2015 GT Fuel Mileage
06-10-2015, 09:15 AM
#11
Former Sponsor
Join Date: Nov 2014
Posts: 105
Hey everyone,
The comments about modern fuel systems being made for ethanol blended gas are absolutely correct.
The issue with ethanol gas sitting for longer than 30 days is not necessarily phase separation but the shelf life of ethanol blended gas. Typically that gas can begin to lose volatility in as little as 30 days. That's not to say it will be unusable, but will begin to lose volatility and may start to form gum/varnish. The best practice to avoid any potential for gum & varnish build-up during extended storage is to fill the tank about 95% full, add a high quality fuel stabilizer/ethanol treatment and run the engine for 5-10 minutes to ensure the whole fuel system is treated and protected.
Phase separation occurs when as little as 4 teaspoons per gallon of fuel is absorbed. It won't just separate out from sitting for extended periods of time. You then end up with an ethanol/water mixture on the bottom of the tank and gasoline on top. The best way to avoid this is to try and keep the tank full as much as possible. This will cut down on room for condensation to form which is generally the #1 cause of phase separation
Please let us know if you have any questions.
Have a great day!
The comments about modern fuel systems being made for ethanol blended gas are absolutely correct.
The issue with ethanol gas sitting for longer than 30 days is not necessarily phase separation but the shelf life of ethanol blended gas. Typically that gas can begin to lose volatility in as little as 30 days. That's not to say it will be unusable, but will begin to lose volatility and may start to form gum/varnish. The best practice to avoid any potential for gum & varnish build-up during extended storage is to fill the tank about 95% full, add a high quality fuel stabilizer/ethanol treatment and run the engine for 5-10 minutes to ensure the whole fuel system is treated and protected.
Phase separation occurs when as little as 4 teaspoons per gallon of fuel is absorbed. It won't just separate out from sitting for extended periods of time. You then end up with an ethanol/water mixture on the bottom of the tank and gasoline on top. The best way to avoid this is to try and keep the tank full as much as possible. This will cut down on room for condensation to form which is generally the #1 cause of phase separation
Please let us know if you have any questions.
Have a great day!
06-10-2015, 03:00 PM
#12
2nd Gear Member
Join Date: Nov 2012
Location: AZ
Posts: 225
Are your gripping that getting 30mpg in a V8 on the highway. it's not a Prius...
That's what I get in my V6. My mixed driving is about 22 and that is shifting before 3000rpm. I'll get it on everyonce in awhile, but most of the time is just cruising around town and to work.
That's what I get in my V6. My mixed driving is about 22 and that is shifting before 3000rpm. I'll get it on everyonce in awhile, but most of the time is just cruising around town and to work.
06-22-2015, 01:22 PM
#14
EXTREME Moderation
Join Date: Apr 2005
Location: BLAM-O
Posts: 7,895
Gas Mileage? Really??? If that is truly a concern you should not have bought a GT. Like any other pony/muscle car....met to breathe and run. Best I've done on a 200 mile drive is 20. Mostly around the 14-15. Passes everything on the road but a gas station...I'm OK with that.
I use 93 with 10% ethanol (at least it is labeled as 10%) all the time and have no issue. The engines today are made for it and so is the fuel tank and fuel system. Plus unless it is a garage queen you will never have the same fuel sitting in that car for long anyway so the water should not get a chance to fully separate from the fuel.
I just made a 2400 mile road trip and averaged just over 23 mpg. Mostly highway, but a lot of hills and mountain roads too. My mpg's seemed very low during the first 1000 miles or so, and then it seemed to improve slightly, just like the manual mentioned. This was on 91 octane, which is all we have in Cali.
10-06-2015, 08:04 AM
#15
Former Sponsor
Join Date: Nov 2014
Posts: 105
Hey everyone,
Sorry for digging up an old thread but we recently completed some videos that are relevant to the conversation about today's fuels. The two links below take you to a couple of short videos about some common myths you may have seen in other additive videos. Please let us know if you have any questions or comments.
Have a great day!
