quartus Posted November 19, 2009 Share Posted November 19, 2009 Can I bump up the boost on my 86 GL-10 EA82T? I'm only getting ~ 5psi full boost. Link to comment Share on other sites More sharing options...
eulogious Posted November 19, 2009 Share Posted November 19, 2009 If you are not getting 7 psi, you probably have an exhaust/vacuum leak some where in the system, and that's why you can't hit 7 psi. That or something is up with the waste-gate setup... I am not exactly sure what, but those would be where I would start. In my 1990 Loyale ea82T with 198,000 miles on it, I hit 7.5 psi WOT, no mods done, bone stock. As for the boost controller, you can get a manual one and use that to adjust the boost and plumb it in. Just google for it. I believe any manual boost controller will work, but I wouldn't mess with the stock system too much. The ea82T is a picky son-of-a-bi@#h, so I would leave it stock. I personally want it to last as long as it can, and when it goes, its EJ swap time I will never up the boost, it just equals trouble. That just my 2 cents. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 19, 2009 Share Posted November 19, 2009 5 psi is wastegate pressure. Sounds like your boost control isn't working. It's important to find out why as the computer may have a good reason for reigning in the boost - malfunctioning knock sensor, etc. GD Link to comment Share on other sites More sharing options...
quartus Posted November 19, 2009 Author Share Posted November 19, 2009 5 psi is wastegate pressure. Sounds like your boost control isn't working. GD So you're saying my wastegate is opening and limiting my boost to 5psi? Parden my noobyness (1st turbo) but I thought the boost control was physical, ie wastegate spring strenght and the pressure (vacuum?) applied to the diaphragm module(?) attached to the wastegate. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 19, 2009 Share Posted November 19, 2009 The wastegate is set for something *below* the max boost setting. This allows the computer to open the wastegate when it determines boost has reached a preset max. The VF turbo's generally have wastegate's set to open at right around 5 psi. Then the computer holds back the manifold pressure till it's preset is reached and allows the wastegate to open via a PWM solenoid. If, for any reason, the computer determines that full boost is unsafe, then it just opens the PWM solenoid at 100% and you get boost only to mechanical waste-gate pressure. GD Link to comment Share on other sites More sharing options...
quartus Posted November 19, 2009 Author Share Posted November 19, 2009 If, for any reason, the computer determines that full boost is unsafe, then it just opens the PWM solenoid at 100% and you get boost only to mechanical waste-gate pressure. GD I think I have a purely mechanical setup, I just tinkered with it and it appears that the pressure/vacuum diaphragm attached to the wastegate has just a single line going straight to the turbo (intake manifold side) discharge hence the wastegate opening is "assisted" by intake boost pressure. I tested this theory by disconnecting the vacuum (pressure) line from the diaphragm and test driving it. The boost went easily pass the 5psi and I stopped boosting at 9psi (for fear of blowing out something) but it could of went even higher (maybe the psi equivalent of the spring tension holding the wastegate shut). I didn't see any obvious adjustments to the diaphragm to limit the "assist". Anybody have any experience with these? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 19, 2009 Share Posted November 19, 2009 (edited) Your's has been modified then. The wastegate should not be run directly from the manifold like that. It is possible to increase the wastegate spring pressure, yes. I had a friend that put a VF7 on his Samuri and he opened the vacuum pot and replaced the spring inside with a lower rate spring. The wastegate at that point was set to open around 1 psi. Then he added an external spring to the arm and an adjustment bolt to adjust the tension. With a little experimentation he was able to adjust it to 4 psi where he wanted it with a high-comp. motor. You could do the same - just add a spring and adjustment bolt to the wastegate arm to keep it closed till the pressure rises enough to overcome the additional spring force. It's not a difficult thing to fab up. Also - wastegate's aren't "assisted" by the pot. That is their sole source of power to overcome their closing spring's. Without the wastegate pot it will easily boost to 20 psi or higher before you start to see turbine surge. The EA82T won't make it that far though. Without that pot..... there is NO wastegate. The ECU will also cut off your fuel somewhere around 10 or 12 psi. GD Edited November 19, 2009 by GeneralDisorder Link to comment Share on other sites More sharing options...
