SGII shows best acceleration load
 

We now have the ability to determine fuel consumption during acceleration under different engine loads. It’s not cheap, as it requires you have access to a Scangauge II with v. 4.06 performance upgrade, a second SG or UG to show engine load during testing, and a cable to piggyback the two devices. I got my SGII v. 3.17 upgraded by Linear Logic for $18 under the Ecomodder Group Buy (regular price for the upgrade is $25).
The upgraded SG-II adds performance data logging, so SG owners can log fuel consumption during cruising and acceleration. I thought I could test fuel consumption during acceleration pulses with the SG alone, but in performance logging mode, it uses all available displays to show time, distance, speed, etc. That meant I couldn’t display engine load to keep acceleration consistent. I already own an UG, so I bought an OBD-II cable splitter, with one J1962M end and two J1962F ends, to plug both my SG-II and UG into my 2006 Scion xB. The UG was used solely to display % engine load during data collection. The SG collected performance data.
SG performance mode automatically logs speed, distance, and time (every .4 seconds for 24 seconds) , plus one user-selected parameter. For the testing, I chose GPH as my user-selected parameter, since the logged time intervals are consistent, while fuel consumption logged as MPG varies with varying distances traveled at different speeds during pulses.
I did three test runs in the same direction in the same location on the same day, November 23, 2011. The road was dry, temperature was 55 degrees F, winds <10 mph, skies cloudy and overcast. I accelerated from 25-40 mph in 4th gear on each run, and added the fuel consumption for the cumulative time during each pulse. One pulse was at 82% LOD, one at 90% LOD, and one at 70% LOD. I’ve been using 83% LOD in my 1NZ-FE engine, having determined long ago that it gives better results than 75% LOD. After each run, I transferred the data to a notebook and then to a spreadsheet.
Following are performance data from my 82% LOD pulse. First column is elapsed time. Second column is GPH fuel consumption rate. Third column is distance traveled. Fourth column is speed. Fifth column is actual fuel consumed during the 0.4 second time interval, calculated from the GPH rate. If I’m burning fuel at 1.51 GPH, I’ll consume 1/3600 of 1.51 gal. in 1 second, and 1/9000 of 1.51 gal, or .00168 gal. in .4 sec.
4 1.51 131 24 0.000168
4.4 1.54 145 25 0.000171
4.8 1.57 159 26 0.000174
5.2 1.57 175 26 0.000174
5.6 1.6 190 27 0.000178
6 1.61 206 27 0.000179
6.4 1.61 222 27 0.000179
6.8 1.65 237 28 0.000183
7.2 1.65 254 29 0.000183
7.6 1.7 271 29 0.000189
8 1.7 289 29 0.000189
8.4 1.8 306 29 0.0002
8.8 1.83 323 30 0.000203
9.2 1.84 341 30 0.000204
9.6 1.86 359 32 0.000207
10 1.89 377 32 0.00021
10.4 1.89 396 32 0.00021
10.8 1.93 414 33 0.000214
11.2 1.93 434 33 0.000214
11.6 2 453 34 0.000222
12 2 473 35 0.000222
12.4 2.08 494 35 0.000231
12.8 2.11 515 35 0.000234
13.2 2.12 535 35 0.000236
13.6 2.12 556 37 0.000236
14 2.16 578 38 0.00024
14.4 2.16 600 38 0.00024
14.8 2.21 622 39 0.000246
15.2 2.21 645 39 0.000246

