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hyperion said:
Has anyone adapted a Tachometer or coolant temperature guage for their Prius?
I'm curious what you'd do in response to seing the engine RPM displayed since it will vary in a complex manner not easily related to the vehicle speed. The engine will run at different RPM on different runs over the same route due to changes in the state of charge etc. Repeating a modest hill climb at the same indicated MPH can yield different RPM.

I'm not the thought police, install one if you want, I'm just curious what use it will be. The coolant gauge could give you confidence, suposing you don't trust the computer and its sensors and might forwarn you of a pending melt down. Why not a tranny temp gauge? A battery temp gauge? Disk rotor temp gauge? Wheel bearing temp gauge? EGT gauge? Non-contact infra-red temp sensors could monitor the tire temps and many other parts for an overtemp situation. Cylinder head temp might be useful as well as the exhaust manifold. Temp gauges for each motor/generator. Manifold vacuum gauge might be handy too. I'm sure you could think of many many more oportunities to install gauges that will accurately report information to you that may, in some instances be of little or no use.

:wink: Pat :wink:
 

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Graham's wonderful miniscanner provides much of what you request and a whole lot of other things. It is incredibly helpful understanding what the Prius is doing in response to your driving behavior. Unfortunately it only works in the 2001-03 Prius, not the 2004. There is currently a group of people working on building a similar device for the 2004. When they get it working, I'm sure there'll be lots of announcements here and on all the other Prius boards.

Though the engine RPM is not particularly related to vehicle speed, it's highly correlated to engine output power, and that's very useful information. Engine coolant temperature is very useful to know when the Prius has finished its warm up mode and is in high efficiency mode. Battery current is quite useful to understand how much you're using the battery and especially how well the regenerative brakes are doing. Battery state of charge is like a fuel gauge for the electric side of the car, but in the 2004, I understand the energy display does a much better job of presenting this than in the 2001-03.
 

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RSnyder said:
Graham's wonderful miniscanner provides much of what you request and a whole lot of other things. It is incredibly helpful understanding what the Prius is doing in response to your driving behavior. Unfortunately it only works in the 2001-03 Prius, not the 2004.
In case it wasn't obvious let me publically confess that I was attempting to be sarcastically humorous, to "stir the pot" and was not seriously suggesting a desire for or benefit from a lot of additional instrumentation.

Having been trained as a physicist (mostly experimentalist not ivory tower theorist) I have an appreciation of instrumentation, where appropriate and useful. I have EGT, boost pressure, and tranny temp on my turbo-diesel with automatic. The engine and trany are both NOT STOCK and it is altogether likely that I could "overdo it" if I didn't have feedback from this instrumentation. The Prius is about as foolproof as a modern transportation canister can be made.

I'm not convinced that knowing a lot more information than provided by Toyota is either appropriate or useful the vast majority of the time for the majority of drivers. I suspect the instances where a driver would be able to make an informed beneficial decision to do something different because of having oodles of more instrumentation would be quite limited.

None of the forgoing was to imply that it might not be fun or interesting, just not, for the most part in a majority of instances, practical or useful.

I thiink for the most part it would be like listening to Mozart while watching it on a real time audio spectrum analyzer but not having access to any controls but the volume. You couldn't "DO" much about any instrumentation based observations.

Except for the distraction to the driver (there are already enough of those) it won't hurt anything but someone's pocketbook. I think it would allow most drivers to make beneficial adjustments to the car's performance along the same magnitude as changing the color of the paint and interior upholstery.

The best mileage enhancing instrument I have ever seen for standard gasoline fueled ICE powered vehicles (Otto cycle) has been the vacuum gauge set up to read manifold vacuum since it so strikingly demonstrates the immediate deleterious effect of excess throtle depression. Those simple times are history as regards vehicles of the complexity and sophistication of the Prius.

That said, I do keep an open mind and am more than willing to entertain an argument to the contrary, especially if presented in a complete consistant logical manner. I learn the most when shown to be wrong.

