Daox's 2004 Toyota Prius Build Thread

[MetroMPG]

One small potential downside to using neutral coasting in a Toyota hybrid (not sure about others) is it disables regen if/when you use the brake pedal.

[alohaspirit]

Originally Posted by MetroMPG

One small potential downside to using neutral coasting in a Toyota hybrid (not sure about others) is it disables regen if/when you use the brake pedal.

ouch


does engine braking enable regen?

[bwilson4web]

It is easy to shift into "D" when you need to brake. Often I'll modulate my approach to stopped traffic at a light with "D" coasting and if the light changes, shift into "N" until I need to accelerate.

Eventually, I plan to rig up automatic "N" that goes on when the accelerator and brake are off. Touching either the accelerator or brake would engage "D" and normal brake pressure modulation would work as before. This is the beauty of electronic shifting.

Bob Wilson

[NeilBlanchard]

You can also use 'B' to get regenerative braking.

[Matt Herring]

Originally Posted by MetroMPG

One small potential downside to using neutral coasting in a Toyota hybrid (not sure about others) is it disables regen if/when you use the brake pedal.

True metro...its a situational decision at the top of a hill to use neutral coast or ICE coast. If I'm running low on battery I'll keep it in ICE but if I'm at 5 or higher bars I usually go with neutral coast.

It is quite easy to keep the battery at optimum charge so rarely do I need to ICE coast unless I have been doing heavier EV use than normal. I've found that under normal operation I actually have to protect from overcharging because the regen is so efficient.

[Daox]

B I believe would work, but B also allows engine braking which isn't desirable unless you're driving down a mountain and your pack is already full.


I also had my first two fill ups in the past few days.

The first tank was a woeful low 50.1 mpg. But, I hear to expect above average fluctuation from tank to tank due to the bladder gas tank. So, I wasn't too distressed. The MFD said I was ~55.5 mpg.

The second tank was much higher @ 59.1 mpg. Thats the ol bladder at work. MFD again said ~55.3 mpg.

I also had some big problems with getting into the efficient SHM with this past tank. I simply couldn't get it to go to 14 IGN on the scangauge. This morning, after a fresh tank of gas I was able to get into it much easier. MFD reported a very nice 71.9 mpg on the commute to work this morning. I'm crossing my fingers that this can be repeated.

[Matt Herring]

I compute my fill mpg every tank but it's not a good indicator at all of actual mpg. Over a dozen tanks it's been as high/low as 10% from the MFD. For my ecomodder fuel logs I use MFD -2% (so 63 mpg on my MFD ends up being 61.74 for my fuel log...I just adjust my miles driven to get to that number). Over those 12 tanks my actual fill mpg is within 1% of my MFD so I think the MFD -2% is a pretty good way to accurately guage mpg.

Don't worry about the first couple tries at SHM...I failed miserably at it. Over an 800 road trip I posted 51 mpg trying it for the first time. I'm up to around 59 mpg highway now so it takes some time to get it down.

The 14 IGN is super tough to hold on the highway and I usually only get into it by going from 16 down to 14 rather than trying to stick it at 14. By the time you get to 14 sometimes you have already lost alot of speed and have to use pedal again. That's why I have been just keeping it at 15 or 16 If I can't hold at 14 (or going right to IGN 5 and riding it out as long as I can...especially down hills as your accel in IGN 5 is almost like ICE coasting).

[Daox]

The other problem I'm having with SHM (super highway mode) is that my scangauge version does not work with the xgauge feature to get GPS (gas position sensor, or the gas pedal position). It seems this is a key feature to have when using SHM. I'm going to be calling up linear logic quite soon to talk with them about this and see if I can't get an update or something.

[Matt Herring]

Are you talking about TPS for Throttle Position? Do you have SGII or the prior model?

[Daox]

No, I'm talking about a xgauge feature they call GPS which tells you your gas pedal position (since its drive by wire). Supposedly you park your GPS at 16.5 and you should hit SHM pretty easy. I got this info from DiamondLarry who is knocking out some insane mileage numbers (mostly from avoiding the highway though). He said he has knocked out 70+ mpg highway segments with pulse and SHM for glides.

I just got off the phone with linear logic and they said that they can update the scangauge to a different version that would probably work, but no guarantees. Ack, a week or two without the scangauge, what will I do?!?


For a very nice list of scangauge xgauge options for the Prius (most are useless though), try this link.

CleanMPG Files - Prius xgauges