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-   -   any way to get SGII to show which gear I'm in? (https://ecomodder.com/forum/showthread.php/any-way-get-sgii-show-gear-im-2348.html)

blackjackel 05-15-2008 01:52 AM

any way to get SGII to show which gear I'm in?
 
I heard the most fuel efficient way to drive in an automatic is the absolute slowest speed on the highest gear, I Want to know where that is, is there any way to make scan guage let me know which gear I'm in? I know that you can find out via RPM but I don't know how to do that and my searches on the forums have been fruitless :/

Daox 05-15-2008 06:59 AM

I'm pretty sure there is no way to do this.

dcb 05-15-2008 08:51 AM

The information might be on the obd bus, but that is a long way from getting a scangauge to display it, unless you are ron delong, or his latest version allows you to display any pid you want. Any open source obd scanner software could be adapted to display it (again, assuming it is available on your car)

$19F4 Gear box ratio
$19F5 Current gear
http://www.obdproject.com/OBD2Info/Specs/pidlist.htm

IndyIan 05-15-2008 09:17 AM

I assume you have a 5 or more speed automatic? Just count the shifts, if you are using 30% or more throttle you should be able to tell. I also find in my auto neon that there is a big difference between the top gear with the torque conveter locked and top gear without it locked. Its about 3L/100km.
So the faster you can get your tranny locked in top gear the better your mileage will be so I accelerate from a stop and pulsing at about 40% throttle. My car will hold the torque converter locked to about 60% throttle at 50mph but its a 3 speed, most cars will unlock with much less.
Most automatics dive to the highest gear anyways with light throttle, so you have to train yourself for how much gas you can give without forcing downshifts. But for highway I still say go for the converter lock up and try to keep that.
Ian

dcb 05-15-2008 09:26 AM

Hmm, what about a lockup indicator (an led on the dash that lights up when the torq converter lockup solenoid is energized). That would be basically an LED, a resistor, and some wire.

Who 05-15-2008 11:12 AM

My wish would be some type of ratio of RPM to speed (KMs or miles). It could be Speed per 1000 RPMs or just a simple RPMs/Speed. That would be a simple way to know if there is lockup and also give a fairly static ratio number that should correspond to which gear you are in. The major plus would be that it wouldn't be vehicle dependent as that information is now. From what I've been told the SG can't display a calculation based on two input items.

blackjackel 05-15-2008 11:21 AM

Quote:

Originally Posted by dcb (Post 25986)
The information might be on the obd bus, but that is a long way from getting a scangauge to display it, unless you are ron delong, or his latest version allows you to display any pid you want. Any open source obd scanner software could be adapted to display it (again, assuming it is available on your car)

$19F4 Gear box ratio
$19F5 Current gear
http://www.obdproject.com/OBD2Info/Specs/pidlist.htm


I guess i'm in luck cause I have the latest version (with xguage). If I'm right, you want me to program those pids into xguage:

http://www.scangauge.com/support/pdfs/SGMan5_0.pdf

I'm assuming that I should enter the PID into where it says TXD in the manual link above... am I right?

blackjackel 05-15-2008 11:29 AM

Quote:

Originally Posted by IndyIan (Post 25988)
I assume you have a 5 or more speed automatic? Just count the shifts, if you are using 30% or more throttle you should be able to tell. I also find in my auto neon that there is a big difference between the top gear with the torque conveter locked and top gear without it locked. Its about 3L/100km.
So the faster you can get your tranny locked in top gear the better your mileage will be so I accelerate from a stop and pulsing at about 40% throttle. My car will hold the torque converter locked to about 60% throttle at 50mph but its a 3 speed, most cars will unlock with much less.
Most automatics dive to the highest gear anyways with light throttle, so you have to train yourself for how much gas you can give without forcing downshifts. But for highway I still say go for the converter lock up and try to keep that.
Ian

Just came back from a quick wikipedia read of torque converters, and with my basic and limited understanding I ask: How can I tell if my torque converter has locked? How can I tell when it has unlocked? And are you saying that I should drive as slow as possible with it locked (highway)?

Also, for city, are you saying I shouldn't accelerate slow? I should give it a good push to get the torque converter to lock early? (not floor it, but yeah).

Who 05-15-2008 11:57 AM

Quote:

Originally Posted by blackjackel (Post 26019)
Also, for city, are you saying I shouldn't accelerate slow? I should give it a good push to get the torque converter to lock early? (not floor it, but yeah).


There's going to be an envelope. Accelerate too slowly and a bigger percent of travel time and distance will be spent in lower less efficient gears. Accelerate too quickly and you could be running open loop and you'll also be producing a lot of extra heat that doesn't necessarily translate into forward motion. The challenge is to find the sweet spot and that could vary with load and terrain.

dcb 05-15-2008 11:57 AM

Quote:

Originally Posted by blackjackel (Post 26016)
I guess i'm in luck cause I have the latest version (with xguage). If I'm right, you want me to program those pids into xguage:

http://www.scangauge.com/support/pdfs/SGMan5_0.pdf

I'm assuming that I should enter the PID into where it says TXD in the manual link above... am I right?