:D Pat :D
 

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Discussion Starter #5
Well Pat, If you are at all curious about any car you drive and ask questions which can't be answered by a half dozen Toyota service managers then you endeavor to seek the answer elswhere. Not one service manager I have asked can tell me what the lowest idle RPM is when battery can receive a charge and the life of any engine can first be determined by engine or in this case "coolant" temperature. It was a serious inquiry. If there is someone that has this type of package with maybe an oil pressure guage also put me down for the package. You may drive around waiting for an idiot light if you wish but this is the only complaint I have with my car and cannot believe that Toyota would not offer something like this instead of a navigating package
 

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Hi Pat,
Consider this argument to the contrary:

The battery current meter in the miniscanner lets me know when regenerative braking is effective and when it's cut out due to ABS panic. It also lets me know when I've reached the maximum regeneration I'm going to get. So on the big downhill as I leave my house for work, I can usually push the battery state of charge up about 2% vs. the 0.5% I'd been getting prior. Of course, since they paved over all the potholes a couple days ago, it's not nearly as hard to get it right, but the meter still helps.

Anyway, the original post didn't say the instrumentation was needed to help improve driving technique or mileage. Learning about the Prius is a great practical way to learn a lot of Physics. Lots of people dream of modifying their Prius. Instrumentation can help you understand if a modification you're considering would really make sense.

The Toyota Hand-Held Tester used by the Prius service technicians is proof of concept that such an instrument can be built. But with no documentation, it's hard to figure out the messages used by the ECUs. So wish the group that's working on it good luck!
 

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Discussion Starter #7
Robert, Thanks for your reply and I will endeavor to learn more aboput Graham's mini scanner. I think what upset me most and it's the only complaint I have of my Toyota dea;ership was the service managers treatment of my questions. They were the same as Pat's. "What do you care?" Being WW 2 vintage, this is the first Japanese car I have ever purchased and I truly would loved to have been able to purchase it from Detroit. I am extremely impressed with the whole Toyota organization but this manufacturing for a group of buyers who do not care "how things work" bothers me immensly. I have found that it will take about $362.00 to purchase enough service manuals to get some of the questions answered. I learned more about my cars operation from a VHS tape made by Toyota specifically for their service managers. Not one of the service managers I spoke to had seen the tape. I missed one on "E" bay and waited for a month for another to pop up and I had to go to dealer in Australia for it. And as far as operating car with the "idiot" lites only, even with my "variable" eye glass prescription I can not make out which lights are illuminated because of the distance and have you tried to get your head "closer?"
 

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Hey, P E A C E guys, I'm a gadget freak extraordinaire. I never said all the instrumentation wouldn't be fun or neat. I tried to say it wouldn't make a significant beneficial impact for the majority of drivers. Wouldn't you find it a tad difficult to pay proper attention to your driving while "studying" the screen? Is it worth it for the couple percent improvement that you MIGHT make?

Now if you want to evaluate from the basis of the "WOW!" or "Gee Whiz" factors, I freely admit it is super duper,.

:D Pat :D
 

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Discussion Starter #9
Pat, sometimes for the curiousity factor I use the energy portion of my screen. It's usually left on climate control for any changes in programs necessary. When you were driving a "real" automobile, did you find yourself staring at the tach or guages? I'll bet not, except for the occassional glance at the speedo. Personnally I think you are way off base on your assumptions! This car is no where near as complex to drive as for instance a new Lincoln, Buick or Lexas. Ask the car rental guys how many questions they get on "how do you start the darn things and get the headlights off. They are now with "onstar" much more difficult to drive while trying to keep your mind on the road.
 

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To note, if you have a sufficiently fast internet connection, you can download all you care to from http://techinfo.toyota.com/ (a 1day pass is $10). They have most Owner's Manuals, Recalls, TSBs, Repair Manuals & Supplements, etc. for Toyota/Lexus/Scion sold in the US since at least the '90s.

If you're going for some of the more technical stuff, I'd suggest looking for the Toyota New Car Features guides/manuals as well for the 2001 and the 2004 model years. These guides are written for dealerships to understand the new models and changes coming out in that model year, and can sometimes get rather technical about the features. Yes, it covers all Toyota models, but much of the 2001 guide is on the Prius, and I suspect something similar for the 2004 NCF guide as well.

alternately, the repair manuals for most Toyotas on a CD form do tend to show up on eBay fairly frequently.
 
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