New sm16g...will this fix boost creep???

[evo9mrtt]

Hey guys sorry I haven't posted in forever. I recently put a brand new small 16g on my car and broke it in for 350ish miles. The small 16g I had on before would boost creep like crazy all the way up to 17psi. After putting this turbo on I still get boost creep all the way to 17psi still. I've read on other boards that if I put a mbc on the car and turn it up to 16psi that I won't get creep anymore. Does anyone know if this works? Right now I just have a vaccume line going from the wg to the T that runs to my tial bov. Any help or if anyone knows if this works would be appreciated.

[thiazole]

Why not just port the wastegate relief passage in the O2 housing a little bit? Boost creep is caused when the wastegate isn't releasing boost fast enough to keep the pressure down.

[evo9mrtt]

The o2 housing that's on my car now has excessive porting done on the exhaust and wg side. Its matched to the evo3 o2 housing. Chris webb was the one who sold me my exhaust...which I love...and also ported the o2 housing for me

[evo9mrtt]

I have the supporting mods to turn the boost up also. I have pte680cc injectors with a walbro 255hp and a aeromotive a1000fpr for fuel and v2 for tuning.

[JayRolla]

Porting the o2 doesnt do much for boost creep since you need to restrict airflow past the turbo to help stop creep. What you want to do is port the exhaust housing of the turbo to allow more air to reach the wastegate by making an easier path.

[JayRolla]

I have the supporting mods to turn the boost up also. I have pte680cc injectors with a walbro 255hp and a aeromotive a1000fpr for fuel and v2 for tuning.

Turning the boost to 16psi will just allow the car to reach 16psi faster and then start creeping from there. So you would creep too around 20+psi which would make things worse.

[evo9mrtt]

Ok that's what I thought might happen. Lol I just don't want to take the turbo back off cause I just put it on. I wish there were an easier way. But I think I will just deal with it for now. I just wanted to get it fixed so I could actually have it tuned to a certain boost

[evo9mrtt]

I should also add that my car is 3" from the turbo back and is straight piped. I'm planning on adding the vibrant stealth black muffler with dual tips to stop getting so much flak from the law and to get the "stock" looking exhaust

[thiazole]

I wonder if one of these would help: http://stores.punishment-racing.com/-strse-14/Mild-Steel-Atmosphere-Dumped/Detail.bok
Cheap enough that it might be worth trying if you don't mind dumping the wastegate to atmosphere (and yes, this is for an internal wastegate - the external wastegate O2 housings have the dump tube in 2 pieces). I don't really like the idea of hurting airflow to reduce boost creep, so I'd rather see you try something like this.
The "sure thing" solution is to go to an external wastegate. You also don't have to dump to atmosphere with an external wastegate if you don't like that idea - I use the Punishment recirculated O2 housing myself, and it works great - I didn't see any difference in performance or spool up when I switched from dumping to atmosphere. I just didn't like the extra noise dumping made. This is kind of an expensive route, though, between the O2 housing and the wastegate. I got my O2 housing during their black Friday sale a lot cheaper (and the next black Friday sale is coming up in a couple more months). You could also always pick up a used Tial. I see people selling them for pretty cheap all the time.

[Cloud]

Porting anything but the wastegate itself is unlikely to help you.

[JayRolla]

I wonder if one of these would help: http://stores.punishment-racing.com/-strse-14/Mild-Steel-Atmosphere-Dumped/Detail.bok
Cheap enough that it might be worth trying if you don't mind dumping the wastegate to atmosphere (and yes, this is for an internal wastegate - the external wastegate O2 housings have the dump tube in 2 pieces). I don't really like the idea of hurting airflow to reduce boost creep, so I'd rather see you try something like this.
The "sure thing" solution is to go to an external wastegate. You also don't have to dump to atmosphere with an external wastegate if you don't like that idea - I use the Punishment recirculated O2 housing myself, and it works great - I didn't see any difference in performance or spool up when I switched from dumping to atmosphere. I just didn't like the extra noise dumping made. This is kind of an expensive route, though, between the O2 housing and the wastegate. I got my O2 housing during their black Friday sale a lot cheaper (and the next black Friday sale is coming up in a couple more months). You could also always pick up a used Tial. I see people selling them for pretty cheap all the time.

