Calling all Prius Drivers! Need Advice

[broski499]

I drive a 2008 Prius and have really been struggling lately even getting the EPA 46 mpg. Granted it has really been a hot summer in Ca so having to crank AC all the time hasn't helped.

What do you do that has helped you achieve the best MPG.

Any favorite technique or modification you utilize?

I already have LLR tires and check them regularly. I stay on top of maintenance as well. I drive very conservatively and use an Ultragauge.

Thanks for help!

[Ecky]

I don't own a Prius but have driven one pretty extensively.

-What's your mix of city and highway?

-What speed do you drive at? 30mph is probably where you'll get the best economy, and it drops sharply above 60-65.

-What tire pressure? I run ~50 in my Insight.

[S Keith]

Sounds good to me. In AZ heat with full A/C use, 42 is a challenge.

[roflwaffle]

That sounds like normal mileage with high AC use.

https://priuschat.com/threads/how-to...a-c-use.97814/
https://priuschat.com/threads/ac-com...-on-mpg.95749/

The INL found that AC on max with full blower drops mpg from 52.7 to 41.3.

https://avt.inl.gov/sites/default/fi...hevamerica.pdf

My guess is most cars take a big mpg hit with the AC on high though, so you're still probably coming out on top overall.

Offhand I think parking in shade, using a sun shade (ideally on the outside, but you'll probably get weird looks), and cracking the windows will help, as will window tinting.

[S Keith]

Originally Posted by Old Tele man

Wife has been able to manage 47 mpg here in Tucson, AZ, with mostly 45 mph urban driving, and A/C blasting. Of course, our Prius is a later GenIII 2014 model.

Having driven our Prius in LA / Burbank area, I'm going to guess that freeway driving is your problem: (a) you have to floor the pedal to merge with (b) 75-80 mph traffic that's supposed to be only going 65 mph. Remember EPA mpg tests are basically performed at 55 mph, with a few 'brief' spurts up to 65 mph.

Maybe prior to 2008, but not anymore:

https://www.fueleconomy.gov/feg/fe_test_schedules.shtml

2008 EPA tests are much more representative of real-world than the fluffy numbers pre-2008.

[vskid3]

How long are your trips? Warm up will hurt you even if it's hot out and having to cool the cabin multiple times/for a short drive doesn't help either. I usually use auto AC and set the temp in the mid-upper 70s. Shorter trips take a hit, but long trips use similar amounts of fuel as not using the AC.

For driving technique, I usually accelerate briskly (usually about as fast as regular traffic) and P&G under 40MPH where possible. At higher speeds I just use cruise most of the time. I get right around 50MPG with cruise at 70-75MPH with auto AC. If I'm going 80 it'll dip down to the mid-40s (not that an ecomodder would ever drive those speeds...).

[S Keith]

Originally Posted by Old Tele man

The Highway schedule tests are different from the City schedule tests.

Notice THEIR graph statements:

• City Schedule - "Maximum Speed = 56.7 mph"
• Highway schedule - "Average Speed = 48.3 mph"

Neither represent realistic HIGHWAY speeds of 65-75 mph!

You're reading selectively. Is there a reason you didn't hit the High Speed Tab? All 5 tests apply.

"Beginning with 2008 models, three additional tests are used to adjust the city and highway estimates to account for higher speeds, air conditioning use, and colder temperatures."

Example:

2007 Prius:
Pre-2008: 60/51/55 (city, hwy, combined) - numbers that few achieve
2008+: 48/45/46 - numbers that are readily achieved via "normal" driving

[S Keith]

Originally Posted by Old Tele man

Yes, the High Speed schedule is only fractionally better, with "Average Speed = 48.37 mph":



A highway speed of 48 mph would get you run off the roadway on most interstates where 65-75 mph is the posted speed, not the actual traffic speed!

The average isn't relevant. Either you're being stubborn, or you're deliberately obfuscating or there is a third option that isn't obvious to me. As you can clearly see, approximately 50% of the test is at or above 65 mph with a peak at 80mph. The accels actually further degrade mileage more than sustained cruising at high speed. If you've driven high traffic urban/suburban freeways, you could easily see how that drive cycle would correspond to typical urban freeway rush hour driving with high speed sections and full stops.

Your understanding of the EPA tests as expressed in your original post on the subject is clearly outdated. Updated EPA testing includes sustained driving at 65mph with bursts as high as 80mph not the 55 with bursts to 65 you stated. It's as simple as that.

You've been given the correct information. Ignore it and cling to your outdated beliefs if you choose. I'm not going to argue with a wall anymore.

[broski499]

Originally Posted by Ecky

I don't own a Prius but have driven one pretty extensively.

-What's your mix of city and highway?

-What speed do you drive at? 30mph is probably where you'll get the best economy, and it drops sharply above 60-65.

-What tire pressure? I run ~50 in my Insight.

I'm about 80% city. I live in Southern California so it is a bit hilly where I live.

I'd say most of my driving happens at speeds around 40-55mpg.

Yeah I'm running my tires at 50psi right now.

[broski499]

Originally Posted by roflwaffle

That sounds like normal mileage with high AC use.

https://priuschat.com/threads/how-to...a-c-use.97814/
https://priuschat.com/threads/ac-com...-on-mpg.95749/

The INL found that AC on max with full blower drops mpg from 52.7 to 41.3.

https://avt.inl.gov/sites/default/fi...hevamerica.pdf

My guess is most cars take a big mpg hit with the AC on high though, so you're still probably coming out on top overall.

Offhand I think parking in shade, using a sun shade (ideally on the outside, but you'll probably get weird looks), and cracking the windows will help, as will window tinting.

Wow, I knew AC would have an impact but had no idea it was that huge. Yeah I park my car in a car port at home and use a sun shade. Will have to try it on the outside haha.