site seemed to hint that there were laboratories testing this stuff, but is any of that data available to the public?
I guess I've always been a skeptical person when it comes to claims made by companies. It's amazing how much of our perception of brands is colored by marketing.
But JohnnyBahamas, where did you get those pictures from? I don't know if I would consider one set of photos proof of anything, unless they were done after a series of tests in a carefully controlled environment. And even then, I'd want to compare them to valves that were exposed to top tier gas, everything being identicle except for the fuel used.
I always assumed the additives claims were just marketing BS. Have there been any scientific studies comparing the different fuel brands? That Costco web site seemed to hint that there were laboratories testing this stuff, but is any of that data available to the public?
I guess I've always been a skeptical person when it comes to claims made by companies. It's amazing how much of our perception of brands is colored by marketing.
05-23-2013, 07:42 PM
#40
It's all the same gas basically. Who's going to call them out on it? The international refinery police? 
Just pick a gas station that looks like it is in good shape and hopefully no water or other contaminants in the station tanks than normal.
Stay thirty my friends.
Just pick a gas station that looks like it is in good shape and hopefully no water or other contaminants in the station tanks than normal.
Stay thirty my friends.
05-23-2013, 08:59 PM
#41
My evidence is, as you properly note, anecdotal. The scientific method was not used.
Further anecdotal evidence, I had the intake manifold off again just this last Sunday, May 19th to preemptively replace the infamous plastic 'T' coolant junction that only turbo Cayenne's have that I did not know about back in 2010. Unfortunately, I didn't think to take photos of the clean valves after the last 24,000 miles using Chevron and Shell. Not an exaggeration to write that the valves are clean as a whistle now. Again, only anecdotal.
Important to note, as a sage previous poster pointed out, that unlike the 991 with its direct fuel injection, the valves in that picture have intake manifold injection... so similar valve build up can not be an issue on the 991.
Last edited by JohnnyBahamas; 05-23-2013 at 11:02 PM. Reason: to add the line across the bottom.
06-21-2013, 10:39 PM
#42
Rennlist Member
The 100 octane gasoline is only available at 76...in Cali since max Octane at any gas station (chevron/ shell) is 91, I personally prefer chevron but I now go for mixing up 100 with 91 at 76 to get to 93 or above octane rating. I feel a marked difference in car performance!
I saw it says to use 93 octane, and all I can seem to find in the Bay Area, CA is 91 octane.
Is there anything above 91 available? Paid this much - want to get the most out of it
06-22-2013, 12:48 AM
#43
The 100 octane gasoline is only available at 76...in Cali since max Octane at any gas station (chevron/ shell) is 91, I personally prefer chevron but I now go for mixing up 100 with 91 at 76 to get to 93 or above octane rating. I feel a marked difference in car performance!
I saw it says to use 93 octane, and all I can seem to find in the Bay Area, CA is 91 octane.
Is there anything above 91 available? Paid this much - want to get the most out of it
06-22-2013, 09:08 AM
#44
Intermediate
Join Date: May 2009
Location: Palm Bay, FL
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Using Sunoco gasoline here. I will note that, according to Sunoco 
, they are the "largest manufacturer and refiner of racing gasolines in the world." Over 5 years, my Cayman S seemed to do very well with it and we will see about the 991. I will note for the record it is also reasonably priced in comparison to other available choices (no Costco locally).
http://www.racegas.com/
, they are the "largest manufacturer and refiner of racing gasolines in the world." Over 5 years, my Cayman S seemed to do very well with it and we will see about the 991. I will note for the record it is also reasonably priced in comparison to other available choices (no Costco locally).http://www.racegas.com/
06-22-2013, 12:16 PM
#45
Burning Brakes
Using Sunoco gasoline here. I will note that, according to Sunoco , they are the "largest manufacturer and refiner of racing gasolines in the world." Over 5 years, my Cayman S seemed to do very well with it and we will see about the 991. I will note for the record it is also reasonably priced in comparison to other available choices (no Costco locally).
http://www.racegas.com/
, they are the "largest manufacturer and refiner of racing gasolines in the world." Over 5 years, my Cayman S seemed to do very well with it and we will see about the 991. I will note for the record it is also reasonably priced in comparison to other available choices (no Costco locally).http://www.racegas.com/
here is a link
https://www.penfed.org/Platinum-Cash-Rewards/
I have no other affiliation with this FCU....I do however despise commercial banks and most commercial and investment bankers...