Gernby

iTrader: (1)

lobuxracer,

I figured you would be the one guy that would be able to give me a clue about the possible effects on the tranny.

When I'm on the highway, I have a hard time setting the cruise at 60-65. I find myself driving manually at 75-80, and getting 25-26 MPG.

BTW, I'm very surprised that this car doesn't get EVEN CLOSE to the mileage my '94 Lincoln Mark VIII did (4.6L V8 with 270 HP) when I was trying. I was able to maintain over 32 MPG on pure highway, and very high 20's mixed.

Gernby

iTrader: (1)

I forgot to mention that it is still too hot here to turn off the A/C.

kensteele

hehe, OMG. "N" is for towing cars....not for better gas mileage in a wrecked economy LOL.

kensteele

You might be able to save some money but it's like a jogger who smokes. Unless you are saving money in EVERYTHING you do, what is the real benefit? Why choose the car? Why not stop drinking coffee or buying lottery tickets or less haircuts as often or skip a movie? <= more effective methods.

Gernby

iTrader: (1)

Ken,

If "N" was for towing, then why is it right next to "D" with no obstruction in shifter movement? If I were designing it specifically for towing, I would put it right next to "P".

Again, this isn't about saving $1 each month on fuel. This is an experiment on how close I can get my city mileage to highway mileage. I don't see it any differently to anyone else tyring to see how quickly they can do a 1/4 mile, or how impressive their dyno plots can look.

lobuxracer

iTrader: (2)

My knowledge and experience with autos is pretty weak. I've only rebuilt one, and I didn't pay a lot of attention to the details. The one thing it will do is wear the friction materials they use ever so slightly more rapidly.

By the same token, sitting at a stop with it in gear heats up the fluid because all the energy from the engine (you know, torque x rpm) is getting transferred to the fluid through the torque converter. Admittedly it isn't much power, but that's kind of the trade off. And you're saving that rather small amount of power by shifting into neutral. You're also using up the fluid because it can only tolerate so much heat for so long.

Yeah, they designed it with this in mind, and they've determined you don't ever have to change the fluid (yeah, right) but it's really a pick your poison affair. Every shift involves a wet clutch braking something, every stop without disengaging shortens fluid service life and wastes fuel. I suspect replacing the friction materials will ultimately be a lot more expensive than the fuel consumption.

I took a peek at the rebuild procedures for the gearbox, and it's not something I'd be excited to do. At least a manual is pretty simple and doesn't have a maze of little passages to clean and assemble as dust-free as is humanly possible.

And I have the same fascination - why won't it break 30 mpg? I have a hard time understanding how an engine can be so advanced in its technology, but unable to deliver thermal efficiency we've seen from lots of previous incarnations of powertrains. I know part of it is emissions compliance, but still, we're not getting any better highway mileage than a new 'Vette, and those things make quite a bit more power when you step on the loud pedal.

tqlla3k

iTrader: (1)

You know.... I thought about that too. My cousin gets 27MPG driving as hard as he wants.... and he drives through stop and go traffic, in his IS250

I got 22MPG on my IS350, driving like a wuss all the time. The MPG on the 350 is a huge disappointment in my eyes. Its supposed to get 22/28, and I got 22 tank average(A lot of highway cruising, I guess its slightly hilly where I am at).

In contrast, my 3000GT(MT) is supposed to get 19/25. I get 23-24MPG in the 3000. I guess its due to the fact that I :
A) put the car in nuetral going Slight inclines
B) when I am slowing to a stop light
C) when I am stopped at a stop light.

I was really expecting the IS350 to get me 25MPG+. That being said... I still ordered another new IS350, guess I am not the environmentalist, I hoped to be.

lobuxracer

iTrader: (2)

You realise you can extrapolate your arguments in both directions to complete absurdity?

Just like Gernby, I think it's an interesting exercise to see how high I can push the economy. It's not about money, it's about setting a goal and achieving it. If it really were about money, I wouldn't own a car, I'd have my company lease one for me and pick up all the expenses. I'd be a real Naderite and take public transport everywhere, or I just wouldn't leave home, I'd have everything delivered and do all my work through virtual presence. But that would be absurd. So I'll save money in some places so I can splurge in others. Just like everyone else does.

PhilipMSPT

iTrader: (5)

The flaming has arrived Gernby!

I've been watching over this thread and I understand your concern about gas saving.

However, let's talk about function.

People who "want to save gas" find cars that can truly "save gas." The 2IS is already pretty efficient in saving gas for the amount of power they provide. However, to expect that you can have gas-saving abilities similar to that of a 4-cylinder engine is beyond the capabilities of the given V6s.

Your assumption of "saving more gas" on Neutral is valid, but it is not functional to a sense that automakers will run a car in Neutral whenever it stops to increase their average City MPG. Whether or not you "can" put the car in neutral, it doesn't mean that you "should."

TO COMMENT ON YOUR ORIGINAL THOUGHT:

"It is NOT designed to thousands of extra shifts from "D" to "N" and back."

Gernby

iTrader: (1)

I call total BS on the cousin's IS250 getting 27 MPG no matter how hard he drives it. The weight and efficiency of the 250 can't be THAT much better.

Regarding the other comments about putting it in nuetral other than at rest, I think that would have a negative effect on fuel economy. If you are rolling, it is better to keep it in gear. Modern engines actually use ZERO fuel when the throttle is closed in gear at a roll that results in a higher RPM than idle. I verified this with my WBO2 sensor in my S2000. When I left it in gear and let off the throttle, my WBO2 would go to 20.9:1 (air) until I aproached the idle RPM then it would go to 14-15:1 (stoich).

lobuxracer

iTrader: (2)

That's called decel fuel cut. It's been part of TCCS since 1988 when I bought my GTS Corolla and wondered why the engine went flat coming to a stop between 1800 and 1200 rpm. All the manufacturers do it, not for CAFE, but for emissions. I'm quite sure they're still doing it, and there's likely a test for it somewhere in the massive tome they call a service manual.

Nextourer

Just because you can afford it, doesn't mean we should be wasteful. If he wants to save a few drops, let him cause it will eventually accumulate. I just wished every car had a feature that would shut off the engine when stopped. That'll save fuel, lower exhaust emissions which helps with pollution AND heat in the city.

Anyway, Gernby, I'm not sure about the N part but I do notice that if you coast, D and N make a very slight difference when I watch the instant fuel economy gauge on my dad's Camry. However, on long stretches of downhill, I'll leave it in gear and drop to 3rd and let it engine brake at ~60km/h (which is the speed the Camry's gearbox holds when in 3rd).

al503

I beg to differ. When I'm stuck in traffic and rolling along at just over 1000 rpms, I look at the 'real time mpg' gauge and sometimes it's at infinity and others, it's around 60-90 mpg. I think the engine gets a very small amount of gas regardless of throttle position and the engine is turning over above idle.

Gernby

iTrader: (1)

Regarding engine braking, I have been doing it as much and as early as I can to reduce idle time at stop lights. I wait until the RPMs get to about 1K before switching from "D" to "N". This is just another of my game tactics.

Gernby

iTrader: (1)

I wouldn't be surprised at all if the ECU starts delivering some fuel and spark at 1K RPMs. If it waited for the engine to reach idle speed exactly, it would stumble for a second on rapid RPM drops. However, if you monitor the AFR via WBO2 as you engine braked from 60 to 0, I'm sure you would see 20.9:1 until you got to around 10 MPH.