FNBADAZ06 Posted February 24, 2012 Share Posted February 24, 2012 Winter blend fuels....... Many claim a significant drop in fuel economy when the winter blend fuels are pumped into their gas tanks, thinking that the fuel "quality" has gone down and is the root cause of the drop. Is there any truth to that ? Some MAY see a drop in MPG's over the winter months, but I'm not convinced it has anything to do with the fuel.....in fact, I think I see a marked improvement on performance with winter blends !!! In fact, in my Lexus GS430...which requires 91 octane fuel, I switch to 89 octane in the winter months. While the savings are minimal at the pump ( roughly .10 per gallon difference at approximately 16 gallons per fillup equals around $1.60 savings), I get an MPG bump on average of around 1.5+ MPG per gallon in the winter !!!! While some of this may be attributable to not running the A/C (the car has auto climate), in the winter the colder, denser air may also require your ECU to inject more fuel to keep the AFR's correct. This denser air, combined with the greater fuel amounts injected into the cylinders also means MORE HP being produced by the engine Our cars also may stay in a rich operating mode longer as it takes longer for the engine to get up to operating tempature and to light off the cats when it's cold in the morning. The lubricant viscocities will also be thicker when it's cold out, causing more internal friction and drag in the engine, transmission, and rear differential. And, unless you're checking frequently, tire pressure's drop as air temps go down, which can add to additional rolling resistance. Yet, with all these negatives, I get roughly 25-40 more miles out of a tank of fuel in the winter months.....my usual range of 320 miles per tank can soar up to as high as 350+. I'm guessing that the mild octane bump that winter blends provide which allows me to run on 89 octane MIGHT be getting me a hotter burn in the cylinders, upping the cylinder pressure per injector cycle, giving me more power per lbs of fuel burn ??? Don't know......but I can definetly tell you that winter blend fuels give me a BOOST in MPG, and allow me to use the less expensive 89 octane fuels...all without sacrificing any performance. Thoughts, or comments ??? Link to comment Share on other sites More sharing options...
Two Fangs Posted February 24, 2012 Share Posted February 24, 2012 That is really interesting. I don't monitor my fuel mileage, so I really don't have a dog in this hunt as far as corroborating data. I could espouse a bunch of theory, I guess, but I would like to see if other share this experience with increased mileage and performance. :popcorn: Link to comment Share on other sites More sharing options...
FNBADAZ06 Posted February 24, 2012 Author Share Posted February 24, 2012 That is really interesting. I don't monitor my fuel mileage, so I really don't have a dog in this hunt as far as corroborating data. I could espouse a bunch of theory, I guess, but I would like to see if other share this experience with increased mileage and performance. :popcorn: Like the Vette, there's a driver's information screen on my factory NAV which shows real-time instant fuel economy, average fuel economy, AND....a history of my fuel economy for the last 8-12 fill ups As I drive with this screen up most of the time, I can see the statistics the car is compiling, along with showing me my throttle habits (with the real-time instant MPG). Another interesting thing my car has is a power/normal/snow button, that changes the throttle input/response and transmission shifts. In power mode the throttle response is quick and the car will launch in 1st gear (5 speed auto). In snow mode, the throttle response is VERY lazy (feels like the e-brake is on) and the transmission leaves from 2nd gear. If I leave it in snow gear, I can eek out a mile or two more MPG when on the freeway as compared to normal or power modes. I'm guessing because the throttle inputs are so subtle (read, slow)that it's easier to keep a steady state cruise with minimal throttle change, versus an aggresive throttle input to accelerate harder than I need to. Do you think the winter fuel mixes are inferior or superior to the summer blends ? I would think with the lower vapor point, winter fuels would have an advantage ? Link to comment Share on other sites More sharing options...
Two Fangs Posted February 25, 2012 Share Posted February 25, 2012 I finally made it home and had a chance to actually read this. The winter fuel certainly vaporizes at a lower temperature, it is one of the things that allows for fast starts and better cold weather drivability. The largest proprietary change between summer and winter blends lies primarily in the butane content. There is more butane added to gasoline in the winter (it is very cheap and abundant, and hence, the price of gas goes down) versus barely any in the summer. So the answer most likely lies in the simplest of scenarios, and that is the energy capability of the fuel. In the winter, we lower the vapor point of the fuel by adding butane. Butane contains approximately 21,200 BTUs per pound, compared to gasoline at 17500. So it would make sense that the winter blend would contain more potential energy and give better performance. No need to hit the gas as hard, so mileage is assisted also, with the addition of the limited use of the air conditioner, which is most likely the most power-robbing accessory on most engines. I am not sure why anyone would argue less mileage in the winter, unless they tend to spend more time warming their cars up, sitting in bad weather, and modulating the throttle to try and compensate for bad road conditions. Plus, carrying around few extra hundred pounds of ice in the undercarriage. Just my thoughts on the subject, anyone else? Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted February 25, 2012 Share Posted February 25, 2012 It's WINTER blend so that means your fuel/air charge will be much cooler and the car will make more HP. Kinda like nitrous, but totaly different. Link to comment Share on other sites More sharing options...
Two Fangs Posted February 25, 2012 Share Posted February 25, 2012 It is certainly totally different than nitrous injection. And certainly one must consider that colder air charge temperatures will increase performance, but with that additional oxygen content comes an additional fuel content, so we have to consider the levers that are affecting the mileage increase, no? Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted March 1, 2012 Share Posted March 1, 2012 I forgot to insert sarcasm emoticon. Link to comment Share on other sites More sharing options...
Two Fangs Posted March 1, 2012 Share Posted March 1, 2012 :lol :cheers Link to comment Share on other sites More sharing options...
Ted Y Posted March 1, 2012 Share Posted March 1, 2012 What if winter blend had bacon in it instead? (definite sarcasm) Mileage would go up. Link to comment Share on other sites More sharing options...
Two Fangs Posted March 1, 2012 Share Posted March 1, 2012 Cars love bacon, mileage would definitely go down. Plus, the car would get heavier... Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted March 1, 2012 Share Posted March 1, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. Link to comment Share on other sites More sharing options...
FNBADAZ06 Posted March 1, 2012 Author Share Posted March 1, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. But then again, there wouldn't be any carbon monoxide as you would be inhaling bacon grease smoke from the combustion process....right ?????? Link to comment Share on other sites More sharing options...
HOXXOH Posted March 1, 2012 Share Posted March 1, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. That would be Fred Astaire after winning the Austrailian Grand Prix in the 1959 movie "On the Beach". What did I win? Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted March 2, 2012 Share Posted March 2, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. That would be Fred Astaire after winning the Austrailian Grand Prix in the 1959 movie "On the Beach". What did I win? WHO? Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted March 2, 2012 Share Posted March 2, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. But then again, there wouldn't be any carbon monoxide as you would be inhaling bacon grease smoke from the combustion process....right ?????? Either way my heart would stop. I mean, if I had one. Link to comment Share on other sites More sharing options...
HOXXOH Posted March 2, 2012 Share Posted March 2, 2012 I would be overcome by carbon monoxide cuz i had the car running in the garage with the door closed. That would be Fred Astaire after winning the Austrailian Grand Prix in the 1959 movie "On the Beach". What did I win? WHO? http://en.wikipedia.org/wiki/Fred_Astaire You're probably too young to have seen him. Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted March 2, 2012 Share Posted March 2, 2012 Link to comment Share on other sites More sharing options...
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