mausone46

Like Iceman said, I've read in my German P book that all 3,2 with Cat and Us cars need low octane gas because of low compression rate, different story was with 930-20 (no cat) engine with higher compression rate and need of higher octane gas

ADias

My (US) 3.2 has factory cat and requires (factory) premium/super (91/93 US rating) gas.

r911

no cars _need_ low octane gas - they will work fine on it tho...

Pel

Thanks, this makes sense. Looks like we just use a RON rating so effectively. 94 in USA is 98 down under.

theiceman

Yeah will get by on lower octane but doesn't need it . All octane does is prevent predetonation. Higher compression ratio engines will have more predetonation so a higher octane is required. I think after 79. Scs required the higher octane.

73911

Discussing gasoline is similar to discussing politics and religion.

There is very little hard data. Most of the information it anecdotal. I've worked with Sunoco, Shell and VP on various articles. They all claim to have never tested the various additive packages. "We're not in in business of testing additives that are sold over the counter."

Sta-Bil has no public research available.

The sign at the gas station tells you nothing about what brand of gas you're buying. The refiners swap gas all the time. Here in FL we have a lot of Sunoco stations but no Sunoco refinery. I wonder who's gas they're selling?

Then we have RaceTrac with over 650 locations and no refinery.

The biggest problem we have with gasoline is that it goes bad very quickly. Gasoline never goes totally bad but it deteriorates slowly. E10 begins to lose performance in about 45 days.

More on Gasoline

Richard Newton

theiceman

I had my car off the road for two years while I repaired my head studs. I was on one of my last runs of the year. I added my stabil to my tank filled her right up and was changing the oil and doing the valves when I noticed the broken stud
That was October / 2014
That gas went through two winters in that tank and I just fired my car up last weekend.

I was amazed it even started. After I did my base tune it runs and pulls fine. Although I have some start up idle issues.

Gonna burn through this tank and another fresh one before doing any further tweaking though.

So not all gas is swill.

Shell premium btw.

tgil

I read the owners manual for my 1980 911 and you can run 89 octane,the engine can handle it, but better performance is achieved with 91/93 octane.
Everyone I ever met with a 911 runs the highest octane they can find, I think we all feel it is better for the engine. The wording states Porche understands all areas of the world may not have higher octane fuels but reading between the lines suggests using higher octane if available.
I read the owners manual for my 2016 GTI, and it says the same thing, 210 HSP, 6MT, and it recommends regular and says better performance achieved with higher octane, not a word about 87 being harmful to the engine. GTI forum participants tear you up for even suggesting running 87, but the owners manual and the fuel filler area recommend 87 minimum as acceptable. For my GTI, i switch from 89 to 91/93 every other fill up.
Porches only get 91/93.
I have also tried a tank of ethanol free in my 1980 and am still seeing if it runs better, so far its hard to tell any difference with 10%ethanol 91/93.
Hope this helps.

theiceman

As mentioned earlier higher octane ratings prevent pre detonation. Predetonation is also caused by extreme heat so I would agree. Running the highest octane is preferable in an air cooled motor.

Keep in mind modern cars however have the ability to sense pre detonation via the anti knock sensor and retard the ignition timing to protect you from " bad gas" to some degree. Our cars go not have that ability. If your car ask for premium and you run regular I would be cautious of going wot with it.

Spyerx

Around here most of the gas comes from a distribution center that has trucks from all brands getting it, and it will come from one of the 3 refineries in the wilmington area, i'm sure it's all mixed together.
Difference, supposedly, is the additives they mix in at distribution.
True? Who knows.

I run mine on unicorn tears.

stlrj

Here in the SF bay area all gas delivery trucks, regardless of brand, get filled from the same spigot from the same distribution center and the only difference is the additive package. At least, that's what the trucker told me while filling the tanks at my gas station.

Cheers,

Joe
87 Carrera that runs on 87

theiceman

This is absolutely true. The differentiator is the additive packages.

bgiere

For a fuel system cleaner you might try the Redline product..It has a lot more PEA than Techron and will really clean up the intake and injectors....It is like Techron on Steroids..I run it through once per season, my 3.2 was spotless when we inspected. Usually run Shell 93 or 89 fuel.