From the data, I used .005963 gal. gas during 11.6 seconds (29 X 0.4 second intervals) to pulse 25-40 mph at 83% LOD. I used .004688 gal. during 7.6 seconds (19 X 0.4 second intervals) to pulse 25-40 mph at 90% LOD. I used .007563 gal. during 16.8 seconds (42 X 0.4 second intervals) to pulse 25-40 mph at 70% LOD. I had guessed from the collective wisdom here that 90% LOD acceleration would waste gas. I was wrong. We have a better tool than seat of the pants and variable-filled ABA P&G testing to determine best acceleration loads. It’s the Scangauge II with performance upgrade.
I’m including the 90% and 70% LOD data for your perusal. First, the 90% LOD data.
3.2 1.6 110 25 0.000178
3.6 1.62 125 25 0.00018
4 2.05 140 27 0.000228
4.4 2.04 156 28 0.000227
4.8 2.04 172 29 0.000227
5.2 2.04 189 29 0.000227
5.6 2.04 206 29 0.000227
6 2.19 223 29 0.000243
6.4 2.19 240 30 0.000243
6.8 2.22 258 32 0.000247
7.2 2.33 277 33 0.000259
7.6 2.33 296 33 0.000259
8 2.44 316 33 0.000271
8.4 2.46 335 34 0.000273
8.8 2.46 355 35 0.000273
9.2 2.48 376 37 0.000276
9.6 2.48 397 37 0.000276
10 2.59 419 37 0.000288
10.4 2.59 440 38 0.000288

Then the 70% LOD data.
2 1.45 71 25 0.000161
2.4 1.45 86 25 0.000161
2.8 1.43 100 25 0.000159
3.2 1.19 115 26 0.000132
3.6 1.12 130 26 0.000124
4 1.19 146 27 0.000132
4.4 1.2 162 27 0.000133
4.8 2.2 178 27 0.000244
5.2 1.54 194 29 0.000171
5.6 1.54 211 29 0.000171
6 1.56 227 29 0.000173
6.4 1.56 244 29 0.000173
6.8 1.59 261 30 0.000177
7.2 1.62 278 30 0.00018
7.6 1.52 296 30 0.000169
8 1.5 313 31 0.000167
8.4 1.48 332 31 0.000164
8.8 1.54 350 31 0.000171
9.2 1.54 368 31 0.000171
9.6 1.54 386 31 0.000171
10 1.52 405 32 0.000169
10.4 1.52 424 32 0.000169
10.8 1.57 442 34 0.000174
11.2 1.57 462 34 0.000174
11.6 1.55 482 34 0.000172
12 1.61 502 34 0.000179
12.4 1.69 522 34 0.000188
12.8 1.71 542 35 0.00019
13.2 1.71 562 34 0.00019
13.6 1.71 582 34 0.00019
14 1.77 602 36 0.000197
14.4 1.77 623 36 0.000197
14.8 1.75 644 36 0.000194
15.2 1.75 666 36 0.000194
15.6 1.83 687 36 0.000203
16 1.84 708 37 0.000204
16.4 1.87 730 37 0.000208
16.8 1.89 752 39 0.00021
17.2 1.87 774 39 0.000208
17.6 1.87 797 39 0.000208
18 1.97 819 39 0.000219
18.4 1.97 842 39 0.000219

In summary, I used .005963 gal. during an 11.6 second 25-40 mph pulse at 83% LOD, v..004688 gal. during 7.6 seconds at 90% LOD &.007563 gal. during 16.8 seconds at 70% LOD.

Sentra, do you know what the MAP or vacuum readings were at the three different loads? 90% if it is in direct relationship with 90% of available atmospheric pressure should be about 2.7 inches (manifold vacuum) if ambient is 30 inches of pressure. I am wondering if I should apply more throttle to my bike when accelerating or shift to higher gear more quickly or a combination of both

regards
Mech

Old mechanic, thanks for the help on the Metro fan, way off topic but fixed it with zip ties for nothing.

Mech,

I didn't notice. I'm not sure whether MAP or vacuum are supported as gauges for my car. If either are, I'll look to see what they read at the different LODs. I know barometric pressure is reported, and my testing is done at sea level.

No, sorry. UG doesn't support MAP or vacuum gauges on my xB.

Nice data, but which method nets the best MPG, higher load uses the least gas, but also goes the least distance, given the same glide afterwards, you would end up needing more pulses on a given trip.

Assuming the average speed of the pulse is 1/2 way between the begining speed and end speed of the pluse, x the time you could get distance covered, then using the fuel used figure out which is most efficient?

I think then you have to factor over a given distance say 20 miles as more P&G cycles of one method vs different number of P&G cycles at other accelration rates.

