Holset Turbos, PART 3

[aero_sallee]

I was planning on running my h1e with a fabbed-up 16g actuator, I have a friend who did this and has worked great for him. Is this something I shouldn't do then? I'm getting a mitsu-style housing, not a divided t-3. Thanks.

That is what I had on mine. It worked ok, at least up to 18-19lbs. Never got to try higher than that due to insufficient fuel.

 

[aero_sallee]

Wow, you mean you've never seen an O2 wastegate setup? Tons of folks have that setup on their cars.

Since those are typically getting exhaust gas through the internal wastegate hole which only goes into one passage, you will still be venting pressure from two cylinders and not the others.

 

[ceedawg]

Since those are typically getting exhaust gas through the internal wastegate hole which only goes into one passage, you will still be venting pressure from two cylinders and not the others.

Here is a statement I found that dissagree's:

This setup is a new approach to external wastegating. Rather than mounting an external gate on the exhaust manifold, this is a custom-fabricated stainless steel O2 housing with an integrated Formula One-quality Tial external wastegate. In this configuration, the internal turbo wastegate is removed, and bypass gasses flow through the internal wastegate passage and out through a dump tube mounted on the wastegate. This item completely eliminates boost creep, and provides a nice, compact setup for the wastegate, while also venting back pressure from all four cylinders simultaneously (a much better approach to controlling boost, as backpressure is reduced equally in all cylinders). In addition, because the exhaust gasses are collected in the manifold before being expelled from the engine, this setup sounds completely different than a manifold-mounted wastegate and more uniformly vents all of the cylinders.


Turbine housing without an internal gate setup existing:

No offence but I'm using the Holset non-wastegated turbine hsing,so my question would be how would your explanation apply if there is no wastegate hole? Would this infact force me to run the wastegate from the mani?

I think non wastegated turbine hsings are of a totally different nature no?

I thought I've seen this setup on many Supra's and turbocharged BMW's.

Some turbos even have the wastegates bolted on the bottom of the turbine hsings themselves.

Here's a 944 turbo setup with the wastegate being setup on the passenger side of the motor. This is also how my friends 944 turbo is setup. Notice the pipe leaving the turbine side of the turbo with the pipe then running to the waste gate on the other side of the motor. Can't see why one would not work on an O2 housing:

http://www.diateam.no/porsche/turbo968csturbomounted3_1.jpg

What do you guys think?

 

[aero_sallee]

Here is a statement I found that dissagree's:

This setup is a new approach to external wastegating. Rather than mounting an external gate on the exhaust manifold, this is a custom-fabricated stainless steel O2 housing with an integrated Formula One-quality Tial external wastegate. In this configuration, the internal turbo wastegate is removed, and bypass gasses flow through the internal wastegate passage and out through a dump tube mounted on the wastegate. This item completely eliminates boost creep, and provides a nice, compact setup for the wastegate, while also venting back pressure from all four cylinders simultaneously (a much better approach to controlling boost, as backpressure is reduced equally in all cylinders). In addition, because the exhaust gasses are collected in the manifold before being expelled from the engine, this setup sounds completely different than a manifold-mounted wastegate and more uniformly vents all of the cylinders.


Turbine housing without an internal gate setup existing:

No offence but I'm using the Holset non-wastegated turbine hsing,so my question would be how would your explanation apply if there is no wastegate hole? Would this infact force me to run the wastegate from the mani?

I think non wastegated turbine hsings are of a totally different nature no?

I thought I've seen this setup on many Supra's and turbocharged BMW's.

Some turbos even have the wastegates bolted on the bottom of the turbine hsings themselves.

Here's a 944 turbo setup with the wastegate being setup on the passenger side of the motor. This is also how my friends 944 turbo is setup. Notice the pipe leaving the turbine side of the turbo with the pipe then running to the waste gate on the other side of the motor. Can't see why one would not work on an O2 housing:

http://www.diateam.no/porsche/turbo968csturbomounted3_1.jpg

What do you guys think?

That qute is saying what I did basically. They are pulling exhaust through the old internal gate passage after removing the flapper, routing it to the external gate. As far as pulling from all 4 cylinders, yes it would, but only on a non TS turbo. Every divided turbine housing I've seen with an internal gate only taps into one scroll of the turbine housing. They are normally from a diesel app, where running a cylinder a little leaner doesn't come with much of a penalty. I can get a picture of the one off my HX40 if you like later.

For the 944
Of course that would work, because you are tapping into the exhaust pre turbo if the wastegate is on the other side. Unless you plan on pulling exhaust off the manifold or putting pipe between the turbo and manifold to pull exhaust off of then where do you plan on venting from? You have to pull exhaust pressure from AHEAD of the turbine wheel.

