http://www.cstorecentral.com/r...e.pdf

If you check your location you will see which of the 18-20 formulations you are using. Notice any change as the Summer grade should now have been replaced in the tanks with winter [Reid vapor] gasoline?

Looks like Louisville currently uses RFG - North. We already knew we used reformulated, that's why most people cross the bridge to Indiana to get the what is apparently 7.8 RVP Reid Vapor Pressure.Which is easier on our motors? better? RVP is definately cheaper.I was unaware that we switched to the regualr RVP in the winter, what's the difference?

Ouch denver has oxegenated and reformulated

Reid is the amount of working pressure required at a temperature [usually 100F] to avoid evaporative loss.The lower the Reid the lower the amounts of volatile AROMATICS the Gasoline comtains.

Reid is primarily to avoid evaporation while filling the tank...." depending on temperature, a 5% to 8% reduction in mobile source-related emissions could be expected from this 0.5 psi reduction. "

Without knowing the exact ratios of the 500 or so chemicals in the gasoline it is impossible to say which is better for what.....without knowing the separate RON and MON numbers a premium can be good or bad. One premium can knock in your engine while another from a different tank farm may be knockless!

"Adding oxygen to gasoline reduces carbon monoxide in the engine exhaust during engine startup and engine and catalyst warmup. Because warmup takes longer in cold weather, using oxygenates to reduce carbon monoxide emissions is most effective in the winter. The carbon monoxide reduction benefit is greatest for older vehicles with open-loop engine control. The benefit gets smaller for newer vehicles with computerized closed-loop engine control and virtually disappears for advanced technology vehicles. "...................the whole oxygenate thing has to do with cars older than 1990 models ------so other than increasing the octane rating of junk gasoline while decreasing the BTU to worsen mileage and eat hoses and injectors it accomplishes nothing at a higher price on post 1990 especially 1996 and newer cars.http://www.chevron.com/prodser...shtmlh ... er...shtml

"Ouch denver has oxegenated and reformulated"

Doesn't much matter as Denver has such low air pressure that cars are producing only 83-80% of rated power in the first place. Then subtract the oxygenates [4-5% lower BTU in blend].........75% would be excellant!

Remember all engines are rated at sealevel.

Sometimes more. A guy in a mustang dyno'd 276rwhp in Missouri and managed only 202rwhp on a Denver dyno..OUCH!

202/276= 73%.......I said you would be lucky to get 75% of rated power in Denver.

The varying altitudes/fuels/temperature/humidity of the magazine tests make it hard to correlate the data on car comparisons between tests closer than 5%.

Does BMW always get tested at 6AM and G35 at 4PM afterall somebody has to be first.

Over at Supraforums, an MKIV Supra dyno'ed 420rwp in AZ and 407 in Denver. Why would it lose power if the boost setting should be consistent even at higher altitude?

Sopdadope wrote:Over at Supraforums, an MKIV Supra dyno'ed 420rwp in AZ and 407 in Denver. Why would it lose power if the boost setting should be consistent even at higher altitude?

i believe altitude directly affects the oxygen in the air. Temperature and humidity could have been different in the two cities as well.

Dennis is leading to a good point though. Who's to say when and where car mags do there dyno testing or the manufacturer for that. Now maybe if dyno rooms could be controlled environments...sea level, temperature and humidity all standard across the country

The manufacturers test all engines in dyno rooms that are controlled! Everyone has a near sealevel facility where the air input temperature can be set at the SAE 60F standard ---unfortunately the act of packaging the engine into the bay raises the temperature and thus assures that the engine will not produce the rated HP.

They don't say the engine in the car with the hood closed produces x power, they mean the engine on the dyno with nothing around it produces x power [+- 3-5%] as they take the most favorable average. Obviously the same engine in different car configurations will be different.

The HP race has its down sides but hopefully they lie the same amount [percentagewise]. The torque figures are usually more accurate as there is no room for manipulation since a foot pound is a foot pound and engineers have some scientific pride [ethics] unless of course their bonus depends on a fudge here and there!

Which is more important [and likely to be true] 213 pound feet or 260 HP at 6400 rpm?

What does psi measure --- the total amount of molecules of the Nirogen/oxygen mixture or their energy level, does the EXACT % of oxygen stay constant as altitude increases.

You put x number of molecules in a tire and heat the tire, the psi goes up but are there more molecules in the tire?

In a turbo psi is not as important as Boyles Gas Law----density grams per second flow.

You did know that a pound [as in psi] is not a unit of weight as it varies by gravity....how does gravity vary by the altitude.

How do you measure psi as the reference [gauges are calibrated at sealevel [29.92"HG] does the fuel rail ABSOLUTE PRESSURE change as you change altitude what about in the eye of a hurricane.............PSI is a very very inaccurate measurement!

can someone help me find that map again? i'm searching through the archives of that site but there's so much info. i just want a copy of the map to keep for my own personal info.

Mayhem, this is what I came up with http://64.49.216.152/Nacs/reso...6.htmIf that doesn't work then...

thanks balls.

phew, i know i've said that before

I had to fix that link Mayhem. Deesballs say you're welcome!!

I'm planning a road trip to Phoenix/Tucson. Should I worry about the gas ? The RFG map shows oxygenated in Tucson but CBG in Phoenix. Is the CBG worse on injectors ? The 10% ethanol I get in MN doesn't seem to cause any problems, is this the same as Tucson gas ? Don't need injector problems 1700 miles from home. Having just finished the plenum & injector cleaning, I'm looking forward to the trip in the Q. Do you AZ guys know where to get non-RFG there ? Thanks...

Another link to this map with more detail... http://www.aaanewsroom.net/files/boutiquefuel.pdf

Qdog - A couple tanks of gas aren't gonna make an impact. It's having a car all it's life, with a steady diet of this oxygenated / ethanol mix fuel.

My Q is on it's second set of injectors in 100K miles... You should be safe.

When are you gonna be here?