Slade-Runner Posted January 31, 2018 Share Posted January 31, 2018 So at what point do you think it is a good idea or when is it worth it to upgrade your fuel system? My plan for my Spec b right now is to do full exhaust, cold air, turbo inlet, TMIC, boost solenoid, phenolic spacers, and maybe TGV deletes as far as engine upgrades go. So is it worthwhile to upgrade my fuel pump, injectors, and/or rails, or is it not worth it until I get into turbo upgrade. I'm trying to keep my fuel economy (relatively) decent for work travel if I have to drive long distances. My overall objective is to daily driver and a car I can have fun on a track day. Link to comment Share on other sites More sharing options...
relative4 Posted January 31, 2018 Share Posted January 31, 2018 Yes, no need to upgrade fuel till you upgrade the turbo. Link to comment Share on other sites More sharing options...
gkinslow Posted January 31, 2018 Share Posted January 31, 2018 If there is a turbo upgrade in your future you are better off doing everything at once. That way you only have to pay for one tune. Link to comment Share on other sites More sharing options...
BrucesOutbackXT Posted February 2, 2018 Share Posted February 2, 2018 First things to upgrade is the fuel pump and injectors increase fuel flowing to your engine. then tune. You will be surprised at the gain in hp possible. Link to comment Share on other sites More sharing options...
Sgt.Gator Posted February 3, 2018 Share Posted February 3, 2018 No need until you get a bigger turbo. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
BrucesOutbackXT Posted February 3, 2018 Share Posted February 3, 2018 Have you got a great tune or are you still running a stock tune? I think a great tune on stock system should work well for you. What is interesting is your stock program has built in multiple stages of performance. each stage can be tweaked and reloaded and tested. With the right person Tuning getting 20%- power increase with no added parts should be possible and a increase in mpg's. This is my opinion. Link to comment Share on other sites More sharing options...
Slade-Runner Posted February 3, 2018 Author Share Posted February 3, 2018 Have you got a great tune or are you still running a stock tune? I think a great tune on stock system should work well for you. What is interesting is your stock program has built in multiple stages of performance. each stage can be tweaked and reloaded and tested. With the right person Tuning getting 20%- power increase with no added parts should be possible and a increase in mpg's. This is my opinion. Right now I have an Accessport V3, running Stage 1 tune with an Invidia Q300 cat back. I've read several debates on the SI drive, so is each selection an actual different map that can be individually programed or is it just an adjustment to the base map? I've been kind of worried about that, because if a tuner doesn't know the system and only adjusts one map, it theoretically can run the motor lean if it's not selected. Link to comment Share on other sites More sharing options...
Sgt.Gator Posted February 3, 2018 Share Posted February 3, 2018 Right now I have an Accessport V3, running Stage 1 tune with an Invidia Q300 cat back. I've read several debates on the SI drive, so is each selection an actual different map that can be individually programed or is it just an adjustment to the base map? I've been kind of worried about that, because if a tuner doesn't know the system and only adjusts one map, it theoretically can run the motor lean if it's not selected. When Cobb Surgeline did my Si drive in my Spec B they made one map for the Si Drive with 3 different max boost limits on the turbo wastegate. So there is no chance of running too lean, it only controls the psi. The Subaru ECU is not capable of on the fly map switching, but with the Si Drive only controlling boost pressures, you can switch as needed while you drive down the road. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
solidxsnake Posted February 4, 2018 Share Posted February 4, 2018 I see this misunderstood a lot, but in general, SI drive essentially only changes the drive-by-wire throttle mapping. The different boost limits are a side-effect, since in essence, the boost tables are determined by throttle position and RPM. In other words, putting the car in S# and never pressing the throttle past some point (say 50%) is no different than just setting the car to I mode. I'm simplifying it, but there is no way with the stock ECU to actually use SI drive as a true boost controller. Link to comment Share on other sites More sharing options...
d22597 Posted February 4, 2018 Share Posted February 4, 2018 I see this misunderstood a lot, but in general, SI drive essentially only changes the drive-by-wire throttle mapping. The different boost limits are a side-effect, since in essence, the boost tables are determined by throttle position and RPM. In other words, putting the car in S# and never pressing the throttle past some point (say 50%) is no different than just setting the car to I mode. I'm simplifying it, but there is no way with the stock ECU to actually use SI drive as a true boost controller. This isn’t how I understood it working with Cobb’s “boost select” feature. In addition to throttle maps, I thought you get 3 requested torque tables (one for each SI mode). You only get one target boost table, but effectively you’re able to set different boost targets since requested torque values have different target boost values. Link to comment Share on other sites More sharing options...
BrucesOutbackXT Posted February 4, 2018 Share Posted February 4, 2018 In Fueling-injectors you have 4 different setting charted. A,B,C,D all effect how long the injector sprays fuel. In Ignition-Timing-Advance you have 4 different settings charted. In Drive by Wire Throttle there are 8 different maps there are different demands for Torque in them. SI Sharp is the highest most aggressive. The ECU has quite a complex system incorporated . In Drive By Wire map you have two maps for each selection and Limp mode. Link to comment Share on other sites More sharing options...
shralp Posted February 4, 2018 Share Posted February 4, 2018 Cobb Surgeline just did this for me on my Outback when it went in for a dyno tune after my new shortblock/rebuilt heads/JMP upgraded VF52 install. I, S, S# settings are 14.5, 16.5, and 17.5 lbs, respectively Link to comment Share on other sites More sharing options...
solidxsnake Posted February 4, 2018 Share Posted February 4, 2018 d22597: That's correct. My point being that all it's really doing is changing the what requested torque maps to accelerator position. In other words, if you were to physically limit the pedal to not hit 100%, then you could effectively emulate "I" mode while in S# mode (because you would limit the maximum requested torque). In actuality, for a stock ROM the S and S# modes top out at the same exact power, but change the profile of the DBW mapping. You can effectively change boost targets by scaling the S table to top out at a lower value, but my point is that all you're really doing there is effectively pressing the accelerator less. Not saying it doesn't have it's use, but I think a lot of people think that the ECU has three completely different maps, and that's not the case, at least for boost. It's possible with the stock logic to blend the TGV open/closed maps, and if you're clever, you can use the built-in logic to have two effective maps for pretty much everything besides boost and fuel (which I guess leaves ignition and AVCS). This is assuming Cobb hasn't added a ton of extra logic and tables in their ROMs, which I think is unlikely. Link to comment Share on other sites More sharing options...
BrucesOutbackXT Posted February 5, 2018 Share Posted February 5, 2018 Today I blue tooth my OBXT and found what figures. Stock rom loaded for this test. Android / DashCommand app and Torque (Lite) this because paid for version would not install. :-( I used Torque just to check the Boost in #SI S and I modes. Found max-boost came on Gage @ 15-16 psi but only in I mode. seems Turbo's sense engine Load and boost rises on Loading. I mode keep it in a higher gear than sport or sport I. In #Sport I It ran the least boost. never went over 12 psi. but the HP in I mode only shown 243hp in The DashCommand app. But switch the system into #SI were the boost was lower runing the HP clocked some interesting numbers. http://www.vadatachat.com/obxt320%20hp.png 320 hp Link to comment Share on other sites More sharing options...
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