Dicehave123456 Posted January 20, 2014 Share Posted January 20, 2014 So as its not very clear I'd beg to question, but keeping the stock VF40, what mods increase fuel economy? And is there possibly a better eco tune than that which is supplied with a AP? I'd like to get the best of both worlds here as far as speed, but running a LGT Wagon as a Dad Mobile instead of the track monster it used to be, fuel econ would be wonderful Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 20, 2014 Author Share Posted January 20, 2014 Doing a little late night hunting and I found this thread (http://legacygt.com/forums/showthread.php/fuel-economy-improvements-113836.html?highlight=Increase+fuel+economy) but it really only confirmed a few things that I thought, like reducing the most friction possible through tire PSI tranny fluid changing, so on and so forth, but what I am curious about reading is that our motors stock burn a little rich compared to higher staged tuning. So that raises my next question, when does the "ratio" of power to fuel econ start to become less desirable as far as MPGs go. Because I remember my 02 WRX getting around 34mpg on the highway cruising at around 70-75mph, and that was with racing headers, full custom 3.5 turbo back exhaust, catless up/down pipes, t3/t4 hybrid turbo from turbogenetics and supporting modifications (Custom TMIC, Cold Air intake, etc.) Granted I know that this is a bigger motor than the 2.0, but there should be a way of figuring out exactly the peak balance between fuel econ and power/fun. I know I'm popping open a whole can of worms for arguing on this one, but it is something I am rather deadset on finding out. I'd love to still have fun, granted I know since frying the motor shes probably never going to see a track again once the new motor is swapped in but I'd love to make it last till the time my son starts driving and he thinks his car is hot shit, then maybe she will see action again. Till then, shes gonna have to be daddys grocery getter, and 21mpg average for mostly highway miles just wont cut it for me. If i cant get at least 26+ I'll be happy Link to comment Share on other sites More sharing options...
trav Posted January 24, 2014 Share Posted January 24, 2014 I'm looking into the samething. Mileage is not what I was hoping for. After i'm done with school in about a year it won't matter to me so much. Would like to find another way as well.. Link to comment Share on other sites More sharing options...
StoplightAssassin Posted January 24, 2014 Share Posted January 24, 2014 http://www.autoweek.com/storyimage/CW/20111216/NASCAR/111219919/AR/0/NASCAR_-sprint-cup_-drafting_daytona.jpg Link to comment Share on other sites More sharing options...
doobaruGT Posted January 24, 2014 Share Posted January 24, 2014 when does the "ratio" of power to fuel econ start to become less desirable as far as MPGs go....and 21mpg average for mostly highway miles just wont cut it for me. ...As soon as you push the pedal And yes, the factory tune is rich and the AP maps can help with that given you have the appropriate mods. Updated parts list since original part-out here. Original Full part-out of my LGT HERE! Link to comment Share on other sites More sharing options...
MasAyinde Posted January 24, 2014 Share Posted January 24, 2014 go stage 2. I just averaged 28 mpg driving from philly to DC Link to comment Share on other sites More sharing options...
trav Posted January 25, 2014 Share Posted January 25, 2014 A Cobb access port is on my shortlist. Stage 2 is a bigger turbo and high flow down pipe right? A bigger turbo means a new intercooler and bigger injectors as well correct? Link to comment Share on other sites More sharing options...
trav Posted January 25, 2014 Share Posted January 25, 2014 Oh I forgot to add that drafting is out of the running... Link to comment Share on other sites More sharing options...
iNVAR Posted January 25, 2014 Share Posted January 25, 2014 stage 0 involves some reading. You should start there, especially this subforum: http://legacygt.com/forums/forumdisplay.php/turbo-powertrains-2-0gt-2-5gt-2-5xt-12.html Link to comment Share on other sites More sharing options...
stm25rs Posted January 25, 2014 Share Posted January 25, 2014 stage 0 involves some reading. You should start there, especially this subforum: http://legacygt.com/forums/forumdisplay.php/turbo-powertrains-2-0gt-2-5gt-2-5xt-12.html Especially the stickies. Stage definitions: http://legacygt.com/forums/showthread.php/unofficial-legacy-gt-stage-upgrade-definitions-48123.html Upgrade path guide: http://legacygt.com/forums/showthread.php/turboi-wiki-twist-178684.html Link to comment Share on other sites More sharing options...
trav Posted January 25, 2014 Share Posted January 25, 2014 Read'em thanks for the pointer to it. Lillis like an AP will be top of list. Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 27, 2014 Author Share Posted January 27, 2014 I'm glad to hear all of this, and I'm glad to know that if the settings are changed then then fuel economy will get better. But then what stage will get me better gas mileage? I have all ready done tests of my own (Considering the fact I'm working from home right now I have way to much time is on my hands) the whole tire inflation and drafting thing is completely marginal at best, when both are used together it only accounted for .5 mpg on the same 100mile trip I used to test the cars actual mpg. So I hear that stage 2 supposedly sets everything to where people are reporting 27-32mpgs, but wouldn't adjusting the stock settings achieve similar results? I know people make stage 0 tunes just for what I'm asking, but I want to know what stage makes the better MPGs. Because I know the high flow parts might make enough of a difference theoretically Link to comment Share on other sites More sharing options...
hobo2701 Posted January 27, 2014 Share Posted January 27, 2014 stage 5 for sure. built twin turbo H6 Link to comment Share on other sites More sharing options...
