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!

 

[JayRolla]

You need to tighten up the wastegate arm because its adjustable. After that you may have some boost creep if the turbo has not been ported to stop it.

 

[TurboDreamzGST]

When u say tighten up the wastegate arm, would the arm b going into the wastegate or threading out further?

 

[viperlp01]

You actually need to loosen it up.. Loosen the arm until you have to stretch it on just barely... You will take off the c clip that holds the arm to the wastegate flapper and the spin the arm out to loosen and then put it back on and put he c clip back on...

 

[TurboDreamzGST]

Oh ok that seems easy enough...thanks for the help! After I do this, is there any possibility that a MBC will work?

 

[tjbiker031]

It should, the wastegate and MBC basically work together.

 

[TurboDreamzGST]

Ok...so basicly I take the c-clip off the arm where it is held to the flapper and than thread the actuator rod out of the piece that attaches to the flapper and re-install and this will lower my boost, correct? Than once this is all done I should be able to re-connect the MBC and it should work as well right?

 

[jeffo]

The EVO3 16G is notorious for boost creep. I recommend sending the turbine section to FP. They do a fantastic job porting the wastegate area, and I can now set my boost anywhere from 10-25psi and have it hold rock steady.
keydiver

 

[JayRolla]

I meant to say loosen the arm, that was my bad.

He is having boost control issues, we will deal with the creep issues once he gets the boost lower at least. Also its pretty easy to port the turbo yourself, a lot cheaper than sending it to FP to do the same thing he can do himself.

 

[JusMX141]

The problem is the 22mm wastegate hole in the knockoff turbine housing. The Chinese are generous enough to supply you with a 34mm flapper, but the hole they drill in the housing couldn't properly control boost on a weedeater. Don't bother sending it to FP....they'll laugh at you. You can port it yourself with an electric die grinder and a carbide bit.

You need to turn this:

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into this:

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The MHI version of this turbo is bad enough at controlling boost....the Chinese version is even worse. I hate to be the first to say it, but you get what you pay for with a $220 turbocharger.

 

[TurboDreamzGST]

It was already ported when I bought it

 

[JusMX141]

Practically every listing advertises the knockoff Evo III as "ported" as well as "clipped". Clipped, they are not.

The knockoff turbine housings are cast from a ported MHI housing, but they're not really "ported". The wastegate hole itself will be as shown above unless you used a tool bit on it before you installed it.

 

[TurboDreamzGST]

So basicly even if I adjust the waste gate arm I still won't be able to lower the boost?

 

[JusMX141]

The problem isn't the tension of the arm, it's the tiny hole's ability to transfer boost pressure past the turbine housing. This is also known as "boost creep", and is normally a result of an exhaust system that flows too freely.

Boost creep can be so bad that in some cases guys are able to remove the actuator arm altogether and let the flapper open freely, and the turbo will still generate over 20psi on it's own.

 

[14spectre88]

So basicly even if I adjust the waste gate arm I still won't be able to lower the boost?

Just as JayRolla said: Take care of the actuator first and if you have boost creep deal with that. I'd definitely port it yourself (I am a strong believer in 'if you want a job done right, do it yourself'), you'd probably be spending as much on buying the tools needed as you would on paying for it. Plus, you may need to port other parts later on and this would be good experience for you. Just my two cents...

P.S. One thing I didn't mention is your actuator may be broken. This happened to me a while ago and I had no boost control whatsoever. I bought a new one from road race engineering and that fixed the problem. This might not be your problem but it COULD be.

 

[TurboDreamzGST]

Ok so if I port out that waste gate flapper, that will drop my boost down to a safe level and than I'll be able to use the MBC in the future to raise boost when im ready?

 

[14spectre88]

Ok so if I port out that waste gate flapper, that will drop my boost down to a safe level and than I'll be able to use the MBC in the future to raise boost when im ready?

Assuming the actuator is functioning properly and you have boost creep, yes, porting it should help fix it. Here's a tech article you can read up on:
boost creep wga mods

 

[Dsmj89]

How about you save yourself the headache and just go external wastegate ? That's what i'm doing.

 

[14spectre88]

How about you save yourself the headache and just go external wastegate ? That's what i'm doing.

He already said he's on a tight budget...

 

[Dsmj89]

Sorry didn't see that.

 

[ba109296]

Did you try to loosen the arm up yet? I have the road race version of this turbo and I can control boost pretty well. Actually if you get rid of the boost controller you can pretty much control the boost with the actuator arm.

 

[dylnwit]

Take the arm loose, and drive it around a little, If your still boosting like crazy even though the flapper can freely move, then it's boost creep. If you can barely boost, then it's actuator related.

I'm not doubting Justin on this, he knows a lot more about turbos than I do, but this is the quickest way I know of to test this without pulling the whole thing off the car.

 

[cody92talon]

your actuator is bad. i had just bought one a little while back becuase i was short on cash. an mine would only hold 10 psi then fall away to 5psi. even with a MBC no matter how far in i turned it it still wuoldnt go up. so i replaced the actuator with my stock one. and it fixed it you'll have to reem the hole out that slips on to the flapper arm because the stock one is slightly smaller but after u do that it will fit.

 

[asg1089]

alright well i am having similar problems with my recently upgraded evo3 16g. 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 gits at roughly 12psi and doesn't go any highter. i do not have a mbc and my turbo is not ported in any way. so the general idea that you guys are saying is to first extend the wga as much as possible and see if that helps. and if that does nothing to run the car with the wga not attached and see if it still reaches full boost? i'm somewhat confused on what is being said here. help is greatly appreciated. thanks.

 

[TurboDreamzGST]

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?