Mrstacy Posted January 17, 2017 Share Posted January 17, 2017 Given the scenario where you have both an E85 tune and 91 octane tune, what happens if you have a tank of e85 and then find yourself not having access to e85 and having to fill up right away or risk running out of fuel? If i'm understanding correctly, the flex fuel option would automatically account for the mixture in the tank? Thank in advance. Link to comment Share on other sites More sharing options...
FLlegacy Posted January 17, 2017 Share Posted January 17, 2017 The flex fuel option includes a sensor to determine the concentration of ethanol, and then the ecu adjusts the tune on the fly. Link to comment Share on other sites More sharing options...
Mrstacy Posted January 17, 2017 Share Posted January 17, 2017 ^ Mucho Gracias FLlegacy. But.. If I get just an E85 tune and a separate 91 octane tune, what would happen? Do I need to let my car run to empty and refill with 91 if caught away from e85 with a quarter tank? Trying to do my due diligence before I consider an e85 tune. Sounds like waiting for a flex fuel solution is best so far. Link to comment Share on other sites More sharing options...
FLlegacy Posted January 17, 2017 Share Posted January 17, 2017 You would definitely need to run out as much 91 as possible before filling up with e85, but most tunes will allow some variation, you should talk with a tuner about your plans and see what is possible and then plan accordingly. Link to comment Share on other sites More sharing options...
jojorios Posted January 17, 2017 Share Posted January 17, 2017 I thought flex fuel still wasn't an option for us? Or has that changed? Another Question for Fahr_Side: I know I have read about 4 or 5 transmission issues that have occurred since joining the site, and with BBPeik working on an STI swap after his went, what have you observed with the stock tranny in what it can/can't handle? Link to comment Share on other sites More sharing options...
Mrstacy Posted January 17, 2017 Share Posted January 17, 2017 I thought flex fuel still wasn't an option for us? Or has that changed? I have same understanding, but Cobb has some for other models just out. Maybe someone will attempt to fit for our cars. Link to comment Share on other sites More sharing options...
BBPeik Posted January 18, 2017 Share Posted January 18, 2017 Well I can tell you the stock trans does not seem happy with over 400 hp. Go figure. My someday I will be done with it thread. Link to comment Share on other sites More sharing options...
fahr_side Posted January 18, 2017 Author Share Posted January 18, 2017 (edited) At the moment it's Cobb in the lead on flex-fuel, with their bondage partners ECUtek sharing that technology. On Opensource there's a stable 16-bit solution in Carberry but the 32-bit patch isn't ready for prime time yet. Note that Cobb's solution like others senses alcohol content in fuel and blends between two sets of tables according to that value, it's not binary. Note that means it cannot sense octane rating directly, so for example if you tuned for 93 and E85 you are not safe on 91. Transmissions are a bit beyond the scope of my post and I haven't tuned any 2.5 liter cars on the mini-6MT or 5+1MT. They do okay on the WRX models but I don't see any reason it would hold any more torque than the old 5MT it's based on. Edited January 18, 2017 by fahr_side Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
GTEASER Posted January 18, 2017 Share Posted January 18, 2017 Well I can tell you the stock trans does not seem happy with over 400 hp. Go figure. Some_Zero and acumenhokie have both verified this. GTEASER's 2012 Legacy GT - Sold GTEASER's 2009 XTeaser - Sold GTEASER's 1992 Legacy SS - Sold Link to comment Share on other sites More sharing options...
jackal8788 Posted January 23, 2017 Share Posted January 23, 2017 ^ Mucho Gracias FLlegacy. But.. If I get just an E85 tune and a separate 91 octane tune, what would happen? Do I need to let my car run to empty and refill with 91 if caught away from e85 with a quarter tank? Trying to do my due diligence before I consider an e85 tune. Sounds like waiting for a flex fuel solution is best so far. FWIW, I had separate tunes for 91 and e85. I switched back and forth a handful of times and never had an issue. When I went from 91 to e85, I would usually run rich for a short period until the fuel trims adjusted. Conversely, when I went from e85 to 91, I had a brief period where things were a little on the lean side but within perhaps 20-30 minutes of driving, the fuel trims adjusted again and compensated. I normally drove the car with a lighter right foot for awhile after switching fuels until AFRs stabilized but it was never a big deal. I would say as a general rule it's wise to run out as much of the old fuel as you can, then when you do re-fuel and re-flash, just drive moderately until you see your fuel trim and AFRs back in line. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
Mrstacy Posted January 23, 2017 Share Posted January 23, 2017 ^ Thanks. What PSI are each of your tunes and is your engine stock headers and pistons? Link to comment Share on other sites More sharing options...
jackal8788 Posted January 23, 2017 Share Posted January 23, 2017 ^ Thanks. What PSI are each of your tunes and is your engine stock headers and pistons? My e85 tune had a peak of 23 PSI and my 91 octane tune peaked at 18.5 PSI. Everything from an engine standpoint was stock aside from the fuel system upgrades so I was likely pushing the limits of the stock head studs and thus the head gasket at those pressures. I never had an issue, but I also wasn't a very aggressive driver. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
Mrstacy Posted January 23, 2017 Share Posted January 23, 2017 ^ You've been e85 tuned for how long? How do the two tunes compare? Link to comment Share on other sites More sharing options...
