Better mileage tips for Prius??
 

Hi everyone!

I currently am driving a bone stock 2004 Toyota Prius. I'm looking for more ways to improve my gas mileage. I've heard about the driving techniques such as pulse & glide, and "stealth mode", and I'm currently working on improving on those, but that's it so far. Does anyone have any input on the best speeds or techniques to use P&G? And if there are any other gas saving techniques I can try?

Are there any aero mods anyone has done, or would do to a Prius? Any other mods or tips for best milage? I keep the car clutter free on the inside to reduce weight. Does anyone know if removing the window-shade-vents thing would reduce drag at all? I'm talking about those aftermarket plastic vents that go at the top of the window so you can open them a little bit without rain or snow coming in. Thanks in advance!

Steve

The window shade things add drag.

If you're in a cold place, you can take foam pipe insulation and stuff it into the front grille. This will help the engine warm up faster, and retain that heat better. Warm engine = efficient engine.

Your car is already one of the most aerodynamic cars out there. It'll take something major to really improve on that. More effective would be to adjust the "nut behind the wheel" - driving technique. ;) I'm getting mid-50's in a 12-year-old car with no major mods. Grille block, tire pressure, and a Scangauge. You already have a built-in gauge on yours.

Yes, it is really cold out here in IL. I was going to block off the grille, to make a little more aero, and to warm up the engine quicker. It seems whenever it gets to single digit temperatures here the car doesn't get really warm at all, even with the heat blasting for 20 min drives. I need to inflate the tire pressure more, too. How much over the Max psi is still "safe"?

Note that by blasting the heat, you're taking heat from the engine, and slowing its warmup.

I can't recommend anything above max sidewall (usually 44 psi). But I myself have mine at 55. I know others who go even higher.

Block off the grill and run the heat on recirculate until the engine gets to hot or the windows fog up inside the car from too much humidity. You should be able to get plenty of heater heat out of that engine with the grill blocked off even in single digit temps. I did the same on my xB and saw great mileage (mid 40's) in single digit temps and had too much heat in the cabin (190degree engine) driving slowly. Had to open up the grill block a little to keep from overheating.

Steve ,
Have a look at a site called "Autospeed" www.autospeed.com and use the search facility for info on modding your car for both better economy and performance.
The site is free.

When you search use "Toyota Prius" not just Prius which will not give you any results.

There are a a couple of good articles on improving airflow which should be of interest.

Cheers , Pete.

Nearly forgot...this site is also worth a look www.siliconchip.com.au
The site is for an electronics magazine "Silicon Chip" and features an article on a 100 MPG Prius project car.

Cheers , Pete.

You should also look at acetone, xylene, and torco gp7 as a gasoline additive mix!


Paul

I think you should not look at acetone et al for additives. I have seen no controlled tests that confirm anything. Plenty of "well, I put some in, and I got better mileage!" claims, but when real testing happens, the gains disappear.

Look at this site priuschat.com it has a lot of good info.

Pump up the tires, at least to the sidewall max, or be daring like me and do 62/60PSI. In winter block up the grill fully top 2 slits and bottom 5 slits with foam pipe insulation. Get and use an engine block heater if possible, it makes a big difference in the first 5 minute MPG. Use your heater sparingly, set the temp to the lowest it will go. Go easy the first 10 minutes if possible, your using the battery mostly until the coolant warms up, but if you demand power you'll get it, at a cost of MPG. Your main battery is also cold so try to do as much regen as possible in the first 20-30 minutes to warm the battery insides by ohmic heating (internal resistance). Once that windshield is defrosted turn the heat off or almost off as much as you can stand, a Prius has no excess heat to spare. Change the oil to 0W20, works fine.

In the summer keep the grill blocks in the upper slits. Use the AC as little as possible when not on the highway and keep the temp up as much as you can stand. If you have the engine block heater still use it, the first 5 minutes cold kills the benefit of a good run the day before. You could also get the "B" type rear spoiler that is on the newer touring edition, it is a little longer and provides a very small aero benefit.

And yes, the biggest is driver training. P & G, slower speeds, watching traffic patterns, learn to glide...glide...glide! Once YOUR trained it's easy to rack up well beyond the EPA.

Wayne

Thanks again everyone for all the info! I really appreciate it!

Thanks Wayne. I've seen ya over on PruisChat, too. I'm under Tree Hugger over there. I have my tires set at 45 all around (rated 44 max). Should I go even higher than that? At what point does the risk of a blowout, or any other problems with the tires start to get serious? Also at what point do you usually notice increased wear in the center of the tread?

Do you use 0W20 year round, or just in the warmer months?

Also with the upper grille, is there a risk of overheating in the warmer months around here, or is there enough flow from the lower vents? Do you think I could get away with leaving the lower vents closed, and just have the top ones open? I was thinking about fabbing up a more durable block out of aluminum or fiberglass for the upper and lower vents that would still be removable. They would not only keep the car warmer, but improve aero a little, too.

Regarding the use of acetone, and additives I would check with www.mpgresearch.com and talk to the moderator "diamondlarry" who has a 2007 toyota prius that has tested this out.

