What kind of gas are you using?, modern 91/93 with ethanol or non-ethanol with octane booster Options

[boxster914]

I've just been given two conflicting suggestions:

Run non-ethanol 89 octane gas and use a lead substitute (instead o' lead)

or

just use modern 91/93 octane gas that contains ethanol.

I had been using non-ethanol gas in my 72 Beetle and then switched to modern 91/93 gas with ethanol and it seemed to develop a hesitation on acceleration.

I just got a 71 914 and am interested to know what you all are using so I can decide which gas to use in it.

[Racer]

Comes down to what's available. Some states don't allow non-ethanol fuels to be put in cars. others have no issue with it.

These cars were built to run on leaded regular (which of course did not have ethanol). Good luck finding that (IMG:style_emoticons/default/wink.gif)

Most cars get buy with any 87-93 octane fuel, ethanol or not. If you've advanced your timing trying to squeek out the last few hp, running 91 or higher could help with some predetonation.

If you are using an ethanol fuel in a car that sits awhile, run some kind of Stabil/Heet/Water evaporator to help keep lines and injectors/carbs cleaner.. not spotless, but cleaner.

Feel free to add a lead additive if you are worried about valvetrain wear.

Asking what fuel to use is like asking what oil to use. Everyone will tell you something to conflict with the last opinion!

[Mark Henry]

These cars were built to run on leaded regular (which of course did not have ethanol). Good luck finding that (IMG:style_emoticons/default/wink.gif)

Feel free to add a lead additive if you are worried about valvetrain wear.

Asking what fuel to use is like asking what oil to use. Everyone will tell you something to conflict with the last opinion!

My mechanics know their stuff, and both recommend running 91 from Chevron or 76. Ethanol is tough to avoid here in CA.

I can get higher octane—and even leaded race gas—by driving over to Sears Point, but I very rarely do so. I tend to forget which octane I should go for, and whether it would be helpful or harmful with an engine built and tuned to run on our crappy 91-octane gas. Will say it made 169.9 rwhp (so, 190-200 hp at the flywheel?) from 2.2 liters on CA 91 and runs beautifully throughout the rev range.

I'd be very curious to hear what someone like Jake Raby or others here have to say about the occasional tank of leaded race gas, and if there are any benefits. I suspect any octane bump would be wasted?

Some of this is folklore.
All VW and porsche heads are fine on unleaded, they have steel seats which are not effected by the lack of lead. The folklore is from old cast iron heads where the seat is cast as part of the head and needed lead to act as a lube so the seat would not degrade. There were cases back in the day of low budget VW builders who used cheap cast iron seats and guides, but factory seats were steel. I think you can only get steel seats now days.
Don't run leaded if you have an O2 sensor, the lead will deposit on the sensor and ruin it.

AV gas uses a completely different octane rating procedure and is a waste of money. The same can be said running race gas if your CR is set for pump gas.
Octane boosters and top end lubes to me are all snake oil designed solely to pick your pocket. I've tried but some of the products, but except for occasional FI cleaner I don't use them. I only use busy stations that I know is filling the premium tank weekly.
Don't blame the gas for a mechanically poor engine.

If you drive your FI teen regularly and you have new E10 certified fuel hose you should have no problem with E10. For carbs the new gasket kits have diaphragms that are more ethanol resistant. If your car sits for long periods just with my nose I can tell that E10 starts to go skunky within a month. Not sure how to store a car with E10, I'd likely run the system dry for storage.
One plus of E10 is it actually cools the head better than pure gas.

I run 91 pure gas pretty well all the time, although I did run a few tanks of 93 E10 through my /6 with webers with no issues this year. The winter (or 6 month storage) all I do is run in with some sta-bil and fill the tank with 91 pure gas.
Longer storage I run it dry, but it's in a heated shop, my '67 bug is in unheated storage so I drain and fill my tank 2X year.





Do I have pure gas or E10? Quick down and dirty.

-Find a small but tall glass container. (large test tube)
-Fill 1/10 with water, mark with sharpie.
-Fill with gas.
-Shake and let it sit a couple minutes.

The gas and water will separate with water on the bottom, if it looks like the same 1/10 of water then it's pure gas. If it looks like the water has doubled in volume (2/10 ths) then it's E10.

YMMV