Actually the dump will make it worse since its flowing better. People have actually welded washers with a small hole at the end of the dump tube to restrict the flow and stop the boost creep.

I would just get the fuel setup to run e85. Thats what I did. I had creep but now with the e85 I run the turbo on pretty much an open wastegate to get as much boost as possible.

[thiazole]

Actually the dump will make it worse since its flowing better. People have actually welded washers with a small hole at the end of the dump tube to restrict the flow and stop the boost creep.

I would just get the fuel setup to run e85. Thats what I did. I had creep but now with the e85 I run the turbo on pretty much an open wastegate to get as much boost as possible.

Making the wastegate flow better won't increase boost creep. The more air that flows through the turbine, the more boost you run. The more air that flows through the wastegate, then less air can flow through the turbine and therefore the less boost you will run. The problem is that his wastegate isn't flowing enough to divert enough exhaust away from the turbine. Do you think that by blocking air from flowing out the wastegate that less air will flow through the turbine as well? Why not just weld the wastegate shut, then?

[sbiggi]

On a small 16g, why yould you want to run less the 16psi when you have supporting mods?

Just turn the boost up to 18psi and tune for it.

The only way to avoid boost creap is to bypass enough exhaust around the turbine.

-A atmospheric dump tube will help since it doesnt have any exhaust pressure on the other side like a recirc.

-Or port the tubine housing around the entry to the wastegate to make the path easier.

My vote though is to just turn up the boost. This isnt a honda. :D

[dsm_gsx97]

+1 for letting them hang.

You should be able to run E85 also for even higher boost if you wanted however you'll need to watch your injector duty cycle because those injectors might be close on E85.

I should also add that my car is 3" from the turbo back and is straight piped. I'm planning on adding the vibrant stealth black muffler with dual tips to stop getting so much flak from the law and to get the "stock" looking exhaust

A muffler won't change a thing other than sound (which will taint the beautiful sound that exhaust produced). I can't believe your getting crap for that exhaust. It looks non turbo stock until you get close enough you see it's 3" pipe coming out that muffler and not a 2".

You just need to quit wearing your hat sideways and you'll quit getting messed with by the law lol. :D

[prophecymiller]

Actually the dump will make it worse since its flowing better. People have actually welded washers with a small hole at the end of the dump tube to restrict the flow and stop the boost creep.

There must be other factors here that we aren't seeing. This just doesn't make sense as the atmo. dump would have to release pressure from the turbine:confused:

HERE (http://codsm.org/forums/showthread.php?t=3419) is a thread that shows the difference between wastegate inlets between a T25 and 16g...If you look carefully, the wastegate inlet on the 16g is flush with the turbine scroll and also not radiused as well as the T25. Notice the T25 has a very nice smooth radius at the wastegate entry along with the top of the port being slightly recessed back from the surrounding wall. You want to mimick the T25 if possible in my opinion. Don't go too crazy with recessing the inlet though, as you will lose some velocity to increase wastegate flow...this is one of those compromises between working right and making more power:D

[thiazole]

I think I know where Jay is coming from. If you weld a wastegate shut (for example) a turbo will hit a very high boost level in the lower rpm range. But, because you will be choking the compressor, boost will fall with rpms (seemingly the opposite of boost creep). The problem is that boost creep and boost falling off because a compressor is choking are two completely unrelated phenomenon. If you had a compressor that was rated at infinite flow and pressure ratios, the boost would just keep building and building with rpms with a wastegate that is welded shut. Choking the compressor isn't really a solution for boost creep since the point of fixing boost creep is to be able to run a safer boost level, not simply to prevent boost from rising with rpms.

[Cloud]

I get the feeling you guys are talking about two different things. Atmospheric dump on the turbine outlet gives you more creep, not on the wastegate outlet. The thing that usually happens though is they get merged and in that situation it seems that less backpressure on the merged exhaust has a higher effect on turbine flow than wastegate flow and creep occurs from that as well.

As I stated before, your best bet is porting the wastegate hole itself, don't port it large enough so that the flapper won't seal but it is a small orifice and is definitely the most important restriction.

