Quickly Clarified - Single Scroll vs Twin Scroll Turbos | Pros & Cons
Vložit
- čas přidán 30. 05. 2024
- In my previous video about Equal length headers vs unequal length headers, I briefly mentioned how equal length headers allow for a twin scroll turbo setup to be implemented. However, what actually is a twin scroll turbo? In this video, we’ll be going over what that is and what are the advantages and disadvantages of such a setup.
Single Scroll vs Twin Scroll Experiment: dsportmag.com/the-tech/twin-s...
Sections:
0:00 - 0:27 Intro
0:27 - 0:39 Sub
0:39 - 0:58 How Turbos Work
0:58 - 1:55 Single Scroll Turbos
1:55 - 3:11 Twin Scroll Turbos
3:11 - 4:03 Pros and Cons Comparison
4:03 - 4:49 DSPORT Experiment
4:49 - 5:30 Outro
Songs:
Kazem John - Cha
/ cha
Kazem John - Bounce
/ bounce
Alainite - Explore This (prod. WISHBOI)
• Explore This (prod. WI... - Auta a dopravní prostředky
The collector is actually like a reserve bank of energy so the turbine wheel is not accelerated in a pulsing manner which means between each pulse the turbine decelerates and looses energy, the next pulse then has to re-accelerate the turbine to the prior velocity before it can accelerate it further, again wasting energy.
The idea is the same as aero ducts for cooling. As the volume of the area increases at the collector the velocity of the gas decreases but the pressure increases. This helps buffer the pulse feed into the outer, lateral section of the turbine wheel, loading it evenly with a higher pressure gas. As the gas transitions to the axial flow section of the turbine wheel, the gas is squeezed into a smaller volume which accelerates it's velocity. As the gas reaches the opening in the housing the design of the dump pipe along with the cooling gasses 'contracting' attributes, causes the accelerating outflow of gas to draw the gas behind it along with it.
That's where the correct header pipe diameter and resonator profile and placement come in, the reverberating LOW pressure wave that travels from the resonator cavity back towards the turbine should ideally reach the dump pipe / turbine immediately before the next high pressure sound wave from exhaust pulse.
That's why it's critical to place any crossovers/bridges correctly and to choose the correct diameter exhaust. *Not just for performance at maximum output, but for maximum performance where the engine needs it most.... Where it most suffers from lag where you intend to use the engine the most, with a small, compromising consideration for maximum performance. 😉
A machine is a chain of links that all must lift be able to lift the weight, so the machine is only as able as it's weakest link allow it to be. If you approach fluid dynamics and thermodynamics with this perspective, instead of simply taking at it with a bigger sized hammer (10L displacement, Nos, engine that can only function at high boost & full throttle to badly create the same performance/torque as a lesser, more harmonized/civilised engine is able too with much less parasitic losses to friction, heat, sound and vibration. (And thermo/fluid dynamic deficiencies.)
thank you! very well said! pinned your comment...
Pig
ضغط زر ض١
my 2019 JCW Mini Cooper has a twin power turbo, or 'twin scroll turbo' - i had no idea what that meant until i watched your video. Very informative. Thank you!
Glad the video helped, thanks for the feedback!
Late to the party, but a great video ty.
Me and my mate were trying to get our head around the power differences between a BMW 218d and 220d. Both N47 (don’t laugh) 1995cc in-line 4s.
It was only after this video we understood the Turbo common rail vs BMW “TwinPower” / variable geometry turbo.
That explains the ~40bhp difference between the two. Thank you!
Very detailed and straight to the point! Thanks
Thank you!
very informative and awesome editing video. Thank You
Glad you liked it!
Subscribed 👍🏼 love these informative videos
thanks man, glad you do
*Great video, concise and educational.*
thankyou for the feedback!
Very informative, thank you for sharing!
Glad you found it helpful!
Good clear explanation, thanks.
no problem!
awesome graphics - great explanation- thanks
Thank you! glad you liked it!
Awesome video. Thanks for sharing
thanks!
Very educational video
It's funny, I just tuned my 2019 wrx and put a new intake, catback, ebcs, bpv and aos. For the first time since putting all the parts on and getting a proper tune done, I went wot and wondered why I didn't feel boost past 5k rpms in sport sharp and this makes complete sense. (Forgive my noobness in not understanding the difference between the two.) Also makes so much more sense as to why the wrx and sti have two different type of header setups. Thanks for the video!
Of course! Glad it helped
Thank you. It is very informative.
Glad it was helpful!
