Tinkering with the Prius

andyprius · 01-19-2009, 12:43 PM

So far I have not tinkered with Prius to any extent. Generally I would tinker to look for problems and to increase mileage. I find it hard to believe that people are getting a consistent 60mpg in any or most conditions. I wonder if there isn't some minor differences between Prii that make one more efficient than another. The only mechanical parallel that I can think of would be old technology, such as a float on a carburetor being out of adjustment, plugs not gapped right or an idle screw out of adjustment. Are there any adjustments on the Prius that could affect performance and efficiency. It is not that I do not believe these 60mpg claims, but wonder why the average Prius driver cannot attain these numbers. I will not run stop signs and take turns at 35mph to get these numbers.

miscrms · 01-19-2009, 01:49 PM

IMHO, here are the things that most affect the Prius's efficiency:

1. Driving Style
2. Weather
3. Tires/air pressure/alignment
4. Maintenance

There's really not much to adjust or maintain on the Prius. The air filter getting dirty is about the one thing I can think of, along with eventually cleaning the throttle plate. Everything else is controlled by the computers in a closed loop fashion. Its measured, adjusted, re-measured, and re-adjusted continually so things are pretty much always correct. The main thing you can do is learn how to drive it. That doesn't mean driving unsafely, or like a grandma. It means developing a deep understanding of how the car works, and how to convince it to operate in the most efficient fashion as often as possible. A good start on this path is to invest in a scan gauge, and spend a good deal of time reading the threads on this list regarding how to use it to know what the car is actually doing internally at any given time.

If you haven't already, one of the biggest things you can do in winter is install a block heater and grill block. Getting the engine up to temperature sooner, and keeping it warmer longer makes a big difference. Even here in Phoenix I run a half grill block in winter, and know people who use block heaters. You'll also find a lot of threads on these topics. Ideally you would use a scan gauge to monitor temps so you can run as much blocking as is safe in your climate/driving conditions.

Any more hardcore manipulation would require changing settings in the engine computer, HV controller, and battery computer. Since a lot of these settings are in place to protect the electric motors, inverters and batteries, and to keep emissions low, changing them is pretty risky, and potentially illegal. A few of the PHEV conversion folks have started on this path, but even they haven't really tried to change the ECU or HV controllers yet. Just the battery management system.

Rob

sandman · 01-19-2009, 02:58 PM

Quote:

I find it hard to believe that people are getting a consistent 60mpg in any or most conditions.

Most people are not getting those numbers in the winter.. I am down to about 52-55MPG, but in the summer I had like 15 tanks over 60MPG..
Tire pressure helps a lot and learning to P&G will really boost your numbers, but to get over 60MPG you must be willing to slow down especially on the interstate I average about 64MPH..

Quote:

why the average Prius driver cannot attain these numbers

Trust me I am the average Prius driver. I have had my Prius for about 10 months and if I can do it anyone can..If you are really serious about learning how to get those type numbers and you live close to one of the Hybrid MPG groups (like the Milwaukee Hybrid Group or the Cincympg Group) Thats a great place to learn..

Quote:

I will not run stop signs and take turns at 35mph to get these numbers

.

Why do people think to get these numbers that we hypermilers drive unsafe its just the opposite we drive much safer than the average driver by going slower and always looking ahead..

kohnen · 01-19-2009, 06:37 PM

If you want to keep yourself busy tinkering, might I suggest:

1) Change the power steering fluid regularly.
2) Every 20 k miles or so, replace the cap, rotor and spark plug wires.
3) If you play your stereo loudly, I'd drop in a high current alternator in there.
4) Put a beefier clutch and a stronger spring plate in there too.
5) Get yourself a Teflon lined throttle cable to minimize wear.
6) Adjust the idle; Priuses tend to stall out at stop lights.

I'm sure the regulars here can help out with other similar improvements!

andyprius · 01-19-2009, 07:44 PM

Thanks for all the answers. I have already done most of the suggestions. With the exception of changing the accelerator cable ( I thought it did not have one.) I generally drive 55-60 on the freeway anyway. If Im able to find a road where I can do 25 to 40MPG for a long length of time, I can easily get 60MPG plus. For the most part these roads do not exist, in CA, also the lights change here after one drives over a sensor, if there is no cross traffic. And then most of my trips are 5-10 minutes. I think the people getting 60-70 mpg are good Prius drivers that also have perfect routes of at least 30 min.

