EVOIII 16G, cant control the boost...

[TurboDreamzGST]

Ok so I have a 98 GST Spyder, the list of mods are an ebay version of the ported EvoIII 16G turbo (i couldnt afford the Mitsu version so please dont judge), Megan Racing O2 Housing, 3" custom cat-back exhaust, Greddy type-RS BOV re-circulated,autometer boost gauge, and a manual boost controller. After recently blowing my T-25 i needed a turbo fast because this car is my daily driver so I picked up the EvoIII off ebay and after the entire installation is done, I'm driving the car and noticed the my boost gauge is easily reading 22 PSI at only about 3/4 throttle and no where near redline so I quickly let off and tried adjusting my MBC. i had no luck because even with the MBC turned all the way down, the turbo is still easily hitting 22 PSI with much more left in it, so I took a MBC off of my friends 95 GST and put it on mine because I thought maybe my MBC wasnt working properly but once again, no matter how much I turned down the MBC, my boost was still unbelievably high. I know for a fact that the controller is hooked up right because Ive installed MBC's on my 2 previous DSM's with no problem and I also checked VFAQ.com and some posts on here just to make sure that I wasnt going crazy. I even went as far as to change out my boost gauge thinking that maybe mine wasnt working properly but still no luck. I really dont feel that I have the supporting mods to be running anywhere near 22 PSI or greater (because if i kept my foot on the pedal, the boost would surely rise above 22 PSI) and I just need help figuring this out. I did notice that the wastegate actuator arm is threaded, should I tried seeing if i can move that either further into the wastegate or back it out of the wastegate? I'm just lost and dont have a clue on what to do but like I said this is my daily driver so for now i'll be baby-ing it because I'm not in the mood or financial situation to replace the motor or turbo all because i cant control this boost. BTW the boost isnt jumping around either, it seems pretty steady. Please please please help!

 

[Dert]

ebay turbos are know for having stuck wastegates that need to be adjusted as stated above and in alot of cases replace the actuator, you can pick one up for cheap or even replace with your stock one and it will most likely solve your problems, most ebay turbos are set at about 9psi so your mbc should work providing you installed it correctly

 

[JusMX141]

Now that everyone keeps mentioning boost creep it made me start thinking...would I first put the turbo on I had the Megan racing O2 housing on and than the rest of the exhaust was stock and the turbo was still boosting at the same of around 22 PSI at 3/4 throttle and after the cat-back exhaust it still did it so would this problem I'm having still be boost creep related?

It could still be a result of the tiny hole, or your wastegate actuator diaphragm has a hole in it. If the diaphragm has a hole, the wastegate would never open which would definitely result in an overboost situtation.

 

[cody92talon]

i agree with him your diafram could poosibly have a hole. i thought mine was boost creep to but like i said in my other post my ebay 16g had a screwed up actuator an i just replaced it with my stock one an it fixed it

 

[viperlp01]

Im sure it is the damn arm guys ... My ebay turbo did that same thing and my buddys... Adjust it to be just tight on the arm and the boost controller i made works like a champ.. I hold 20 psi all day... One problem i have is the wastegate flapper arm(the piece that enters the hot side that holds the flapper) slides out and leave a part of my wastegate hole open so it results in a slower boost but i still eventually hit my target boost..

 

[JusMX141]

One problem i have is the wastegate flapper arm(the piece that enters the hot side that holds the flapper) slides out and leave a part of my wastegate hole open so it results in a slower boost but i still eventually hit my target boost..

This must be more of an issue than I thought it was!

Anytime I get an eBay 16G in at the shop I make sure that the sleeve (the part you're describing) allows the flapper to be centered perfectly over the hole, then I tack weld the sleeve to the housing in three or four places to prevent it from moving.

 

[jeffo]

if i hit the gas in second gear the turbo easily maxes out my boost gauge at 20psi and soon hits fuel cut. and also if i get on it in third, my boost gets at roughly 12psi and doesn't go any highter.

That's exactly how my car was until I had FP port the turbine/wastegate. If I jumped on it in first or second the boost would just climb to 24-25psi.

 

[asg1089]

this is on an mhi evo3 anyways not the ebay one. so you say send the turbo out and get it ported and it will solve all of my problems? or should i just get supporting fuel mods and say screw it? or just do both and be safe on either end? hahaha thanks for the help

 

[14spectre88]

this is on an mhi evo3 anyways not the ebay one. so you say send the turbo out and get it ported and it will solve all of my problems? or should i just get supporting fuel mods and say screw it? or just do both and be safe on either end? hahaha thanks for the help

I say get a MBC first of all. How do you expect to control boost without one? Once you do that and you're experiencing boost creep read this. If you want to run over 16 lbs. of boost with your 16g you need the fuel mods for sure. But the only way to control boost is with a manual boost controller...it, in my opinion, should be the first thing on your list.

 

[asg1089]

yes, i agree it is first on my list. i'm going to go with the hallman pro with the cockpit controller. along with the supporting fuel mods. but thanks for your help.