Not Divided Mod

[jibberishballr]

I was reading this thread and wondering if it works. It doesnt seem like it would be that hard to do at home. Anyone have any expierence with this.

Heres a link to what im talkin about:

http://www.dsmtuners.com/forums/showpost.php?p=50427715&postcount=20

Also i realize you cant run external once you do this.

 

[DGajre777]

One important omission from his response was whether or not it disrupts flow at full boost. I have no doubt it will help with creep, but that has nothing to do with turbo performance. Like the other guy said, you can also fix creep by putting a 2-1/4" exhaust back on.

Keep in mind that exhaust is split between the WG and turbine outlet passages whenever you're at full boost. In otherwords, the WG flow characteristics and how they "play nice" with the turbine exit flow is VERY important, because it happens when you're asking for maximum performance.

I don't see how diverting the WG exit flow into the way of the turbine exit flow could do good. The turbine exit *was* a nice, round, smooth passage for those gasses to pass through which gives a lower restriction. Admitted, the WG has a bi*** of a time getting out that door, but once it's there, it gets merged with the turbine exit flow in a very nice way in the stock O2 housing. If you start having to share that nice round turbine exit passage with other flow, the turbine is going to have higher backpressure. This gives a lower pressure differential before and after the turbine wheel which means less torque to the compressor wheel.

I can't put numbers on it, so it might not be that bad, but nobody has compared an undivided housing with, say, an external gate on an otherwise identical setup.

I'm curious to see what Dejon has to say about it affecting performance. I sent another e-mail, waiting to hear from him.

Good post BTW.

 

[jibberishballr]

I'm curious to see what Dejon has to say about it affecting performance. I sent another e-mail, waiting to hear from him.

Good post BTW.

Dave from Dejon was kind of short with me. The first time when i asked if it helped cure creep he said yes and didnt really tell me much else. I asked if there were side effects such as performance and he told me "maybe saving your engine."

 

[kenamond]

Dave from Dejon was kind of short with me. The first time when i asked if it helped cure creep he said yes and didnt really tell me much else. I asked if there were side effects such as performance and he told me "maybe saving your engine."

Dave's a good guy. He's probably a bit sick of me as a customer though; we've been mailing UICP parts back and forth for the past 2 months.

 

[jibberishballr]

Dave's a good guy. He's probably a bit sick of me as a customer though; we've been mailing UICP parts back and forth for the past 2 months.

Yea i dont know the guy personally, just when i emailed him he wasnt really "excited" about helping me.

 

[92awddsm]

I run the pte 5252 e(60-1 with p-trim turbine wheel) with the divided housing. Its not what I ordered but I was in a bind so I had to use it instead of sending it back and waiting on what I wanted. So far, I see full spool(27psi) around 4100 rpm. 30 psi by 4200 rpm so I dont think it hurts spool that much. I am sure that it does hurt performance because the fastest I have ran with it at 27 psi is 118mph. I ran the same mph with my t04b v-trim externally gated at 25psi. I know it isnt a tuning problem because both were tuned on the dyno. I dont have any boost fluctuation at all during high rpm/high boost so I dont think the wg is blowing open. If I could do it again, I would have waited for the correct turbo with the undivided housing.

 

[DGajre777]

I run the pte 5252 e(60-1 with p-trim turbine wheel) with the divided housing. Its not what I ordered but I was in a bind so I had to use it instead of sending it back and waiting on what I wanted. So far, I see full spool(27psi) around 4100 rpm. 30 psi by 4200 rpm so I dont think it hurts spool that much. I am sure that it does hurt performance because the fastest I have ran with it at 27 psi is 118mph. I ran the same mph with my t04b v-trim externally gated at 25psi. I know it isnt a tuning problem because both were tuned on the dyno. I dont have any boost fluctuation at all during high rpm/high boost so I dont think the wg is blowing open. If I could do it again, I would have waited for the correct turbo with the undivided housing.

Interesting. Is it possible that the decrease in psi could be because of you going from external wastegate to internal gate? We know that external gate gives better boost control but since the size of the gate is bigger couldn't that have contributed to it?

 

[DGajre777]

Update. Here is a response from Dejon...