 

[gixrman]

Wow, you mean you've never seen an O2 wastegate setup? Tons of folks have that setup on their cars.

Yes I have. But that does'nt help me. I don't have a internally gated housing so I did'nt understand what you were talking about. Looking at some cast manifolds they bleed off from the #1 runner to the WG that was my idea for just running off of one pair of exhuast runners to the WG. I'm just trying to get an idea of what will work the best.

 

[420a-t]

I just got off the phne with Nick at the turbo trader and he said in about 3 weeks, he's getting in new stainless steel housings for the holsets. They will have a mitsu-style inlet on them. He said they're going to be a little more money, but they are shiney!

On another note, he also said he has some used hx-40 and hx-35 that he's getting rid of if anyone is having trouble finding one at a decent price. Nice guy.

Continue on about wastegates....good info!

 

[gixrman]

EDIT: Well, I do know the VE will be lopsided favoring the gated cylinders heavily. This will lead to a lean condition in those cylinders and a rich condition in the others. Because the ecu doesn't have a massflow meter for each cylinder.

Not to keep asking the same question but I had to go back and re-read your statement. The exhuast as already been acounted for how is going to produce a lean/rich condition? The WG is just bleeding off pressure to the turbine, so if it gets it from both or one as long as its controling spool how does it effect VE?

 

[Steve93Talon]

Not to keep asking the same question but I had to go back and re-read your statement. The exhuast as already been acounted for how is going to produce a lean/rich condition? The WG is just bleeding off pressure to the turbine, so if it gets it from both or one as long as its controling spool how does it effect VE?

Because backpressure in the manifold affects VE (think of going from a .63 to a .82 AR hotside). If you're only wastegating one side, then there's a free flowing path for the gas to escape when the gate opens.

 

[Boo5t_Addict]

If you bleed pressure out of one cylinder its VE will change, because VE is determined by the efficieny of air getting into and out of a cylinder. VE is all about flow. You change the flow, you change the VE.

 

[gixrman]

Ok so why do some manifolds come this way? Some have the WG flange off the #1 runner (Turbonetics) and I have seen a few examples of this. Is this just poor designing then?

 

[Steve93Talon]

Ok so why do some manifolds come this way? Some have the WG flange off the #1 runner (Turbonetics) and I have seen a few examples of this. Is this just poor designing then?

A wastegate on one runner of a manifold with an undivided collector will still equalize pressure within the manifold to some degree. It's still not the ideal way to do it, hence why most of the better manifold designs put the gate at the collector or on the o2 if the turbine housing allows it.

 

[Maglin]

Here is something that I talked about in part 2 and will rehash. If you are looking to run a large frame turbo then you don't need a large WG as you will not be "bleeding" the exhaust as much when you are running 45+ PSI. I've seen a lot of manifolds that are divided T4 and have 2 44mm TIAL flanges one one each half. I guess if you want lots of lag and only run 26 PSI then fine you might need that much WG MAYBE. But my moto is go big or GTFO. So I'm going to be running 45-65 PSI on this manifold. I have a 44mm TIAL and I'm actually thinking it's going to be to big. If you have 2 large WG's then when both open at the same time you might actually see a decent boost drop off and ocolating (sp) pressure. With a smaller WG you won't have so much gas escaping right when the gate opens and probably have a much easier time doing what you want with it.

I plan on building a 2->1 pipe for the Shearer manifold to run a single 44mm TIAL. If by some act of god I'm struck by lighting and want to run only 20 PSI then I'm pretty sure I would maybe need 2 WG's. I hope you can pick up what I'm throwing down here. It's kind of garbbled but I think you get the drift of what I'm saying. If you only want to run 20 PSI don't even bother with a T3 or T4 manifold. Heck I would stick with a 16G then. But if you are looking to get into some serious boost and serious power you really don't need 2 WG's as you'll be running a bunch of boost. Unless you like the bling factor then definitly go with 38mm gates.

 

[ceedawg]

That qute is saying what I did basically. They are pulling exhaust through the old internal gate passage after removing the flapper, routing it to the external gate. As far as pulling from all 4 cylinders, yes it would, but only on a non TS turbo. Every divided turbine housing I've seen with an internal gate only taps into one scroll of the turbine housing. They are normally from a diesel app, where running a cylinder a little leaner doesn't come with much of a penalty. I can get a picture of the one off my HX40 if you like later.