Paul

I think the optimal speed for the prius is maybe 30-45 MPH. Perhaps a pulse up to 39 and then glide down to 30 or so. Make sure you get LRR (low rolling resistance) tires when you replace them. Keep the fan setting low or off when you don't need it. Try to keep rolling and never completely stop (but be careful of course). Combine trips to keep engine warm for a longer percentage of drive. When you see a red light slow down way in advance so you can keep going at 10-20 mph until it turns green (traffic permitting). Park facing out so the car is ready to go when you start, instead of having to back up. Park in an area shielded from cold winds. Park with hood facing south for solar gain during daytime. Try to maximize the glide where you are neither using power or charging.

With the tires go as high as your butt can handle, I run my OEM Goodyear at 65 psi on city streets, no problems. The wheels will probably blow before the tires, the manufacturers burst test tires well above max psi on the sidewall. Just try to avoid good size potholes, the higher the pressure the greater chance a belt can be damaged by a sudden impact like the edge of a pothole. No center tread wear greater than the rest of the tread, very even.

0W20 should be OK in the summer if your average temps don't go above 85F or so. In summer I run 0W30 Castrol Syntec European Formula.

If your goping to block any part of the grill full time it should be the upper. The lower third of the radiator is cooling the hybrid inverter and that is an expensive part to replace. The engine itself runs cooler than most, so the upper grill is fine. I've run a upper grill block up to 110F OAT with the engine running 195F. But what you may want to do is fabricate a screen for behind the lower grill to block debris from the A/C condenser, a somewhat common problem.

Wayne

Although the acetone will help the engine run better and cleaner than it already is running the gas tank has a bladder that WILL be damaged by the use of additives other than the safe Torco GP-7 . . . so . . . NO acetone or Xylene in the tank!!! Except for a quick cleaning ala gumout or other injector cleaner but burn that tank of gas as quickly as possible to minimize the exposure to the tank bladder. Tire pressure is ok but the tires are already pretty low rolling resistant. Grill block should help keep the front end warm but as posted above a little cooling for the inverter is a good idea although I think it may be water cooled too. Speeds over 40mph keep the engine running with the 2004 model as I found by driving one - newer models will shut down under light load downhill even as high a speed as 55mph. Regen with the brake use very lightly and you should learn the 4 sweet spots on the throttle where it regens - coasts - electric only - engine starts and maybe figure out some sort of detent modification to help keep them on those spots. As usual back into your parking space so you can drive straight out without the ICE starting. The Scangauge will provide you with a lot more driving info than the on board computer so get one/use it. The A/C runs off the high voltage hybrid battery so if you have a lot of regen energy you can crank up the A/C and use it for cooling - not a problem in the winter of course. I added some (1/2 bottle) Slick50 oil additive to the 2004 I drove and it helps the mileage a lot along with Castrol synthetic blend the mileage jumped up a lot from the stock oil the dealer was using.

JanGeo:

"I added some (1/2 bottle) Slick50 oil additive to the 2004 I drove and it helps the mileage a lot"

I was wondering if you have some mpg data that would show how much your mpg increased due to the Slick 50??

Paul

Hard to say exactly since I didn't get to drive it much other than that oil change run I made but it went from the 50mpg range to about 67mpg as I recall after the oil change and adding the Slick50. It was a friends car and she didn't watch the mileage that well and has since traded it in for a leased 2007 Model Prius.

I know that using Slick50 gear lube in my xB tranny really helped - about 3-5 MPG more and changing to the Synlube after a month with the Slick50 showed no further improvement so it seems the Slick50 helped as much as changing the tranny to Synlube and was cheeper. I just don't think the Slick50 would be as long lasting as the Synlube will be. This is why I just went right to the Synlube which solves the oil changing issue and has Moly, Graphite and Teflon in it for friction reduction. As I now approach 20k miles (69 to go) and we had this warm 58 degree day yesterday I saw mileage in the high 40's on a trip home and back on a typical route even with some red lights and extra stops for traffic so it seems to be getting BETTER as I drive more!

Grill Block
 

FireEngineer:

Please forgive my ignorance, but would you be able to tell me exactly how I can block the grill? Any change you could attach a picture of how a blocked grill looks like?

Thanks for your help.

fireengineer hasn't posted on the forum in almost 2 years and I doubt that he is still around.

though I don't have a picture to show you on a vehicle, maybe I can describe what he is talking about.

https://i46.tinypic.com/2afh0n7.jpg
this is a pipe insulator on a pipe. notice the slit down the length of the insulator. that is how you get it onto the pipe.
https://i46.tinypic.com/200vix0.jpg
before you put it on a pipe, it is hollow in the middle. the idea is to purchase these things (usually in 3-4 foot sections) from lowes or other home improvement store and cut it to the length of the grill opening. slip the piece over the existing grill bars in order to fill in the space between the bars.

if this explination is horrible, I apologize. at least I tried.



**********edit********

I found exactly what you want. it isn't the same car but concept is the same.

https://forums.tdiclub.com/showthread...ipe+insulation