I don't know, how could anyone without a science lab? Do you want to
fix boost creep? Then this is a solution. I don't intend to get into a
theory argument that I can't resolve. END OF THREAD
Dave

> Hello Dave,
>
> Thanks for your response. Two more questions and then I won't bother you.
>
>
> Does the undivided housing disrupt air flow at full boost? Performance
> wise how will diverting the WG exit flow into the way of the turbine exit
> be good for air flow? Doesn't having an undivided housing cause higher
> backpressure since the turbine exist has to share it's housing with the
> other airflow?
>
> Thanks for your time.
>
> Dee.
> DGajre777.

 

[jibberishballr]

Seems like its clear that it solves boost creep but i still have no idea if i would ever consider doing it just because no one knows if effects performance, efficiency,etc. I wish we could get a solid answer with some support to back it up.

 

[MyBeatGSX]

Update. Here is a response from Dejon...

I don't know, how could anyone without a science lab? Do you want to
fix boost creep? Then this is a solution. I don't intend to get into a
theory argument that I can't resolve. END OF THREAD
Dave

Wow he just became my new favorite sarcastic, mouthy vendor.

I don't think he wants to answer your questions. And I can't blame him because he's right, you can't prove anything without some kind of flow bench or something along those lines, so why debate it.

 

[DGajre777]

So as we stand, in theory, it will affect performance, but no one really knows.

Anyone want to do some testing on divided and undivided housing PTE turbos?

 

[ShapeGSX]

My counter-theory is that the wastegated exhaust hits the divider wall
because its forced between the wall and flapper door, and enough volume
can't escape.

Destroying your turbine efficiency will also reduce creep by not ever spinning the turbo as fast as it COULD. Don't do this.

Moving the pivot of the wastegate is a good idea, so long as you can reverse it once you get to the track. The issue is that moving the pivot so that there is more throw will give the exhaust pressure on the wastegate flapper more leverage on the spring in the wastegate actuator. This will cause the wastegate to crack open and cause your boost to drop, particularly at high RPMs.

 

[kenamond]

Destroying your turbine efficiency will also reduce creep by not ever spinning the turbo as fast as it COULD. Don't do this.

Moving the pivot of the wastegate is a good idea, so long as you can reverse it once you get to the track. The issue is that moving the pivot so that there is more throw will give the exhaust pressure on the wastegate flapper more leverage on the spring in the wastegate actuator. This will cause the wastegate to crack open and cause your boost to drop, particularly at high RPMs.

There's got to be a WGA out there that will open the WG flapper 90* (or heck, 60*) and hold it closed at high boost.

 

[DGajre777]

Destroying your turbine efficiency will also reduce creep by not ever spinning the turbo as fast as it COULD. Don't do this.

Good point, but what does removing the divider have to do with turbine efficiency? The turbulence caused by mixing airflows will slow down the airflow, but how does this affect turbine efficiency? The turbine still pushes the same amount of air regardless of a divided or undivided housing.

 

[ShapeGSX]

Good point, but what does removing the divider have to do with turbine efficiency? The turbulence caused by mixing airflows will slow down the airflow, but how does this affect turbine efficiency? The turbine still pushes the same amount of air regardless of a divided or undivided housing.

Put a 1" diameter restrictor on your turbine outlet, and I bet you would see a difference. That is taking the issue to the extreme, of course.

By introducing more exhaust volume (hot, pre-turbine exhaust, no less) right at the turbine exit, and in a manner that has it shooting straight across the path of the turbine will cause the flow through the entire turbine to lessen. A restrictor on the turbine outlet is doing the same thing.

 

[kenamond]

Good point, but what does removing the divider have to do with turbine efficiency? The turbulence caused by mixing airflows will slow down the airflow, but how does this affect turbine efficiency? The turbine still pushes the same amount of air regardless of a divided or undivided housing.

The turbine system will be less efficient. The turbine will still have the same map, but you'll have less pressure difference across it and/or less airflow through it. So you'll back up your flow with increased backpressure, and you'll act like a smaller A/R turbine.

 

[MyBeatGSX]

I'm in complete awe that this is still even being debated. There is nothing to argue, nothing to discuss. Its a known fact and dead issue, undivided housings kill turbine efficiency, end of story.

No it won't act like a smaller A/R housing. A small A/R housing will spool faster and have more backpressure at higher RPM. An undivided housing will not spool faster, it will spool the same and as soon at the wastegate opens turbine flow will take a sh!t because as shape said, the WG exhaust now shoots sideways and tries to squeeze in with the turbine exhuast. This severely limits flow through the turbine. That's why it doesn't creep anymore. Because you have so much post turbine backpressure its like having the stock exhaust on or probably worse. Even though no one has flowbench tested results to give a really scientific positive answer, you don't need them. The fact that it prevents creep proves that it hurts turbine flow by a large amount.




