my turbo gone?

[giovanniv]

Ok so when I 1st got my mbc I turned up the boost on my little 13g turbo to 14lbs and it pulled pretty good and everything until about 2 weeks ago. The only thing that I can think of that I changed was that I put on an hks ssq bov then I switched to an evo mr bov so that isn't problem. My problem is that my turbo takes very long to spool to full boost. Like it feels somewhat laggy. It used to reach full boost around 4k rpms and now it doesnt reach full boost till around 6k rpms and this is at WOT. There is NO shaftplay at all or anything. What do you think my problem is? I'm not sure if it's a boost leak because my boost guage reads -23 vacuum (guage is a little off). Anyone know what can possibly be wrong?

 

[LiquidX]

If you think it's a boost leak, then do a boost leak test. Also check to see if the wastegate is working properly. Could be stuck open and exhaust gasses are bypassing the turbine.

 

[giovanniv]

No I said that it couldn't be a boost leak bro but I will check on the wastegate flapper.

 

[LiquidX]

Regardless, you should still do a test to be sure. I'm sure others will say the same on that.

 

[giovanniv]

Regardless, you should still do a test to be sure. I'm sure others will say the same on that.

Ok I will do one soon but I checked on the wastegate and it is fine. I was supposed to be checking if there is any movement in the arm correct?

 

[LiquidX]

Yes, you want to make sure the wastegate works by testing the actuator and also disconnect the arm and check to see if the flapper freely opens and closes.

 

[giovanniv]

How do I disconnect the arm?

 

[LiquidX]

There is a peg on the wastegate flapper and the arm attaches to that. First pull off the clip keeping if from popping off and then work the arm off of that. If you can test the wastegate with a compressor by pressurizing it at the vacuume inlet and the flapper opens, then it's not stuck. Just fyi.

 

[giovanniv]

I just did a blt and I got ALL leaks that it had. The little hose coming off the wastegate was ripped a little. I took it out for a spin and it feels a little quicker on the spool time but it's still hitting like 4k rpms then full boost which is now 12lbs.

 

[LiquidX]

Is that full boost at 4k like it used to be at?

 

[giovanniv]

No full boost used to be hit at around 2800rpms. But I have read that when you have your base ignition timing set retarded, boost is built up faster and since then I have advanced my ignition timing to around 5*....

 

[JusMX141]

I'm not sure if it's a boost leak because my boost guage reads -23 vacuum (guage is a little off).

No I said that it couldn't be a boost leak bro but I will check on the wastegate flapper.

Vacuum is read at the manifold between the throttle body and the intake ports on the head. This would only be an accurate method of checking for leaks between the throttle body and the head....but unforunately there's about 12 feet of piping between the turbo and the throttle body where a boost leak could be present.

 

[giovanniv]

Well when I did my BLT it was holding 20lbs for way over 30 seconds so I don't think that there is a boost leak anywhere....

 

[JusMX141]

Ah good....I just wanted folks to know that using the vacuum gauge as a boost leak tester isn't an accurate method.

I'd point my finger to the wastegate system, possibly the flapper is stuck open slightly.

 

[giovanniv]

Hmm well I have a spare 16g wg flapper sitting in my garage that I know works but is it the same as the one on my 13g so I can just swap them? I think they are arent they?

 

[JusMX141]

Do you mean the flapper, the actuator, or the entire turbine housing?

Flapper itself yes, actuator yes, entire housing no.

 

[giovanniv]

Ya I meant the flapper and actuator. But wouldn't there be a little play in the actuator and like the rod if the flapper was slightly open?

 

[JusMX141]

Ya I meant the flapper and actuator. But wouldn't there be a little play in the actuator and like the rod if the flapper was slightly open?

Not if the actuator's in the fully closed position but the flapper is hung open a little.


The sleeve could also walk out of the turbine housing slightly, which wouldn't allow the flapper to cover the hole completely. This would be the result:

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[TofastForU_99]

yes check the flapper. i recently had a 14b that the flapper worked itself over and was not over the hole. my boost took forever to spool and it ended up melting and cracking.

 

[giovanniv]

Ok and if it is the flapper that isn't fully closing is there a way to adjust it or would I just have to replace it?

I read another one of the threads where you helped out jusmx and it was about the sleeve being out of the housing. You said to slightly hit it with a hammer till the flapper closes. Well my question now is can I tap that slightly while the turbo is on the car? Like I don't want to go through the hassle of taking it all apart just to hit in the sleeve a little (I would take it apart but I am leaving on vacation in about 3hrs.) Like since you can obviously tell if the sleeve is moved out or not do you think it is possible to just tap it back in?

 

[Jets303]

The wastegate flapper could have warped a bit??? Tap it back in place and make sure its flush