Slust

So I can only offer a small data set. Thinking maybe we can have a central thread so people state what they are getting in the different modes. State what your typical driving pattern is like (thick traffic, lots of short trips, little traffic and long trips, mixed freeway and city, mostly highway, etc.).

Where you live makes a HUGE difference. For example when I lived in NoVA/D.C. with my previous car it got around 14-18mpg. When I moved here it went to 24-27mpg.


So far with the IS350 I've gotten 22-24mpg, mostly 22.4mpg. I would say 50/50 or 60/40 mixed freeway and city driving. I do hit a lot of traffic but it is nothing like LA or DC traffic. In fact, when I first moved here I didn't even recognize it as traffic ...but it is still stop and go during peak traffic hours.


ECO Mode (full tank)
Gauge says: 21.5mpg
Manual calc: 22.2mpg

Normal Mode (full tank)
Gauge says: 21.7mpg
Manual calc: 22.4mpg

Best was 24.0mpg - first tank - Normal, drove rather wimpy.

Normal Mode (With a few Sport/Sport+ outbursts)
Gauge says: 21.7mpg
Manual calc: 22.4mpg

Normal Mode (With a couple Sport/Sport+ outbursts)
Gauge says: 22.7mpg
Manual calc: 23.3mpg

Sport Mode (full tank)
Gauge says: 23.0mpg ...so far (seriously doubt it will last lol )
Manual calc: ???mpg


I know we didn't buy our cars to be Prius v2 drivers but I think most of us would like decent gas mileage to go with our performance. I tried ECO mode on a couple tanks and I'm just not seeing any value with it. Normal mode actually gives me better gas mileage. I'm really hesitant to try a full tank on Sport because I know this engine is hungry and not fuel efficient, but that is my current test ...a full tank on Sport. So far the gauge is reading 23.0mpg but it's early in the tank. I'm not driving super aggressive but I'm not holding back either. If someone is driving slow I'm passing them because well... this car is super fun on Sport and there is a lot less throttle response lag in Sport.

I took someone's word here that Sport/Sport+ is limited to the first 6 gears but it went into 7th gear when I got around 70mph. So maybe when you hit high 80s you get to 8th gear, will have to play around with that. One thing I did find interesting is that even though you are in 7th gear the engine is still at 2.6-2.7k RPM. The picture is blurry because the road isn't smooth so trying to hold the camera straight is really hard.

Should be interesting to see how far Sport will drop my mpg. I think UncleSpud drives in nothing but Sport+ mode so maybe he can chime in.

TheShaddix

Definitely not the most efficient engine out there. One realization I've finally come to is...Fuel economy is only as good as your right foot. In any car... I used to have a prius, but drove it hard (it's not that slow in sport mode) which defeated its purpose. If you're concerned with fuel costs, you just need to drive accordingly. I notice that when I'm mellow with the throttle, eco mode on & AC off, it's actually really efficient. The second I start doing some spirited driving it just drains gas. The best way is to just enjoy your car, see fuel costs as your normal expenses like food, etc. and not be so worried about those numbers. Imagine what people with suv's are going through and you'll feel better. I only look at the mpg gauge when I'm bored driving long distance at night...Also, once you get an intake and exhaust, it's game over for fuel efficiency due to addicting sound

SilentWish

thank you so much for the data!
i was wondering the same question as well and then saw your post!
much appreciated!

i'm also interested to know if sport mode (i dont have 350) will impact gas mileage a lot

btw, in the 2IS there was a switch to keep power ECT on
there doesn't seem to be a way to default drive to sport mode on the 3IS?

Im2bz2p345

Awesome thread Slust. I was looking around for something like this where people can directly compare the "real world" MPG numbers in the various drive modes.

If any other owners could chime in, that would be GREATLY appreciated. It's quite surprising to hear that there isn't much of a difference between Normal & Eco mode. I was thinking the slower throttle response in Eco would have contributed a tad more to mpg.

I would be interested in reading the response of someone that drives the IS350 F-Sport in Sport+ mode all the time or the majority of the time.

~ Im2bz2p345

fastdak25

I just hit 1/4 tank left, driven sport + since full in my 3IS 350 AWD. average right now is 19.4 with about 60% highway 40% city streets. equipped with takada intake and fsport exhaust

Slust

The main expenditure of gas is always at the front end because you are coming from a complete stop so to build up your speed you need to depress the pedal much harder. If you already moving than you are simply maintaining your speed. Obvious stuff aside, if we 1+1 this... The reason I think Normal has been better than Eco (for me) and possibly even why Sport mode is doing pretty good so far IS the throttle response.

You simply don't need to press the pedal that hard, either coming from a complete stop or passing someone. Passing someone on the freeway with Eco mode on requires you to push the gas pedal pretty hard in comparison to Normal or Sport, especially if you are trying to downshift to get speed. And once you get that speed built up you may feel inclined to keep that up. If you are in Sport mode and simply see passing someone as a means to end rather than trying to show them up, prove how fast your car is or show them how frustrated you are than it shouldn't take you much gas in Sport mode to pass someone. Because the throttle response is already there waiting for you. The car is already in a lower gear in case you need it. This may sound like an evil villain but... it only takes a slight press.

