just got here, some questions

[perris]

hey guys, just got here, love the forum

I have a solstice gxp, standard transmission, I bought the car for the performance but I also love pushing the envelope in the other direction as well

doing nothing special, setting my cruise control to 62 mph I get 39.5 miles to the gallon over 300 miles of hilly terrain

this is without turning the engine off or doing anything special except I do my best not to hit the brakes

here's the question though;

when I turn off the engine my odometer stops recording so it's impossible to get an acurate read unless I leave the ignition on

doesn't leaving the ignition on do something to the electrionic ignition?

I would rather not leave the ignition on but if you guys tell me there is no harm done that will make me feel better

here's and interesting example of an experience of mine that is counter intuitive;

when I go down a certain road with very steep hills and valleys I get about 50 mpg (coasting without turning the engine off)

I get the same mpg when I go in the other direction so it's not a downhill thing

I don't understand how going up and down hills gets me better gas mileage then going flat even though I coast, this is a counter intuitive result

here's another question;

I read on the forum there are devices that give real time fuel economy...mine only gives overall average and I have to zero out the readout o get real time...this makes it hard to see where and how I get best results real time

what program do you guys use?

anyway, great to see people that enjoy this perameter of performance like I do

[SVOboy]

I have never had any problems with leaving the car in the on position, you need to so your steering won't lock!

Sometimes hilly terrain is better, use more on the way up but less on the way down and you get a net benefit. *shrug*

www.scanguage.com

Welcome to the site!

[Bill in Houston]

Going up hill the car runs at a higher efficiency than it does on a flat road.

This is a weak analogy, so don't stretch it too far. If you had to move 10 cinder blocks 100 yards, would you rather
1- carry them up a flight of stairs, put them and yourself in a wagon, and ride the wagon down a long ramp to the end of the 100 yard course

OR

2- put them in the wagon and pull that wagon 100 yards.

I'd rather carry them up the stairs. I'm more efficient at the higher output.

But that's just me.

[GasSavers_StanleyD]

I drive flat for about 70 miles EACH way daily. Once I decided to take the hilly route for a couple days to compare traffic patterns/ect and noticed that I got better gas mileage even though the traffic was not much different. I guessed thats it was prob due to the hills (the hilly route is prob about 40 miles, so the commute only differs during that hilly 40 mile part). Anyway I figured that while going uphill I stored potential energy and then just coasted on the downhill portion. So Im only on the pedal for the way UP the hill and never touch the petal during the downhill portion. maybe using your gas for HALF your ride is what gets you better mileage. ALSO, I try to build up speed SLOWLY while going downhill ( I just press a little bit towards the bottom of the hill since gravity speeds me up almost to the speed I want) I then use my momentum to try to make it to the top while using as little gas as possible and maintaining a reasonable speed. If no one is behind me then I dont care about speed. As long as I make it to the top Im happy.
Hope this helps in explaining why mileage is better on hills. Your using momentum from the downhill portion (which required no gas) to go up a hill with less gas. So your only gasing HALF the ride and even less since your momentum acrries you at least half of the way BACK up the hills

[Hockey4mnhs]

you already figured out one of our proven ways off getting mileage. does the hilly route have slower speed limits? that might be a factor also

[perris]

Originally Posted by Bill in Houston

Going up hill the car runs at a higher efficiency than it does on a flat road.

This is a weak analogy, so don't stretch it too far. If you had to move 10 cinder blocks 100 yards, would you rather
1- carry them up a flight of stairs, put them and yourself in a wagon, and ride the wagon down a long ramp to the end of the 100 yard course

OR

2- put them in the wagon and pull that wagon 100 yards.

I'd rather carry them up the stairs. I'm more efficient at the higher output.

But that's just me.

I don't get it though...you can't get more out then you put in, if you expend x energy going up you should regain less energy going down

given this scenario, that the engine runs more efficient under load thenm no laod it would make sense a jack rabbit a bit (of course deminishing returns and we would have to see what best excelleration would indicate as far as efficiency) and then coast would get more mileage then a slow start and steady speed.

that's counter intuitive but there it is...it's not a mpg thing either because my car gets better mileae in 5th doing 62 then it gets at any other speed

though to be fair, if I am going less then 30 and coast to stops and turns I get better mileage over all then a steady speed limit so I guess it's true, the car under load is more efficient then the car is with no load

counter intuitive but there it is.

anyway, this engine delivers 260 hp, 260 lbs of torque, does just a bit over 5 seconds 0-60, it is a rocket yet it is so efficient if I don't get rough it is unbelievable to me

so, you guys are saying turning the engine off causes no damage to the the points in the electronic ignition?

there are points in electronic ignition though most people think there are not

hey...here's another great thing about this car;

I get quite a few braking oportunities then you guys indicate is normal/..AI never counted but it's a rare case I don't have breaks.

[Hockey4mnhs]

yeah i always flip mine back into the on positon it has never done anything wrong to it. the main thing in eoc is the tranny wear on autos, but i dont think you have a auto so your fine.

[slurp812]

I believe the ignition on thing is from the old point days. Iv done it to my car, but not really enough to make a difference. I do very little EOC

[perris]

Originally Posted by slurp812

I believe the ignition on thing is from the old point days. Iv done it to my car, but not really enough to make a difference. I do very little EOC

there are points on electronic ignition too they just need less attention then on a mechanical ignition

[perris]

Originally Posted by perris

I don't get it though...you can't get more out then you put in, if you expend x energy going up you should regain less energy going down

given this scenario, that the engine runs more efficient under load thenm no laod it would make sense a jack rabbit a bit (of course deminishing returns and we would have to see what best excelleration would indicate as far as efficiency) and then coast would get more mileage then a slow start and steady speed.

that's counter intuitive but there it is...it's not a mpg thing either because my car gets better mileae in 5th doing 62 then it gets at any other speed.

well, I found my answer here

I made three runs using each method, alternating methods to try to avoid any changes due to other factors. The runs weren't perfect; in the B cases I sometimes overshot the target speed, and was unable to shift from 1st and 2nd quickly enough to shift at the target 2500rpm. On trials 3A and 3B other traffic slowed me briefly (part of segments LM and ST respectively).

In each case I had the car off briefly while recording information prior to the initial run or from the previous run. I turned the engine on, reset the Scangauge trip counter, and drove.


Run    Initial   Max   Avg   Max   Max    Fuel
      Air Water Water Speed Speed Engine  Eff .
      ?C   ?C    ?C   km/h  km/h   RPM   L/100km
1A    10   82    84    51    82    2844   6.6
1B    14   86    84    61    83    3559   6.3
2A    14   84    84    53    81    2710   6.6
2B    13   85    84    64    86    3308   6.5
3A    13   84    83    51    79    2738   6.5
3B    10   82    83    62    85    3513   6.2


Rapid acceleration to cruising speed is more fuel-efficient than slow acceleration. Presumably the greater fraction of the drive spent in high gear at cruising speed more than makes up for the hard acceleration.