14b to s16g, no boost unitl 4500 rpms?

[dsmike]

replaced my 14b with a small 16g (ported and clipped) this wknd. only free mods, 2.5 exhaust, and 190 fp. no boost all the way to 4000 rpms, then 4500 i get about 2 psi. full boost of 16 psi at 6500 rpms?

ps: i have spent the last hour and a half searching, but didn't find posts with similar problems.

 

[flytalon93]

Possible boost leak somewhere?

 

[dsmike]

no boost leak, but the wg seemed a little loose. tightened that, now boost starts at 3700 rpms, full boost at 5500 rmps. are the 14b and s16g wastegates interchangable?

 

[JJNovo]

I had a similar problem once.
It turns out the bushing that the wastegate flapper shaft rides in, worked it's way partially out of the turbine housing. This caused the flapper to become stuck in a 1/4 open position. And over time, caused a crack to develope in the flapper seat(?).

I found this during a change over to a 16g. With the turbine housing removed, I tapped the shaft and bushing back in with a mallet. Then it work freely, but I bought a new turbine housing with the 16g so did not reinstall the old one.

 

[dsmike]

damn, i really didn't want to pull the turbo. any way to rig without removal?

 

[JJNovo]

If you first remove the actuator arm, does the flapper move freely? If not, try the below.

Have a look at the bushing. If it looks like it is out of the housing more than 1/8" - 1/4", then that could/would possibly be the reason for your boost not building at lower rpms (stuck flapper).

I think that if you removed the one or both of the rad fans, that would give you enough room to work with.

 

[dsmike]

thanks, i'll try that tonight. so the air may be escaping before it has enough time to build boost?

 

[JJNovo]

Exactly.

 

[Blk95gs]

im having the same problem. I called Forced Performance, and they advised me that sometimes the actuator arms can become slightly bent in shipping. My wastegate stays slightly open at idle because of this, and i make boost around the same time as you. try putting on the 14b actuator and see if you still have the same problem. if not, then the arm is bent on the 16g one. so bend it back if it is.