Jake Ok

That's what I say too, but this post seems to think otherwise. I'm confused?

Jaak Lepson

The best gas I have found is Shell 91. I used to use Sunoco 94 for all my vehicals till the ethanol was added. I notice a difference ... especially with gas milage. I switched to Shell and it seems to be the best in the Tornto area ... no ethanol yet. I have posted on earlier links the issues with ethanol (10%). Although if you need a clean air test ... run a tank of 94 and refill before the test.. Numbers will be good!

CN

My experience:

Ethanol makes the air cooled engine run much hotter in hot weather. I use Ultra 94 with ethanol in cooler weather but in the heart of the hot summer, I prefer 91-93. The 94 starts to "ping & gurgle" after June.

Jake Ok

I've read that once you go to a higher octane, you can go back to a lower octane gas?

Mark Lue

Tonight I filled up with 94, in a few days I'll see for myself if it works for me.

pzull

The reason for 94 gasohol feeling perkier is probably because the knock sensors on you car has detected some knock with 91 and then retarded the timing. With higher knock resistance of 94, the knock sensor/ECU will increase the ignition timing and therefore you get incraesed power

Engines running hotter on gasohol is sure sign that it does not adjust for additional fuel enrichment required with E10 gasohol (about 5% more fuel required) and thus running leaner than optimum.

Gasohol does not keep well in the car or in the gas station. It has tendency to separate from gasoline and absorbs water. Gasohol that isn't "freshly brewed" may actuall have lower octance and hence start pinging.

Ethanol as an oxygenate has cleansing properties and produce less carbon than MTBE which is the more common oxygenate (octane booster). When switching to gashol for first time after prolong use of normal gas, check your fuel filter often and change if necessary as the ethanol would/should have cleaned out some muck in the fuel system

As my car is tuned optimally for gasohol (E10), I have no issues with hotter engine nor pinging (but I do insist on fresh brew and never have a full tank unless I am going to use it within a week. For trackdays I get the gasohol on the same day but have no way of knowing how fresh it is at the station. BTW, gasohol where I live is 8% cheaper than normal same octane gas (because of tax breaks to promote ethanol uisage) so I have a 3% savings on fuel costs

Jake Ok

As a test, I filled up a couple day ago with sunoco 91...what a difference. I could feel hesitation when pushed hard, not as smooth when boost is reaching its max. I can confirm that Tuned turbo cars run best with 94 oct. Can't wait till my next fill..back with Sunoco 94.
It may be different with the 996..any feedback?

Jaak Lepson

Try Shell 91 ..... used to be a Sunoco regular ... now with Shell.

The DareDevil

Anyone here use Esso?

Jake Ok

I have experience several bad fill ups with ESSO. The fumes smells like rotten eggs

Mark Lue

The verdict is in for me, it felt the same but I got less km using Sunoco 94 than the Shell 91. Use what works for you.

pzull

Should be about 5% less mileage right for same driving style?

Mark Lue

The weather has been mild compared to the winter months so I didn't expect much difference but it was about 30 km difference which equates to more than 7% as I was getting over 400km in the winter months.

Jaak Lepson

Just filled up at Shell (LR) ... and noted the following:

Shell 87 has ~10% Ethanol

Shell 89 has ~5% Ethanol

Shell 91 has no Ethanol.

This may make a difference ... the lack of Ethanol in Shell 91. Sunoco 94 has ~10% Ethanol.