FR-S Low MPG

[Koa]

Originally Posted by Dake

Apparently stating twice "Level ground" ie "average conditions" wasn't enough so I'll state it a third time:

Under average conditions on level surfaces in regular traffic.

No where did I say this is what happens every time, all the time, regardless of the world around me. This is for tooling over to the grocery store for a gallon of milk. That is not how I drive on a track day or how I even drive merging onto the highway.

This method does not "lug" the engine in anyway in those general circumstances. If the conditions are not appropriate for a low RPM upshift, wait until a higher RPM. Yes, throttle position matters and that is taken into consideration.

Also, I'm glad people driving turbos have an apparently better understanding. I think the most important thing to understand is: we're not driving a turbo.

It's just that throttle position is much more evident when driving a turbo platform, sorry for the confusion

[strat61caster]

Originally Posted by Kaotic Lazagna

http://www.fuelly.com/car/scion/fr-s/2014/07Vios/287038

Slowly accelerating, camping in the slow lane (when possible). LOL. I'd rather spend/save money for parts than on gas =P

Primarily freeway driving, but I deal with Cali's Bay Area traffic daily (so I would say equivalent to 50/50 city/freeway driving).

While impressive I do wonder if you've ever surpassed 3,000 rpm

You can do Laguna Seca or Thunder Hill in a day, there are some people who would kill for that opportunity, do it! Get one tank in there in <15 mpg! Hell even an AutoX to get you down in the 20's, the car gobbles that stuff up.

[Kaotic Lazagna]

Originally Posted by strat61caster

While impressive I do wonder if you've ever surpassed 3,000 rpm

You can do Laguna Seca or Thunder Hill in a day, there are some people who would kill for that opportunity, do it! Get one tank in there in <15 mpg! Hell even an AutoX to get you down in the 20's, the car gobbles that stuff up.

I shift at 3k.

Usually on each tank, I'll floor it in 3rd gear up to 6k rpm as well, just to blow out any deposits.

I wouldn't mind doing an auto-x. I think it'll be fun.

[Tromatic]

Originally Posted by Dake

If you want the best mileage, you have to think like a modern AT. It upshifts as soon as it possibly can to keep the RPMs as low as possible. If you're waiting until 4k (or even 3k) RPM, that's too high.

Around town in regular traffic I regularly upshift at 2000-2200. That gives adequate acceleration and does not bog down the engine.

To equate it to MPH I go:

1st to 2nd: almost immediately (and don't even leave second for a rolling stop)
2nd to 3rd: 12-15mph
3rd to 4th: 19-20
4th to 5th:28-30
5th to 6th: 38-40

The reality is, from a dead stop I often skip-shift first to third, third to sixth; from a rolling start it's second to fourth, fourth to sixth. Again, this is on mostly level terrain, in regular traffic. On any given tank of gas I still get after it when the spirit moves me and I still do 70-75 on the highway, but the rest of the time that's how I shift and I maintain a steady 30-32 mpg.

How badly it must suck to be you to have this car and drive like that.

[Tcoat]

Originally Posted by Tromatic

How badly it must suck to be you to have this car and drive like that.

I don't think mine has ever seen a shift at under 3000. Many/most of them are pushing 5000!

[tennisfreak]

Originally Posted by Tcoat

I don't think mine has ever seen a shift at under 3000. Many/most of them are pushing 5000!

I believe the user manual specifically states that shifting before the rev limiter greatly reduces ownership satisfaction and strongly recommends against doing it.

[paulca]

Fuel used = Throttle position * RPM * time.

50% throttle at 1,500rpm will use half the fuel that 50% throttle at 3,000rpm will. (Assuming a linear map, which we don't really have). Maybe a little less, 1-2% less at 1,500rpm.

I use both the instant and average and I work on the principle of how much torque do I need. If I don't need torque to accelerate I shift for about 1,500rpm

Tonight on the way home I was at 30mph in a 30mph zone in 6th, circa 1,250rpm, maintaining speed and the instant MPG was reading 62mpg.

