2009 Prius Base - Ecomodded

A bigger difference between dead band, EV and neutral P&G can be seen on my SGII. On my commute because my glide is greatly disturbed by the quick, steep uphills in miles 2-7 my SGII reports brief stints over 1000 mpg. In dead band and EV it is commonly in the 3500-4000 mph range for longer stretches.

I'd love to have an 11 mile highway commute where I could P&G for miles on end but in my situation it's not possible.

 

What's your commute like in terms of speed limits? Is most of it highway driving?

Can you further describe what you mean by "I try to keep my mpg about 1/2 my speed at all times which is my basis since I don't have a scangauge to monitor rpm's."

 

Makes sense...thanks for the added info. Probably the one poor decision with the Prius was to not include an rpm guage display so those without additional instrumentation could monitor their engine use. With the SGII it's great info. and a good reminder to stay at lower rpm wihtout revving.

 

I've driven my route using heavy P&G over the hills and I've driven it using slow consistent accel up the hill (staying under 41 mph and in EV mode) and my SGII numbers just do not favor P&G in those sections of my commute...this is for me...maybe not for you.

In my old vehicle (4 runner) the P&G in those sections was a great option because...#1 the 4 runner had no EV option and #2 the 4runner was able to run at a lower rpm up the hills so the glide on the backside was heightened in mpg by less strain on the pulse.

My commute is unfortunately not "slow rolling hills"...it's severe hills grouped very closely together so when gliding on the back side the speed gained on the downhill is quickly gobbled up by the drastic incline on the next hill.

I'm fully in favor of highway P&G and in city P&G if you can pull it off safely...but...I feel like the "uphills both ways" driver on my commute...so many closely grouped hills. If you could drive my commute...you'd have a better idea of what I mean.

 

Seems logical but in P&G I am usually in neutral on the downhill coast...how do you accelerate in neutral (or are you taking about pulsing on the downhill in drive and coasting to the top of the next hill)? While gliding in drive is not wasted energy because you are recapturing it from wheels in the battery compared to gliding "x" number of feet further in neutral vs. that lost distance gliding in drive it is a loss of energy to allow the engine to resist your progression. Somewhere there is lost distance (and potential energy) in drive coasting vs. neutral coasting...no? The only way to compare the two is with a little experimentation with the SGII...I'll check it out.

I'll toy with your reverse P&G option on my commute to work tomorrow to see what the SGII numbers bear...thanks for the input!

 

For Usb and interested viewers,

Here a link to a vid I took today on my commute to work. I'm using dead band to gain max mpg while also accelerating and staying in dead band (no arrows on the energy screen). At the end of the vid note when I tap the accelerator I go into EV mode. There are two very brief periods on this vid when it flashes back to ICE but then quickly back to dead band. This is while traveling at 32-35 mph on a nice flat stretch during my commute to work (and I've kept it in this mode up to 41 mph). My SGII reported 66.4 mpg on this commute.

Question for you...why would it be beneficial to me to P&G using fuel to pulse when I can stay in this mode for approx. 1/3 of my trip and get 3000+ mpg? Hopefully this vid helps you better understand the technique I am using to maximize my mpg on my way to work.

I also included a pic of my consumption screen from my commute today (the 20-25 min. bar that is under 50 mpg was from sitting in idle at the bank teller window...however, I used no fuel to do it because my min temp was above 160...SGII confirmed this...Prius consumption screen factors in idle time as 0.0 mpg while you are not moving similar to a gps). 61.7 mpg on the consumption screen is over 379 miles.

Comments/questions?

 

The vid is only 1 minute long so it's a very brief glimpse into my route but it does show how I move along the route in dead band and EV mode up to 41 mph (and able to accelerate up slight hills and on flat stretches) vs. using P&G.

Note: I'm not saying that I'm getting max mpg doing this but this is the best method I have found (so far) to get my best mpg on my commute.

 

The answer is...both. Why do either/or when you can do both?

Monitoring speeds while driving and not over-revving the engine and rpm up hills and off the line at lights will greatly affect mpg in a positive manner. Obviously, the Prius is rated better for city driving vs. highway but that doesn't mean you can't get well over EPA driving on the highway. It's just that at highway speeds (41 mph and up) the ICE is forced to run (most of the time) and you can't take advantage (as much) of EV or dead band mode (when you see 99.9 on your consumption readout).

In terms of the grill block it depends what type of block you are building. Mine is built purely to decrease the time the start up cycle has to run to get up to temp so I can get into using EV mode quicker. (i.e. engine heat that normally exits through the grill is blocked by the grill block which captures the heat and causes the engine to heat up to temp quicker). My stock Prius start up time in 40-45 degree weather was about 6 mins. After installing my original grill block that dropped to under 5 mins (in the same weather). After adding more material to my orginal grill block I'm now in the 1-2 minute range (but temps have been about 10-15 degrees warmer so it is not all due to grill block).

Grill blocks can also be built for aero to lower CD and improve the overall "slippery-ness" of the car. Because the Prius CD is so low already most Prius owners that mod their car tend to not build aero grill blocks because improving aero on an already slippery car is not very efficient (cost vs. gain).

But, tires at max psi, belly pans, passenger side mirror deletes, etc. can improve the overall CD of the Prius and raise mpg. Pulse and glide will GREATLY increase mpg if you're not taking advantage of it now.