Bazazu

Places actually switch out gas in the wintertime?

You mentioned "winter grade fuel"

Do they put some additives in it for winter or something ?

dr_gallup

Gasoline is a generic term for a very complex blend of hydrocarbons and additives. It varies by region, altitude and season; there are dozens on different blends being sold throughout the country over the course of the year. And I'm not talking about brands. The biggest difference between summer and winter grades is the "Reid vapor pressure" which is a measure of volitility. In the winter the RVP is higher to promote evaporation for good cold starting ability. In summer it is reduced to improve hot starting and reduce evaporative emissions.

The most noticeable problem is when you have a tank full of high RVP fuel and get a sudden warm spell. By the way, car companies do lots of testing to make sure you don't have a problem. You would not believe how many prototype vehicles are running around Death Valley in the middle of summer doing hot testing and up in Canada right now doing cold testing. Hopefully, Nissan has done their homework for the Z!

Here is a link for the different RVP regions just in the state of California:

http://www.arb.ca.gov/cbg/rvp/carvp_color.pdf

There are many other properties of gasoline that are controlled but the effects of most of them are not so evident to the consumer.

iris

I once got a quick and dirty lesson on oil/gasoline at an oil refinery in Long Beach, So Cal - this need to produce special "summer" gas is especially true in Cali, what with the stringent gas emissions regulations. I don't know the special additive they put in, but I do know that it's harder/more $$ to produce this gasoline w/less emissions (obviously). Also, the "summer" for oil refining is not the normal 3 months, at least in Cali, but instead like 6 months long.

Boomer

I have never heard of this practice of different formulations for the time of the year before. Fascinating. It's always interesting to learn something new. How long has this practice been going on? Is this now standard practice in all states, or only those that require adherance to Calif. emissions standards?

dfresh713

iTrader: (2)

I've driven close to 100 miles after the dte light comes on and the light starts flashing. I drove for about 40 miles with the needle resting on the point on the dash and still filled up with 18 gallons. I think I had about 2 more gallons left in my car.

blastoff99

iTrader: (5)

There must be some sort of award here for resurrecting a thread from so long ago.