Yes, a slight correction is needed. What's needed is compute miles per gallon for 1 pulse and 1 glide. Assuming your pulse in linear then you'll cover 0.104 miles with 83% and 0.069 miles with 90%.

"True" FE for 83% would be (0.104 + X)/(0.005963+Y) where X is the number of miles in your glide and Y is the gallons of fuel in your glide. 90% FE would be (0.069 + X)/(0.004688+Y).

If EOC then Y=0. I ran the numbers for that. As long as your glide is >0.065 miles then 90% is better. That would most likely be true since your pulse distance is 0.069 miles, and I assume your glide distance is greater than your pulse distance. If your glide distance is 0.5 miles then the 90% gives you a 20% improvement relative to 83%

Nice test, BTW.

A typical glide from 40-25 mph in my boxy (8.77 CdA) xB is ~30 seconds, and almost every subcompact to mid-size car does better. Adding a 30 second glide to the data yields the following results:
http://i1179.photobucket.com/albums/...B/PGSGdata.jpg

The results get better with lower speeds. My pulse:glide ratio is 1:3 (10:30) in fourth gear 25-40 mph P&G. It's 1:5 (8:40) in third gear 15-32 mph P&G. It's 1:10 (3:30) in second gear 11-25 mph P&G.

I think the additional data addresses everyone's concerns. The SGII only logs 24 sec. of data, so it doesn't have the capability of recording a complete P&G cycle. I've counted off a lot of 40-25 mph glides, & 30 seconds is very typical for my car.

Not trying to be critical in any way, just bouncing ideas around as you & DD are way above me in number gathering and crunching, but.

Only kind of weak spot I can see is having to use GPH with 2 decimal places to convert to gallons per 4 seconds. I bumped my fuel cost to $10 a gallon, that way TFC (total fuel consumed not Cost) gives accuracty to the 1/1000 of a gallon. Using your data loging you would see where the TFC was at start of the pluse, and at then end, find the difference and I think it would give a better amount of fuel used (elimiate a lot of rounding error).

David

Thanks, David. I'll have to check whether the SGII's performance mode monitors TFC.

I agree better resolution would be nice. I started by monitoring liters per hundred kilometers, but changed to GPH for this past round of testing. I suspect the available resolution using GPH is adequate for my purpose of determining best acceleration load.

Old Tele, for sure, that would be nice. A savvy person might be able to daisy chain another device using the other RJ-45 port on the SG.

Here's a photo of my SG/UG data logging setup.
http://i1179.photobucket.com/albums/..._0128Small.jpg

I tried David's suggestion to log TFC after setting my fuel cost to $10/gallon. Unfortunately, it did not vary a bit from $1.03 during the entire pulse cycle, even after I went into EOC. Scratch that idea.

I ran two 95% LOD pulses, one logging GPH, and one logging LPH. I was pleasantly surprised to find I could simply set my fluid measurements to liters, leaving distance in miles, and then I could log LPH. When/if I convert the data to GPH or MPG, or keep them as LPHK, the LPH data show more resolution. The LPH fuel usage goes from 0.07 to 10.9, v. the GPH range from 0.02 to 2.81

Using the GPH data below for comparison with the figures above, I used more fuel for the same period of time to accelerate the same speed over the same distance at 95% LOD.
0.004774444 sum gas used in pulse
19 # intervals 7.6 time to pulse
12/3/11 95% LOD P&G 25-40. 60 degrees, sunny, dry. Wind quartering rear 25-40 mph.

After I finished the 95% LOD runs, I played with some 10-25 mph P&G. Here are the results (sea level flat drive).
http://i1179.photobucket.com/albums/..._0129Small.jpg

Just out of curiosity, what is you MPG at 32 mph in 4th gear?

I get ~51-52 mpg @ 32 mph in 4th gear, and ~55 mph @ 32 mph in 5th gear.

Thanks, I was curious how much the P&G EOC effort is worth. It can save quite a bit, but you have to know what your doing. 20 mpg gain when comparing 5th gear 32 mph vs 90% 4th gear P&G, down to almost 0 gain at 70%LOD.

