jb123mb

Has anyone on the forum made this upgrade, if so, what were your thoughts?

Stenzel-Germany

Hi,

First: Technically absolutely fascinating.
Second: Absolutely Expensive :-) (around 11000 USD)

This is not a simple replacement turbocharger upgrade.

You need the charger, matching exhaust manifold, water lines, oil lines, heat shields, all gaskets and screws. The "BOV" should also be changed. (with TS the connection is on the compressor housing)

Got all the parts here.

Turbocharger from BS, (largest MB V8 Twinscroll) exhaust manifold GT 290 63s

But not installed yet. wintertime.

best regards

Stenzel

jb123mb

Great winter project, please keep us updated on your progress!

What site did you use to get part numbers and prices, all the online websites i went to, did not provide any information, even after i added a BS VIN!

thebishman

Do you mind me asking what purpose you have in mind by switching out the turbos?

jb123mb

The AMG GTR handles so well that it could easily use more power!

I drove a friends Renntech 761HP and even that car felt like it would benefit from Twin Scroll Turbos.

Renntech said that they have done a few AMG GTR's with twin scroll turbos and they made 850HP on a conservative pump gas tune

I am also considering a 720s, but i prefer the handling of the AMG GTR.

dlefty

Out of curiosity, why go through all the work and parts needed for twin scrolls when turbos such as the PTG1000 exist for those looking for great power and that are direct bolt in?

jb123mb

Just installing a larger (single scroll) turbo, would create more power loss down low for any gain higher up .... twin scrolls are more efficient, with less of a loss at low rpm.

dlefty

Yes, correct….but how much additional power do you want down low (we can all agree some amount is a good thing I’m sure). If on a track, initial throttle tip in with say an extra 150+ HP at a lower RPM….you pick, will require the driver to modulate throttle differently, or have TCU potentially tuned for by gear or by RPM torque limiting or ramp up to keep the car from being a handful…..has anyone GOOD in the tuning world sorted that yet for the twin scroll?

My above comment is based on what’s available now, and the fact that two of the powerful twin scroll platforms, GT63 and E63 as an example, feature 4matic “all wheel drive” structures.
Combine that with stock turbo tuned GT - GTR they can be a bit “punchy” down low but still run out of breath up top.

I think there is some better linearity potential with big power gain and the curve continually climbing to red line vs. stock turbo housing flattening post 5-6k rpm….even with the stock housing turbo upgrades. It boils down to how the turbo ramps up in lower RPM I guess to see if it can satisfy the drivers hopes and requirements.

Back to OP’s topic, of twin scroll talk only

Stenzel-Germany

Hi,

Was a lengthy process. I will make a verified parts list after installation.
Only then do I know if everything really fits.
I'm still hesitating as to whether I'll also install the bigger BS intercoolers at the same time.
This may change the parts list.


Kind regards.

Stenzel

Stenzel-Germany

Hi,

Benefits Twin Scroll:
Better response. (ceramic ball bearing)
Fewer losses (principle: 4 smaller exhaust gas turbines instead of 2 larger ones)
Decoupling of the exhaust ports (only 2 cylinders with maximum ignition distance, per exhaust gas turbine)
Heat insulation of the exhaust turbine housing.

I'm expecting faster and better low-end response, and an increase in top-end power.
This is not possible at the same time, with upgrade turbos.


But, to be completely honest:

The (better?) result doesn't even really matter to me.

Now the responsiveness is great. The performance is definitely more than sufficient. (Currently from 2400rpm > 900Nm)
Even now, you have a massive problem getting the torque to the road. Most of the time it is already "regulated away"
All-wheel drive can implement a lot better. But there is also a certain appeal in the GT.

My (joke) argument is always:
If it were any good, you would have all-wheel drive in Formula 1. :-)

I'm simply fascinated by the twin scroll concept and therefore simply had to have it.

Enjoy it, as so often, even if it would bring absolutely NOTHING. :-)
Only 1 rule has to be observed: It must, never have disadvantages. ;-)


Kind regards.

Stenzel

dlefty

Cant wait to see your results, and your thoughts to if ultimately the effort and additional parts are worth it vs. what’s out there.

