Boost Creep...

[Mr Peepers]

Been fighting it for a while on other peoples' setups and been fairly successful. But of course, it ends up I can't cure it on my own

14b with a 7cm^2 turbine housing, 3" turboback with no cat, only a 3" vibrant resonator. Dejon super sidemount, piping, etc etc.

Ported the turbine housing for creep(twice since I thought I may have problems holding boost if I went too far) and moved the pin on the flapper arm so it could open near 90*. Creeps above 15 psi towards 20 around 4.5-5k. Unhooked the WGA arm completely so the flapper could be open ALL the way and it STILL creeps to 20 psi by 4.5-5k in higher gears.

Don't know what to do at this point, it's a 14b for crying out loud. Guess I'll just have to run 20ish psi, luckily I haven't seen more than 1 count of knock; oddly.

Boooo. I still find it ironic though.

 

[fwdmaster]

Didn't you cure your boost creep with your modded wastegate actuator?

 

[Mr Peepers]

If it still creeps even with the WGA arm disconnected, no MWGA is going to help; sadly. With the way the flapper lever is set up with the "flapper adapter" it essentially does the same thing. Since it creeps the same with the arm attached and detached, the flapper travel isn't the issue. Just a very creep prone setup.

I may try a 6cm^2 housing and see if that helps, although tapping the 14b for all it's worth sounds more entertaining.

 

[Grescht]

gotta love creep. My E316g Creeps like there isn't a wastegate at all. It's at 20psi before the end of the launch. It's in the shop gettin ported tho. I bought an external dump for the internal gate. Maybe it'll help.

 

[grantman10]

I noticed something when i had a external dump o2 housing, then switched to a 2.5" stainless housing. The external 02 housing's wastegate passage will outflow any other 02 housing, because it has a super unrestricted outlet (duh). So an external 02 housing is beneficial if ones current 02 housing's wastegate passage is restrictive, but will not overcome poor turbine housing design restrictions.

After seeing no creep with the external 02 housing, when i switched to the 2.5" stainless I crept to 16-17 psi by the end of third no matter what. While i could hold 12psi to redline with the external 02 dump.

This is on a ebay 16g (unported) , 2.75-3.0" megan racing downpipe, no cat, and a full 3" stainless mandrel bent exhaust with two 4" resonators (japanimportshop).

YMMV

 

[grantman10]

What o2 housing is on this car? Is it possible that the 02 housing is the restriction and not the turbine housing? I know its a long shot.

I mean, if it still creeps with the arm disconnected, a restriction in the path of the wastegate gasses could still cause the creep, regardless of how easily it could flow through the turbine housing. Or is that statement false?

 

[Imback]

Oh the irony ..... It's ok i'm creeping too and followed your instructions to a T. Guess were in the same boat. =) 21LBs here i come.

 

[JusMX141]

You have too little exhaust restriction, Peepers. Changing back to the 6cm2 housing might remedy this, but you'd be losing flow at the turbine itself which really isn't worth it.

Try adding a little backpressure to your exhaust system. I think you'll find the boost creep problem will solve itself.

The only other solution may be an o2 dump, which would be annoying but have less retriction than the exhaust system you're currently running.

 

[IMANDREW18]

hey i know this is a blog about your problem but i have the same exact problem. i am worried to say the least... help me

 

[Mr Peepers]

It is extremely free flowing and that's probably 99% of the problem, but I don't want to add an exhaust restriction to control the creep; then it'd win

The o2 housing seems like the last possible cause, besides perhaps that my 7cm^2 housing was cast/machined a tiny bit differently and in turn doesn't have the little "lip" at the bottom of the WG passage to catch much exhaust gas. I would love to throw an evo3 o2 mani on since it actually has a very different casting compared to 1g and 2g o2 housings but I don't know of any for cheap at the moment. I will port mine out a little bit and see if there is a noticeable difference, otherwise maybe make my own tubular one. I can't go o2 dump, that'd ruin my ability to get into boost without the entire neighborhood knowing and be all sneaky like.