BW S256 Tial 40mm...Boost Creep

[1997hciv]

Well I have been dealing with a boost creep issue for a while now and I have tried everything I can think of except changing my entire set-up which is looking better everyday. I have a BW S256 with an external 40mm wastgate dumped into the atomosphere with a punishment racing O2 housing. This O2 and wastgate setup has been run on all of my setups dating back to my EVO 3 16g 6 years ago. Ok so the wastegate opens up at 15psi around 3800 rpm then like it should but then the boost just keeps going past 22psi before I have to let off the throttle. I took apart the wastgate and the diaphram doesnt have any holes in it but it does look used. I have even tried to run it without my BC but still the same result. Also it creeps more in the cold weather. Please Help!!

 

[T9S1i]

What spring is in the wastegate?
Where is the wastegate located? Manifold, or o2 housing?

I would just suggest that you upgrade the fuel system so that you can just run higher boost! Thats the best method of fixing boost creep! haha

 

[1997hciv]

Haha thats funny. I have link with 850's, rewired 255lhp so fuel is not the issue. I can run over 20 but being as how this is my DD I dont want to push it. It is located on the O2 housing with a 1 bar spring I think the color is green.

 

[TurboAnything]

Did you port the wastegate hole in the turbine housing? That hole is not very big untouched.

 

[1997hciv]

No I did not touch it, I was trying to avoid that as I dont have any experience with griding even though there are many articles on it I just dont trust myself but a buddy of mine is letting me borrow his 38mm O2 setup to see if that helps and if not then it will be porting time or replumbing the whole system but if it does that means its the wastegate or the internals such as the actuator or diaphram but I will just buy a new seeing as how the ol 40mm has seen better days.

 

[Steve93Talon]

You absolutely have to port the hole on the turbine housing to run an o2 mounted gate without creep. Take a look at how the FP bolt-on housing is designed to get an idea of how much flow the gate should have feeding it. I attached a pic of a ported BEP housing that was able to hold about 21psi to redline without creeping.

 

[1997hciv]

OK so I guess I am going to have to port it because I do not want to change my entire setup. I have been reading the forums on how to port the turbo but it was mostly on the 16g's with an internal gate. Steve, could I port the wastegate exit hole a bit since I dont have a flapper but instead have an external 40mm?

 

[Steve93Talon]

could I port the wastegate exit hole a bit since I dont have a flapper but instead have an external 40mm?

Yes, that's exactly what you need to do. The housing in the pics was using a 38mm external gate on the o2 housing with no creep.

 

[kawboy]

Whats a good way to grind on the BEP housing? It's pretty tough

 

[cheap90gsx]

Carbide burr with a electric die grinder.

 

[kawboy]

Anybody have anymore FP or ported BEP pics

 

[kawboy]

Also.. I'm assuming I'll want a double cut egg shaped carbide burr.

Do I need the extended length 6 3/8" shank or would a 2" work

 

[1997hciv]

Well after many months of lazyness and a light foot I got the itch to really see what this car has when the boost is under control. I have taken it apart this past friday and started to grind away the housing using a die grinding and an aluminum oxide grinding stone as I couldnt find a carbide burr on a spur of the moment. So far it looks good. I will post pics this week when I am completed to get some feedback on my first porting job.

 

[1997hciv]

here is a quick pic off my phone. It is ported more than the one picture that was able to hold 21psi. My car still creeps and now I think its my wastegate. But on the bright side it is much better since it does stay below 20 for a while now but I still let off before it goes above 20.

 

[Gooberlog]

here is a quick pic off my phone. It is ported more than the one picture that was able to hold 21psi. My car still creeps and now I think its my wastegate. But on the bright side it is much better since it does stay below 20 for a while now but I still let off before it goes above 20.

It looks like you ported the other side of the turbine housing. This isn't bad as it will increase flow and CFMs but you need to port the side of the turbine housing where the o2 housing bolts to (where a wastegate flapper door normally is) so that it opens up in to the external gate and the airflow is not hitting a wall. From the pic above it looks like you increased flow coming in to the housing but unless you port the other side where the air exits, it will creep even worse.

 

[1997hciv]

Yea I did that too. I almost got rid of the whole lip that the internal flapper rests against. I was afraid if I went anymore it would not hold up to the pressure and crack. I think I will end up trying to get a manifold mounted wastegate and just run two gates. Or just run the one off the mani and leave the one on the O2 alone and closed up.

 

[Gooberlog]

damn still creeping ported out huh, you could try a tial 44mm or 60 mm, i think they might have an adapter or you may have to get a new o2 housing or a different manifold. Not sure if waste gate size is your problem though, 40mm is getting pretty big.

 

[Steve93Talon]

What spring is in your gate?

 

[1997hciv]

it opens at 15psi. I think it is green