Ellesedil Posted January 23, 2017 Share Posted January 23, 2017 ^ You've been e85 tuned for how long? How do the two tunes compare? Might I suggest reading through his build thread that's linked in his signature? His first post there talks about getting ready for E85. I kinda feel this conversation is veering from the original topic for this stickied thread. Link to comment Share on other sites More sharing options...
Mrstacy Posted January 27, 2017 Share Posted January 27, 2017 Best match for the stock motor is a TD05H-18G hybrid in the VF-54 housings.. Does anyone have a idea of what vendors sell this type of turbo? Thanks in advance. Link to comment Share on other sites More sharing options...
islandborn Posted January 27, 2017 Share Posted January 27, 2017 does anyone have a idea of what vendors sell this type of turbo? Thanks in advance. bnr Link to comment Share on other sites More sharing options...
GTEASER Posted January 27, 2017 Share Posted January 27, 2017 Lets stay on topic gents. Roadblocks and solutions. MrStacy, talking to you, bud. We don't need another thread here, especially a stickied thread, to be full of 5000 useless posts with banter not pertinent to the topic. GTEASER's 2012 Legacy GT - Sold GTEASER's 2009 XTeaser - Sold GTEASER's 1992 Legacy SS - Sold Link to comment Share on other sites More sharing options...
fahr_side Posted January 28, 2017 Author Share Posted January 28, 2017 Does anyone have a idea of what vendors sell this type of turbo? Thanks in advance. PM please. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
mijophil Posted February 5, 2017 Share Posted February 5, 2017 1. Stock cat. We usually refer to the cat pipe as a J-pipe now, rather than downpipe, due to the geometry. The stock cat is very restrictive. Pushing boost past about 16.5 or 17psi creates very high EGBP (exhaust gas back pressure) which we can evaluate via exhaust gas temperature. High backpressure means the cylinders don’t get scavenged of exhaust gas properly which negates the benefits of squeezing more air into them. Stage 1 tunes top around the 230whp / 305wtq mark, mostly due to the restriction in exhaust flow and limited boost Do we know just how restrictive the cat is? I wonder what kind of difference there is with a cat delete and tune vs a typical stage 2. Link to comment Share on other sites More sharing options...
fahr_side Posted February 6, 2017 Author Share Posted February 6, 2017 Do we know just how restrictive the cat is? I wonder what kind of difference there is with a cat delete and tune vs a typical stage 2. Cat delete + tune = stage 2 Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
jmaddocks Posted February 19, 2017 Share Posted February 19, 2017 I'm assuming we should source the exhaust cams from an 08+ dual-AVCS STI? Any problems running them with the VF-54, obviously with the car tuned with the cams installed? Link to comment Share on other sites More sharing options...
fahr_side Posted February 20, 2017 Author Share Posted February 20, 2017 No assumption necessary, it's been mentioned several times. They fit directly with no mods. I would advise you to install the valve springs also. I don't know of anyone doing this mod together with a stock VF-54 though I don't foresee any problem. You'll pick up lots of midrange torque but the turbo will still fall on it's face up top. For sure you'll have to re-tune for the cams. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
jmaddocks Posted February 20, 2017 Share Posted February 20, 2017 No assumption necessary, it's been mentioned several times. To clarify, I didn't know if there was an upper end to the STI model years (i.e., 2008-20xx), and I didn't see that. Sorry if I missed it. You'll pick up lots of midrange torque but the turbo will still fall on it's face up top. For sure you'll have to re-tune for the cams. That's what I figured, but my wife will kill me if I buy an 18G along with the $3k+ engine rebuild, so it'll have to wait... Link to comment Share on other sites More sharing options...
foxrider28 Posted February 20, 2017 Share Posted February 20, 2017 To clarify, I didn't know if there was an upper end to the STI model years (i.e., 2008-20xx), and I didn't see that. Sorry if I missed it. That's what I figured, but my wife will kill me if I buy an 18G along with the $3k+ engine rebuild, so it'll have to wait... Just send your core in to be built while you rebuild the engine and explain that it's necessary because it's a key part of the engine and it won't operate properly if you don't. [emoji6] Link to comment Share on other sites More sharing options...
TGD Posted June 20, 2017 Share Posted June 20, 2017 Hey I’m very new to this so please forgive my ignorance but from my understanding a car with an upgraded BPV, turbo back exhaust and the upgraded turbo mentioned should be okay to run with nothing else on pump gas, but mods like an oil to air, TMIC/FMIC, fuel pump and injectors will improve reliability/ cooling.??? Link to comment Share on other sites More sharing options...
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