Jimmye212 Posted October 7, 2017 Share Posted October 7, 2017 I would like to start off by saying that I know similar questions have been asked many times, but I have searched and read through all of them extensively but have not seen a definitive answer to my question. I have a 2009 lgt with the 5eat, so there is no VB mod available. I already have a tranny cooler and did a full flush with oem Subaru fluid and a can of bg atf additive. The transmission itself has 160k miles on it and shifts smoothly and firmly, with the exception of an occasional “thud” when shifting from 3rd to 4th with zero throttle (thud goes away with partial or full throttle.) Also, every once in a while when starting off the line in first at full throttle it seems as if it has a bit of a stutter, then continues on. I’m currently doing an engine rebuild with a brand new ej257 short block and would like to upgrade my stock, likely worn, turbo. I’ve pretty much narrowed my options down to a bnr evo3 16g or a bnr 18g. I’m not positive which one will be easier on the transmission. The 16g will have more torque down low but the 18g should produce more power overall. Plus if I go the 18g route that means I will need to get injectors. So, I’m basically asking which turbo would be the right choice for my application, or if either one will likely grenade my tranny (which wouldn’t be great right now, considering how much money I have into the rebuild already.) Thanks for any help! Link to comment Share on other sites More sharing options...
Jimmye212 Posted October 17, 2017 Author Share Posted October 17, 2017 Any input on this? Link to comment Share on other sites More sharing options...
Jimmye212 Posted November 28, 2017 Author Share Posted November 28, 2017 Bump Link to comment Share on other sites More sharing options...
wbrawley Posted November 29, 2017 Share Posted November 29, 2017 Is yours a VF52 stock or smaller? If it is, 16g shouldn't be much difference, injectors would be worth more in maxing out that size turbo. Link to comment Share on other sites More sharing options...
kzr750r1 Posted December 3, 2017 Share Posted December 3, 2017 I'm running a 16g with stock injectors. You could also have JMP rebuild your stock turbo. Unless you have wads of cash to throw at a project put it back together with minimal mods and have a good tuner ready to work with you on restart map and guidance. Link to comment Share on other sites More sharing options...
Jimmye212 Posted December 22, 2017 Author Share Posted December 22, 2017 I have the stock vf46 right now. Both the 16g and 18g would be a considerable upgrade, but I'm specifically asking about how the tranny will hold up and whether the 16g would be more likely to harm the transmission due to the low end torque. Link to comment Share on other sites More sharing options...
robburns201 Posted December 22, 2017 Share Posted December 22, 2017 anything to do with the 5eat i would ask Hexmods Link to comment Share on other sites More sharing options...
utc_pyro Posted December 22, 2017 Share Posted December 22, 2017 climberD sold his car and is out of the game The '08+ tranny seems to hold up better to power mods than the '05-'07 (presuming no VB upgrade). The weak spot is more the center diff then the transmission core, so peak torque in low gears is more the killer. You'll need to do some compensation in the ECU to deal with it though. For oen you'll probably want your tuner to set your 1-2ng gear per ger boost lower to limit toque going to the diff. Next you'll want them to adjust the calculated and requested torque to be in the ballpark of reality. I think both of these are still only available in the opensource camp instead of accessport, so you'll need to find a tuner willing to go down that road. You'll also need a tuner willing to play with beta definitions. Link to comment Share on other sites More sharing options...
Jimmye212 Posted December 23, 2017 Author Share Posted December 23, 2017 I had been planning on going to EFI Logics in CT after hearing great reviews about them, and they are only 40 minutes away. I believe they only do accessport tuning for subarus, but I could be wrong. Does this mean they wouldn't be able to adjust the calculated and requested torque/line pressure? Also, you mentioned that peak torque in low gears is the killer for these transmissions. Will the BNR 18g be hitting peak torque in low gears? I'd imagine the 16g would. I appreciate the help! Link to comment Share on other sites More sharing options...
fishbone Posted December 23, 2017 Share Posted December 23, 2017 Since I'm lurking new posts, alright I'll bite and chime in. The problem with the 5EAT is not the capacity to hold power, but the beating it takes between shifts. Once the clutches are engaged, it can hold a fair amount of torque. The less torque it gets hit with at shift points, the better, so I would opt for a turbo that runs out of steam at redline, which is neither BNR turbos Not sure what kind of life the 5EAT has lived for the 160K miles it has on it, but if I were you I would save money in the bank for a trans replacement at some point. The prospect of running the 5EAT "naked" at Stage 3 levels is kinda hair raising for me. Trans cooler helps. Using Amsoil ATF also helps. Shifting in manual mode also helps (line pressure is highest in manual mode). And I think what you can also do is work with the tune to make it pull timing (and thus power) at shift points. But either way, I would say that if you want hope for a trans to last you, you gotta look into doing a valve body mod. Doesn't matter what clutches you put into it, the damn thing shifts soft. Link to comment Share on other sites More sharing options...
utc_pyro Posted December 23, 2017 Share Posted December 23, 2017 I had been planning on going to EFI Logics in CT after hearing great reviews about them, and they are only 40 minutes away. I believe they only do accessport tuning for subarus, but I could be wrong. Does this mean they wouldn't be able to adjust the calculated and requested torque/line pressure? Also, you mentioned that peak torque in low gears is the killer for these transmissions. Will the BNR 18g be hitting peak torque in low gears? I'd imagine the 16g would. I appreciate the help! No they wont be able to edit it. Thus the TCU wont know how much torque the motor is actually making. It has to do with the loading on the center diff. Particularly shock loading as fishbone stated. If they tune it to have a more lazy spool up without as much midrange torque the transmission will survive longer. Link to comment Share on other sites More sharing options...
fishbone Posted December 23, 2017 Share Posted December 23, 2017 Which defeats the purpose of going big turbo. Why go big if you're going to neuter it. Unfortunately the reality is that 5EAT + Stage 3 = short life Link to comment Share on other sites More sharing options...
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