01-19-2009, 12:43 PM	#1
andyprius Senior Member Join Date: Feb 2005 Location: Sacramento, California. Posts: 779 My Car: 2005 Prius Model: Package: #3 Thanks: 3 Thanked 1 Time in 1 Post Friends: 1	Tinkering with the Prius So far I have not tinkered with Prius to any extent. Generally I would tinker to look for problems and to increase mileage. I find it hard to believe that people are getting a consistent 60mpg in any or most conditions. I wonder if there isn't some minor differences between Prii that make one more efficient than another. The only mechanical parallel that I can think of would be old technology, such as a float on a carburetor being out of adjustment, plugs not gapped right or an idle screw out of adjustment. Are there any adjustments on the Prius that could affect performance and efficiency. It is not that I do not believe these 60mpg claims, but wonder why the average Prius driver cannot attain these numbers. I will not run stop signs and take turns at 35mph to get these numbers.

01-19-2009, 01:49 PM	#2
miscrms Plug Envious Member Join Date: Aug 2007 Location: Phoenix, AZ Posts: 1,334 My Car: 2005 Prius Model: Package: #4 Thanks: 6 Thanked 97 Times in 67 Posts Friends: 4	Re: Tinkering with the Prius IMHO, here are the things that most affect the Prius's efficiency: 1. Driving Style 2. Weather 3. Tires/air pressure/alignment 4. Maintenance There's really not much to adjust or maintain on the Prius. The air filter getting dirty is about the one thing I can think of, along with eventually cleaning the throttle plate. Everything else is controlled by the computers in a closed loop fashion. Its measured, adjusted, re-measured, and re-adjusted continually so things are pretty much always correct. The main thing you can do is learn how to drive it. That doesn't mean driving unsafely, or like a grandma. It means developing a deep understanding of how the car works, and how to convince it to operate in the most efficient fashion as often as possible. A good start on this path is to invest in a scan gauge, and spend a good deal of time reading the threads on this list regarding how to use it to know what the car is actually doing internally at any given time. If you haven't already, one of the biggest things you can do in winter is install a block heater and grill block. Getting the engine up to temperature sooner, and keeping it warmer longer makes a big difference. Even here in Phoenix I run a half grill block in winter, and know people who use block heaters. You'll also find a lot of threads on these topics. Ideally you would use a scan gauge to monitor temps so you can run as much blocking as is safe in your climate/driving conditions. Any more hardcore manipulation would require changing settings in the engine computer, HV controller, and battery computer. Since a lot of these settings are in place to protect the electric motors, inverters and batteries, and to keep emissions low, changing them is pretty risky, and potentially illegal. A few of the PHEV conversion folks have started on this path, but even they haven't really tried to change the ECU or HV controllers yet. Just the battery management system. Rob __________________ Hers: '08 Prius, Magnetic Grey, Package #4 His: '05 Prius, Driftwood Pearl, Package #4 + leather, wheel ring delete, Optima Battery kit, Salvage/Rebuild w/ plug envy

01-19-2009, 06:37 PM	#4
kohnen Grumpy, Cranky Senior Member Join Date: Jun 2007 Location: Fullerton CA Posts: 181 My Car: 2007 Prius Model: Package: #6 Touring Thanks: 0 Thanked 2 Times in 2 Posts Friends: 4	Re: Tinkering with the Prius If you want to keep yourself busy tinkering, might I suggest: 1) Change the power steering fluid regularly. 2) Every 20 k miles or so, replace the cap, rotor and spark plug wires. 3) If you play your stereo loudly, I'd drop in a high current alternator in there. 4) Put a beefier clutch and a stronger spring plate in there too. 5) Get yourself a Teflon lined throttle cable to minimize wear. 6) Adjust the idle; Priuses tend to stall out at stop lights. I'm sure the regulars here can help out with other similar improvements!

01-19-2009, 07:44 PM	#5
andyprius Senior Member Join Date: Feb 2005 Location: Sacramento, California. Posts: 779 My Car: 2005 Prius Model: Package: #3 Thanks: 3 Thanked 1 Time in 1 Post Friends: 1	Re: Tinkering with the Prius Thanks for all the answers. I have already done most of the suggestions. With the exception of changing the accelerator cable ( I thought it did not have one.) I generally drive 55-60 on the freeway anyway. If Im able to find a road where I can do 25 to 40MPG for a long length of time, I can easily get 60MPG plus. For the most part these roads do not exist, in CA, also the lights change here after one drives over a sensor, if there is no cross traffic. And then most of my trips are 5-10 minutes. I think the people getting 60-70 mpg are good Prius drivers that also have perfect routes of at least 30 min.