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

[Johny Blackstain]

For what it's worth, I've access to 87 ethanol free and that's what I run in my Civic... mpg went up 6 miles per gallon (IMG:style_emoticons/default/blink.gif)
I also have access to 110 ethanol free but it's over $8 per gallon (IMG:style_emoticons/default/dry.gif)

[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

[Johny Blackstain]

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.

Mark- I was told that Porsche knew unleaded was coming so they also started using sodium filled valves early?

[bbrock]

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.

Mark- I was told that Porsche knew unleaded was coming so they also started using sodium filled valves early?

I thought this was just to improve heat transfer from the exhaust valves rather than anything to do with lead. Also, per your earlier comment about better mileage with ethanol free gas. Yes. Pure ethanol has about 30% less energy per gallon than gasoline so the reduction in fuel economy depends on the strength of the blend.

Another small thing about octane. You may still run into lower octane fuels traveling in high elevation areas. You don't need as much octane in the thinner air. Until just a few years ago, our regular gas was all 85 octane but then it switched to 87. I think that happened when they started blending more ethanol in our fuel as ethanol has higher base octane than gasoline. I wish we could go back to the 85 octane because it usually had little or no ethanol.

[Johny Blackstain]

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.

Mark- I was told that Porsche knew unleaded was coming so they also started using sodium filled valves early?

I thought this was just to improve heat transfer from the exhaust valves rather than anything to do with lead. Also, per your earlier comment about better mileage with ethanol free gas. Yes. Pure ethanol has about 30% less energy per gallon than gasoline so the reduction in fuel economy depends on the strength of the blend.

Another small thing about octane. You may still run into lower octane fuels traveling in high elevation areas. You don't need as much octane in the thinner air. Until just a few years ago, our regular gas was all 85 octane but then it switched to 87. I think that happened when they started blending more ethanol in our fuel as ethanol has higher base octane than gasoline. I wish we could go back to the 85 octane because it usually had little or no ethanol.

I was also told that lead also helped with valve lubrication and no lead in the gas = hotter valves, hence sodium filled. Also, the regular leaded gas from back in the day was 89 octane which is why we have "plus" today.

[bbrock]

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.

Mark- I was told that Porsche knew unleaded was coming so they also started using sodium filled valves early?

I thought this was just to improve heat transfer from the exhaust valves rather than anything to do with lead. Also, per your earlier comment about better mileage with ethanol free gas. Yes. Pure ethanol has about 30% less energy per gallon than gasoline so the reduction in fuel economy depends on the strength of the blend.

Another small thing about octane. You may still run into lower octane fuels traveling in high elevation areas. You don't need as much octane in the thinner air. Until just a few years ago, our regular gas was all 85 octane but then it switched to 87. I think that happened when they started blending more ethanol in our fuel as ethanol has higher base octane than gasoline. I wish we could go back to the 85 octane because it usually had little or no ethanol.

I was also told that lead also helped with valve lubrication and no lead in the gas = hotter valves, hence sodium filled. Also, the regular leaded gas from back in the day was 89 octane which is why we have "plus" today.

That makes sense. My understanding is that lead was originally added as an octane booster and had a side benefit of coating valves and seats to create a cushion that helped protect against pounding which led some manufacturers to go with cheaper cast iron seats. Makes sense it could help lubricate and reduce friction too.

I should clarify that I was saying ethanol has higher octane than unleaded gas.