I felt like I was traveling with a band of gypsy's during this video.
Great detailed video….thank you
You're welcome!
Left a like. Very informative
Thankyou! Much appreciated
amazing video!
Thanks!
I own a mark V supra and trying to educate myself. This video is amazing. Thank you. So in 911 turbo they use twin turbo setup and both of them are twin-scroll?
oh that's cool man, hope you're having fun with it. and yes, they have a twin turbo, twin scroll setup. glad you enjoyed the video and found it helpful!
Saaaaaame lmao happy to see I'm not alone on this xD
Same bro. I put a jb4 on my 2.0 Supra it is so fast
Excellent video
Glad you liked it!
Very educational very right to the point the only issue I have is that you can't leave out Saab Saab was the leader in putting turbos into everything they have a twin scroll system that one side is bigger than the other that way at low RPM you have low and boost and at top RPM you have top-end boost its supposed to give you both and have a little bit of lag it actually is a very good
Great video!
thanks!
Super helpful thank you. I was more curious about exhaust manifolds and how they feed into the turbo as i was thinking bout changing my exhaust manifold to have two cylinders each feed to one channel of a dual exhaust but my car is turbo'd so the manifold already Does that, what i now need to figure out is how the exhaust come off the turbo as my car came stock single piped with a dual tip, while it looks alright, it sounds lame and i know the dual tip is a lie, i want true dual exhaust but i dont know enough about how the exhaust comes from the turbo to the back of the car
Great vid!
thanks!
The graph alone should tell you that the data and cons you’re providing are not correct. I don’t see that red line going above twin scroll at all throughout that graph so the loss of power up top is not shown. Additionally the twin scroll prevents a cylinders exhaust gas being forced into an opposing open valve to an unfired cylinder. Twin scroll is definitely the way to go but with v band becoming increasingly popular for fitment and seal and reliability, it’s worthless and not practical with twin scroll ( the original reason I clicked the video) . The twin scroll splits the banks so there are no opposing forces through the exhaust cycle thus becoming more efficient draining not only lower end boost response but nearly identical if not better, top end performance.
yeah a little oversight on my part, "theoretically" it might have less top end since the divider seems to restrict it but real world data (which is what matters) appears to show otherwise
Poppppopoo
Awesome video mate. Is there anyway I can get the Subaru rumble noise on a equal length header/twin scroll turbo? I have JDM 2008 STi GRB hatch with EJ207 engine. ..
Thank you! Unfortunately I don't think you can do that on a twin scroll EJ20, but I could be wrong since people have put UELs on the FA20. You will definitely lose the benefit of a twin scroll if you do change though...
Twin scrolls spool up faster in theory but with certain cars/scenarios they don’t and can reduce the maximum amount of power you will make throughout the power band. I’ve always wanted one until I did my research and saw actual race cars that used multiple different types of twin and single scroll turbos and they found that the single scroll made more power and spooled up quicker in their situation.
exactly... all boils down to the actual use case in question...
Given equal size turbos between single and twin scroll, and correct setup, this should not be the case.
@@JeffGoris but we aren’t talking about same size turbos now are we? Same size turbo the twin scroll would make less power. For same power turbos you would need a larger twin scroll turbo which would still reduce the responsiveness. With ball bearing turbos spooling as quick as they do these days it’s really hard to justify the extra complexity of a twin scroll setup when it isn’t all that much more responsive and makes less power in the end.
Why aren't we talking about same size turbos with the only difference being twin vs single scroll? Where does it say that? Btw, when I talk about size I'm talking about inlet area, turbine size, etc. Not the overall physical dimensions of the turbo. A downside of twin scrolls is that they are more complicated and larger, for the same inlet area, turbine size, etc (this is mentioned in the video). The only way to compare the two properly is to have all other parameters the same like inlet area, turbine size, etc with the _only_ difference being the twin scroll (and it's larger housing).
I assume that on a 3 cylinder engine a twin scroll setup wouldn't make sense, but in what sensible scenario where all the other parameters are the same would the single scroll outperform a twin scroll in terms of responsiveness and peak power. Note, you can put ball bearings on twin scroll too.
And why would you bother with the extra complexity and cost? Because they perform better in pretty much every way. Faster spool/less lag meaning more boost at any given revs, more power across the rev band, better fuel economy, lower exhaust gas temperatures. Many manufacturers have and are using twin scroll setups: BMW M3, M4, Hyundai i30N, some Audi and Porsche inline 6 turbo engines.