For the 944
Of course that would work, because you are tapping into the exhaust pre turbo if the wastegate is on the other side. Unless you plan on pulling exhaust off the manifold or putting pipe between the turbo and manifold to pull exhaust off of then where do you plan on venting from? You have to pull exhaust pressure from AHEAD of the turbine wheel.

On a non TS hsing or divided TS hsing with an internal gate I know this already! I have a non gated hsing with no internal wastegate hole. Your talking about something totally different.

Remember with the non wastegate setup if the wastegate is not mounted on the mani,where you would just weld two tubes from the collector and have runners 1-4 join and 2-3 join just above the flange by the collector to meet the one wastegate, the exh still has to leave the turbine hsing and go thru the O2 sensor housing. That's why I'm saying mount the wastegate on the O2 sensor housing and forget about putting it on the mani.. I cannot see why it would not wrk being mounted on the O2 hsing after the non-wategated Holset turbine housing. There is no internal wastegate hole on this type of holset TS turbine hsing also. You will either put two gates on each side of the TS mani or just mount it on the O2 sensor hsing just after the Non wastegated TS holset turbine hsing. Remember there is no internal wastegate hole on these.


On the 944 the wastegate is'nt mounted pre-turbo. The wastegate is actually mounted on the turbine housing with the dump tube leaving and headed toward the passenger side of the motor. This turbine hsing has an inlet and TWO outlets. One for the exh and one to mount the wastegate.

 

[ceedawg]

Yes I have. But that does'nt help me. I don't have a internally gated housing so I did'nt understand what you were talking about. Looking at some cast manifolds they bleed off from the #1 runner to the WG that was my idea for just running off of one pair of exhuast runners to the WG. I'm just trying to get an idea of what will work the best.

Some cars have the wastegate mounted down strem on the exh or on the O2 hsing is what I was saying especially if the using a non wastegated hsing with no kind of former internal wastegate setup.

 

[ceedawg]

A wastegate on one runner of a manifold with an undivided collector will still equalize pressure within the manifold to some degree. It's still not the ideal way to do it, hence why most of the better manifold designs put the gate at the collector or on the o2 if the turbine housing allows it.

Thank you Steve which is kinda my point hence another reason why I've said I've seen wastegates bolted straight on the turbine hsing lke the pic I have of the 944. This cannot be too different from mounting the wastegate on the O2 sensor hsing when a non wastegated TS or non TS hsing does not allow. If I'm still off base here please let me know.

 

[Boo5t_Addict]

Ok so why do some manifolds come this way? Some have the WG flange off the #1 runner (Turbonetics) and I have seen a few examples of this. Is this just poor designing then?

The design of having a wastegate on one runner is a poor one. It's described in Corky Bell's Maximum Boost, but basically you're only bleeding one cylinder directly, while the other 3 pulses have to reverse direction and go up that runner. The idea is to have uniform flow, and not a turbulent flow. The most efficient way of controlling boost is with a wastegate off the collector, and all 4 runners feeding it.

 

[aero_sallee]

On a non TS hsing or divided TS hsing with an internal gate I know this already! I have a non gated hsing with no internal wastegate hole.

On the 944 the wastegate is'nt mounted pre-turbo. The wastegate is actually mounted on the turbine housing with the dump tube leaving and headed toward the passenger side of the motor. This turbine hsing has an inlet and TWO outlets. One for the exh and one to mount the wastegate.

Where is the wastegate on there? The one going to the turbine inlet is the crossover pipe from the exhaust manifold which is on the other side of the engine. (check the second picture. )

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Reference this photo of a 944 engine. The exhaust manifold is on the other side of the engine.

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I'm not trying to cause any problems, maybe I'm just missing something in the picture and there is a third outlet I'm not seeing.

 

[T9S1i]

Where is the wastegate on there? The one going to the turbine inlet is the crossover pipe from the exhaust manifold which is on the other side of the engine. (check the second picture. )

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Reference this photo of a 944 engine. The exhaust manifold is on the other side of the engine.

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I'm not trying to cause any problems, maybe I'm just missing something in the picture and there is a third outlet I'm not seeing.

I dont see a wastegate on the turbine. But in the second picture, where the exhaust pipes meet and start to go under the motor on the left side there is a flange on the exhaust before it gets to the turbo, is that where the wastegate would bolt?

Sorry dont want to download the picture to make a circle around it, its pretty clear its inbetewen the exhaust pipe and that plastic bag at the bottom left of the picture.

 

[ceedawg]

Where is the wastegate on there? The one going to the turbine inlet is the crossover pipe from the exhaust manifold which is on the other side of the engine. (check the second picture. )

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Reference this photo of a 944 engine. The exhaust manifold is on the other side of the engine.

