Good work guys. I'm going to wait and see how AngryDad fares with his updates before I pull the trigger. But getting the instant mileage to go in 1 mph increments is big to me. This 5 mph increment is worthless. Too many variances there. I agree it's not an important issue in the grand scheme of the "hack", but it's important to me.

I'm used to paying good money for this kind of work too. If I can't do it myself, and have to hire it out, it costs big bucks. Props to AngryDad for his opensource "freeware".

 

who else checks this thread many times of the day to look for a post from angrydad? lol

 

*raises hand*

 

Can someone please check to see if they can see the trip info in the diag screen and let me know? Also let me know if you have angrydad's first hack installed or not.

 

I do not have trip info in the diagnostics screen. It is greyed out. The only modifications that I have made to the software were angrydad's patch and a custom startup .bmp.

 

OK, so anyone without angrydad's patch that DOES have it? Bluenoise seems to be the anomoly here so far.

 

I'm running the one posted here, so maybe kennyc still has his Trip Information screen, too. If not, it might just be because I'm running the 3.30 stuff.

 

Just an update for you all...

Doing all this seems to throw errors in the navi.. If you go into Diag and then hold menu for 5 sec and when the next screen comes up, one of the option lets you look at the log. It has failures for navi.exe and the HMIxxxx. file...

Also on this mod, the AC control does not work very well.. The only buttons that do is the fan speed and the high does not even turn it to high... The other buttons display correct when you select it via the buttons, but when you press them on the touch screen nothing happens..

Also, my F-CAN still shows OK with ERRORS..

Arg! Grant it these all work, just wish they didnt throw errors. The AC thing does not bother me too much but is a bummer. So close yet so far.

 

I'm lucky. I work with the guy. So when he finally cracks that damn "ok" button I'm the first guinea pig to try it on my TL.

 

For me the ac on and off works as does the fan speed as you describe. However I don't really care about the A/C controls as they all have dedicated hard buttons on the console.

The only thing that really matters to me is the slightly easier access to the diag menu and the trip computer.

 

anyone would like to help me please? lol would someone send me a disc of this?
~Jason

 

Well after tracking the Navi Trip for a while it seems it is more confusing than useful.
The Navi Distance to Empty seems to flucuate all over the place and it depends on when you read it.

I took another reading in my car before I left work to go home for lunch and the Navi DTE showed 213. Then when I got back to work after lunch, 23.3 miles round trip, I forgot to read it. I turned the car off, remembered and turned the ignition back on. The Navi DTE showed -- so I started the car. Then it read 230?? So I drove 23.3 miles and Navi thinks my range increased by 17 miles.

This isn't the first time I've seen a weird drop. Previously Navi read 318 DTE and then after 12.4 miles it read 257.

All the while the MID DTE shows a pretty consistant steady decrease as I drive, as it should.

However AMPG and Miles track very well with MID but the time is always a bit higher on the MID. So far over the course of 4 hours, there is a 7 minute difference with MID reading longer.

So at this point I'm pretty much going to give up on the Navi trip meter and use it purely as a secondary trip meter for AMPG and to look at the cute bouncing blue IMPG line. I also doubt the IMPG but have yet to be able to really test it.

Oh well, cool looking but not really useful.

 

To determine miles per gallon certain values will need to be known:

Fuel pressure
Injector size
RT injector pulse lengths
RPM
Wheel speed (or overall distance traveled)
Wheel size (or overall distance traveled)

If any of the above changed from when the software was developed the calculation will be off. It seems very odd though that it calculates inconsistant data. Inconsistent data, even at 0.1mph resolution is worthless data. It almost seems like the function was never completed for use and it still contains bugs.

I find it impossible that the car runs more efficiently at 75mph then at 65mph. Even with the addition of continously variable valve timing the engine is not going to perform that much better at high speeds.

To get better gas milage your IPW would have to drop from 65 to 75 mph. This can be easily monitored using a scan tool. If your IPW is 100ms at 65 mph and it's 100ms or more at 75mph then you know the calcs are completely wrong.

 

It seems to me the engine is just running at a more optimal RPM for efficiency. It is burning more gas at the higher speed, due to additional air resistance, but I thought that maybe the engine/TQ/Transmission is making better use of the energy in that additional gas. I can try watching the ml/s number at the two speeds and see how it compares in relation to the mm/s numbers. It's some simple math to figure out the instantaneous MPG from that.

 

You can typically expect 25% less fuel economy between driving 55 and 70mph. Like I said, I'm sure variable valve timing reduces this motor vs the 'standard' combustion engine, but I doubt it actually increasses efficiency.

Also, keep in mind that only 10-15% of the power created by the motor actually reaches the ground, meaning that it would take a HUGE increase in effieciency to make a noticable difference difference, especially of 10mph.

In my car (Infiniti G35) I can watch my instantanious fuel economy on a bar graph. The economy is very smooth, and hardly moves when traveling at highway speeds. Next time I'm on the highway I'll grad 55, 65, and 75 mph readings to see how much fuel economy I lose. It'll be nice to see some 40+ mpg numbers though!