At least you are going into it with realistic expectations a a good optimism!

Many, including myself have been eyeing up dpi f this for a while, glad to see it happening!

jb123mb

GAD has a twin scroll upgrade kit

https://www.gad-motors.de/gad-parts/turbocharger-kit-

jb123mb

Twin Scroll vs Single Scroll test.

https://dsportmag.com/the-tech/twin-...-great-divide/

502Bill

While the spool of twin scrolls cannot be denied, I believe there value is more application specific. Twin scroll offers advantages that are better realized with larger housings. I am skeptical you will “feel” or realize any performance gains on the 4.0L platform vs. using improved housings. Since this unique engine mounts the turbos in the V, this negates any significant advantages of a twin scroll. I’m sure the power curve would move slightly to the left, but this car has never suffered from lag when compared to a traditional V8 design. At least from my experience.

I am running Pure 900 turbos. If memory serves me correct, they are simply larger wheels in honed OEM housings. My biggest issue is controlling wheel spin on acceleration. The cost/benefit is even less apparent if roll racing than off the line drag racing. I would suspect any advantages would have to be dialed back with your right foot if you plan on increasing power.

jb123mb

Do you have any Dragy results 60-130 mph, 100-150 mph?

502Bill

I do not. But may consider it now, lol. I dropped my guns a while back. If you’re chasing numbers, go for it. I just feel it’s with the “noise” of any outcome. In the end, ya, it’s superior. But I choose to focus on other nonsense to achieve similar results. The nut behind the wheel is more influential pound for pound.
Tunes hold all belts.

jb123mb

What tuning software do you use or is it tuned via a shop?

502Bill

Custom in house tune by Eurocharged. I did have a stage 2 can tune by EC, but wanted something more specific for my application.

user33

<Chuckle> As a software guy, a common comment is "Yeah, it was a hardware problem ... a nut loose on the keyboard!"

It's an adaptable concept.

Stenzel-Germany

Hi,

I've been busy with the BS Twin Scroll and the exhaust manifolds.

Since the BS has a flatplane crankshaft, it naturally has a different firing order and its own exhaust manifold.

The 4 x 2 exhaust outlet channels are evenly combined.

M178 Flatplane (BS) firing order: 1-8-2-7-4-5-3-6

Zylinderhead 1 / Turbo 1 / Port 1 cyl.: 1&4 gives 1 (827) 4 (536) 1 (827) 4 etc.
Zylinderhead 1 / Turbo 1 / Port 2 cyl.: 2&3 gives 2 (745) 3 (618) 2 (745) 3 etc.

Zylinderhead 2 / Turbo 2 / Port 1 cyl.: 5&8 gives 5 (361) 8 (274) 5 (361) 8 etc.
Zylinderhead 2 / Turbo 2 / Port 2 cyl.: 6&7 gives 6 (182) 7 (453) 6 (182) 7 etc.

Fits all: 1---4---1---4 / 2---3---2---3 and 5---8---5---8 / 6---7 ---6---7

Even Spark Spacing: 3/3/3/3 (Per Turbo port)


Since the crossplane has a different firing order, it also needs different exhaust TS manifolds.
Available from GT 4 door and E/S class with twin scroll turbos

Here, too, there is a separate exhaust manifold for each cylinder head.

M178 Crossplane firing order: 1-5-4-2-6-3-7-8

Zylinderhead 1 / Turbo 1 / Port 1 = Cyl.: 1&2 gives 1 (54) 2 (6378) 1 (54) 2 etc.
Zylinderhead 1 / Turbo 1 / Port 2 = Cyl.: 3&4 gives 3 (7815) 4 (26) 3 (7815) 4 etc.

Zylinderhead 2 / Turbo 2 / Port 1 = Cyl.: 5&7 gives 5 (4263) 7 (81) 5 (4263) 7 etc.
Zylinderhead 2 / Turbo 2 / Port 2 = Cyl.: 6&8 gives 6 (37) 8 (1542) 6 (37) 8 etc.

Not quite evenly: 1--2----1--2 / 3----4--3----4 and 5----7--5----7 / 6- -8----6--8

now ignition distance: 2/4/2/4 instead of 3/3/3/3 (per turbo port)

Is that now (AMG probably builds it like that) a drama? :-) or does it make sense to build a new exhaust manifold?

