Flinkly

I just found it (in the tune, but have always seen it), and not sure if your tune has it, but my 08 runs at 14.4 AFR at idle. it's got -.441 in the closed loop table A in the 850 RPM row for .2 and .3 g/rev. save some gas at idle/coasting. and just thinking about it while posting, but is idle above 850 when temps are below 60? might account for some reduction in MPG at lower temps. idling at higher AFR. I'll check on this the next time I have my tune open in Romraider...

I've got a 4 port usb hub in the dash, and the PLX sensor modules daisy chain together, so you can link "a lot" together and only have one USB cord/connection. My basic setup is tactrix plugged in at my feet, USB snakes up to behind my cubby gauge pod, where I have my two PLX sensor modules and USB hub, then 1 USB cord comes from the hub and goes to my center console box. in there I redid my AUX "panel" to include a cute little Molex Wiring key and a female USB plug end (the wire from the 4-port hub in the dash). The Aux is still usable, there is a little hole where I can plug in a molex connector/key and flash ROMs (it connects my green test connector, cause I got REALLY tired of connecting/disconnecting that thing... and my wife got tired of seeing it at her feet) and the female USB plug end for inserting a USB cord to my laptop to log or flash. I used to have a USB jack on the face of my gauge pod, but the wife didn't like the way it looked, and REALLY hated when I plugged the laptop in and set it in her lap... she hates the gauges too, but those aren't going anywhere. which reminds me, I need to do update my build thread for the little AUX panel redo...

plx boost gauge. I bought it more just to keep an eye on things when I went stage 2. bought alongside my plx AFR guage/sensor. should probably remove all the extra hose I have between the manifold and the sensor. I just connected it up and left the extra in case I needed it, and never removed it after I got it all in place and working. probably an extra 3 feet of 1/8" ID hose... both can be logged in romraider, alongside normal ECU parameters, but I've never considered logging boost/vacuum. I've already got romraider connected with my AFR for when i'm interested in logging that. http://www.plxdevices.com/product_info.php?id=SEMOSMVB

hmm, maybe I should add my boost(vacuum) gauge to the parameters I log... I do pay attention to what it says, and have solved a few blown hoses that way. I wonder how accurate it is in vacuum, or boost for that matter.

hmm... there does always seem to be two sides to each coin: Colder (Denser) air means more engine power, but increased drag. I can believe it, and I agree that the boxy forester is for sure less aerodynamic. in essence, you'd still be making the same increased power from the colder air intake (as a forester would), with less drag then them whether it was cold out or not. also, I assume you already know almost all the stuff i'm saying. I mostly put it in writing for everyone else and to further the discussion. and my MPG appears to be on the way down for the year. I have been tuning for the last couple months though, so I think my MPG is suffering from that a little as well. but the cold sure isn't helping. at least my linear trendline of the last 3-4 years shows a healthy increase in MPG. just gotta keep the slope positive.

You're temps are still normal internally, but you and the cold are both taking more of the engine's heat (energy) than on a "nice day". You're blasting the heat to stay warm inside, and your engine is losing heat thru the oil pan and block (and the radiator, etc.). The engine is maintaining a reasonable internal temperature, but it's using more energy to maintain that then normal, and thus has less energy to put to the ground. Even your exhaust is flowing less due to the outside temps robbing the exhaust of more heat energy, increasing your exhaust gas's volume, which reduces your exhaust gas's velocity. This is why we ceramic coat and wrap headers and uppipes, to keep velocity high for the turbo. And coat and wrap downpipe's so that the turbo/engine doesn't have to work any more than it needs to push the exhaust out the back end. and obviously, i'm simplifying things here, but it's true. Also, i'm not saying that there aren't tuning parameters that are reducing MPG either, just saying that they aren't by any means the only culprit. but maybe I should keep this talk somewhere else since this is specifically for "ECU tuning for Fuel Economy", not "modding for Fuel Economy".

geebus, can that guy use some longer screws!?! Sent from my XT1028

but at cruise, the throttle plate would be adjusting for the change in density. overall, no matter the outside temp, the same "load" is needed to keep a subie moving at 70mph. i think reduced efficiency would be a more likely cause, from a colder running engine. more heatloss to the outside causing less efficient use of gas. we need grill louvres (for subies not equiped). closed for warmup and cruise. decreased drag, increased efficiency. would even force more air thru the tmic, so even denser air for more power (to justify it to the non-efficiency minded turbo subie crowd). also better mileage means saved gas funds, to use for more mods! Sent from my XT1028

what's your stumble look like? in logs, like what does your correction+learning look like plotted agains rpm when warm? or your wideband vs. rpm? my afr goes nuts, and correction+learning peaks there. i don't believe i've had a misfire though, and i notice mine most at 1.8k Sent from my XT1028

i have a clank in he rear over large-ish bumps, it's my avo rear sway contacting the muffler flange on the drivers side... Sent from my XT1028

just to add more parameters to log, maybe your coolant temp is dropping down and effecting fueling. i still keep thinking of somehow making/adding a homebrew grill louvre system for shorter winter warmup and better cruise efficiency/drag. Sent from my XT1028

very true (on the "random" effects of your fueling mods), hadn't thought of that. Are your per injector compensation tables zero'd out? and what type of headers are you running? OEM? Thanks for the info on reduction vs. shift of the stumble. now I just need to figure out how to justify the $150 expense with my "accountant". hard to justify "fixing" something if it isn't perceived as being broken. Same with getting a DW65C (and new pump housing) to replace my Whinebro...

