Hyper Mileing

[Da Klugs]

Originally Posted by shilala

Atta boy.
I can't imagine stuffing my fat ass in a Prius.
I'd need some grease and a big shoehorn. I had to drive those little cars when I was a kid. I don't think I'd be able to bring myself to doing it all over again.

The thread title is misleading. Just my lil way of amusing myself with experimenting with how my driving style impacts mileage. It's been interesting how little changes (limiting RPM not speed) can have big impacts on city MPG. Big changes can have additional impact... rolling stops, using neutral etc.

[shilala]

Originally Posted by Da Klugs

The thread title is misleading. Just my lil way of amusing myself with experimenting with how my driving style impacts mileage. It's been interesting how little changes (limiting RPM not speed) can have big impacts on city MPG. Big changes can have additional impact... rolling stops, using neutral etc.

I was confused so I went back and read some more and I get it now.

[Da Klugs]

Originally Posted by shilala

I was confused so I went back and read some more and I get it now.

He he.

Re the Prius, I rented one a few weeks ago in MD to see what was what. Not the compact car of our youth. Pretty roomy due to its jelly bean shape. Lots of width and leg room. I was surprised. Got 48 MPG just flogging it and going 80 on the highway was overall pretty impressed. A blinged out version/better looking car might be tempting. Like the concept of regenerative braking in any vehicle to help the city MPG. If you look at the newly released Mercedes they use a battery no larger than the normal one to do the duty and a generic inline electric motor. More performance and better mileage = a good thing.

[shilala]

Originally Posted by Da Klugs

He he.

Re the Prius, I rented one a few weeks ago in MD to see what was what. Not the compact car of our youth. Pretty roomy due to its jelly bean shape. Lots of width and leg room. I was surprised. Got 48 MPG just flogging it and going 80 on the highway was overall pretty impressed. A blinged out version/better looking car might be tempting. Like the concept of regenerative braking in any vehicle to help the city MPG. If you look at the newly released Mercedes they use a battery no larger than the normal one to do the duty and a generic inline electric motor. More performance and better mileage = a good thing.

I looked at the great big Tahoe Denali Hybrid.
All that tech cranks out a whopping 17mpg.
I like a lot of metal and I enjoy feeling like I'm driving my living room to the store. If they get around to building an STS that gets 30mpg, it might pique my attention. Otherwise I'm trapped in the stone-age.

[Da Klugs]

Originally Posted by shilala

I looked at the great big Tahoe Denali Hybrid.
All that tech cranks out a whopping 17mpg.
I like a lot of metal and I enjoy feeling like I'm driving my living room to the store. If they get around to building an STS that gets 30mpg, it might pique my attention. Otherwise I'm trapped in the stone-age.

Thats really my interest in all this. I get 27 on the highway which is pretty good for a 5000 lb car. City is the issue. Adding a lil hybrid stuff to this type of car at a small premium in cost would make lots of sense and is going to happen much faster than anyone thinks. Just enough to get you going 30-40 mph till the next stop/regenerate is a huge opportunity for improvement.

[Langod]

Originally Posted by Da Klugs

The thread title is misleading. Just my lil way of amusing myself with experimenting with how my driving style impacts mileage. It's been interesting how little changes (limiting RPM not speed) can have big impacts on city MPG. Big changes can have additional impact... rolling stops, using neutral etc.

Be aware that coasting in neutral with most modern automatic transmission cars will actually hurt your mileage. (I don't know if this is true with maunal transmissions too) A modern automatic -- when you are coasting with your foot off the gas, will drop into a mode where it only fires cylinders frequently enough to keep the engine spinning, but while in neutral, it actually uses more gas because it's at a full idle. You can see it on some car's computers -- my wife's Subaru Legacy shows the mpg meter max out at 99.9 mpg (which means it's probably higher) while coasting in gear as opposed to about 65mpg on the same hill/speed while in neutral.

Noticed my Maxima seems to get better mileage in gear also. (tough to tell for real -- no computer display).

I just do it to save more gas money for my '03 SVT Cobra -- has a supercharged V8 that I've gotten down to 2mpg whilst "driving spiritedly". (it normally gets about 18-20mpg around town, though)

[Da Klugs]

Originally Posted by Langod

Be aware that coasting in neutral with most modern automatic transmission cars will actually hurt your mileage. (I don't know if this is true with maunal transmissions too) A modern automatic -- when you are coasting with your foot off the gas, will drop into a mode where it only fires cylinders frequently enough to keep the engine spinning, but while in neutral, it actually uses more gas because it's at a full idle. You can see it on some car's computers -- my wife's Subaru Legacy shows the mpg meter max out at 99.9 mpg (which means it's probably higher) while coasting in gear as opposed to about 65mpg on the same hill/speed while in neutral.

Noticed my Maxima seems to get better mileage in gear also. (tough to tell for real -- no computer display).

I just do it to save more gas money for my '03 SVT Cobra -- has a supercharged V8 that I've gotten down to 2mpg whilst "driving spiritedly". (it normally gets about 18-20mpg around town, though)

Have read the same things re neutral. Not the case on my Audi. Runs at 1100-1200 RPM while in gear and I think the AWD comes into play re the efficiency. In neutral, drops to 800 rpm. Huge difference in the Mpg and the "feel". Closest thing I can think of is my old 70's Saab with the "freewheel" option. Seems much less transmission drag is the difference coupled with the lower rpm.

Got 10.5 on the way to work. I was late and hittin it!

