hacker-pschorr

That's why I only get gas at Costco 10 miles away with a BP 1/2 mile down the road. Unless I need gas now or I'm not heading in the direction of Costco.

Also Costco has the cheapest premium in town and one of the only 93's (rest are 91) for the cars that need premium. Wisconsin regulates the base price of 87 so everyone is always within a cent or two.

bureau13

http://www.cartalk.com/content/premium-vs-regular-0

Go to number 2, regarding the idea that premium gas has "more detergents." Of course, the internet is not always infallible (ha) and I'm sure, neither is CarTalk, but this is what I've always heard and believed. FWIW...

Don Carter

Check out the 7th question in this Shell V-Power FAQ . Premium has a higher concentration of additives than the other grades of gas at Shell. The latest formulation now has 7 times the additives required by law (it was 5 times just a couple of years ago but the latest Nitro+ product upgrade increased the concentration)

mark kibort

ive never heard a ping in any of my 928s or the ones i help build. ever. 110degreees at thunderhilll racing, 5 liter, 5 liter part euro, the 4.7, and the 6.4 liter, and have only used 100 octane one time when it was required by SpeedGT race folks.
i was leary of using the 91 on the 11:1 + stroker, but near 10 years later, its showing no signs of any issues, been on the dyno a dozen times and i think Bill went on a cruise with me with his shark tuner showing no knocks over a wide range of speeds and loads.

i think 91 is more than find for most all 928s.. now as far as ethanol is concerned. i have no idea . ive heard its a power killer for the track, by 2-5%

Don Carter

Jeff,

If you read the details on number 2, you see that they call it a Myth, but they don't dispute that premium has more additives. They really shouldn't have called it a Myth if it's true....

"It's true that premium gas does contain special or extra detergents, but in our opinion they're of no additional benefit."

928S MN

Mark,

The only reason I could see the ethanol containing gasoline being a power killer at the track, is if the fuel injectors are having to run at 100% duty and have nothing left to compensate for the slightly lower BTU value. You need to have the capacity to consume a higher volume of the ethanol fuel for an equivalent power output.

mike77

"i have no idea . ive heard its a power killer for the track, by 2-5%"

Well like for like I think ethanol has 30% less energy than petrol. E10 would therefore have only 97% of the energy of petrol. I don't know what effect that would have on bhp. The results I looked at related to mpg and varied from car to car. Some cars showed over a 10% drop in mpg making adding the ethanol pointless/negative in those instances.

V2Rocket

Where are you finding 110 for $6/gal?
There's a place selling 100 at the pump for $8-9 gal in Canoga Park but that's the nearest I know.

I suspect your 110 may be aviation leaded?

bureau13

That's a fair point.

V2Rocket

what sort of ignition timing do these things run?
when did the vacuum dizzy stop production?

in testing with my 9.5CR 944 (with heads like your 928 Euro) i would get pinging at 34-36* timing around 5000+rpm, on CA 91 octane. dialed down to 30-32 and no pinging. nowadays i can run 30 degrees on 87 no problem

The Forgotten On

It's a 76 station in Agoura Hills on 28203 Dorothy Dr. Pretty sure it isn't Av gas.

Speedtoys

Aviation fuel would -never- be found at a street pump. Ever.

Ever.


It is leaded.

996SPECticle

I would actually bet it has 4 tanks
I used to work in electrical contracting and have done at least 50 C-Stores, mostly 7-11/Citgos including the biggest one in TX at the time, maybe in the US in Hillsboro. It seems to me like it wasnt until the late 90's that 2 tanks and blending at the pump became the norm. By then all the tanks and lines to the pumps were fiberglass. When the tank was set in the ground they needed to be filled about 1/4 with water because it might be another month or more before gasoline could be delivered. In case of rain they would "float" if empty and actually break through the concrete laid above. I asked how they get all the water out, the answer, they don't. The pumps are held off of the bottom though.

The worst of ethanol is for a car that has never used it. It will scour clean the inside of the tank of any varnish and it also breaks down all of the older style of rubber lines. It will also eat some fuel pumps to death. Been there and seen clear fuel filters turn to rust color and little bits of hose in it. It really sucks for a "hot" carburetor car, vapor lock, percolation and excessive evaporation seem the norm at times among my friends.
It is my understanding that every car sold in US should be 100% ethanol safe since about ~2008.

As an aside I also have a '66 "Stang with about 10.5+ CR. I use 91 or 93 regularly. I used some 100LL avgas once and swear it made more power A friend sold me on VP (dont know what octane)at a DE and DAAAAYYUM is that stuff like heroin, no other high compares, gotta have it to feed the itch. Oxygenates

mark kibort

i have VP down the street, but dont think 104 octane is going to do anything if i dont have the ability to change timing. PLUS, isnt most of the power made up top anyway and less timing gives more power, right? dont know and too hard to test, but it would be nice for someone to do back to back testing on the dyno with 104 vs 91 .

Speedtoys

Less timing gives more power...

Yes, if you consider timing has a LOT to do with stroke velocity as well.

If you don't have knock issues at x octane, x+y octane will do nothing for you, except lighten your bank account, true.

Be a worthless test to do that.

Ive raced cars where we worked hard to lower octane (rotaries) to get combustion to happen faster.

It's all about understanding why timing, is called timing.