There is an agrument that says, 50% throttle at 1,500rpm to get X torque uses the same fuel as 25% throttle at 3,000rpm, but it doesn't. The higher the rpm the less efficient the engine. This is simply the physics of friction and momentum.

So if you are driving for fuel economy, low revs, high gears, plan ahead, avoid braking and be very gentle and smooth with the throttle.

[Dake]

So if you are driving for fuel economy, low revs, high gears, plan ahead, avoid braking and be very gentle and smooth with the throttle.

Don't tell Tromatic, he'll pity your miserable existence.

Originally Posted by Tromatic

How badly it must suck to be you to have this car and drive like that.

How badly it must suck to have your sole enjoyment be based on racing stop light to stop light (a race you'll lose against a mini-van, or a Cobalt, or a Neon or a...).

I have my fun on track days - cheers!

[Tcoat]

Originally Posted by paulca

Fuel used = Throttle position * RPM * time.

50% throttle at 1,500rpm will use half the fuel that 50% throttle at 3,000rpm will. (Assuming a linear map, which we don't really have). Maybe a little less, 1-2% less at 1,500rpm.

I use both the instant and average and I work on the principle of how much torque do I need. If I don't need torque to accelerate I shift for about 1,500rpm

Tonight on the way home I was at 30mph in a 30mph zone in 6th, circa 1,250rpm, maintaining speed and the instant MPG was reading 62mpg.

There is an agrument that says, 50% throttle at 1,500rpm to get X torque uses the same fuel as 25% throttle at 3,000rpm, but it doesn't. The higher the rpm the less efficient the engine. This is simply the physics of friction and momentum.

So if you are driving for fuel economy, low revs, high gears, plan ahead, avoid braking and be very gentle and smooth with the throttle.

I will just leave this here for you.

[Dake]

Herp derp

[Tromatic]

Originally Posted by Dake

Don't tell Tromatic, he'll pity your miserable existence.



How badly it must suck to have your sole enjoyment be based on racing stop light to stop light (a race you'll lose against a mini-van, or a Cobalt, or a Neon or a...).

I have my fun on track days - cheers!

I stay off the freeways as much as possible because boring. If I do take the thing, it's to get to better curvy bits. It still sucks to be you (not you) if you measure the performance of even a stock FR-S on mileage or freeway use. Why would you not get a Prius if creeping along for mileage gets you tingly?

[Tromatic]

In honor of some of you soul-dead zombies, my next tank will be E85 and I'll see if I can average below 15mpg.

[Dake]

Originally Posted by Tromatic

I stay off the freeways as much as possible because boring. If I do take the thing, it's to get to better curvy bits. It still sucks to be you (not you) if you measure the performance of even a stock FR-S on mileage or freeway use. Why would you not get a Prius if creeping along for mileage gets you tingly?

See, now we're making sense. If you want to pity me anything it's that I'm in Houston where the curvy bits are few and far between. My biggest kick lives in the on and off ramps which thankfully are smooth, banked and made for speed.

But therein lies the difference. The FR-S is my DD. I don't have anything else to "take". So I let it do what it does well, which is be mild-mannered and thrifty during the day to day commute, and loads of tire-squealing, tail-happy fun on the track once a month. Burning fuel just for the sake of it doesn't seem like fun to me; I feel like one of the things that makes this car so special is you can have the best of both worlds.

[Tromatic]

Originally Posted by Dake

See, now we're making sense. If you want to pity me anything it's that I'm in Houston where the curvy bits are few and far between. My biggest kick lives in the on and off ramps which thankfully are smooth, banked and made for speed.

But therein lies the difference. The FR-S is my DD. I don't have anything else to "take". So I let it do what it does well, which is be mild-mannered and thrifty during the day to day commute, and loads of tire-squealing, tail-happy fun on the track once a month. Burning fuel just for the sake of it doesn't seem like fun to me; I feel like one of the things that makes this car so special is you can have the best of both worlds.

I forgive you. Or apologize, whatever is more appropriate!