PtPixel Posted January 27, 2014 Share Posted January 27, 2014 stage 5 for sure. built twin charged H6 fixt Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 27, 2014 Author Share Posted January 27, 2014 As far as my testing for drafting and tire inflation tests go, it was all highway miles. I know that my mileage in a city setting is going to be terrible, and considering most of my driving is highway anyhow that's how I conducted my testing on my usual route of home-daycare-work-daycare-home Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 27, 2014 Author Share Posted January 27, 2014 Hobo, I dont think a fully built H6 Twin Turbo gets any better mileage than your average Tahoe hahaha Link to comment Share on other sites More sharing options...
MasAyinde Posted January 27, 2014 Share Posted January 27, 2014 As far as my testing for drafting and tire inflation tests go, it was all highway miles. I know that my mileage in a city setting is going to be terrible, and considering most of my driving is highway anyhow that's how I conducted my testing on my usual route of home-daycare-work-daycare-home How did you go about testing drafting in a meaningful way? Link to comment Share on other sites More sharing options...
covertrussian Posted January 27, 2014 Share Posted January 27, 2014 My car got 27.8mpg bone stock, slightly it's getting 25 consistently. I'm trying to pin point the reduction to either catless/egtless up, new Denso front O2, or a new Timken front wheel bearing. More on this later though... ... So I hear that stage 2 supposedly sets everything to where people are reporting 27-32mpgs, but wouldn't adjusting the stock settings achieve similar results? I know people make stage 0 tunes just for what I'm asking, but I want to know what stage makes the better MPGs. Because I know the high flow parts might make enough of a difference theoretically Stage definition is such an arbitrary thing that I wouldn't really go by that to determine what improves/ruins gas mileage unless you plan on sticking to Cobb basemaps only. By going to Cobb Stage 2, it means you have a less restrictive downpipe (Decatted or aftermarket), and a major retune. This major retune increases boost, changes timing and fuel. There are just too many changes that are done at once. For this reason I'm trying to test free flowing mods with minimal tune adjustment, I'm trying to find what all needs to be tuned for a free flowing downpipe at this point. To be consist you should have a rear o2 behind a cat on the downpipe. By not having the Rear O2, you are messing with AF #3 corrections, which causes it to swing -5 to .5 lambada, aka really rich! The problem is, with freer flowing downpipe Wastegate Duty Cycle needs to be retuned, since less backpressure means more boost per same WGC %. On my FXT the difference was only 1-2psi, but I'm hearing it's much higher on LGT (bigger turbo). Thus if you do a downpipe and keep 100% same tune, you could be running more boost on highway even if you baby the car. Catless Up Doing a catless up pipe didn't seem to make much of a change city or highway for me I did install a new O2 sensor around the same time, but the odds of it dragging MPG down is odd, usually it's other way around. I though quicker turbo spool was at fault for MPG loss, I disconnected the wastegate arm, that forces the wastegate open and doesn't build boost, no MPG improvement. Yesterday I was playing with Romraider and something hit me, by doing catless up pipe I had to resist patch the EGT gauge, which forces the EGT's to be rather high 1292*F. Looking back on my old logs at cruising speeds my EGT's were under 700*F. Now I haven't found anything in Romraider that really adjusts fuel by EGT (there is only one 2d table and we are below the ON threasholds even with resister.) There might be another place, I'm tempted to reflash the ECU with a new EGT table that makes it think EGT's are under 700*F though... 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 27, 2014 Author Share Posted January 27, 2014 How did you go about testing drafting in a meaningful way? I went about testing the drafting by having a friend who owns a company with large moving trucks stay in front of me for the whole trip via the highway tailgating him around 1-3 car lengths. The drafting becomes marginally better when your basiclly pissing off the trucker in front of you when your completely in their blind spot for rearward vision. The cruise control was set at 70 the entire time for the 40-ish miles it takes me to get to work from my sons daycare Link to comment Share on other sites More sharing options...
