Over Drive

[ThePair]

I'm not sure that either of those would help with a Sienna.

If you know otherwise, please let me know!

Originally Posted by ThePair

I'm not sure that either of those would help with a Sienna.

If you know otherwise, please let me know!

And I will add to Bill's post that the ScanGuage people are very helpful also. I emailed them several times before deciding to buy a unit. Like you, I have a 2006 year model, and it can give me all sorts of information. Probably everything that goes through your vehicle computer can be displayed on the Scan Guage, but only 4 things at a time. Thank goodness, or I wouldn't be able to watch the road.

Check out: http://www.scangauge.com/

[Bill]

Have you emailed either one to ask about it? I know the guys at Aeroforce Technology are really helpful.

Bill

[ThePair]

I know ScanGauge does not show Trans temp for the Sienna -- I asked them.

The AI...I didn't even see the Sienna listed anywhere on their site, so I wasn't sure it would work. I'll need to look into it a bit more...

Wouldn't it be nice if all vehicles with a towing package had the transmission temperature displayed on the dash?

Overheating a transmission due to overheating while towing with no transmission temperature gauge is a design flaw that should be covered under warranty for the life of the vehicle. After all, the factory intentionally chose to hide the transmission temperature from the driver.

[Wavery]

If I keep buying all these gadgets, I'll never be able to buy a later model TM.......

I actually installed a temp guage on my trans when I installed the trans cooler but now you've got me thinking about this stupid thing......... I used to have one of the older versions but my (portable) tool box got stolen a few years ago and that went with it.

I’ve been designing and selling industrial power transmission equipment for 3+ decades.
Industrial applications are “purer” in the sense we don’t deal with automatic transmissions, differentials, A/C compressors, power steering, ECUs, sensors, vacuum leaks, and all the other crap associated with today’s automobiles, but the basic energy principles are the same.

I’ll try to put this in a way that everyone gets…

Horsepower and torque are like weird cousins… they can’t exist without each other, but they really aren’t the same, and the balance of each can vary greatly in any situation.
I’ll give a few basic examples in extreme to try to help everyone understand what I’m getting at…

Example of torque:
Theoretically, if you take a 1hp/1750rpm electric motor and mount it on a table and turn it on, it produces 1HP and spins at 1750rpm. A strong guy with good gloves could probably stop the 5/8” diameter spinning shaft with his hands, since the motor itself produces very little torque.
Now take this same 1hp/1750rpm motor and connect it to a 50 to 1 reduction gearbox.
The first thing you will notice is now the output shaft of the gearbox is probably about 1 1/2” in diameter. If you could measure the power at this shaft you would probably now have something like 3/4hp (loss due to drive inefficiencies/friction) and the shaft would be turning at only 35rpm.
(Piece of cake to stop this, right? …. Wrong! If you attempted to stop this shaft with your hand you would wind up in a bloody ball in the corner of the room.)
While the output HP has actually been reduced, the output torque is now many times the input torque.

Another example of torque due to gear reduction is your basic electric drill. Very little input torque, but gobs of output torque.


Example of HP:
Today’s modern Formula 1 race cars produce roughly 800hp from a rather small 2.4L V8. To produce this HP, the engine runs at very high rpm….idles at 4000rpm and is governed to a max of 19,000rpm. This engine produces tons of HP at these high rpms, but very little torque due to it’s very high rpm powerband and limited displacement. When racing on a hilly track, the main thing that gets it up the hill is momentum, and the HP keeps this momentum going as long as the car is moving at a good rate of speed.
Now if you could theoretically use this same 800hp F1 car and try to tow your TM from a standing start up the same hilly track, you will find you won’t get very far due to the very limited torque of the engine, along with the high gearing of the tranny. (Not the ideal towing package!)

So in summary, you can have lots of torque with very little HP, as well as have lots of HP with very little torque. You can’t have one without the other, but the amounts of each can vary greatly, depending on the application.

Basic “rule of thumb” engine principles:
Smaller, faster rpm gas engines produce very little torque.
Larger, slower rpm gas engines produce lots of torque.
Diesel engines produce even more torque at almost any displacement, and at lower rpm than gas.
(Diesel engines will usually produce less HP at a given displacement than a gas engine, but with much more torque.)

So with some basic understanding of the above, you could then theorize that if you could take the same load and course (lets use the E350 towing a TM, going from NOLA to HTX, and use cruise control to maintain speed (no human variable input)) but have three different setups… the first would be the v6, then the v8, then the v8 diesel. Basically the only thing different is the engines, which of course all offer different HP and torque numbers.
We'll say they all weigh 8000 lbs and the cruise is set to 65mph.

The v6 will struggle the most trying to stay in the powerband and produce the HP and torque required to go up the hills with the load and maintain the set speed.
(The slower the vehicle is moving, the more torque required to get it moving.)
(The faster the vehicle is moving, the more HP is required to keep it moving.)

The v8 will struggle less due to the additional torque and HP.

The v8 diesel will struggle even less due to its tremendous torque at the lower rpm ranges.
I doubt that the engine/tranny would even react to the hills/overpasses.

In simplest terms, torque is what starts your vehicle moving, or headed up hill, or accelerating, while HP is what maintains this once moving, but they both must be present in certain degrees in both instances.




