My new FR-S!

[gizzardgulpe]

With a bluetooth OBDII reader and the Torque app, you can have it save a .csv log of different sensor outputs as you drive. I've done a log of instantaneous MPG and speed then made a graph that gave me some interesting insight into how my Grand Prix works. I don't know if it would lose connection when you turn the engine off with the key on, but you might get a more precise picture of your MPG that way than by adding up your miles.

There is also the Smart Control app that will let you use GPS for speed and distance, though I'm not sure it can output a log as easily.

Anyway, just some ideas. I still like the thought of getting an 86, and I'm in the market for a new car now, but I think they're still a little out of my price range.

[Daox]

Wow, I didn't know you could datalog with torque. That would make testing warm up mods a lot easier! Thanks.

[MetroMPG]

Originally Posted by serialk11r

The other day I decided to reset the trip meter to see how many mpg I could get with the most aggressive engine off P&G possible.

Was that part of your 42 mpg tank?

My step-nephew just bought his first new car: 2015 FR-S, manual transmission.

I don't think he drives with fuel economy in mind.

[serialk11r]

Originally Posted by MetroMPG

Was that part of your 42 mpg tank?

My step-nephew just bought his first new car: 2015 FR-S, manual transmission.

I don't think he drives with fuel economy in mind.

Nah, it was just one trip. Using Torque wouldn't help, I've logged stuff with it before, the onboard average mpg calculator is far more accurate at figuring out total fuel usage. An OBDII reader only captures instantaneous mpg at fairly infrequent intervals.

Using this method, I've been calculating ~90 mpg in "city" driving. For 2.5 miles, the engine only runs for 0.5, and it indicates mpg in the high teens. Seems about right, that's around what the champ P&Gers like PaleMelanesian get. If I keep the engine on the whole time, it'll plummet to the 20-30 range.

The freeway part is more like 45 ish, which is still pretty solid.

[gizzardgulpe]

Ah, yeah I've had to make some accommodations with Torque, but I don't have an onboard mpg calculator, so it's better than nothing.

[UltArc]

Originally Posted by serialk11r

The other day I decided to reset the trip meter to see how many mpg I could get with the most aggressive engine off P&G possible. I was doing a bit over 60mph average on the freeway so this wasn't really shooting for maximum fuel economy. However I was accelerating at the maximum load possible where the engine doesn't run rich, so it was essentially near minimum BSFC the whole way.

The meter recorded a bit over 16 miles for a 34.3 mile trip. I think in reality it's fair to call it 16.0 miles since the car considers rolling with the engine off but key on as 0 mpg when it's really infinite mpg. We'll call it 2.1x the displayed mpg.

Displayed mpg was...23.7. 23.7*2.1=49.8

Computer is probably optimistic, but hey, it's a lot better than 37, and the trip only took 5 minutes more than usual when cruising at 65-70.

Coming back, I forgot the numbers but remembered calculating it to be something like 48mpg in my head.

I can't remember if you mentioned this (I've followed along, but haven't reread this in a long time), but what is the cruising RPM? I feel like that is a bit low for the dimensions/weight of the vehicle/engine.

[serialk11r]

Originally Posted by UltArc

I can't remember if you mentioned this (I've followed along, but haven't reread this in a long time), but what is the cruising RPM? I feel like that is a bit low for the dimensions/weight of the vehicle/engine.

2600rpm @ 60mph ish, 3000 at 70. On cruise control it'll get 35-42mpg in that speed range. It shouldn't matter much for P&G since the engine is only being operated at high power, and peak thermal efficiency is in that range.

50mpg is low? IIRC last time I watched the mpg meter on a Prius, it was mid 50s at those speeds. The Prius engine is a bit more optimized for thermal efficiency. Like I said, there's definitely some more room to tweak the ECU in this car, I just didn't do it since I didn't want to mess with it too much.

[MetroMPG]

I got a ride in a friend's new 6-speed manual Subaru BRZ today. Neat car.

Her lifetime average (accourding to the dash display) after a few thousand kilometres: 7.9 L/100 km = 30 mpg US.

Not bad! Considering the EPA rating is 21/29 24 mpg US combined for the manual, that makes her a hypermiler! The automatic is rated 28 combined, but I'm sure the manual would beat it.

And she doesn't baby it - she turned the traction control off and got it a little sideways through a wet S-turn on an empty country road. (And she's one of the only other drivers I know who can match-rev downshift).