I did, just figured it was a good reason to bump this old thread showing the awesome results!

 

 

So...did you just use a divided t3 adapter for your ramhorn?

 

IN this situation I dont think you would want a divided manifold. That would completely block off 2 cylinders, the QSV basically lowers the turbo housing size until u start building boost

 

Read the previous pages a bit more indepth, Geis. He used a different approach using a QSV system (popular with many Supra owners that were using much larger turbochargers than this, to try and create a dual purpose effect..) that was fitted to a divided manifold and turbine inlet.

It was NOT a twin scroll housing, and wanted just more consistent fitment. The twin scroll housings for Garrett GTX series are the $500 NiResist castings with a divided channel that ran the entire length of the turbine housing volute. The OP did not purchase that.

 

lol, didn't know how I overlooked this

I realized he was using the valve, just wasn't thinking about how that would block the two runners. I thought I saw him state that it was twin scroll on the first page, guess I misread

Speaking of divided housing, are there still any benefits to running a divided housing with either a twin scroll manifold, or ramhorn with divided adapter?

 

Benefits as in......?

 

Quicker spool, lower egt, more back pressure on the low end and less higher in the powerband, better cylinder scavenging etc... Basically anything similar to true twinscroll tech.

Or is there pretty much no reason to run a divided housing unless you are going to use a quick spool valve.

 

I mean, basically, the entire concept of changing the dynamics of the turbine's housing to change the behaviour of the turbocharger. Like I had always said, more of these behaviours have to do with the fact that for the most part, with 1 or 2 exceptions, the twin scroll phenomenon deals with the concept of making ONE turbocharger of a specific size, exhibit the characteristics of two different turbochargers that have 2 distinct behaviours.

Whether or not the twin scroll design acts alone in order to achieve this, or allows the utilization of other devices both mechanical or electronic, has always been difficult to pre-calculate before its use; especially when you're talking about turbochargers that have extremely variant sizes, on engines that have varying efficiency levels. So, it's not really a "yes" vs. "no" type of question. It's more of a "I'm going to see where this will change"

For larger turbochargers within the mid-sized to "large" range such as the GTX3576R and above, the use of the divided or true twin-scroll turbine housing alone really doesn't help much in the way of allowing it to act as a true twin-behaviour monster.

Now, you can try to calculate the backpressure ratio of the turbine housing relative to the exhaust wheel, and try to use the dynamometer to determine where it will "spool up", ( an RPM rotational speed meter is much more accurate, but this is Honda-Tech, home of the cheapo, so no one is really going to invest in that ), but it's not going to really make it conclusively demonstrative of whether or not there's a net benefit[ overall that a good independent boost controller, a good engine package and camshaft coupled with at most, possibly a QSV system will do much more than the turbine housing itself in terms of making these behavioural changes. But the same can be done with an open volute turbine housing of a slightly smaller size using the same sized turbine wheel. This is where it gets a little experimental, ya see?

When it comes to the much SMALLER of the series of turbochargers, the twin scroll characteristics tend to reveal themselves, because there is less overall volute size to deal with, with which a nice compact exhaust manifold is used that is already utilizing higher exhaust velocity, (compared to the ever popular Kooks-manifolds that most Honda users try to convince themselves should be used for more "flow") in which the twin scroll exhaust energy division allows for better separation of exhaust pulses that allow for better jet-streamlining which therefore, creates the "spool up" that all the people think they want out of the turbocharger. But it has its drawbacks too.

Lower EGTs are based upon other factors, the turbine housing itself does very little to effect that unless something is physically affecting it, like a QSV. Look to your fuel type and ignition (as well as combustion temperatures) to determine that.

So, when asked if I see a benefit, I don't say "yes" or "no" blindly... I usually start with.. "Well, it depends.."..

Fair enough?

 

It is. However, I thought (no expert obviously) that the physics simply pointed toward all twin scrolls regardless of size having better (wider) overall powerbands in general because of the streamlining you discussed, as well as better scavenging because of a higher pressure difference and so on. That (supposedly) leads to cooler combustion temps as well, which allows for more spark advance.

I'm pretty sure there's a fair amount of evidence using graphs (I understand they don't necessarily reflect all the characteristics in the real world, but a wider powerband is a wider powerband) that twin scroll in general are the superior choice.

I will refine my original question; will a divided housing combined with either a twin scroll mani or say a ramhorn with a divided adapter create torque quicker than it's single scroll variant, and will it lose any top end as a result.