[Langod]

Originally Posted by Da Klugs

Have read the same things re neutral. Not the case on my Audi. Runs at 1100-1200 RPM while in gear and I think the AWD comes into play re the efficiency. In neutral, drops to 800 rpm. Huge difference in the Mpg and the "feel".

Originally Posted by Sancho

This is somewhat more of an instance than the rule, many transmissions dont freewheel while in gear and the slipping is taken up hydraulically etc.

From what I've read, the tranny doesn't freewheels (if I understand what you mean) -- The wife's subaru's RPM is still "normal" for the speed it's going in gear, but like I said it pegs the MPG readout. Moving to actual neutral does drop the RPM to 800 or so, but the MPG readout reads much less.
(According to this short article your car actually uses no fuel whatsoever while coasting in gear.)
I don't know for sure, just reporting what I've read. I'm not a mechanic -- I can understand a manual tranny, but automatic transmissions might as well be magic to me.

And just for giggles, here's an article from Road & Track regarding gas saving tips and myths.

[Sancho]

Originally Posted by Langod

Be aware that coasting in neutral with most modern automatic transmission cars will actually hurt your mileage. (I don't know if this is true with maunal transmissions too) A modern automatic -- when you are coasting with your foot off the gas, will drop into a mode where it only fires cylinders frequently enough to keep the engine spinning, but while in neutral, it actually uses more gas because it's at a full idle. You can see it on some car's computers -- my wife's Subaru Legacy shows the mpg meter max out at 99.9 mpg (which means it's probably higher) while coasting in gear as opposed to about 65mpg on the same hill/speed while in neutral.

Noticed my Maxima seems to get better mileage in gear also. (tough to tell for real -- no computer display).

I just do it to save more gas money for my '03 SVT Cobra -- has a supercharged V8 that I've gotten down to 2mpg whilst "driving spiritedly". (it normally gets about 18-20mpg around town, though)

This is somewhat more of an instance than the rule, many transmissions dont freewheel while in gear and the slipping is taken up hydraulically etc.

We must remember, maximum combustion efficency and maximum fuel economy are two drastically different things. Max economy, most older cars you want to sit at ~55mph as that was where the epa mileage test spends most of its time and thereby you could wieght the epa rated mileage in your favor. The new test Im not so sure as I haven't run one of those in a while...

Max efficency, wide open throttle baby

[Da Klugs]

After the game last night coming home from Sams tried "the extreme". What could I get based upon getting up to the speed limit (eventually), cruising to stop on neutral, low rpm, force upshifts, etc.

Rolled almost to a dead stop in my driveway with 31.7 MPG showing on the display. Max speed 35 mph. Max RPM 1600 where it would upshift. Cruising rpm 1200. Idle RPM 800 when in neutral. About 2 miles. 2 stops that I rolled at about 3 mph, one left turn in neutral and the left into the driveway rolling to a stop with just a bit of brake.

Got me thinking that with all the electronic gizmos they put on cars today it would be pretty easy to add an "eco mode" that does all the things I am trying manually, automatically. They have performance switches on our cars changing the shift patterns, suspension settings etc, why not the other direction? Switch that moves the shift patterns to the minimum RPM, automatically "freewheels" the transmission and also changes the throttle to much less sensitivity (lots of pedal movement for a little increase in RPM). Seems like it would be much less expensive then "retooling". Would give each of us the option of having different types of MPG and performance vehicles with the flip of a switch. In my case, for city driving this might mean a doubling of mileage. Pretty interesting.

[borndead1]

Did you use cruise control too Dave?


I had a '03 Prius. It got about 48 MPG when the weather was warm, about 42 in the winter. NO BALLS whatsoever.

But on the highway with the cruise set at 75 it was reading over 55 MPG, and going through town with the cruise set at 35 it was reading 99.9 MPG (running on pure electricity).

Sounds great, right? I never realized how much I hated that car until I got my '09 Corolla. Smoother ride, better handling, way more power, and I'm getting over 30 MPG. Plus the car was built in America. Plus I won't have to shell out $4,000 to replace the hybrid system.

Anyway, my point was that cruise control does make a noticeable difference in your mileage.

[Da Klugs]

Originally Posted by borndead1

Did you use cruise control too Dave?


I had a '03 Prius. It got about 48 MPG when the weather was warm, about 42 in the winter. NO BALLS whatsoever.

But on the highway with the cruise set at 75 it was reading over 55 MPG, and going through town with the cruise set at 35 it was reading 99.9 MPG (running on pure electricity).

Sounds great, right? I never realized how much I hated that car until I got my '09 Corolla. Smoother ride, better handling, way more power, and I'm getting over 30 MPG. Plus the car was built in America. Plus I won't have to shell out $4,000 to replace the hybrid system.

Anyway, my point was that cruise control does make a noticeable difference in your mileage.

Sub 35 mph stop and go so cruise doesn't come into play. My point is that I got over 31 mpg in a 4400 lb 350 hp car city driving through extreme behavior modification. Normal driving = around 14 with no thought to it. My point in all of this is that some "automation" would yield results somewhere in between and not carry the same concerns or costs associated with hybrids etc. The aspect of choice, clicking the Eco button on a car who's normal performance is appealing to us, as an option that might almost double city fuel economy, just makes the concept very intriguing to me.

[Da Klugs]

Cable didn't have the game tonight.. no nfl network. Was late coming up to the office to watch and have a cigar.

Put it in "sport" seemed to shift at 6000 RPM + and held gears at anything less. Didn't make many friends on the way here.

Got... 10.8 MPG and it felt great.