Sorry for digging up an old thread but we recently completed some videos that are relevant to the conversation about today's fuels. The two links below take you to a couple of short videos about some common myths you may have seen in other additive videos. Please let us know if you have any questions or comments.
Have a great day!
10-06-2015, 05:07 PM
#16
2nd Gear Member
Join Date: Jul 2015
Location: TX
Posts: 150
Had I bought my GT expecting good gas mileage I might be a touch upset. Around town I get between 12 and 16 mpg depending upon how big a ***** bag I am. I just love lighting up the rear tires going around corners. It's like crack cocaine.
Keep in mind: I work from home and most of the driving I do when I get out is very short w/ lots of stop signs, stop lights, slow moving traffic, etc. The car never gets to just cruise.
On the drive to Arkansas I saw 24.8mpg cruising between 70 and 80. I was very happy.
During my loop from Rogers Ar to AR 123 down to Clarksville then back up the Pig Trail to Rogers driving spiritedly I maintained ~20mpg.
I have to wonder if the final gear in the diff should be changed. The performance pack puts in a shorter gear to help increase acceleration. However, that means the engine spins faster for a given speed. Would going back to the stock gear make any difference for fuel economy (as if I really care)?
Keep in mind: I work from home and most of the driving I do when I get out is very short w/ lots of stop signs, stop lights, slow moving traffic, etc. The car never gets to just cruise.
On the drive to Arkansas I saw 24.8mpg cruising between 70 and 80. I was very happy.
During my loop from Rogers Ar to AR 123 down to Clarksville then back up the Pig Trail to Rogers driving spiritedly I maintained ~20mpg.
I have to wonder if the final gear in the diff should be changed. The performance pack puts in a shorter gear to help increase acceleration. However, that means the engine spins faster for a given speed. Would going back to the stock gear make any difference for fuel economy (as if I really care)?
10-07-2015, 10:03 AM
#17
1st Gear Member
Thread Starter
Join Date: Jan 2015
Location: California
Posts: 65
Had I bought my GT expecting good gas mileage I might be a touch upset. Around town I get between 12 and 16 mpg depending upon how big a ***** bag I am. I just love lighting up the rear tires going around corners. It's like crack cocaine.
Keep in mind: I work from home and most of the driving I do when I get out is very short w/ lots of stop signs, stop lights, slow moving traffic, etc. The car never gets to just cruise.
On the drive to Arkansas I saw 24.8mpg cruising between 70 and 80. I was very happy.
During my loop from Rogers Ar to AR 123 down to Clarksville then back up the Pig Trail to Rogers driving spiritedly I maintained ~20mpg.
I have to wonder if the final gear in the diff should be changed. The performance pack puts in a shorter gear to help increase acceleration. However, that means the engine spins faster for a given speed. Would going back to the stock gear make any difference for fuel economy (as if I really care)?
Keep in mind: I work from home and most of the driving I do when I get out is very short w/ lots of stop signs, stop lights, slow moving traffic, etc. The car never gets to just cruise.
On the drive to Arkansas I saw 24.8mpg cruising between 70 and 80. I was very happy.
During my loop from Rogers Ar to AR 123 down to Clarksville then back up the Pig Trail to Rogers driving spiritedly I maintained ~20mpg.
I have to wonder if the final gear in the diff should be changed. The performance pack puts in a shorter gear to help increase acceleration. However, that means the engine spins faster for a given speed. Would going back to the stock gear make any difference for fuel economy (as if I really care)?
That being said, I get around the same city mileage (12-16) depending on how frisky i feel that day. Lets be real, I put an exhaust on it and i love putting my foot in it to hear the tail pipes. That being said, I saw 30 mpg (no lie) on the way from the san fernando valley (socal) to Stockton (norcal-ish). The end result for that leg of the trip was 28.5 ish mpg, and the overall for the trip, including a trip into SF, then back to stockton, some test drives in between, and back home was around 26... And i wasn't very nice to it during the test drives...
That said, when i cruise at 70mph, that equates to an indicated 2k on the tach.. at about 75, it's about 2150