With 1&6 / 2&8 / 3&5 / 4&7 it would get evenly 3/3/3/3.


Or i am wrong in the end?


Kind regards.

Stenzel

Acta_Non_Verba

Hi Stenzel,

OUCH.....At first you made my head hurt :-)!

After I stopped sleeping, I think you have a very good analysis of exhaust port flows as a static process (more coming about dynamic). From your results, and because of the 180* firing (times 2) of the flat plane engine, I don't see those exhaust manifolds even a consideration which I believe you don't either.

On the cross plane manifolds, yes, the pulses are going to be uneven because of the firing order necessity of the 90* firing on a 90* Vee platform. On the surface, this would suggest a unique exhaust manifold to best utilize the twin scrolls, however, given the "inside vee" exhaust ports and what that manifold would look like I am guessing real estate in the Vee with twin scrolls would become a problem. And, because of the uniqueness of the crossplane firing, I cannot imagine (in my mind anyway) any combination of exhaust distribution through twin scrolls that could equal the flat plane...maybe closer but I cannot see equal? Do you?

Once you are past this point of static analysis, then you have the more dynamic challenge of valve timing, both on exhaust side (flow and backflow) and intake side(s) as how will the exhaust scavenging (by changing the port assignments) impact the turbo flows on the hot side and how will that impact exhaust backflow into the intake charge side of that or mating cylinders? VVTs set up differently on flat to cross plane setups. The flat plane can take advantage of more VVT because of the 180* firing.

I see in the "aftermarkets" they appear to be using twin scrolls on stock M177 exhaust manifolds. Aftermarket is seldom perfect, but more bolt on just to sell things.

As I've come to know your capacity for technical expertise, I am interested in following this to see how you proceed. I know you will think through each step arriving at a sound conclusion. RESPECT!

Please keep posting...one of the best posts yet!

Acta

Stenzel-Germany

Hi Acta and others,

Well, my post wasn't really self-explanatory. Try again. :-)

Of course, the ignition interval is uneven. It's always like that with 90° crossplane V8 crankshafts. That's why it sounds like it sounds. :-)


I'm more concerned with the even, maximum ignition interval of the individual turbo port.

Just like building headers. Always found -> 4 in 2 in 1 ideal. That's exactly what you have with Twin Scroll. With the turbo advantage, pipe lengths almost don't matter.


Just look at 2 cylinders thats on one TS Turbo exhaust inlet port (of 4):

M178 LS2 Black Series (Flatplane) stock:

At (720°)/0° ignition cyl. A (90°+ 180°+ 270° other) 360° ignition Cyl. B (450°+ 540°+ 630°other) etc.
Results: -> 360° -> 360° -> 360° -> 360° -> etc.
Perfect. Equal (&max.) ignition interval between the two cylinders per TS port:

M178 Crossplane with Stock GT 290 Twin scroll Exhaust Manifolds:

At (720°)/0° ignition cyl. A (90°+ 90°other) 270° ignition Cyl. B (360°+450°+540°+630°other) etc.
Results: -> 270° -> 450° -> 270° -> 450° -> etc.
Unfortunately, the ignition gap between the two cylinders per TS port is not the same:

Summarizing the cylinders a other way: (1 & 6 / 2 & 8 / 3 & 5 / 4 & 7)
then the ignition interval would also be even: 360° -> 360° -> etc.

The effort would be, to build other exhaust manifolds.

Serious question:

Does -> 360° -> 360° -> against -> 270° -> 450° have advantages?

and:
Does the sound change? (Then "mix" cylinder bank 1 & 2)


Best regards

Stenzel

MikeGLS450

My eyes are glazing over. Does this mean the twin scroll are better suited to a flat plane crank??

Wolfman

E63s and GT 63 4 door use twin scroll turbos as well. But it appears the BS Turbos are larger.

MikeGLS450

Interesting.

Wonder why Mercedes didn’t fit twin scrolls to the GT especially of the E63 or GT63 have them. Maybe the ones from the those two models would be a better retrofit???