 

I tend to agree with kpierson about the instantaneous calcs. All empirical tests I have performed and others have related on this board seem to indicate better fuel economy around 55 MPH with it going down by several MPG(5 or more) when going up to 75MPH. This is the same reason I expressed my doubt about the instantaneous graph above.

The biggest reason I doubt it is because I have driven nearly 100% highway on a tank (during long trip) at near constant CC regulated speeds of 70-80 and at best gotten 31 MPG. If I were to believe the IMPG guage I would expect 40+ MPG at that speed.

 

I should've given it more thought. You guys are right, especially since we're running fixed-ratio transmissions. I think it could be a different story with CVT as the computer can find the ratio that strikes the best balance between RPM, fuel use, and speed. As kpierson mentioned, there has to be more fuel used at the higher RPM and the higher RPM is necessary for higher speed, given the fixed drive ratio.

Brian, I've gotten exactly the results you mentioned on an extended freeway drive where I set the CC at ~73 MPH and average 31 MPG over the drive. I'm going to try a quick test next time I'm on the San Mateo Bridge (long, flat, and straight) where I reset the MID trip computer once I'm at a fixed speed. That's when the Navi TC claims 40-45 MPG. I'll see what the MID says is the average then, too. I bet you're right that the Navi TC is being rather liberal with its claims.

 

Even with a CVT there has to be a final gear ratio that can't be improved upon. They are only infinately adjustable between two points.

 

The only flaw in your theory about speed v. economy is that it doesn't take into account factors beyond gearing and resultant engine rpms.

To say that an engine will automatically get better mileage at 55mph than at 70mph (for instance) is to say that it would then get much better mileage at, say, 20mph in that same gear. Which it wouldn't, because of a host of factors, including fuel flow rates, airflow rates, combustion efficiency, internal (and external) frictional effects, airflow dynamics, and on and on.

Think of it like this: Put your manual transmission in 5th and lug along at 15mph. It ain't gonna get very good mileage, since the engine is dealing with load under less-than-optimal conditions. It's not flowing enough air to support efficient combustion, it's straining against the loads imposed by the weight of the car and the friction of the gears meshing, etc. Now run it up to 50, and you won't need instruments to tell it's operating more efficiently and using less fuel per mile traveled.

Go one step farther and you'll realize there is a "sweet spot" at which a given engine/vehicle combo will operate most efficiently. At this engine speed (which may translate to 55mph or 70mph or whatever), the vehicle will be able to overcome frictional losses, plain old inertia, air resistance and other factors to operate at max efficiency. Above - and sometimes even below - that speed, it will generally return lower fuel mileage.

The point is that you can't say across the board that a vehicle will absolutely get better mileage at 55 than at 75.
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Does anyone know how the "History" function in the Trip Computer is supposed to work?

I've noted that if you check "Reset with Refuel", the History button is usually greyed out, indicating the TC doesn't store any historical data.

But when you reset the Avg. MPG manually by touching that button on the TC screen, it seems to keep info only for a day or two at most.

This doesn't make sense to me, since it seems like it should keep a running history until you clear it (the History). That would be for things like keeping track of mileage for a whole road trip, for instance.

Maybe someone here has used this TC on another Honda vehicle and knows what it's supposed to do (?) Or is this another bug in the hack?
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You are overcomplicating the rule of thumb (it is by no means my theory). It applys to highway driving (constant cruising speed). If you are in your top gear (overdrive, 5th, 6th, etc) the added engine power needed to raise the speed of the vehicle and overcome the added wind resistance will decrease fuel economy, period.

Remember that when you go from 60 to 70mph you are adding an additional 10mph of wind resistance on a less then aerodynamic object (tall wide box).

 

I haven't watched it closely but I was under the impression that it just saved the last data from when you reset the trip computer. So if you reset it, you will always have the last data saved until you reset it again. This makes it very easy to monitor from tank to tank, especially when combined with reset with refuel. I think when you select reset with refuel it automatically clears the current history and will then save new history when you refuel next.

 

Anyone wants to send me a copy of a disk? or something?
~Jason
*please?

 

Thanks, Brian, but I'm talking about the "History" data on the second screen page of the TC display. The AMPG reading is on the first page, then there is the History button at the lower left.

If it just keeps the data from the last time you reset it, then it just does the same thing as the AMPG on the first screen! I figure it has to be some kind of cumulative total, but mine doesn't seem to hold the data very long. It DOES show a date range, and mine now shows 2 days worth of data, even though I reset the AMPG during those two days.

I can't figger it out!
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AngryDad - any update?!

 

I know which history you were talking about.

As I said, when you hit the reset button on the Navi TC, it just stores a snapshot of whatever your data was at the time you reset it and saves it until you reset it again. It doesn't update that any further. So like i said, when you reset on fillup, you will now have a history of exactly what the overall results of your last tank was, until you fillup again. (at least this is what I think it does)

 

I was mentioning the CVT only because it allows the ideal drive ratio for any given speed and engine RPM. Regular transmissions cannot do that. So, you're in top gear (fixed ratio) regardless of 55 vs. 70 MPH. Meanwhile, a CVT can keep the engine at, say, 2500 RPM at either speed, if that's where the engine is running most efficiently.