@@JeffGoris when you are looking to size a turbo on a car you have a certain power limit that you are limited to before something hurts the engine. You chose a turbo dependent on your power goals, every tuner knows this. The first thing a tuner asks you when you go to the dyno is what are your power goals.
Nice explanation, also both the Mini Cooper F56 1.5t and 2.0 use twin scroll.
yup! a lot of modern cars use twin scrolls nowadays
JDM WRX STI from 2004 above all utilise twin scroll turbos.
Nice video. Ty
thanks!
Please turn down the music..... Thanks
Good info, BUT that background music was distracting!
thanks! would it have been better if it was more instrumental (piano/jazz) kind of music, or was it too loud?
@@JCMediaYT Correct on both. The style of music was a bit too busy and it was too loud to hear your ideas
@@komoru noted, many thanks for the feedback!
Don't always have room for a twin-scroll unfortunately, especially when working with larger displacement engines.
Wery cool bro !
Good video.
Thanks!
Maybe this is a dumb question, but why not quadhscroll turbo? One for each cylinder on a 4-potter? Diminishing returns?
I think that's mostly down to cost from increased complexity making it not as viable, especially for production vehicles. They do exist though, if I'm not wrong Garrett recently developed one...
After a pulse of exhaust, there follows a lower pressure wave. When this lower pressure wave passes through a single scroll turbo at the same time as the next pulse from the next cylinder exhausting gasses, the negative pressure wave reduces the pressure of that second exhaust pulse. This happens because the exhaust valves of consecutively firing cylinders are open at the same time for a brief while. However, the negative pressure wave will be over by the time the next (third) cylinder pulses - you will never get a situation with 3 exhaust valves open. There would be no benefit in having more scrolls. The closer the firing of the cylinders, which occurs with the more cylinders you have, the more beneficial the twin scroll turbo would be. Having twin turbos, of equal size, on a 6 or 8 cylinder engine you have each turbo on half the cylinders so that gives you the same benefit as the twin scroll - you do not have consecutively firing cylinders venting exhaust gases to the same turbo. I do not believe that the Porsche twin turbos use twin scrolls - it would be pointless - they have twin single scroll turbos. I do believe that they have twin variable geometry turbos (VGT). VGT is another video.
video very pog
poggers indeed
2012
Peugeot 3008 1.6thp low end 240 torque
Very god feeling
Lets say that you want to build a competition drift car. So, you want the turbo to perform better through out the top end area of the rev range hence, single scroll turbos will be better for a track only car? B'cus in drifting youre always near the redline.
Is Single Scroll better for this application?
i would still go for a twin scroll, because of the better response and also because the top end isn't going to be too different to a single scroll, despite the graph shown. in other words, the response and turbo lag would be more important in this application
The 09 jdm Subaru STI comes twin scroll as well..... Vf49.
yup, corrected it in the subtitles, thanks for the correction
JDM WRX STI start using twin scroll turbo since 2003
Question.
Can you run two twin scroll turbos on a V8 platform?
I’m sure it wouldn’t work on an I4/I6 platform due to lack of cylinders but I do believe it could work on a V8.
Thanks.
absolutely! and yea, its not really viable on a I4 platform for that reason, but it might be possible on an I6 platform
They work great on four cylinders. The pulses are much more defined.
@@user-pb9hy9uj9p yes, but theoretically they could be way more efficient in a twin turbo layout on a V8. I believe Ferrari already uses twin, twin scroll turbochargers in the 488, Sf90, and F8 engine. Have to imagine the lag would be non existent with great bottom end torque.
The USDM Subaru STi is a single scroll, the JDM Subaru STi is a twin scroll with ELH from the factories
2:17 surprise surprise the evo manifold has a crack 😂😂
woop, didnt even notice that
My guy. You need to turn down the music when you talk. But this is very educational.
thanks for the feedback, i'll keep that in mind
Jason thanks for the video. Is it possible to run a twin-scroll turbo with unequal length headers?
nope it's not possible. you can maybe mount a twin scroll turbo on an UELH but it'll be useless since the gas pulses have to be even for any benefit to be gained
@@JCMediaYT I see. The only difference between twin scroll and single scroll of a turbo of the same type is the housing right?
@@kzz8971 if i'm not wrong, yeah its just the housing
Most factory twin scroll setups are actually unequal length, look at the manifold on the Evo for example.
Neat
Great video! Me es smarter now🧐
The CT5 has a twin scroll turbo, it has alot of low end torque. Basically no turbo lag at low rpms.
How do you make your car habdle a twin scroll?
