• Reply

#15 of 18 Re: Break in changes in city mileage. [sooththetruth] by gimmestdtranny

Jul 17, 2010 (4:47 pm)

Replying to: sooththetruth (May 10, 2010 9:42 am)

Here in Cda, the V6 is suppose to run on 87 octane. The V8 on premium.
There are few misconceptions greater than there is between reg and premium gas.
 
Here are the (rather simplistic but) basic facts.
 
- There is more BTU in regular gas. If your manual calls for regular, do NOT use hi test.
 
- Hi-test has less BTU (energy) in it. Hi-test is design to have a higher (read slower) flash point. i.e. it is meant to be burned in combustion chambers which have a high compression ratio. Fuel ignites easier the more it is compressed. That is why older cars that have carbon build up in the C chamber, (which raises the CR due to its basic volume sitting there) often don't ping and run on when owners switch to mid or hi-test. You see....it is the red hot carbon that ignites the gas when the ignition has already been turned off, and hence causes the dieseling or run-on. Because the regular gas has a lower flash point (quicker to burn). So that is why hi-test often eliminates ping and run-on.
 
- there are no more deterents or additives in hi-test than there is in regular.
 
- if your car is designed to run on regular, it will have more power, and run more efficient to boot. (no blind test required)
 
- upper class luxury vehicles (and some lesser ones) often use a detonation device that operates electronically. It can sense regular gas if an owner uses regualr gas in a car that requires premium. But this only fools the engine into thinking it has the proper grade gas. It makes adjustments to engine timing etc to do this. But owners of cars that require premium should switch back as soon as their next tank. Running hi-test in a car that requires regular, actually tends to strangulate the engines ability to perform as manufactured.
 
- because fewer owners purchase premium at the pumps, it is always older gas. Makes sense right? So again, use regular if your car is designed for it.
 
I am amazed at these MPG figures real world owners are getting, and I really enjoyed seeing some of the detailed write-ups here. Very impressive.
 
I am in the market for a Genesis I think. But I am sorta poor and need them to depreciate a little more before I can find one I can afford. Was the first year 2009? Did they have any issues? I sorta hate to buy first year of anything.
If anyone here (non-smokers only please) decides to sell their (V6 only) any year considered, Genesis because their needs change, send me a message here or PM. My notifier is turned on. thanks and enjoy your new rides everyone

• Reply

#16 of 18 mileage after second fill up - 4.6 by harrybush00

Jan 06, 2011 (10:27 pm)

• Reply

#17 of 18 2009 3.8L Mileage @ 47,000 Miles by lakerunner4h

Jul 27, 2011 (11:49 am)