 

You seem hell bent on believing your own reasoning for saying yes from this last post than worrying about whet I answer the question or not, Geis


My answer to this is still as it was 2 months ago when you asked this then. From my experience, when I have a smaller volute using the same sized exhaust wheel, no, not really on average.

Otherwise, as I stated earlier, it depends. But my experience carries little weight here because I don't have a million dynos to post around.

 

I asked this question a couple months ago? Honestly, you must be confusing the question then, because other than perhaps twin scroll turbos themselves I have not asked anything about divided housings and whether or not there is superior use for them. I quite simply was making an argument against what you said about twin scroll turbos in general, because I have seen evidence and believe to have a reasonable understanding of their function

Pointing out that I'm hell bent on some 'self rationalization' or w/e you would like to call it is not a true rebuttal to anything I said. Come on man, I'm not asking to argue about twin scroll, feel free to point me out where I'm wrong if you wish but that wasn't what my original attention was with the question.

 

Tony kind of addressed this early on explaining you're still going to sacrifice power somewhere or have a dip or turbulent transition from the valve opening. I don't think its as simple as twin scroll is always going to be better just because.

 

Oh, so now I'm confused? ... yes. You ARE asking me to argue about twin scroll, vs I there design methods, and I DID answer this question earlier, and didn'the say you were completely wrong, just that it works in certain areas and situations and not others. I've said this twice now, and explained where, and how. Tony has done this as well. If you don't know how to read my explanations, I really don't know what to more to tell you, but I won't continually repeat it in 3-4 different ways.

I'm not attempting to be difficult, sir, but this has been already asked and answered. Your response is simply "but I've read everywhere that says otherwise ". Ok. So you have. Great. Tony and I have done the real world tests, and the designs I've worked with over the last 5 years show continuity with that of Tony's experience .

My job isn't to convince you, or create chaos to change the minds of the masses. I've tried that and it doesn't work. So, I can only say is time for you to try it for yourself by investment of turbos, time, resources, and believe what you find. Ok?

 

Care to show us on my graph where any of those things happened? Now my car isn't a "twin scroll" but there are no real downsides apart from the 3/4" extra space you have to account for in designing the rest of the kit. Sure i might have lost MAYBE 10whp at 9k rpm but my car made over 500hp from 5.8k-9k which is an ACTUAL powerband as compared to 99% of every other honda that makes max power for maybe 500rpm.

 

And that's the thing. No "GRAPH" can really show that. All it will show is that someone who used a divided housing (which always contained a larger volute than the open turbine inlet of something smaller) and ran the same boost and made more peak power. Of course it did!! It's a larger volute that allowed for more exhaust energy to pass through!

What elijahcole92 did was show what a QSV does with a divided housing, not what a twin scroll can do physically alone. It's apples to cantalopes comparing.

What one does is utilize what I stated earlier :

Again, because of so many turbos with so many different combinations, I don't know about Tony, but I surely didn't keep this type of data in a graphical format that could be posted on this stuff for over 6-7 years just to have it handy to argue with people on web forums. We simply took it as supplementary data; we had other things to concern ourselves with at the time. Sorry if we seemed selfish at the time.

But again, I have no problem with people not believing how I state my answer or whether or not I'm disputed by internet propoganda. (Remember, it was Ful-Race that used the "twin-scroll" nomenclature incorrectly in the 1st place as a marketing tool).

If you feel differently, and want to prove to yourself or whomever you see fit, please, become the better expert by going through similar tests with multiple turbochargers in a test format (you'll find dynos don't really help), and recreate the test conditions to come to a hypothesis for yourself.

But to say that I'm "confused" in an effort to deflect a lack of comprehension of my answer, that I've given repeatedly....As you would say..."C'mon, man! That's just being silly on your part."..

Okie dokie?

 

Now you tell me where the hell you see a question about twin scroll in this discussion

So it's either one of two things:
A) You didn't understand the question
or
B) Divided housing (somehow now) = twinscroll, which obviously isn't true.

 

No way to really know without doing back to back, QSV vs open volute.

Not a honda but a good comparison of twin scroll vs open volute.

Seems like the QSV behaves similar to that

 

It actually kinda pisses me off that you say this, because as shown above you clearly are putting words in my mouth; there never was a question about true twin scroll turbos. You then accuse me of calling you confused as if it were an insult, when I'm merely pointing out that you somehow are misinterpreting the question.

Furthermore, using my expression of exasperation in this discussion as a shot towards my credibility is insulting, especially when you ignore the second half of that statement where I point out that even with the twin scroll discussion, you hadn't (at least at that point) given any real rebuttals.