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I'm not trying to cause any problems, maybe I'm just missing something in the picture and there is a third outlet I'm not seeing.

No I think you are perfectly correct and I am mistaken with my photo.

 

[Steve93Talon]

Thank you Steve which is kinda my point hence another reason why I've said I've seen wastegates bolted straight on the turbine hsing lke the pic I have of the 944. This cannot be too different from mounting the wastegate on the O2 sensor hsing when a non wastegated TS or non TS hsing does not allow. If I'm still off base here please let me know.

I think you're confusing the fact that the gate is "on the o2 housing" with being plumbed into the exhaust post-turbine wheel. When an o2 mounted gate is used, there's still an internal passage on the turbine housing BEFORE the volute, which allows the gas to bypass the turbine wheel and flow into the gate which is mounted on a common flange with the turbine outlet pipe, commonly referred to as the o2 housing. Variations on this idea would be like the FP bolt-ons, where the gate is actually clamped directly to the turbine housing. In absolutely every instance (runner, collector, o2 housing, internal,...) there's one common thing: the gate is before the turbine wheel. If your divided or undivided turbine housing doesn't have a hole before the volute, then your choice is limited to a manifold mounted gate.

 

[dsm-onster]

. . . If you are looking to run a large frame turbo then you don't need a large WG as you will not be "bleeding" the exhaust as much when you are running 45+ PSI. . . .

. . . I plan on building a 2->1 pipe for the Shearer manifold to run a single 44mm TIAL. If by some act of god I'm struck by lighting and want to run only 20 PSI then I'm pretty sure I would maybe need 2 WG's. I hope you can pick up what I'm throwing down here. It's kind of garbbled but I think you get the drift of what I'm saying. If you only want to run 20 PSI don't even bother with a T3 or T4 manifold. Heck I would stick with a 16G then. But if you are looking to get into some serious boost and serious power you really don't need 2 WG's as you'll be running a bunch of boost. Unless you like the bling factor then definitly go with 38mm gates.

This makes total sense. But I don't think the hx40 8blade or h1e can support over 35 psi with a decent set of cams.

I agree. If you're going with this much boost (looks like your hx52 can do that), smaller WG openings are better.

I still don't see how a single gate with a divided inlet to the gate cannot cross-contaminate. Below is what I'm picturing in my head at the very begining of the exhaust valve lift and at the very end of the exhaust valve lift. There still is a pressure differential with no wall highlighted by the magenta circle. . . unless some how there is a venturi effect at that point, there will be cross-contamination:

 

[gixrman]

Damn it I don't want to run two gates. I guess this is the reason you don't see to many manifolds like this. Thanks for the examples. Any ideas to help me out for wastegate placement?

 

[Maglin]

I still don't see how a single gate with a divided inlet to the gate cannot cross-contaminate. Below is what I'm picturing in my head at the very begining of the exhaust valve lift and at the very end of the exhaust valve lift.

Matt. Picture this. When the gate is closed their is very minimal, and I mean minimal, exhaust flowing between the "Y" pipe for the WG. When the gate is open is where you would see the most flow between the 2 parts. This is also going to be when you are seeing some high RPM's as well and the negative effects would probably not even be noticeable even on a dyno as it would probably be so small you wouldn't be able to see it over the normal variance on runs on a dyno. But I do see what you are thinking.

 

[ceedawg]

Matt. Picture this. When the gate is closed their is very minimal, and I mean minimal, exhaust flowing between the "Y" pipe for the WG. When the gate is open is where you would see the most flow between the 2 parts. This is also going to be when you are seeing some high RPM's as well and the negative effects would probably not even be noticeable even on a dyno as it would probably be so small you wouldn't be able to see it over the normal variance on runs on a dyno. But I do see what you are thinking.

I agree that it would be very very minimal the effect Matt keeps talking about as well.

 

[Spidey]

I think this thread needs to be cleaned up, or split, a lot of this stuff has nothing to do with Holsets, although good information.

On topic, my 8-blade HX35 with the stock twin-scroll T3 turbine housing, is doing 38lb/min @ ~20psi on a stock 2g MAS. As a side note, my manifold is undivided, has a Tial 38mm off the collector, and the Holset turbine housing was previously internally wastegated, the flapper hole has been welded shut. I'm seeing very fast spool-up, I've Google'd the number stamped on my turbine housing with no results, I'm guessing its one of the smaller turbine housings(12cm maybe), as it was previously internally wastegated.

I'll post some DSMlink logs and hopefully some dyno results in the near future, as I've yet to do any tuning, which is what surprises me most about the spool-up.