FR-S/BRZ MPG

[devinclfalcons]

Does this 4 mpg difference change any one's mind about the automatic?

[serialk11r]

It better change Toyota/Subaru's mind about the way they're setting up the manual with its short 6th gear... 25% shorter than the auto, that's completely unacceptable when everyone else is specing more appropriate gear ratios. Whatever happened to being an industry leader in fuel economy.

I think the city economy shouldn't be anything to worry about though, the closer gears should be a help if anything. Just don't rev to 3000 while only barely pressing the gas the way they do in the EPA test.

[devinclfalcons]

I really wanted the manual... But now with this

Its even more surprising that the auto gets 3 better mpg in the city too

[serialk11r]

In city driving, if you don't drive EPA style you'll do better than the auto. In the city your engine is not doing anything a lot of the time, and the hydraulic pump on the auto will sap some energy. The gears are also closer on the manual so you don't lose as much energy spinning the flywheel/crankshaft/pulleys only to have the rpms drop for the next gear. 47 pounds less weight doesn't hurt either.

I looked it up, the EPA shifts at 15mph, and then 25mph, while accelerating at 3.3mph/s maximum...I went ahead and calculated how much load that was on the engine. 25% load...so they feathered the throttle to 3000rpm in each gear. No wonder they got 22mpg. Press down on the throttle halfway, shift anytime you want before 3k, you'll do much better.

This actually explains why sports cars have such horrible city fuel economy ratings despite being relatively lightweight. Since the EPA test has slow acceleration, a sports car's more powerful engine will be run at barely any load. High rev engines are hurt even more since the shift points are speed determined, not rpm. No wonder Mustangs and Corvettes force you to shift to 4th after 1st, otherwise they'd be posting more like 15mpg city. Imagine what happens to MT 911, the operator would have to barely touch the gas at all and rev to 3200.

[Allch Chcar]

Originally Posted by serialk11r

But yea, 4.100 diff will sorta kill your mpg. 10% less load at these ultra low load levels could be a lot of efficiency lost (probably like 5%). If the spec sheet is not lying about the diff option I think I would want the 3.727. No one needs to be accelerating really fast below 30mph.

Originally Posted by Spaceywilly

Read the link. GT with LSD is 12.8 L/km. G w/out LSD is 13L/km, on the JC08 circuit listed above. If you drive 100% highway maybe it will be 5% difference, but if you do that don't buy an 86.

http://toyota.jp/86/001_p_001/spec/spec/index.html

edit. sorry, it is 12.4 vs 13, so 4.8% difference. At 30mpg highway that would be 1.2mpg. Big whoop

Heh, Cereal was almost spot on.

The stock JDM 3.727 gear is good news for me. It means there is a cheap taller rear gear available.

[OrbitalEllipses]

Originally Posted by Allch Chcar

Heh, Cereal was almost spot on.

The stock JDM 3.727 gear is good news for me. It means there is a cheap taller rear gear available.

Cheap being the relative term here. Do you plan on importing the gears themselves, since I assume you simply need the ring & pinion to stuff into what is presumably the same case?

[serialk11r]

I remember old greg saying that the gears should be interchangeable with a bunch of other Toyota Torsen diffs, grabbing one off a Lexus IS is maybe cheaper than getting a 3.727 from Japan?

[Xlr8]

I just played with the numbers last night. Taking the combined ATs 28MPG and MT 25MPG combined figures and figuring 15000 miles a year driven. I come up with about 64 gallons of fuel difference. So if you multiply by decent round figures of $3.50 a gallon that comes out to $224 dollars a year. At that savings rate it will take between 4 and 5 years to recover the initial up front cost of the auto.
If I'm off on my numbers let me know. But that's just some rough numbers I came up with last night

[serialk11r]

That sounds about right. The problem is EPA test is an average of a bunch of tests, none of which reflect real driving.

If you drive mostly city, then manual will be better on gas if you are driving it correctly. On the highway, the auto will be better because of the gears being longer.

[devinclfalcons]

Any chance of getting the 3.7 differential on the manual? Is it possible to change the ratios on your own?

[carbonBLUE]

Originally Posted by csaba

The gas in Europe is higher octane up to 98 burns cleaner and has more energy so the cars takes less gas for the same power.

actually their standards are different from ours.... their 98 is our 93..

(europe) 98 RON Octane x 0.95 = 93.1 AKI Octane (US measure)
(japan) 100 RON Octane x 0.95 = 95 AKI Octane (US measure)

[Allch Chcar]

Originally Posted by devinclfalcons

Any chance of getting the 3.7 differential on the manual? ...

I doubt it.

Originally Posted by carbonBLUE

actually their standards are different from ours.... their 98 is our 93..

(europe) 98 RON Octane x 0.95 = 93.1 AKI Octane (US measure)
(japan) 100 RON Octane x 0.95 = 95 AKI Octane (US measure)

Thank you CarbonBLUE. They do have higher octane than for eg. California, but every else in the US has better fuel than California.

[HitTheGas]

Originally Posted by devinclfalcons

So it appears the MPG figures are now official...

http://www.ft86club.com/forums/showthread.php?t=3859

MT: 22/30/25

AT: 25/34/28

The auto gets 34 highway while the manual gets 30. That may have just made my decision as I drive 90 miles round trip to work...

But what about the burnouts?

Think about those poor poor burnouts, they need a home.



*cut to a commercial, sarah mclachlan music playing in the background , a manual trans staring up at you w/ sad scared eyes *

"Won't you save the manual?"

"Every day more and more people choose automatics, while perfectly working manuals are left to be scrapped. For less than the cost of an auto, you can save a manual today. Won't you please help save the manuals?"

[ayau]

So is it confirmed that the USDM models will get different gearing/final drive ratios than the JDM version?