And like kenamond said, there HAS to be a wastegate can with enough arm throw to get that flapper open 90*. I'm sure that crappy 45* opening they have now accounts for 90% of creep problems. This might be something we should all look into, it could be the final solution to DSM creep problems, then we can patent it and sell it and be millionares!!

 

[MyBeatGSX]

I just made an interesting discovery. I saw this on FP's website.

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Judging by how long that can is, that actuator has WAY more throw than the pancake looking one that MHI's come with. FP calls it a "high output adjustable wastegate actuator". Why don't they make ones that fit DSM compatible turbos? Or does its long shape have to do with the adjustablity and not the range of motion of the arm?

 

[ShapeGSX]

I just made an interesting discovery. I saw this on FP's website.

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Hmm, I think I have one of those on a shelf somewhere.

 

[MyBeatGSX]

PUT IT ON! PUT IT ON!

 

[ShapeGSX]

It won't just bolt up. I'd have to make a bracket for it.

But I can check the throw of the actuator.

Mine originally came off of an FP Green with an internal gate. I'm not sure if it is identical to the model shown in the picture.

Of course, I have to actually FIND it first!

There are a number of internal wastegate actuators out there these days, btw. I've even seen one with a second vac port on it designed to hold the wastegate shut with boost pressure when you are below the desired boost level (like some of the externals).

 

[kenamond]

I'm in complete awe that this is still even being debated. There is nothing to argue, nothing to discuss. Its a known fact and dead issue, undivided housings kill turbine efficiency, end of story.

I think that some of us are trying to fully understand the implications of a non-divided mod. And I think everyone's on the same page.

No it won't act like a smaller A/R housing. A small A/R housing will spool faster and have more backpressure at higher RPM.

I meant that it would act as a smaller A/R housing at high RPM. Both have flow problems at high RPM.

as soon at the wastegate opens turbine flow will take a sh!t because as shape said, the WG exhaust now shoots sideways and tries to squeeze in with the turbine exhuast. This severely limits flow through the turbine. That's why it doesn't creep anymore. Because you have so much post turbine backpressure its like having the stock exhaust on or probably worse.

That's what I said in my first post on this thread.

Even though no one has flowbench tested results to give a really scientific positive answer, you don't need them. The fact that it prevents creep proves that it hurts turbine flow by a large amount.

I was a bit more conservative; it'll hurt performance, but how much is at best an educated guess and dependent on the setup. But I wouldn't do it to my housing.

 

[92awddsm]

Interesting. Is it possible that the decrease in psi could be because of you going from external wastegate to internal gate? We know that external gate gives better boost control but since the size of the gate is bigger couldn't that have contributed to it?

It never lost psi. It ran the same speed in the 1/4 mile at a lower pressure on a smaller turbo with an external wg. I think the divided housing really hurts top end performance.

 

[MyBeatGSX]

It won't just bolt up. I'd have to make a bracket for it.

But I can check the throw of the actuator.

Mine originally came off of an FP Green with an internal gate. I'm not sure if it is identical to the model shown in the picture.

Of course, I have to actually FIND it first!

There are a number of internal wastegate actuators out there these days, btw. I've even seen one with a second vac port on it designed to hold the wastegate shut with boost pressure when you are below the desired boost level (like some of the externals).

Let me know if the throw on that actuator is longer. Do you know of anywhere that sells aftermarket internal actuators?

My moderately ported E16G starts to creep very fast after 6,700rpm and hits 25psi by 7,000rpm in 3rd gear (set at 20psi). I just found out this past weekend that I have a huge boost leak at the TB shaft seals. I don't even want to know how high its going to creep after I fix that. I also don't plan on porting in anymore because I don't want to start hurting turbine flow, I did enough to fix the majority of my creep problems (25psi by 5,000rpm before), but not so much that I thought it would destroy the flow inside the housing.

 

[DGajre777]

I think that some of us are trying to fully understand the implications of a non-divided mod. And I think everyone's on the same page.

Yeah, what ^^^ said.

 

[DGajre777]

Back from the dead.

What about using this o2 housing with an non-divided/cut mod turbo? - http://www.dsmtuners.com/forums/showthread.php?t=227609