Dicehave123456 Posted January 27, 2014 Author Share Posted January 27, 2014 My car got 27.8mpg bone stock, slightly it's getting 25 consistently. I'm trying to pin point the reduction to either catless/egtless up, new Denso front O2, or a new Timken front wheel bearing. More on this later though... Stage definition is such an arbitrary thing that I wouldn't really go by that to determine what improves/ruins gas mileage unless you plan on sticking to Cobb basemaps only. By going to Cobb Stage 2, it means you have a less restrictive downpipe (Decatted or aftermarket), and a major retune. This major retune increases boost, changes timing and fuel. There are just too many changes that are done at once. For this reason I'm trying to test free flowing mods with minimal tune adjustment, I'm trying to find what all needs to be tuned for a free flowing downpipe at this point. To be consist you should have a rear o2 behind a cat on the downpipe. By not having the Rear O2, you are messing with AF #3 corrections, which causes it to swing -5 to .5 lambada, aka really rich! The problem is, with freer flowing downpipe Wastegate Duty Cycle needs to be retuned, since less backpressure means more boost per same WGC %. On my FXT the difference was only 1-2psi, but I'm hearing it's much higher on LGT (bigger turbo). Thus if you do a downpipe and keep 100% same tune, you could be running more boost on highway even if you baby the car. Catless Up Doing a catless up pipe didn't seem to make much of a change city or highway for me I did install a new O2 sensor around the same time, but the odds of it dragging MPG down is odd, usually it's other way around. I though quicker turbo spool was at fault for MPG loss, I disconnected the wastegate arm, that forces the wastegate open and doesn't build boost, no MPG improvement. Yesterday I was playing with Romraider and something hit me, by doing catless up pipe I had to resist patch the EGT gauge, which forces the EGT's to be rather high 1292*F. Looking back on my old logs at cruising speeds my EGT's were under 700*F. Now I haven't found anything in Romraider that really adjusts fuel by EGT (there is only one 2d table and we are below the ON threasholds even with resister.) There might be another place, I'm tempted to reflash the ECU with a new EGT table that makes it think EGT's are under 700*F though... Let me know when you narrow it down as far as what pieces are actually creating the most effective fuel efficiency over the stock parts, because I know the less restrictive usually the better from what I remember with my 240, but then its also some of the user error when you decide that your foot gives more throttle when someone decides to ride your ass and you get the primal urge to just dust them and go farther away from them and have them be stuck behind someone else instead but also in the same breath I am going to get a cobb tuner soon, so if getting a custom map made for the base map or higher stage maps is what it needs than so be it, you gotta spend a little money to save a little money some times. But the car will be getting catless up and down pipes here soon just because they are cheaper to come by, and the current up is leaking due to aging and rust. But let me know what you narrow it down to, I would like to know, because if the more restrictive factory parts are what it takes I will just buy the OEM and call it a day Link to comment Share on other sites More sharing options...
covertrussian Posted January 28, 2014 Share Posted January 28, 2014 But let me know what you narrow it down to, I would like to know, because if the more restrictive factory parts are what it takes I will just buy the OEM and call it a day I doubt I've ever seen it be better to breathe through a straw then through a hose. Stock exhausts are restrictive, these exhausts are 2.37" OD, which is fairly respectable for an NA 2.5L, but even for turbo 2.0L it's tiny. I'm reducing the overlap via AVCS, setting cruise area to be all 0's and lowering target PSI to see if that helps improve efficiency. Thing is AVCS is already at 0 for 2400-3200 RPM at low load, so 70mph driving was already with fairly low overlap. I have some highway driving ahead of me this weekend so plan on testing it then, my base MPG right now is 24.4mpg hway (as of yesterday). After one highway fillup I will either reflash the ECU, with EGT Scale to make my current 2.2kohm 1/2watt resistor read 700*F, or just get a 500ohm resistor from radiadioshack... 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
covertrussian Posted February 12, 2014 Share Posted February 12, 2014 Figured I would update you with my progress, so far my MPG is up to 27.5ish just with tune updates. You can see the details of what I changed to improve MPG over at my build thread. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
Max Capacity Posted February 12, 2014 Share Posted February 12, 2014 My 09 Spec B has gotten well over 30mpg following a buddy who was towing his 32ft 5th camper up to Loudon last July for the NASCAR race. The car is on Cobb stage 1 93 octane. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
covertrussian Posted February 12, 2014 Share Posted February 12, 2014 The gearing of the spec B is what makes it get better MPG's. A while back BMW (or some german company) did a study and they found that reducing the RPM attributed to the best gas mileage gains because of less friction. I would love a 6 speed, even with increased gas millage it would take years for it to pay itself off... 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
PtPixel Posted February 12, 2014 Share Posted February 12, 2014 The gearing of the spec B is what makes it get better MPG's. A while back BMW (or some german company) did a study and they found that reducing the RPM attributed to the best gas mileage gains because of less friction. They had to do a study to figure out that less fuel ignition/s caused lower mileage? I would love a 6 speed, even with increased gas millage it would take years for it to pay itself off... http://legacygt.com/forums/showpost.php?p=4607468&postcount=15871 Link to comment Share on other sites More sharing options...
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