Now getting back to the overdrive issue…
To successfully use OD while towing, you need to be very conscious of many variables.
First, you would need enough HP to maintain speed of your rig without the need to downshift to increase torque to climb hills/overpasses. Most smaller vehicles (v6’s) would lack this ability since they lack HP/torque, and a downshift would be required to produce more HP/torque to maintain speed up the hill. The downshift would actually produce more HP from the engine as well since the engine would move into the “sweet spot” in its powerband. This constant changing is what you want to avoid.
This means you would need to find that correct highway speed for your load and your TV to produce enough balance of HP to lock the converter without it needing to kick in and out. While I may agree that today’s TVs with larger v8’s and for sure diesels, would have this ability under good circumstances, the v6 would certainly not.

Originally Posted by harveyrv

I actually installed a temp guage on my trans when I installed the trans cooler but now you've got me thinking about this stupid thing.........

Same here. When I rebuilt the engine in my Astro, I went ahead and installed the trans cooler, temp gauge sending unit, and routed the wire, while it was easy to do. It was a few months later when I actually got around to actually mounting the gauge inside and connecting it all up.

The one gauge I find myself still wanting is a tach, so this little gadget may be the ticket.

I'm assuming you can arrange the gauges in groups of 4...say one page of 4 with fuel economy stats, and maybe the second page of 4 would be for various temps, and then maybe a third with engine performance, etc??
I also really like the idea that it's portable, so you can move it from one TV to another. Very cool.

Originally Posted by ED-n-KEL

Same here. When I rebuilt the engine in my Astro, I went ahead and installed the trans cooler, temp gauge sending unit, and routed the wire, while it was easy to do. It was a few months later when I actually got around to actually mounting the gauge inside and connecting it all up.

The one gauge I find myself still wanting is a tach, so this little gadget may be the ticket.

I'm assuming you can arrange the gauges in groups of 4...say one page of 4 with fuel economy stats, and maybe the second page of 4 would be for various temps, and then maybe a third with engine performance, etc??
I also really like the idea that it's portable, so you can move it from one TV to another. Very cool.

I am not sure whether you are referring to the Aeroforce that Bill has, or the ScanGauge that I have, but I will give some details on the ScanGauge II.

On a lot of vehicles when you plug the unit in, a bunch of info is automatically available. Outside of the regular gauges, some of these are: Fuel Pressure, Throttle Position Sensor, MPG, GPH (Gallons per Hour), Ignition Timing, Air Intake Temperature, Engine Loading, etc. In addition to these, you can plug in a code and get: Transmission Temp., Torque Converter Slippage, Transmission Gear Ratio, and a bunch of other stuff. Basically, most anything that goes through the vehicle computer can be displayed on the Scan Gauge II.

In the gauge mode, 4 things can be displayed at 1 time. I have Transmission Gear Ratio (to know exactly what gear I am in), Torque Converter Speed Ratio (indicates whether the torque converter is locked or not), Current MPG, and Transmission Temperature. You can put any reading in any location. You can also reset the Current Mode at any time......I do this to see what my mileage is on 2 lane road @ 55 mph vs. a stretch of interstate @ 65 mph, or watch the mpg go south with a couple of stoplights in a hilly town.

With 2 button pushes, I can switch to the Trip Mode. There are 4 different time periods that can be viewed. Current (since the engine was last started), Today, Previous Day, and Tank. Some of the things viewed with these are: Hours, MPG, Max. Water Temp., Max RPM, Max. Speed, and I can’t remember exactly what else. When viewing the Tank Mode, it will also indicate total gals. of gas used, gals until empty, total hours and hours until empty, and cost per mile.

When setting up the ScanGauge, you need to enter the gas tank size, type of fuel, engine size, and a couple of other items. The 1st and 2nd gas fills need to be entered also, and subsequent if you want to keep the Tank Mode accurate. The data entered during fill up is number of gallons (until you get a good overall average), and cost per gallon. I no longer need to adjust the gallons, as the ScanGauge is within a 10th or 2 either way of my actual fill-ups.

There are also multiply display colors available, as well as a custom color function.

If a check engine light comes on, the ScanGauge can read the malfunction code. You can also reset the check engine light via the ScanGauge. That in itself would have saved me $70 diagnostic fee when I didn’t tighten my gas cap enough on another vehicle I had.

When I 1st got the ScanGauge, the functions were overwhelming for a bit until I read the manual and experimented with it. Now, it is a neat little tool to try and tweak my gas mileage, and also it is a better way to keep tab on my truck critical information.

Toyota 4 Runner V8 (2008).
Here is, to me, alarming information on page 167 of my factory owners manual.
"Do not continue hill climbing or hard towing for a long time (how long is "long"?) in "3", "2", or "L" position. This may cause severe automatic transmissin damage from overheating. To prevent such damage, "4" position should be used in hill climbing or hard towing".
Now my interpretation of this statement is to use overdrive for towing unless climbing a short hill!
This is contrary to what I have been told in the past and sure contradicts good information throughout this thread.
I contacted my local Toyota service department and they said to downshift on hilly terrain.
I contacted Toyota customer support, they said to downshift when on hilly terrain.
Of course I agree with the downshift policy.
I suggested the customer service folks might want to take a look at the owners manual and consider a change in their statement or they are goiing to pay for a lot of burned up automatic transmissions.
They said they would make a note of it, yeah sure!