Subaru Forester Owners Forum - View Single Post - 4EAT FXT

JCT · 05-05-2008, 05:29 AM

Yes, I have a Cobb AP V2 that should be here in the next couple of days. I haven't even gone to stage 2 yet, but I read about so many people going there and then wanting more that I just assume I will want more. Part of why I bought a FXT was the ease of doing an STI conversion so I'm pretty committed to a turbo upgrade.

I could be mistaken, but since I'm environmentally conscious and run a catted DP, I don't think boost creep will be an issue for me. (?)

With that in mind, I believe a 7cm housing would provide me quicker spool than 8cm without boost creep issues on the Evo3 18G. And it would save $100+.

I decided against the VF43 because there is no OTS support for it. If I'm going with that size of turbo, I may as well go VF39 since there is so much support, maps and replacement turbos for it out there and no real performance hit vs. the 43. The 39 is the only option that will allow me to run OTS maps. However, If I got a screaming deal on a VF43, i'd definitely consider it.

I prefer stock injectors because you have to draw the line somewhere and i don't want to end up getting really bad gas mileage. It's not a cost thing, injector upgrades aren't too expensive, I just want to draw a line and try not to cross it, because I know from experience with past vehicles if you dont' draw a line, it will never be enough and I'd keep redoing what I've already done. :) Maybe injectors arent' the best thing to draw a line with, IDK.

Do any of you see a DISADVANTAGE to spooling too fast with the 4EAT, like with the VF34? I'm not really sure what the ideal full boost rpm is with a 3200 stall torque converter. I have always thought that the faster your turbo spools, the better. But I read a thread somewhere that someone specualted it might be bad to boost too soon with a 4EAT, but I'm struggling with why. It may not have been a good source.

05-05-2008, 05:29 AM	#5 (permalink)
JCT Join Date: Feb 2008 Location: Salt Lake City Posts: 399 Gallery: 0 iTrader: 2 / 100%	Yes, I have a Cobb AP V2 that should be here in the next couple of days. I haven't even gone to stage 2 yet, but I read about so many people going there and then wanting more that I just assume I will want more. Part of why I bought a FXT was the ease of doing an STI conversion so I'm pretty committed to a turbo upgrade. I could be mistaken, but since I'm environmentally conscious and run a catted DP, I don't think boost creep will be an issue for me. (?) With that in mind, I believe a 7cm housing would provide me quicker spool than 8cm without boost creep issues on the Evo3 18G. And it would save $100+. I decided against the VF43 because there is no OTS support for it. If I'm going with that size of turbo, I may as well go VF39 since there is so much support, maps and replacement turbos for it out there and no real performance hit vs. the 43. The 39 is the only option that will allow me to run OTS maps. However, If I got a screaming deal on a VF43, i'd definitely consider it. I prefer stock injectors because you have to draw the line somewhere and i don't want to end up getting really bad gas mileage. It's not a cost thing, injector upgrades aren't too expensive, I just want to draw a line and try not to cross it, because I know from experience with past vehicles if you dont' draw a line, it will never be enough and I'd keep redoing what I've already done. :) Maybe injectors arent' the best thing to draw a line with, IDK. Do any of you see a DISADVANTAGE to spooling too fast with the 4EAT, like with the VF34? I'm not really sure what the ideal full boost rpm is with a 3200 stall torque converter. I have always thought that the faster your turbo spools, the better. But I read a thread somewhere that someone specualted it might be bad to boost too soon with a 4EAT, but I'm struggling with why. It may not have been a good source. __________________ 05 XT 4EAT Last edited by JCT : 05-05-2008 at 05:36 AM.