There is some info here, but it doesn't look like a straight forward PID mapping and has vehicle specific settings for gear ratio:
http://www.scangauge.com/support/pdfs/XGAUGE.pdf
I don't know xgauge, so all I can say is maybe, do some experimenting, good luck, and report back :)

blackjackel 05-15-2008 12:48 PM

Quote:

Originally Posted by dcb (Post 26027)
There is some info here, but it doesn't look like a straight forward PID mapping and has vehicle specific settings for gear ratio:
http://www.scangauge.com/support/pdfs/XGAUGE.pdf
I don't know xgauge, so all I can say is maybe, do some experimenting, good luck, and report back :)

just got off the phone with scanguage customer support, told me that ron is out of town for now and that he'll be back on monday... you say "his latest version allowes you to display any pid you want", what did you mean by "his latest version" ??? does he have a newer scanguage firmware or are you talking about the new scan guage itself (xguage) ?

anywho I've been told that I cant find anything out till ron gets back, so I'll be talking to him on monday, stay tuned folks!

dcb 05-15-2008 01:14 PM

Quote:

Originally Posted by blackjackel (Post 26038)
..you say "his latest version allowes you to display any pid you want"...

I said *unless* it does allow you to display any pid you want, I have no idea, I don't have his latest version that he is shipping.

tasdrouille 05-15-2008 01:34 PM

With the xgauge you can display any pid you want. The tough part is just getting a hold of how to interpret the response and display it properly.

Have a look at this Xgauge coding document.

IndyIan 05-15-2008 02:01 PM

Quote:

Originally Posted by blackjackel (Post 26019)
Just came back from a quick wikipedia read of torque converters, and with my basic and limited understanding I ask: How can I tell if my torque converter has locked? How can I tell when it has unlocked? And are you saying that I should drive as slow as possible with it locked (highway)?

Also, for city, are you saying I shouldn't accelerate slow? I should give it a good push to get the torque converter to lock early? (not floor it, but yeah).

As you probably read a torque converter is basically a subsitute for a manual clutch, so it allows you to idle in gear, gives you a smooth start from a stop.
They basically work like a turbine connected to the engine throwing oil at a turbine connected to the transmission. As you can imagine their is always some difference in the speeds of the two turbines which is wasted energy. So to get good mpg they have converters that lock the turbines together and have no waste. Most cars only do this in top gear although I believe some do this in every gear (old mazda 626's).
Watch your rpms as you get up to speed on the highway, your car will shift into top gear and then shortly after the rpm's will drop a couple hundred rpm more and now the converter is locked. Now rpms move in lockstep with the speedometer. There is no slippage so your not losing hp into the converter.

Also torque converters are more efficient at higher rpms so using 30% throttle gets some revs going and less slippage therefore less waste and you get up to top gear and locked quicker.

With the automatics we can't give 60% throttle at 2000rpm in every gear like many here so we can't always run our engines in the most efficient way but we can pulse and glide just as efficiently in top gear if the converter is locked.
Once you know what to look for you will easily be able to tell when the converter is locked.
Your car might lock the converter in every gear too which is much harder to detect so an Xgauge showing this would be useful. I think you'd find that you get lock at 3000rpm for example then you know to make the engine rev more on acceleration.
Hope this helps,
Ian

JohnnyGrey 05-15-2008 04:42 PM

Find a pinout diagram for your transmission's wiring harness. By tapping one or more of the proper solenoid wires, you can get an LED to glow when you're in top gear. Don't attempt this if you think you'll screw something up.

RH77 05-15-2008 06:29 PM

Just through observation and the shop manual, I've noted the following in the Integra:

-TC happens at 35 mph or higher (at full operating temp)
-There are 3 levels of TC lockup: partial, half, and full
-Gears 2-4 are effected
-Hill logic control is independent of lockup

The last point helps me know about lockup behavior. Climbing a hill or on-ramp, the TCU will hold the 3rd gear, for example (unless the throttle is lifted). The the unit will then determine that a constant RPM allows some degree of lockup.

The telltale is the shift to 4th. In most vehicles, shifting gears in lockup is jolting -- the full force of the engine output is placed on that gear change (no cushion from the converter). Some cars perform a brief unlock, shift, re-lock -- which is still noticeable and often a hard shift.

Another "seat of the pants" way to tell if you're in lock is to give the vehicle a little throttle pressure and back off. If the tach gently moves 100-200 RPM or more, it's generally not locked (if not, then it shifted out). If I EOC, the TCU gets rather confused and denies lockup until such distance that the Math checks out for the hill-logic control. During full warmup and no EOC, TC lock is deliberate and noticeable right at 35.

I tend to get up to TC lock (35 mph) briskly -- since the ECU retards the timing on every upshift for a "smoother" engagement, FE drops at each shift. It's built-in and I can't do anything about it -- it's probably not a lot.

Some cars react differently, but I've tightened the throttle linkage to the max extent. This creates more fluid pressure for tighter shifts, earlier (and more noticeable). Some will argue that it causes earlier kickdown. It all depends if the vehicle has an aggressive Transmission Control Unit -- in my case it doesn't. I'm also told that harder shifts are better than slipping ones for longevity.

BTW, what kind of car? GM generally has a smooth, sliding action to their TCs and unlock with the slightest lift...

RH77


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