Too much boost

[nicknorth11]

I've changed some things over the last year or so (since I've last boosted the car regularly) and now boost won't go under 20 psi or so. (I haven't removed anything turbo/manifold related, though.) I have an internally gated 53051re (ball bearing pte 50 trim). I called PTE and they said they only sell 10/11 psi and 15/16 psi springs. I have bypassed everything else and connected a new hose directly from the turbo housing to the wastegate actuator and it still won't go below 20 psi. The flapper moves freely. In a desperate move, I attempted the spring mod, found here: http://www.dsmtuners.com/forums/art...r/211040-how-mod-your-internal-wastegate.html I initially tried with one spring and then added another 1/3 of a spring. Neither did anything.

Any ideas what I'm up against here, or how to fix it?

 

[born2tune]

stupid question, are you're vacuum lines good and right?

 

[nicknorth11]

Yeah.

 

[ypnas777]

What have you changed?

 

[dsmvenge]

Did you do anything to the exhaust or ic piping. Sounds like your getting some nasty spike

 

[nicknorth11]

Fuel system, cooling system, ignition system, throttle body, switched from mbc to ecmlink controlled boost. I don't see how any of these things would have an effect given that I bypassed everything and ran a single hose from the Turbo housing to the waste gate actuator.

Is it possible that the actuator diaphragm could've gone bad from sitting too long?

I was doing some research and found that it could be build-up on the flapper.

Any thoughts on either of these things?

 

[supravw]

My money would be on a damaged diaphragm in the wastegate, that was my first thought actually. Build up on the flapper would just cause a slower spool, sense it's not keeping the flapper from moving freely. Try a different wastegate and see if that works.

 

[turboglenn]

I've seen issues like this on a friends SRT4 with a ball bearing 50 trim also (ironically) anyway, his wastegate wasn't opening enough to get the boost to stay low (like many people's troubles with spiking and creep on 16g's)

I ended up pulling the turbo apart and portingthe living ish out of the housing and wastegate hole. Then modified the wastegate's mount to allow it to open further/easier (almost no preload on the gate flapper and arm) this helped a great deal on his but it wasn't until he went to an external gate that the problems were solved 100%

thing is the turbo (and this is just my theory) was so easily spooled from being bal bearing, and the wastegate opening wasn't near enough to bypass enough exhaust and this caused him to have boost that wouldn't go below a certain psi (it was more like 22psi or so on his car)

by the way, the spring idea looks like a pretty good solution to what we did with modding the WG actuator mount.

I have one question though, you have more than enough fuel and great management, why are you looking for anything under 20psi? ( i would gess traction in first gear maybe ) but really that turbo although in it's efficiency range at 17psi, it really isn't waking up and making great power until about 24psi or so and if it were me i wouldn't be looking for anything under 20psi unless it were an issue with FWD traction in 1st and 2nd gear. but either way it's your car and your choices as to what you do with it.. i was just wondering

best of luck on it,

 

[nicknorth11]

Thanks Glenn. I probably wont mess with this turbo anymore since I want to switch turbos anyway.

You are exactly right about the boost level. 1st and 2nd gear need to be lower boost.

 

[nicknorth11]

So I've talked to PTE and they also think it is the diaphragm. The good news is any mitsu PTE turbo internal gate will work as a replacement for mine. So if anybody has one, let me know!

 

[nicknorth11]

Well, I finally went out and got a new regulator for my compressor. Turns out I'm lucky to only be boosting around 20psi. The actuator doesn't fully open until 28psi! I found a used 10psi actuator really cheap that will work great for the cold weather, and I'll keep my eye out for a 15psi one. Thanks for the help everyone.

 

[macks96boltdsm]

do the awd swap thats what im about to do then all problems are solved

 

[nicknorth11]

I'm gathering up the parts right now and plan to do it next winter (or earlier if I'm lucky).