The dreaded gas mileage question!

goldcup · Mar 21, 2014

I have about 400 miles on my 2014 TA. Just got back from a 140 mile highway cruise and started with a full tank After the cruise I'm nearly empty. I don't mind the cost but I'll be filling up every time I start it at this point.
My previous vipers while not hybrid type mileage got pretty good highway mileage allowing for fairly long drives between fills. Anyone else noticed? Significant improvement after break in? Let the ridicule begin!

zim32 · Mar 21, 2014

goldcup said:
I have about 400 miles on my 2014 TA. Just got back from a 140 mile highway cruise and started with a full tank After the cruise I'm nearly empty. I don't mind the cost but I'll be filling up every time I start it at this point.
My previous vipers while not hybrid type mileage got pretty good highway mileage allowing for fairly long drives between fills. Anyone else noticed? Significant improvement after break in? Let the ridicule begin!

Wow..that seems awfully low...I put approx. 600 highway miles on and although I didn't do an exact check I believe I got about 250 miles per tankful. Probably running between 2500-4000 rpms on average and running thru 4th-6th gear with frequent shifting. Mark

goldcup · Mar 21, 2014

I'm doing the same. Thought it might be all the throttle changes

LouN · Mar 21, 2014

I am doing the same as zim32 on my 2013 SRT. Are you getting on it and revving it out often, because then it just ***** down the petro.

Bobpantax · Mar 21, 2014

During the first 1000 miles, the idle is set at 1000 RPM. I also think that they may have it run a bit richer during this period. After 1000 miles, the idle drops down. My gas mileage improved after that. But, for some reason my foot has a disorder called acceleration and velocity Tourette Syndrome which significantly impacts my gas mileage.

goldcup · Mar 21, 2014

I have the same disorder! I like to do 400-500 mile cruises and filling up every 180 miles will get old. I'll do it but it will get old!

Bobpantax · Mar 21, 2014

Not if it only takes 1.5 hours to go the 180 miles. You just need to use your molecular transporter and your Klingon Cloaking Device. LQ.

Dom426h · Mar 21, 2014

goldcup said:
Just got back from a 140 mile highway cruise and started with a full tank After the cruise I'm nearly empty.

To calculate your gas mileage more precisely:
1. Fill the tank up
2. 0 your odo trip
3. Drive till less than a quarter
4. Fill up
5. Divide Miles Driven by Gallons put in
= Miles per Gallon

Report back :2tu:

johniew398 · Mar 21, 2014

I'm getting about 11.9 MPG. Not bad for pulling somewhere close to 700 HP. (it's not stock).

goldcup · Mar 21, 2014

I've Done the calculation! But the gen v does it for u

I think I'm averaging 11 something, all highway.

Bobpantax · Mar 21, 2014

Fuel tank capacities:

Gen III - 18.5 gallons.

Gen IV - 16 gallons.

Gen V - 16 gallons.

Transmissions and diffs:

Gen III - 5th and sixth gear are overdrives. 3:07 diff.

Gen IV - until 2010 model, 5th and 6th gear were also overdrives. In 2010 model, fifth gear became a true gear and sixth gear remained an overdrive. 3:07 diff.

Gen V - true six speed. 3:55 diff.

The above differences require more pedal discipline of the Gen V driver from the driver to obtain the same gas mileage on the highway as a Gen IV driver when both are in sixth gear but, the upside is that on the Gen V you can set the speed with the cruise control and maintain a constant speed which, although boring, will improve your gas mileage.

goldcup · Mar 21, 2014

My ACr was significantly better on the highway. But a richer tune for the first 1k would explain the extra consumption. It does appear to be running rich now that I think about it.

goldcup · Mar 21, 2014

Good point,the difference in 5th and 6th is significant in the GenV compared to my 08 ACR. Pedal discipline????? I've never been good at that

Bobpantax · Mar 21, 2014

To clarify post #5 above, the idle will drop to 700 RPM by the end of 1000 miles. This is programmed in at the factory. So when you first get the car, when you first start it up for the day, it will idle at 1000 RPM ( to be precise its probably 950 RPM) and stay there. By 1000 miles, it will start up at 1000 or so but after a few moments it will drop down to 700.

ViperSmith · Mar 21, 2014

Straight highway driving I hit about 20-21MPG

Around town or getting on it, I see around 11.

goldcup · Mar 21, 2014

I can deal with 250 miles per tank, I get tired of pumping gas

Bruce H. · Mar 21, 2014

Bobpantax said:
on the Gen V you can set the speed with the cruise control and maintain a constant speed which, although boring, will improve your gas mileage.

Oh sure, you start a TA buying frenzy and then tell us it's boring :omg:

ViperSmith · Mar 21, 2014

goldcup said:
I can deal with 250 miles per tank, I get tired of pumping gas

Move to NJ

goldcup · Mar 21, 2014

Lmao! I haven't found a boring spot on the TA! But cruise control could be it.