So, with this in mind, does the additional speed automatically equate to more fuel usage per distance travelled? I don't know, but here's what I'm wondering:

(Hypothetical)

You're going 55 MPH at 2,500 RPM and the engine is burning 3 ml/second. You increase your speed to 70 MPH, but engine stays at 2,500 RPM. However, due to additional forces of resistance, your engine is now burning 3.6 ml/second to maintain that RPM. So, a 27% increase in speed is using 20% more fuel. This would result in better mileage at the 70 speed compared to driving 55. Of course, these numbers have all been pulled from thin air, so they could be completely implausible. Nonetheless, that's why I was mentioning the CVT factor.

Now, in an attempt to apply that to the TL, what if at 55 MPH, the engine isn't making the most efficient use of its fuel at the corresponding RPM? Let's say it's running about 10% efficient. But, at 70 MPH, the engine is closer to its happy point and it's 13% efficient at that RPM. So, a 27% increase in speed increased the engine efficiency by 30%. Could that be enough to overcome the additional resistances such that fuel efficiency is increased? Again, I'm only pulling out numbers that seem plausible to me and I'm asking because I'm curious. I'm not claiming any sort of accuracy here.

 

I'm by no means a CVT expert but I would guess that the gearing runs out around 55-65 miles per hour (if that high). At that point, the only way to go faster would be to raise the RPMs.

If you could keep the RPMs constant and increase your speed from 55-70 I wouldn't think you would gain any efficiency based on the poor effieciency of the motor to begin with coupled with the added resistance of air.

I like your thinking though, unfortunately I think the only way to find out for sure is to find a CVT vehicle and hit the road!

 

wow, you guys have really gotton technical. my MDX that has a trip computer, it has a bunch of data about configuration for the trip computer in the diganstiocs menu. If you want, i can take a photo of it and post it, and also that trip computer is pretty accurate at time, but not on ditance that can be traveled, it vares by 30 miles. As for the history button, in the MDX, with fuel reset, it isn't greyed out and has the data in it.

 

I just checked the history at lunch and it is exactly as I stated. My history still has the exact values the trip computer was showing before it reset itself the last time (upon refueling). So as I stated the trip computer history is static and is a time stamp from when you hit the reset button last.

As to the dates, mine did in fact only show 2 days also but that may because I was resetting mine frequently due to testing it out. I haven't touched it in about a week so when I fill up this afternoon I'll be able to tell if it in fact keeps the correct data ranges or not, but I do know the history is working exactly as I expected.

 

I'll have to ask a coworker who just bought a new Maxima last week. It has the CVT, but, strangely, it has a manual shift mode similar to the 5AT TL. I don't know what it does exactly, but it would be interesting to take another test drive with him. He knows very little about cars and only chose this car because it had the features and price he liked. If I ask him anything technical about the car, he just shrugs his shoulders and says, "As long as it works, I don't care."

 

I confirmed it today. After filling up, the trip history showed the final values from just before i filled up and the current trip counter was zero'd. THe history stayed the same all the way home.

 

As promised, here you go.

Sorry for the low resolution in the last half of the test but I got tired of documenting all the time and saw how noisy the Navi TC was being (in regards to DTE) and sorta gave up.

As you can see the Navi DTE is overly optimistic at the beginning and then overly conservative at the end with a lot of noise in between.

 

OMG, it actually works.. I just updated my picture and the trip computer on my navi..
thanks guys.. Here is my photoshopped picture


edit by datmrman:
----------------------
Thanks for the nice splash screen. I have moved it to this thread Navi Hack BMP's (Images). This is where it belongs.

Here is the direct link to the picture

 

i think i know why there exist a difference between Remaining Milage from MID and Navi Menu..

One of them takes the reserved portion of the tank in account, and one doesn't... I tried a few times resetting and usually, itz more clear when you finish the tank.. Can someone double check?

 

any update from angrydad?

 

I ran both of them down to zero earlier in the week. The MID went to zero 1.4 miles before the NAV did. A difference of less than 0.07 gallons.

There is still more than 2 gallons reserve in the tank when the range reaches zero.

I really don't see a reason to worry about the differences when there is that much of a reserve.

 

See this thread

/AngryDad

 

could anyone help me with this navigation trip computer? please?
lol
~Jason

 

Hi Guys,

I just did the Trip Computer and A/C Navi hack and I noticed that under the A/C controls the mode selection does not work. The mode selection is the one where you select the direction of the air flow (front vents, floor vents, windshield vents). The fan speed selection works, but there are only 5 settings, versus the total of 7 available fan speeds. The A/C on and off also works. Only the mode selection doesn't seem to take effect when pressed. Is this problem happening only for me or is this just a limitation of the hack?

Thanks.