vroom goes the Prius

[hobbit]

[repost from this morning's failed attempt..]
.
With more attention being paid to "sweet spot" RPM ranges these
days, I finally decided to document up the whole tachometer thing
and encourage others to install their own aftermarket units.
.
__ http://techno-fandom.org/~hobbit/cars/tachack/
.
Includes a whole section on reverse-engineering and fixing this
particular tach to be compatible with the Prius signals, but if all
you want to do is buy and install one, all the info is there.
Except where/how to mount it, that's left to personal taste.
.
_H*

[brick]

I found an inexpensive tach at autozone that worked without any modifications. The only problem I had was finding power, so I ended up running the leads all the way over to the 12V plug and installing wire taps. Definitely the best bang-for-your-buck mod since you can do it for under $20 and finally know when your engine is actually running.

[edmarin]

A couple of question, Where did you install it? Is it digital or dial?
Thank you for the idea,
Ed

<div class='quotetop'>QUOTE(brick @ Apr 9 2007, 09:09 PM) [snapback]420517[/snapback]</div>

I found an inexpensive tach at autozone that worked without any modifications. The only problem I had was finding power, so I ended up running the leads all the way over to the 12V plug and installing wire taps. Definitely the best bang-for-your-buck mod since you can do it for under $20 and finally know when your engine is actually running.
[/b]

[ekpolk]

CAN View is a nice way to solve this problem, especially in 04-05 cars with the analog MFD which takes the CAN V output, without the need for any other add-on screens. I leave mine set to a custom graphic display which shows RPM, Coolant Temp, MPG, and Fuel Flow. I particularly like having the real-time bar graph AND digital readout one on top of the other. Sure, it costs a lot more than an Autozone add-on gauge, but you get a lot more for the money too.

[Gadgetdad]

What do you do with the constant RPM changes with the variable transmission? I watch my ScanGuage hop around as the transmission adjusts to the demand. I'm not convinced a tach would be easy to read as in a traditional engine linked to a non varable transmission.

Lee

[hobbit]

The "instrumented people" have been recently agreeing that staying
between 1500 and about 2300 RPM runs the engine most efficiently.
Let it drop down much south of 1500, and you're falling off the
efficiency curve. The top end is a little more open, but letting
the cruise control ram you up well over 3000 will donk your MPG
numbers too, so manual control on the highways works out better.
.
It's actually a little easier to read, because in that range you
can think of torque as pretty much a constant.
.
_H*

[aaf709]

<div class='quotetop'>QUOTE(edmarin @ Apr 10 2007, 04:19 PM) [snapback]421191[/snapback]</div>

A couple of question, Where did you install it? Is it digital or dial?
Thank you for the idea,
Ed
[/b]

I have seen pictures, but I have no link. I know that someone bought an A/C vent cover that has the spot for the shift lever, BUT they got one for a Japanese Prius. This mean the vent cover replaced the cover on the right side of the MFD. He put the tach in the cavity where the shift lever would normally go.

[ekpolk]

<div class='quotetop'>QUOTE(Gadgetdad @ Apr 11 2007, 12:00 AM) [snapback]421312[/snapback]</div>

What do you do with the constant RPM changes with the variable transmission? I watch my ScanGuage hop around as the transmission adjusts to the demand. I'm not convinced a tach would be easy to read as in a traditional engine linked to a non varable transmission.

Lee
[/b]

This is one reason why I like having the graphic display option offered by CAN View (bar graph format, not like a traditional round gauge). Personally, I think that one of the reasons why Prius has no tach, and the other HSD cars replace the tach with an output gauge, is the engine's seemingly odd rpm response. But remember, it's only odd if you're expecting to see a response like you do in a traditional multi-speed automatic. Once you start to learn and sense the rpm behavior of an HSD car, suddenly what you see the rpms doing starts to seem perfectly natural, which it is, for this car (and other CVT designs as well). The computers know exactly what they're doing, and after a while, the driver can learn this too. But I would expect such learning to be much slower if your only observable data is rpms in purely digital form.