Brian3676, I'd still be interested in seeing a plot of your (fuel) Correction vs. RPM from idle to 3k+ mainly interested in seeing where your fueling harmonics moved to, since this doesn't appear to be a problem that can be eliminated, just shifted and/or reduced (depending on your "fix"). Also, if you have it, a plot of the same thing from before you implemented the STI regulator (to see where your problem RPM area was before).

Parts Subaru OEM Regulator: 22670AA351 Dorman quick disconnect (4x?): 800-120 a few feet of fuel line hose from local auto store... Threads: http://forums.nasioc.com/forums/showthread.php?t=2228118 http://www.iwsti.com/forums/ecu-tuning-performance-electronics/203089-final-tuning-solution-gr-stumble-2400-3000-rpm-using-ap.html http://www.romraider.com/forum/viewtopic.php?f=15&t=4911&sid=ccb38c893b363f0e96ff6e4726adba13 http://legacygt.com/forums/showthread.php/famous-stumble-fixedi-232816.html tuning spreadsheet: http://www.romraider.com/forum/viewtopic.php?f=32&t=5483

what's your correction vs. rpm look like? just wondering if you've moved the stumble. I'd be willing to spend $100 on a Subaru regulator to fix my stumble. I have a stumble at ~1.8k. haven't gotten far enough to try to tackle it yet, but I do hate it. gotta fix my tip-in stumble first... thanks for the info. And the Cobb purchase page has a link to Nasioc (in the reviews) for more info. and that thread has links to other threads, namely one on Romraider, that gives even more specific info.

well, got my first set of parts for the boot, and the parts guy ordered in the wrong set. axle reboots aren't common enough to keep parts in stock. was in a rush and only noticed when I got home that the boot was a hard plastic, and after that noticed it didn't have the 3 bumps to mate with the dents in the cup. now I ordered the actual boot kit set (just inner boot, 28397AG000) for $35. even better than what I paid for the outer boot yesterday ($45). i'll let ya'll know how it works out tomorrow afternoon, but i'm sure it'll go swimmingly.

just to add more info, my "reman" cups had the indents, but were flat on the other three sides. also, the reason my reman doesn't work is cause the boot doesn't have enough flex for as much as a stock outback "bends" the axle. legacies may have better results. I did check around other autozones to see what they had for reman axles and they were all the same (indents and flat sides), and my autozone "didn't believe me" when I told them that the axle isn't right for an outback. they got it back. i'm rebooting my original axle and putting it back in. might check back at autozone in a year to see if they have an actual rebuilt Subaru axle for my personal stock, but I figure i'm redoing boots from here on out. or having a local joint shop redo it if bearings start screaming (assuming they charge less than the $400 price tag of a new Subaru axle).

http://tapatalk.imageshack.com/v2/14/10/24/e9629764ae10fad44e994b13ad22eda4.jpg crappy phone pic, but recently got a 7336 from autozone and i don't know what to say. the tranny end wasn't entirely turned down to the correct diameter, so i had to file the very tip so it wasn't an interference fit. after getting it installed, the boot on the tranny end, as shown, is buckling. makes a nice drone at speed, or anytime i'm moving really. not impressed. my passenger axle is a 7336 also, so not my first rodeo or rebuilt autozone axle. gonna get my old oem rebooted and back on. then look for an oem spare to rebuild and have on hand... Sent from my XT1028

hmm, good find on the tire pressure guage. for some reason i used to be 100% confident in the one i have (even thiugh its the cheapest thing and quite hokey when you think about it). time to upgrade! makes me wonder what mine are at right now. i do sometimes get a tpms warning on hot days + long drives, and i just assumed it didn't like my 36 psi. i'm sure it doesn't like 44+!

also, to the point of tricking the ECU to burn at a different AFR than 14.7, wouldn't you want to go higher? say 15 or 15.5?

about the O2, yeah, it's not narrowband, but it's not as good as "aftermarket" wideband. I was really poking at the ability to put in a Bosch (true) wideband sensor as the front O2, where your ECU could not only have a better view of the world, but you wouldn't necessarily need a second O2 sensor/bung but still get all the information you'd want for tuning. you could still even take the raw voltage and put it thru an aftermarket box to get the same results you have now (kind of a double check, ECU vs. aftermarket wideband, but the same sensor). hard part would probably be in tricking either your aftermarket sensor "module" or the ECU into thinking it was heating the sensor up, since both would "want" to be doing it. As for AVCS, I was thinking about following your lead and seeing what results I could get, but my Stock and Stage 2 tune have a very different look than your Stock AVCS tables. not that I'm very surprised, but we do generally have the same intake/exhaust systems, but these are pretty different. And what about tuning individual AVCS cells for V.E. (volumetric efficiency)? so instead of a guess-and-check method, actually tune "each" cell for efficiency (you could tune a few spots and "infer" between them). not that it would give you best MPG, but it's be a great start, and then try bumping it up/down by 5* across the board and see what happens. For a DBW car, it'd be hard to run within the right cell for an extended period of time to collect data, but not impossible...

wait, can "we" fool the ecu to accept a wideband rather than stock narrow o2? fantastic thread. subb'd.

well, the passenger harness I've seen quoted around 65 bucks, so at least it's not crazy expensive, and should buy you another ~4 years of "trouble free" car use. of course, there's a lot of panel removal to get to everything and I can only imagine how much the drivers side harness costs.

yeah, thats what i did. not up on the accessport to know if that works.