Well older cars like my 1994 Geo cant get a scan guage.. Kinda stinks wish it could :-(

You can install an MPGuino. Unfortunately, you have to be a geek to know where to tap into your VSS, and to configure the MPGuino correctly.

...anyway to get both GPH and INCLINE ANGLE info collected and plotted against one another?

...maybe, GPH from SG or UG, and ANGLE from ipad/smart phone, etc.?

WOW... Ground breaking stuff. .. ...
 

I Have been waiting for soooooo long for devices and 'formulars' to calculate fuel usage on such a fine scale.... Woo-bloody-Hoo ! !! !!! :)

It doesn't matter for my tests, since I used the same stretch of road going the same direction, on the same day. And while we know the engine load will be higher, and pulse times will be longer on an incline (and load will be lower/pulse times shorter on a decline), there's no reason to expect the relative fuel consumption at each load to differ.

Yes, fastegg. I think it's ground breaking, too. I guess it's too technical, or too much work, or too expensive. I'm somewhat disappointed in the lack of interest/lack of comments returned on such breakthrough knowledge.

I wonder if 90% load works out to about the same percentage of atmospheric pressure reading on a vacuum gauge. Highest regards to you Sentra for the dedication to precision in measuring the optimal P&G load levels. It convinces me that I am probably not accelerating quite aggressively enough.

regards
Mech

I also wonder at what point in load you hit WOT enrichment, since the MPG is increasing significantly as the load increases? Could you improve the MPG by pushing it to 95% load?

regards
Mech

IIRC, 98% and 99% engine load acceleration still stayed in closed loop. I did test a 95% load pulse later. It used slightly more fuel, but didn't shorten acceleration time or distance.

Too many other distrations
 

Yeah me too.. I mean literaly every day there's another device that makes my job easier... As i said, i built and road raced motorcycles for 25 years and all our tuning was guesstimates, 1,000's of plug chops, seat of your pants asking someone else or luck.... or hope !!!!
Now we have a choice of SG2, UG, DashDyno, OT-2, ScanXL Pro, Superchips (flash tuners), and another one i found today the 'inTune' touch screen tuning device. (check out this site, tunertools.com its got heaps of new tech) and about a dozen other sites.. and i find it just so bloody fascinating and happy that there are guys out there, all over the world sitting down working out how to make this stuff work, make it cheap, make it compatible with my car (and everyone elses), make it easy to use, make it realiable... and updatable... all that !!!!!! I reckon its f**ken unreal !!! :)
The only problem ive got now is deciding which one to get. I like the DashDyno, as it works out HP and torque, its got a GPS for gods sake to calculate the terain your driving on and accurate speedo, ports for O2 sensors and EGT... (go and have a look at its key features at the Autarra site
auterraweb.com/dashdyno.html ... Right now what i really want is super fine fuel consumtion figures... I need a tool that can tell me if i change tire pressures it can tell me, and by how much..... even only a few short years ago, a device that could do this was not even dreamt up yet, and yet here we are, the UG and SG2 might and how cheap are they ??? ... ... ... ... puts a big smile on my face...
I hope i'm not writing too much ?.... A few months back i bought an Autel MS509 code reader/scanner thingy... $70 'cause my girlfriends Peugeot 307 had a DTC light on... its been on for years, weve been charged $75 twice during servicing to turn the light off but it kept coming on so i bought a cheap scanner so I could turn the light off...and it said 'vehicle speed sensor' fault... there is a speed sensor on each wheel but it wouldnt tell me which one, the local Peugeot dealer wouldn't tell me how to check it.... they wouldn't help me one iota...
they just said "bring it in and we'll work on it" GRRRRRRRR :((( so i'll leave the light on.. its not effecting anything.... Now, an unexpected find was on live view it tells me i can only get TP 85% max...(throttle position will only get to 85%...its fly-by-wire so, i wouldn't know what to look at... this would explain why its sooooo slow on hills.... I walked down to my friendly local Peugeot dealer and asked if they'd come accross this and all i recieved was the backs of their heads.... GRRRRRR :((( Now to put that in perspective, ive rung my local Lexus dealer services dept and they couldn't be helpfull enough... They faxed me pages out of the workshop manual.... talked at length about servicing issues and i asked them if they'd have any idea if i could fit paddle shifters.. He said "leave it with me"... 2 days later he rang me back, he had asked some Lexus electrical guru and told me "no problem" blah-blah-blah... faxed me electrical pages out of the Lexus book with surgestions about the several ways to go about it.... "If you have anything you think we could help you with, call us" Its the black and white difference between 2 cultures....
I'd better stop writing.... i can't remember why i started ! :)

