Good info on twin vs single scroll

Dmak

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Nov 19, 2017
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09 bmw 135i
As more and more single turbo options coming out for the n54. I just really want to look into the benefit vs cost on the single turbo set up. And came across this. Its a very good read. I m sure everyone knows how twin scroll help with spool anf such. This give test + data on the difference.
Plus, i never though of how it help with over lap/valve duration. Very good info here.

http://dsportmag.com/the-tech/twin-scroll-vs-single-scroll-turbo-test-the-great-divide/
 

PUTC

Corporal
Oct 14, 2017
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08 335xi
Wow. I knew a good amount of the information but with the graphs and comparisons it truly puts it into perspective. The same car would be 4 car lengths ahead in a race with just different turbo and header! That’s awesome.
 
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devildog0905

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Jan 21, 2018
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2007 BMW 335i E92
As more and more single turbo options coming out for the n54. I just really want to look into the benefit vs cost on the single turbo set up. And came across this. Its a very good read. I m sure everyone knows how twin scroll help with spool anf such. This give test + data on the difference.
Plus, i never though of how it help with over lap/valve duration. Very good info here.

http://dsportmag.com/the-tech/twin-scroll-vs-single-scroll-turbo-test-the-great-divide/

Thanks for the info! Really settles the debate on single vs twin scroll for me. I need that twin scroll in my life
 
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4N Motorsport

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Dec 11, 2017
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Coming from building and racing Performance cummins Diesel engines. Twin scroll is the only way to go. It all boils down to valve overlap and cylinder firing order. For instance on a 4bt you have to divide 1-4 2-3 on the manifold design. Firing order is 1342. Let’s say you divided 1-2 and 3-4 you would then get exhaust gases going back into the combustion chamber during overlap.
 

Jeffman

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Jan 7, 2017
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Very informative. I think this article also underscores the need for paying close attention to the VANOS tables when tuning.
 

Dmak

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Nov 19, 2017
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Very informative. I think this article also underscores the need for paying close attention to the VANOS tables when tuning.

Thats what i m thinking. More aggressive cam timing can be use. Also, it also look as if the same car with same sized turbo/mod, the twin scroll car would still be quite a bit faster even if peak hp and boost are the same. To me thats just mean less stress to the car. A good twin scroll with a bb turbo, i just dont see how twin turbos can be better.
 

ShocknAwe

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Jan 24, 2018
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great article. Time to see where tuning goes with all the twin scroll bottom mount options arriving. Ought to be fun.
 

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Lieutenant
Nov 5, 2016
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Thats what i m thinking. More aggressive cam timing can be use. Also, it also look as if the same car with same sized turbo/mod, the twin scroll car would still be quite a bit faster even if peak hp and boost are the same. To me thats just mean less stress to the car. A good twin scroll with a bb turbo, i just don't see how twin turbos can be better.
Hey we are making a single kit, so obviously we see some merit. But, do not be fooled. Twins are superior in just about every way. Let me know when a single kit is doing this on the N54. Once it does, I will say ok a singles are equal to a good set of twins. Not only is this near the top of the WHP mountain for the platform, look at that curve. Its a thing of beauty in every way possible. Its better than most Supercharged V8's. Twins are unmatched in terms of response, and power potential, but they are not everyone's cup of tea. So we build it all now...:)

847_726 3K grab_watermark.jpg
 
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ShocknAwe

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Tony, what's the comparison in the weight department between the GC and your bottom mount manifold with turbo, all inlet and outlet piping included for consideration?
 

Dmak

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Nov 19, 2017
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09 bmw 135i
Hey we are making a single kit, so obviously we see some merit. But, do not be fooled. Twins are superior in just about every way. Let me know when a single kit is doing this on the N54. Once it does, I will say ok a singles are equal to a good set of twins. Not only is this near the top of the WHP mountain for the platform, look at that curve. Its a thing of beauty in every way possible. Its better than most Supercharged V8's. Twins are unmatched in terms of response, and power potential, but they are not everyone's cup of tea. So we build it all now...:)

View attachment 8386

The thing with high hp twin is that yes they are better for low end torque. But to push the power, it will be pushing quite a bit of boost as well as heat. At the end it will put more stress on everything. A bigger intercooler/more meth/etc will also be needed.
For an average joe(like me), the idea of having one less possibe turbo to fail, as well as less chance for a bigger turbo to fail due to slower shaft speed, and also less heat produced when running higher boost level and still have pretty good respond down low. The less chance of breaking rods, axles, drive shaft, clutch, etc
Before anyone say the twins can still be tune to have boost later and smoother, it is true, but at higher rpm a single bigger turbo will still be more effection(as in less heat produced)
Also one huge benefit is the selection of turbos i get when going single. The twins we get are really mostly hybirds. I m not saying twins are bad, my plan was get stageb2 twins later this year. But with more and better single turbo options coming out, a twin scroll single really interest me.
P.s that dyno power band look amazing, but that wont happen with a stock engine. And i bet most (90%?) of the ppl are just looking for reliable power while keeping stock internals.
 
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