Holset Turbos, PART 3

[ceedawg]

Originally Posted by dsm-onster

I've never seena wastegate just run off of one side. If you ran a large gate for insurance, I suppose it could be possible. I was thinking about using my wastegated h1e housing (it's internally gated on one scroll) by porting the hole to a much larger size and running a large gate off of it. . . I don't know what the results would be.

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.

So how about just putting the wastegate on the O2 housing, is'nt that a good option when using a TS manifold?

[gixrman]

Originally Posted by dsm-onster

I've never seena wastegate just run off of one side. If you ran a large gate for insurance, I suppose it could be possible. I was thinking about using my wastegated h1e housing (it's internally gated on one scroll) by porting the hole to a much larger size and running a large gate off of it. . . I don't know what the results would be.

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.

Thanks thats what I wanted to know. I have a TAIL 44 that I will be using. Just have to do the 2-1 setup.

[gixrman]

Originally Posted by ceedawg

So how about just putting the wastegate on the O2 housing, is'nt that a good option when using a TS manifold?

How so its already passed though the turbine?

[ceedawg]

Originally Posted by gixrman

How so its already passed though the turbine?

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

[420a-t]

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.

[aero_sallee]

Originally Posted by 420a-t

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]

Originally Posted by ceedawg

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]

Originally Posted by aero_sallee

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/turbo9...mounted3_1.jpg

What do you guys think?

[aero_sallee]

Originally Posted by ceedawg

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/turbo9...mounted3_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]

Originally Posted by ceedawg

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]

Originally Posted by dsm-onster

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]

Originally Posted by gixrman

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]

Originally Posted by 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?

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]

Originally Posted by aero_sallee

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 ext