The hard part is NOT getting addicted to that throttle response. But like Shaddix said, if you manage your foot well than fuel economy shouldn't be too hard. So far I have been driving with the AC on full time and butt warmers on during the really cold days. After this tank I will turn it off and see the difference. The interesting part should be seeing how Sport mode relates to city driving as the constant stop and go could be Sport mode's downfall.


Well it was a hard switch in the 2IS. If you're driving the 250 than you are already getting better gas mileage. I drove the 250 HARD, every day, and still got 25mpg on average.


Your post inspired me to write the above but ya I would really like to see more people chime in, especially those who drive in Sport and Sport+ mode all the time ...and even Eco mode.

The only way I can see Eco mode truly being more efficient is if you totally granny it and don't push the gas pedal hard. You know, those people who enter the freeway at 20-30mph where everyone else is going 70-90mph. << mad face

Those are the people getting insane gas mileage.


Nice, thanks for sharing with us! What do you normally get if you drive just on Normal mode? (if you do)

fastdak25

i drive in ECO quite a bit, and tbo the average miles on a tank usually comes out the same, 19-20 mpg. It's been like this since I installed the Takada intake. I have always got the 19-20 mpg average in ECO. Sport + use to run 17-18 mpgs, after takada install i now get 18.5-19.5

WWM

People say this a lot but that's losing sight of the fact that the base fuel economy ratings for cars are quite different. Yes, you could cane an economy box and get 15mpg, which is what I used to average in my C63. But if you cane a C63, you get 7mpg.

On the other hand, if you mean that people shouldn't expect to get anywhere near to the car's official economy rating if they're constantly driving it hard, I agree completely. I don't even understand that anyway. I love opening it up as much as anyone, but most of my driving is commuting in traffic where I can't do that. In those situations I try to drive as economically as possible.

I've been getting 12-13L/100km per tank the last couple of months. Brutally cold weather and less highway driving, probably only 20% now. Morning commutes are especially bad due to the lower temperatures in the morning and longer time between trips. I've been getting 15-16L/100km on my morning commutes This is driving 99.9% normal mode.

jcheng

Weird. I get almost on avg 23mpg on 95% sport + mode. I drive 75% hwy and the rest stop n go city driving.
I'm by no means a fast driver but also don't drive like an average person.

KumaF

I can definitely relate to that. I do a lot of short trips with maybe a 60% city / 40% hwy split and I am averaging somewhere between 14-15L/100km with 60% driving done in Sport. This winter is unusually cold and the weather does hurt fuel economy quite a bit.

aTeAse

So fuel economy is related to the weight of your right foot.. and not about the difference of driving modes?

jcheng

THIS! /thread!

Slust

So this tank hasn't been the "scientific" tank I thought it would be. I been romping HARD - a few 0-60s, some 0-90s, and of course some 50-90s. Sport mode is so much fun. Anyway the guage is reading 21.7 so far for this tank, so probably 22.3ish in reality which puts it in line with my Normal and Eco mode runs ...that had zero romps. Before the romping I was high 22s on the gauge, even 23 for awhile.

Not sure if maybe the gas stations are phasing out their winter mix or if Sport mode actually has the chance to be more efficient (see reasons above).


Very good to know, thanks!


More data, thanks!


Yes ...and well, no.

I actually think Normal mode is better than Eco mode and right now Sport mode is looking to be more efficient than Normal ...if I can keep from romping. So yes the power of your foot definitely affects your fuel economy ...but I still think the more powerful modes have potential to be more efficient since you don't need to apply as much weight to the gas pedal in everyday situations. The only thing Eco mode does that might get you better gas mileage is that it limits your seat warmers and the AC. Since it lowers the throttle response you have to press the gas harder if you want to pass someone or if you want to merge into traffic at a decent speed.


My Belief in what affects fuel economy
#1 (by far) Where you drive (traffic, humidity, etc.)
#2 (distant second) Winter mix fuel vs Summer Mix
#3 How hard you press the gas pedal
#4 The driving mode
#5 Other factors (tire pressure, air filters, etc.)

WWM

I don't think the fact that you have to press the gas pedal harder in Eco mode makes it worse than normal mode. I'm not entirely sure how it works, but when you press the accelerator does that not determine how much torque/power to apply and thus how much gas is used? All Eco mode does is provide less torque/power for a given pressure on the accelerator. So yes you have to press the accelerator harder than in normal mode to get an equivalent amount of torque/power but it's still the same amount of gas being used up. I think the idea behind Eco mode is to make it harder to accidentally apply too much torque/power than is required. which wastes fuel. It could perhaps have the opposite effect, ie. since the throttle sensitivity is so slight, that people are over-doing it when they try to accelerate fast. That's just a matter of learning the feel of the accelerator in Eco mode though.

crazych42

Yes. In ECO mode I believe you have to give the car more gas to get to the same speed in the same amount of time as it would take in Normal or Sport. The motor has to work harder and wastes more gas. If you want to get to the same speed AND save gas you would have to accelerate slower (less pressure on the go pedal). The purpose of ECO is efficiency; thus it would be less efficient than other modes if you are accelerating hard or aggressively. I think what people are finding is that most folks on here drive their cars somewhat "spiritedly" (we are enthusiasts aren't we?) and the ECO mode is not as efficient as it would be otherwise. Bottom line: If you are in ECO mode, drive it like a baby else you might as well be in Normal or Sport.