Doh! Just read Schwa's post :
I live close to the downtown center of my town, and a huge percentage of my driving are 5-10 minute trips with long cooldowns in between. I also live in the North East where the temps are dropping rapidly as we speak. Maybe I will just get to enjoy the better mileage when I am on certain longer trips and not in my everyday driving.

 

Everything is relative. You are getting much better mileage than you would if you had a conventional vehicle driving the same route, distance and time.

 

Thanks so much for all your replies everyone. Today I let my hubby take my Prius and I am back to driving the van, ouch! Not sure what I was thinking, the van seems sooooo dull now. Won't make that mistake of giving him a turn with the Prius again for a while. Ha!

 

Wow, you guys were right, mpg is going up already !
I had posted earlier about my first tank getting 40 mpg. Now, I am half way through my second tank, and according to my computer am getting 43.8 mpg (I hit the reset button on refill, so this new value is per this tank). I am really excited about this ! I followed advice on other GreenHybrid post's and checked my tire pressure, which was indeed low. So, not sure if it was just fixing the tire pressure that bumped up my mpg, but 43.8 is a great number, I am really happy.
Thanks for the great advice and encouragement everyone !
Kim

 

Hi,

Check your oil level. My 03 Prius was picked up 'over filled.' The oil level was above the 'full' mark.


I drained out nearly a quart of excess oil to bring it about 75% between the 'fill' and 'full' level and gained an extra 10 mpg in my city commute.


BTW, I had seen the same effect in my Toyota Camry and always kept it in the lower half of the oil fill range. It was good for an extra 2-3 mpg in the Camry but the Prius really shines when the oil is in the 'running' range.


http://hiwaay.net/~bzwilson/prius

The reason is extra oil risks: (1) crankshaft counter weight slap, and (2) more mass to bring up the operating temperature. As long as the oil level is above the 'fill' mark, you are in the engine operating range.


Bob Wilson

 

Bill, sounds like your overfill on your 03 was pretty significant, however I'm not a huge proponent of running an engine below the max mark. I've studied cross section diagrams of the Prius engine and as such, a minor "overfill" using a 4 quart oil change, rather than a 3.7 or 3.9 qt. change puts the oil about 1/8 to no more than 1/4 inch higher than the top dot.

Here are my observational conclusions based upon diagram study and factory spec volumes. If with a 4 qt. change you were getting crank slap, there would be pretty serious oil foaming issues, and I'm sure there would be enough resistance that an MIL would happen and a code generated indicating that the ICE had a starting failure or some other poor starting condition. We also have to consider that if you have crank slap, then you might also have an oil pressure problem, due to oil possibly not being available for the pump to use, or that the volume of oil is less due to air incorporation.

Now, based on diagrams, the oil full mark is way below the crank. And additional 1/8 to 1/4 inch in oil volume height in the sump does not even bring the oil level close to the crank. Plus we are forgetting that the oil level in the pan should be lower when the engine is running because oil is up in the top of the engine doing its job and it takes time for it to return to the pan to be recalculated. I wouldn't doubt that at any time nearly half of the pan's capacity is up at the top of the engine rather than in the sump. We forget about the face that when the engine is running the sump should be lower than with the engine off and cold.

Another thing I like to point out is that the dipstick is not a precision instrument. It isn't like it has metric or English graduations on it. It is only a rod with a couple marks on it. I'm sure there is limited variability in them from lot to lot, but to be honest, a little above the mark, a little below the mark it isn't going to hurt the engine any. Without volume graduations and a precision stick length designed to measure volume exactly, the dipstick is there to let you know if you are running dry or if you are doing ok.

I am personally not all that concerned about warming up that volume of oil when I run the car. What I'm more concerned about is having enough oil in the sump that its cooling properties are maximized. Motor oil isn't only there to lubricate and prevent parts from seizing and wearing out, it is also an excellent secondary engine coolant. Nearly all manufacturers now acknowledge the benefits of engine oil cooling and design their engines and sumps to provide some level of engine oil cooling. So, that means, the more oil you have, the more liquid there is to dissipate heat from the engine. This is not to be construed as support for overfill, however it is support for using the maximum amount of oil the manufacturer says should be in the sump. In this case, the car calls for 3.9 qts, which is close enough to 4 qts for me to not worry about that extra .10 of a quart.

 

Hi JeromeP:

___I can agree with you on all points but the graduated marks on the dip stick are very close to what the actuals should be and are. At the low level, either add or change. At the high level, YOU ARE AT MAX FULL. A level between the marks does all that you have quoted + adds a bit of FE that you would not otherwise achieve. I am not saying anything like 10 mpg’s but a mpg or two is certainly possible vs. over the full mark at the price of 2 - 3 degrees increase in oil temps when between the marks. As low a temp as today’s hybrids run, I see absolutely NO benefit of an overfill in reference to the ICE’s bearing temps or ICE longevity. Fill it between the marks and you are completely set. Fill it to Full and you are completely set with the slight loss of mpg’s.

___Good Luck

___Wayne R. Gerdes

 

Jerome,

I was speculating about possible causes but I've seen the effect of oil fill level with my '91 Camry and now our Prius Classic. Since it is easy to avoid, I'm not likly to spend much time trying to diagnose exactly what is going on. I've got another PriUPS weekend project to complete.

After that one, I'll be investigating a curious dip in MPG at 40 and 45 mph and some other enhancements not listed, yet.


Bob Wilson

 

Hi Bwilson4web:

___A bit OT but that is an interesting page you linked. If that Echo is a stick, I bet you could easily hit 60 – 70 mpg’s over your shorter - all city commute with a few FAS’ and/or P&G’s and such. The Echo is no slouch in the FE department given its light weight and the fact it is the source of the Prius II’s ICE although non-atkinsonized. If you were to drive it like it was a hybrid, it has to be worth some incredible FE as well. I would love to take one out for a week or two w/ a scan gauge that can calculate beyond a FAS just to see what they are actually worth knowing what a non-hybrid can do when driving beyond the hybrid’s design envelope …

___As far as going down hill and a pegged Instantaneous, That does not necessarily mean you are running ICE-off. Without actually feeling the ICE-Off condition or having a tach or instrumentation telling you so, it could easily be idling (spinning over using a small amount of fuel) at that speed and it would still peg the instantaneous. It could also be in fuel cut while in regen for a pegged instantaneous as well … Ken1784’s SuperMID would be a good idea as to ICE-Off or not as there was a light indication of ICE-Off if you can believe that!

___Good Luck

___Wayne R. Gerdes

 

Hi Wayne,

Our 2001 Echo was the winner of the Prius vs. Echo buy in 2001. At the time, I couldn't justify the Prius $22 k price. But I just bought a 2003 used Prius for $17.3 k and laughed all the way to the bank.

The 2001 Echo is an automatic and it gives us an honest 32/38 but that was before I learned the hybrid driving techniques. After I get done with my current Prius projects, I'm thinking about trying some of them on my wife's Echo.

BTW, you might enjoy some of the other links showing my approach to instrumentation. <grins>

Bob Wilson