[thiazole]

I get the feeling you guys are talking about two different things. Atmospheric dump on the turbine outlet gives you more creep, not on the wastegate outlet. The thing that usually happens though is they get merged and in that situation it seems that less backpressure on the merged exhaust has a higher effect on turbine flow than wastegate flow and creep occurs from that as well.

As I stated before, your best bet is porting the wastegate hole itself, don't port it large enough so that the flapper won't seal but it is a small orifice and is definitely the most important restriction.

I'm on board with what you are saying. The O2 housing I linked only dumps the wastegate (since the post-turbine part is flanged for a down pipe)
http://stores.punishment-racing.com/-strse-14/Mild-Steel-Atmosphere-Dumped/Detail.bok

[JayRolla]

I get the feeling you guys are talking about two different things. Atmospheric dump on the turbine outlet gives you more creep, not on the wastegate outlet. The thing that usually happens though is they get merged and in that situation it seems that less backpressure on the merged exhaust has a higher effect on turbine flow than wastegate flow and creep occurs from that as well.

As I stated before, your best bet is porting the wastegate hole itself, don't port it large enough so that the flapper won't seal but it is a small orifice and is definitely the most important restriction.

LOL you are right, I was talking about atmospheric dump on the exhaust.

[prophecymiller]

LOL you are right, I was talking about atmospheric dump on the exhaust.

Haha, ok I'm now confused and wondering where the washer being welded in comes into play? They welded a washer to the turbine outlet?

[evo9mrtt]

Sorry for leaving you guys hanging so long, been super busy at wrok. I think I found the path I'm going to go. Iv been looking into the punishment racing 38mm external wg o2 housing and think I'm going to buy it. The question I have is, what will I have to do with the internal wg on the turbo if I do this?

[thiazole]

I still have my old Punishment atmosphere dumped O2 housing if you are interested. I'd sell it to you for $90 (half price).

[thiazole]

Sorry for leaving you guys hanging so long, been super busy at wrok. I think I found the path I'm going to go. Iv been looking into the punishment racing 38mm external wg o2 housing and think I'm going to buy it. The question I have is, what will I have to do with the internal wg on the turbo if I do this?

You will need to remove the entire internal wastegate assembly including the flapper and weld the little hole closed (not the big wastegate hole - leave that open - the little hole that contained the rod that connects the flapper to the arm outside the turbo). If you don't weld, I'm sure you could take it to an exhaust shop and they'd probably weld it for you for cheap - probably $5.

[evo9mrtt]

Ok if I go the route of that o2 housing I will do that process. I know this may be off topic but I've had this small 16g on my car for 700 miles now and have been taking it pretty easy...5-10 throttle controlled psi at most. Is there a certain milage or time I need to let this turbo break in?

[evo9mrtt]

Thiazole pm sent

[thiazole]

Ok if I go the route of that o2 housing I will do that process. I know this may be off topic but I've had this small 16g on my car for 700 miles now and have been taking it pretty easy...5-10 throttle controlled psi at most. Is there a certain milage or time I need to let this turbo break in?

I've never done anything special to break in a turbo myself and I've never had a turbo fail (and I pushed every turbo I've ever owned to its choke point).

[sbiggi]

Turbos do not break in.

The only things in the engine that breaks in is the rings, and possibly cams if they are brand new.

[JayRolla]

Haha, ok I'm now confused and wondering where the washer being welded in comes into play? They welded a washer to the turbine outlet?

Yes to the dump tube on the o2 housing. The restriction helps the creep, just like stock and 2.5" and under exhaust does. Its just a bandaid fix anyways. Porting is the best bet or go external.

[sbiggi]

Yes to the dump tube on the o2 housing. The restriction helps the creep, just like stock and 2.5" and under exhaust does. Its just a bandaid fix anyways. Porting is the best bet or go external.

Restricting the dump tube, that doesnt make any sense why that would help creep. :confused:

You need the wastegate to be more efficiant at flowing exhaust then the turbine. Making a restriction there would do the opposite.

[JayRolla]

I know, I wish I could find the link. Its on the dsmlink forums but it fixed his creep. Something about how helping flow through the exhaust housing of the turbo and restricting it afterwards to help keep the wastegate flap open. But after thinking about it that doesnt make sense.