I'm somewhat disappointed in the lack of interest/lack of comments returned on such breakthrough knowledge.

I'd read it when you posted it, so forgive my not hitting the thanks button then. I was waiting to buy one of these gauges so as to have some references for the thread in order to comment. You're right about cheap and available, it is surprising to be around it all. I'm less than ten years removed from my last car with points ignition (and the first with a computer aboard).

Great data. Thanks.

I cannot imagine that there are many people that think that 90% WoT would give you the best fuel economy. I know that we have some lights that I can only make at ten miles over the speed limit, or at least I assume so, because I do not drive that fast!

Maybe I can do this instead.

Floor it! You will save money! :D

Not necessarily 90% throttle but 90% load which may only be 50% throttle at the low rpm of best BSFC just below the first torque peak. Try for 1.5 inches of vacuum.
.
It is still counter intuitive to everything we have been taught. But you have to know how to coast after each "rocket burn".

I will just go back to accelerating slowly. Someday I will purchase a gauge. I doubt this forum has any active users that would tell me not to purchase one and I imagine that many of you would tell me that it would pay for itself quickly, but at least the short-term gain is to not buy one.

What is the motivation for your test:

• Never found a BSFC map for your engine (I'm guessing, I can't find BSFC maps for my engines...)?
• Wanted to check a BSFC map against real-world?

Also, for data logging, one could simply video the session and manually extract the data from the video to a spreadsheet, if you wanted to avoid buying as much equipment (er, depending on what equipment you already have). MPGuino could do the same job in that regard. I have a smartphone armband I can use to video my dash (in addition to its real purpose, video of traffic on bike rides, just in case).

christofoo, my motivation was to determine whether the SGII performance data logging could determine best acceleration load. You're correct that I haven't found BFSC graphs for my 1NZ-FE engine. The SGII does that job.

Videotaping a pulse cycle is remarkably crude, imprecise, and laborious compared to the SGII's ability to log fuel consumption, speed, and distance every 0.4 sec.

Xist, trying to hypermile without a gauge is like trying to learn to drive while blindfolded.

I accept your challenge!

I wish you well, but you are seriously handicapping yourself without instant feedback.

I was referring to driving blindfolded, but purchasing a Scangage is a priority after I find employment.

My comment was applicable to either situation ;).

My mom used to meet elderly couples where the wife had never obtained a license and the husband had since gone blind--he still drove. Apparently, she told him him when to turn.

"Turn left--now!"

I do not think that my dad would have remarried my mother if she acted the same way that she does when I drive, and his driving scares me sometimes.

I would think that driving blind would be too much stress for someone that old!

Well, I can drive without my glasses, but that is very unpopular with my passengers!

I've never been able to get "instant" feedabck on my diesel--at least not instantaneous mpg becuase of instrumentation issues (there is no fueling info broadcast through the OBD port). I do have the factory installed trip mpg display which I've learned to use. I reset the trip meter before every trip and pay attention to the way it's changing. I also tried various techniques and compared my trip mpg over certain distances. For example, I tried A technique yesterday on my way to work and had 32 mpg by the time I got to that bridge--today I tried B technique and got 34 mpg over the same distance.

So, I'll say that instantaneous mpg is not a necessity per se, but I absolutely agree that you need some kind of feedback.

this should help
http://imageshack.us/a/img189/2185/pri2010870.jpg

seems biggest concentration of optimum efficiency points are at ~1600rpm around 90% load. although not exactly your engine it is very close.

Where do you read what the load is on that chart?