eulogious Posted November 19, 2009 Share Posted November 19, 2009 The wastegate is set for something *below* the max boost setting. This allows the computer to open the wastegate when it determines boost has reached a preset max. The VF turbo's generally have wastegate's set to open at right around 5 psi. Then the computer holds back the manifold pressure till it's preset is reached and allows the wastegate to open via a PWM solenoid. If, for any reason, the computer determines that full boost is unsafe, then it just opens the PWM solenoid at 100% and you get boost only to mechanical waste-gate pressure. GD Good to know... I learned something new about my turbo setup, thanks GD! Link to comment Share on other sites More sharing options...
quartus Posted November 19, 2009 Author Share Posted November 19, 2009 (edited) ... wastegate's aren't "assisted" by the pot. That is their sole source of power to overcome their closing spring's. Without that pot..... there is NO wastegate. GD OK now it makes sense, the pot is the controller and the wastegate is kept closed by the spring when its not being "controlled". Thanks, now I see I have a mod to make and I know the turbo is good! Has anyone already done this mod successfully, some photos would be great! Edited November 19, 2009 by quartus Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 19, 2009 Share Posted November 19, 2009 It would be easier to just get a manual boost controller - they are cheap and you can dial in whatever boost you want. They just install between the manifold and the wastegate. GD Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted November 19, 2009 Share Posted November 19, 2009 Do not skimp on your boost controller. Yes, you should get a manual boost controller to up your PSI... but do some research and get a good one. I spent $40 on ebay and got a GFB (Go Fast Bits) MBC (manual Boost Controller) for my EA82T. It worked WAY better than the cheap $10 peice of crap i bought before that (some home-made hackjob...) Your ECU monitors intake pressure, and if it goes past 11psi the ECU shuts down the fuel injectors. So you can go up to about 11psi before you reach a limit. However, I wouldn't touch any of this until you have an intercooler installed! Also, find a real bypass valve (not a blow-off valve) and install that in the system as well. Would be a good idea to research turbo setups and how they need to be plumbed. The EA82T is primative and doesn't come with a BPV. Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted November 19, 2009 Share Posted November 19, 2009 Here's a picture of my old setup. Its a EA82T from a 1987 RX Coupe. Should be identical to yours. The Intercooler is from a SAAB 900. The Bypass Valve is as well. The Bypass valve is a generic bosch unit you can find on alot of turbo cars. They have a metal version and a plastic version... metal obviously being the better. The routing of everything is pretty crude and could be done alot more efficiently (like mounting the actuall bypass valve as close to the throttle body as possible). Look at the passenger side strut tower, and you will see a copper valve with a handle on the backside. THat is my manual boost controller. That is the $10 peice of crap I got 1st, and it had a bad problem with "Boost Creep". It also wouldn't hold pressure and my boost would spike alot. It was very annoying and worried me. All of that was solved after installing the GFB MBC. Have fun but be careful. Didn't take long at all to blow the engine up after these photos were taken. The EA82T's are not known for their reliability like all other Subaru engines. Link to comment Share on other sites More sharing options...
Turbone Posted November 20, 2009 Share Posted November 20, 2009 I suggest reading thru this thread - http://www.ultimatesubaru.org/forum/showthread.php?t=88249 It has alot of good info. I was in the same boat as Junkie, bought a cheap MBC but I had worse results than he did. I broke the ring landings off a piston. So, after getting a rebuilt engine, I broke it in then slowly did my mods. I'm using a Hallman MBC now, it works great. I can dial in up to 12lbs, thats where I hit the fuel cut. I run at 10lbs tho, I need it to last the winter. Heres what my setup looks like. Link to comment Share on other sites More sharing options...
vagen Posted November 20, 2009 Share Posted November 20, 2009 (edited) my setup is a lot like turbone's I learned my lesson building turbo datsuns so I knew before anything cool the charge. I'm currently using a $5 Ebay MBC but I have modified it to actually work and I see a steady 9.5 psi. below is a photo of my setup note the BPV (Bypass valve) routes boost pressure back to between the turbo and afm. it opens only when the throttle is closed. this keeps the turbo spinning at speed so when you shift the turbo will reach boost faster. A BOV/BPV will extend the life of your turbo because the turbo doesn't deadhead against a closed throttle. Dead heading will actually stop or even spin a turbo backwards imagine what the bearing is going through when that happens. Edited November 20, 2009 by vagen Link to comment Share on other sites More sharing options...
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