You will need a twin scroll, equal length exhaust manifold and a compatible turbo. The common flange will be T4 Divided
@JCMediaYT
Okay cool. Will it put more pressure on the engine than a regular turbo? I have a MB c300 2.0l. It has a single turbo. Was wondering if twin scrolling it would be a good idea.
In theory would a twin turbo set up work best? A small twin scroll for low RPM and a bigger single scroll for high RPM?
nope, just going twin twin scroll turbos is the better option
👍👍👍👍
Mark VI supra
Mo power baby! Stuuuu stuuu stuuu
Single scroll helped me avoid crashing as u get time to think of its right or nowt!😁🤣🤣
Do all Ecoboosts engines have twin scroll turbos?
I'm not sure about the V6 engines, but the 2.0 and 2.3L EcoBoost motors do have twin-scroll turbos.
I have a BMW N55 and my son has a N54 and I’m sending this to him because we like to troll each other over who’s car is faster.
hahah that sounds fun, what cars do you two have exactly?
@@JCMediaYT He has a 2008 135i and I have 2016 535i. His car is way faster because it’s stage 2+. But I’ll be stage 2+ day after tomorrow once I get the FMIC and catless DP put in.
Why does a twin scroll turbo have to have "decreased size for gasses to flow through". They can make the twin scrolls have exactly the same size for gasses to flow through as for a single scroll turbo. There is nothing about a twin scroll turbo that limits the size for gasses to flow through. Even in your graph of power of single vs twin scroll the twin scroll had higher power right up to redline. Given equal size turbos with the only difference being twin vs single scroll, I believe the twin scroll will develop more power.
I'm not a mechanical engineer (a software engineer instead) but I suspect it's a limitation of splitting the exhausts into 2 and available size in the engine. Rather than dumping 4 (or more?) cylinders into a single collector, you now have 2 and the metallic characteristics require the same which increases the turbo size requirements.
Feel free to disagree with me, I've always wanted to know more about engine dynamics
Twin scroll ALL Day ❤
Great video, but the music really makes it difficult to focus. Maybe just lowering a little would help.
thanks for the feedback! definitely lowered the audio by a good bit for the more recent videos...
Actually, the jdm version of the STi brings a twin scroll turbo and twin scroll exhaust manifold.
Yup, only on the 2.0 version of the ej. Wish it came on the 2.5 motors lol
@@JCMediaYT Correct. Yes that would be nice. 👍🏻
You forgot to add Saab’s to that list of twin scroll turbocharged cars
damn I didn't actually know Saab's were twin scrolled, should've added it to the list hahah
@@JCMediaYT yup the TD04 is a Mitsubishi twin scroll turbo.
Mini Cooper also, both the base 1.5t and 2.0 F56 S
@@JCMediaYT and they don’t blow head gaskets and transmissions like Subarus do hahaha
Good video I have a twin scroll F30 328 BMW but I would like to ask who manufacturers turbos for BMW I mean the Make is it Garrett or Mitsubish .
If you could just silence the background music...that will be great.
Yup sorry about that, I got a lot better at audio mixing and choosing the songs in the newer vids, thanks for the comment!
❤Ditch the loud background music and i will be able to hear and understand what you are discussing and then i will like and sub .
??? if you go to a university lecture does the professor turn on loud annoying horrible music before and wile lecturing his students ???
the newer vids have better audio mixing, thanks
Twin scroll loosing at high rpm????
yup, due to a more restricted flow thanks to the different scrolls and passageways
You could also say a single scroll loses power in higher rpms due to increased flow disruption that is caused by increased exhaust pulses, creating less efficiency versus the twin scroll. The twin scroll might have less flow area but they are better equipped for higher flow rate and with increased boost, the flow will still have significant pressure flow and outperform a single scroll turbo in high rpms. The better the flow, the more air can be pushed under boost conditions. This can be confirmed with the dyno graph in your video, showing the twin scroll still outperforms in upper rpm range.
Ne stu stu stu from a twinscroll ?
the stututu is caused by the lack of a bov/bpv, not the twin scroll
@@JCMediaYT so a45s has stock bov
@@LB83. the a45s doesn't actually come with a bov or bpv at all from the factory
@@JCMediaYT why doesnt it futter then 2bar is way enouth to do it
M an bby-
axau
Hmma
Ae mm
A
Mg
Is video would be more helpful if you did not go so fast and you spoke more clearly. It's like you do not realize that you are speaking to an audience.
thanks for the feedback, i have been keeping that more in mind with future videos