Bobpantax · Mar 21, 2014

I know you are joking. You know that cruise control is boring to anyone with acceleration and velocity Tourette Syndrome. I have had the car now since 12/22 and I have never used the CC. But, if I was going on a long trip, I would. But I know what would happen. I would crank the Stones up on the media center; the music would aggravate my condition; and, the cruise control would be turned off more than on.

Bruce H. said:
Oh sure, you start a TA buying frenzy and then tell us it's boring

Bruce H. · Mar 21, 2014

Bobpantax said:
I know you are joking. You know that cruise control is boring to anyone with acceleration and velocity Tourette Syndrome. I have had the car now since 12/22 and I have never used the CC. But, if I was going on a long trip, I would. But I know what would happen. I would crank the Stones up on the media center; the music would aggravate my condition; and, the cruise control would be turned off more than on.

Yeah, I can totally see that. Maybe consider something more mellow like Pink Floyd to chill with :2tu:

steve e · Mar 22, 2014

Once it breaks in it will get better MPG, but all Vipers **** fuel,and its worth it

SADVIPER · Mar 22, 2014

Feed the monster and it shall feed you back

Bonkers · Mar 27, 2014

Dom426h said:
To calculate your gas mileage more precisely:

I've found trying to calculate MPG on less than ten CONSECUTIVE
full tank fulls is simply a waste of time. You would be shocked at the
variances between one pump and another - even at the same
station. There are WAY too many variables to try to take into
account - time of day, temp, fuel cut off... even scales - (back
when I was paid to do it I recorded 0.75 to 1.2g on the measured
weight.) Don't even get me started on the qualities...

Just from personal anecdotal experience (and for example only) a
true 16g "fill up" at one certain DC gas station would have registered
20g on paper. At the store by the Bridge-Tunnel you wouldn't have
been able to squeeze in more than 12g. If you drove 200 miles on
each tank you would have calculated 10mpg in DC and 17mpg in
Norfolk even though you filled up with the same 125lbs of gasoline.

So far I've used 2,433.133 pump gallons in my GTS. Thats only about
$8,000 over ten+ years... worth every penny in my book...

shine · Mar 27, 2014

I would routinely get 22-23 mpg on highway at cruise speed in my '10 ACR, even with the aero producing drag and no cruise control.

I know that more aggressive gearing in the new Gen Vs though will definitely have an effect on cruise RPMs and fuel consumption (as well as, as pointed out, break-in period). I don't remember the exact RPMs but it seems like, if I remember right, at 65 mph in 6th gear, the car was barely turning over 1000 RPMs with the 3.06 final gear. On my 5-speed automatic Challenger with a 3.55 gear though, I know at 65 it's something more like 2700 RPMs. When it had a 3.06 it was more like 1800.

Steve M · Mar 27, 2014

Bobpantax said:
Transmissions and diffs:

Gen III - 5th and sixth gear are overdrives. 3:07 diff.

Gen IV - until 2010 model, 5th and 6th gear were also overdrives. In 2010 model, fifth gear became a true gear and sixth gear remained an overdrive. 3:07 diff.

Gen V - true six speed. 3:55 diff.

The above differences require more pedal discipline of the Gen V driver from the driver to obtain the same gas mileage on the highway as a Gen IV driver when both are in sixth gear but, the upside is that on the Gen V you can set the speed with the cruise control and maintain a constant speed which, although boring, will improve your gas mileage.

That's not quite how it works...any gear where the output turns faster than the input is an overdriven gear, so anything less than 1:1 (which is 4th gear in all Vipers, 1st through 5th Gen) is considered an overdrive. The standard 5th/6th ratios for the T-56 and TR-6060 through 2009 were 0.75/0.50, making it a double overdrive transmission. In 2010 5th gear ONLY was changed to 0.80, but it's still an overdrive. The 2013-2014 Vipers have a different 1st, 2nd, 3rd, 5th and 6th gears (2.26, 1.58, 1.19, 0.77, and 0.63 respectively) - 5th and 6th are still overdrives, but the 3.55 ring and pinion make them much more usable on the street, at the expense of gas mileage.

Unlike the T-56, the TR-6060 uses a separate 5th/6th gear so they can be changed independently of each other to suit the user's need. If the OP wants better highway mileage, switching to a 0.50 6th gear would help, but it ain't cheap to do especially if you aren't willing to turn your own wrenches.

ACRBruce · Mar 27, 2014

I've been driving the car in Los Angeles rush hour traffic and the car's computer says 14.8 MPG. So I don't think that's too bad.

Bobpantax · Mar 28, 2014

Sounds about right when the acceleration Tourette Syndrome is under control. But it is very hard to do that outside of rush hour constraints. LOL.

The dreaded gas mileage question!

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