 

I will happily show you where your question revolves around the concept regarding "twin scroll". I'll even use your quotes if that's ok with you.

You used the term "twin scroll" in reference to an exhaust manifold -- (Don't worry, even the best people with the best intentions have an "oops" moment).

The premise of your question implies that you are inquiring specifically looking at if there are similar benefits (as defined by you) characteristics as found by the theoretical and actual twin scroll designs found in the turbine volutes are present in those that are utilizing simply a divided system. In your query, you're using both divided apparatus components either in the exhaust manifold flange, or some type of weld flange adapter.

Your definition of benefits is defined by
My answer was contained in my general statement of "it depends".

This statement infers that the use of a divided turbine housing turbocharger is going to contain a divided flanged system either in the Exhaust manifold, or any other part of the "Hot Parts" system. I apologize if I didn't specifically state each and every component of "dividedness", but that's still contained in my answer.

In addition, you're trying to utilize a phrase that just doesn't make any sense phonetically, such as "similar to twin scroll tech". But I was trying to address this point from my earlier statement. Use of a QSV is NOT the same as the intended use of "twin-scroll tech". That's more akin to variable-vein geometry tech that are used on specific turbocharger systems. I didn't want to get into it, but you rather merged concepts here.

What you must understand is that a turbine housing that a divided turbine housing for any of these effect you're trying to achieve is a necessity, meaning that it is needed as a requirement to start the process of creating any of your listed benefits as characteristics. But the divided housing is not a logical sufficiency, meaning that only a divided housing is needed to satisfy the twin-scroll benefits and characteristics that you're looking for. I was trying to sum this up easily and simply with a "rule of thumb" that can be more easily interpreted by all, but I see that it didn't work for you.

There are always reasons to run larger exhaust turbine housings, which is for more peak power in gasoline engines, or more torque for larger stroked engines like diesels, that use smaller compressor wheels to match with the larger exhaust wheels.


In fact, as a matter of manufacturing, all of these huge turbochargers from these major companies ALL use divided housings with larger volutes for higher top end power; that's why they were designed and created. What happens though is that exhaust energy characteristics can only go so far with the turbocharger itself. This is when the use of mechanical aids such as QSVs and Variable-Vein Geometry come into play; to get a Super large turbo that is made for ONE purpose, attempt to provide an additional purpose of obtaining a lower boost threshold more quickly.

Divided housings weren't intentionally designed for that except in larger engine / stroke applications like diesels and busses, but these devices were invented so that smaller gasoline applications can still take advantage of the flow rates of these larger turbos, while still getting some utility in the lower rpm band where exhaust energy from smaller engines like 3.4 litre Supras can retain some driveability...relatively speaking.

So, no, I wasn't confused with the overall question you were trying to ask based upon a premise that you believed was universally understood as fact when it was not, and I attempted to answer your question with the notion that anyone that is trying to obtain these "benefits" by using mechanical devices like a QSV are preemptively using all of the divided components are needed in order to maximize the utility of said device; which includes all flanges and appropriate housings.

I was also saying that each situation is a slightly different, and there is no yes/no answer to this phenomenon , especially when it comes to the larger framed turbochargers that are less expensive and tend to be used more by Honda guys. I'll say it one last time... "It depends". But just because you get a positive result of one aspect, doesn't make it a net "benefit" that falls within your definition. Sorry, it's just not simple.

The only takeaways I can see from all of this berating are these...

1) "Twin scroll tech" only utilizes static design change methodology for the turbocharger and possibly the exhaust manifold itself without the use of mechanical devices that alter the geometry of the exhaust flow energy like QSV devices and Variable Vein Geometry devices. Those do NOT give similar effects as twin scroll turbine housings.

2) As I stated, in Larger-mid-framed turbochargers, the twin scroll "benefits" don't really show themselves; it is easier to obtain those same sought-after benefits with a slightly smaller turbine housing of an open volute design, without the drawbacks or worry of backpressure issues, loss of peak power, etc.

And that when it comes to the much SMALLER of the series of turbochargers, the twin scroll characteristics tend to reveal themselves more (and without mechanical aids), because there is less overall volute size to combat lag, in also which a nice compact exhaust manifold is used that is already utilizing higher exhaust velocity in which the twin scroll exhaust energy division allows for better separation of exhaust pulses that allow for better jet-streamlining to maximize the benefits you're asking about

3) Divided housing = Necessity, but not sufficiency to gain these "benefits"

4) Internet lore is tempting.. But don't take my word for it.. Test for yourself with the correct parameters.


Are we done, now? This is now completely boring, and I'm starting to see flies around this horse.