Twin Turbo vs. Biturbo: Let's settle this.

"macanamera" (macanamera) 06/12/2014 at 10:49 • Filed to: None

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Alright guys, after a heated argument with a friend not too long ago, I want to put this issue to rest. Some people don't let this kind of stuff bother them. I am not that type of person. It seems like everyone has their own ideas when it comes to what these terms mean:

From forums-

"They are two different terminologies for what type of turbo configuration you have in your car. Example: Mercedes bi-turbo, or the Audi S4 2.7 bi-turbo. What this means is that there is a turbo for each bank of cylinders, and they are located on opposite ends of the motor. However, in a car like the Toyota Supra, that car is a twin turbo because it is an inline 6 motor, and the turbos are located next to each other. One feeds off the other (there is a smaller turbo that spools up to create less turbo lag, at which point a larger turbo kicks in for the higher boost). From what I understand, that is the "technical terminology"

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The term twin turbo has been often given to vehicles that use sequential turbos, a small one for low rpm torque, and a larger one for higher rpms and power. The biturbo system uses two equally sized turbos, one fed by cylinders 1-3, and the other by cylinders 4-6. They are not sequential or in series, but in parallel.

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"Biturbo is the same as "Sequential Twin Turbo"
Basically, you have 1 smaller turbo for lower RPM range, and a larger turbo for higher range. It helps greatly reduce turbo lag due to the smaller turbo can produce boost much earlier than a super single or twin turbo setup can do. At lower RPM, the smaller turbo spools and produces boost - then when you reach a preset RPM or boost level, a staging valve opens and directs air to turbo 2(large one) and it now produces the boost for the engine. Usually, stage one turbo is turned off, or its boost is sent into the compressor intake of the stage 2 turbo to achieve a higher output pressure.
Do not confuse Biturbo / Sequential Twin Turbo with "Twin Turbo".
Twin turbo is having two EQUAL size turbo's. Each runs off its own cylinder bank in V or H type (boxer) engines, or off of a turbo manifoldon inline type engines. Both turbos share the load equally in producing boost air. (Like a dual core processor in your PC - both run at same speed, sharing the load equally) So, turbo lag still effects this type of setup, as both turbos will spool at the same time."

From Wikipedia (The Eternal Source Of Trueness and Correctness):

Twin-turbo or biturbo refers to a turbocharged engine, in which two turbochargers compress the intake charge.

So, let me just make this clear (I hope I'm not wrong, that would make me sound dumb). Twin turbo and Biturbo mean the exact same thing. They mean two turbos. There is no difference. It's marketing speak. Mercedes uses the term Biturbo because it sounds uppity classier? BMW uses the term TwinPowerTurbo because it sounds stupid sportier. It has nothing to do with the turbos being sequential or parallel, it has nothing to do with which specific cylinders feed the turbos, it has nothing to do with the size of the turbos, it has nothing to do with where they are located. Bi=Two=Twin. That is all. End rant.

themanwithsauce - has as many vehicles as job titles > macanamera 06/12/2014 at 10:51

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Twin turbo = two turbos

Biturbo = Maserati.

PatBateman > macanamera 06/12/2014 at 10:52

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I'm a supercharger man myself, so dunno.

macanamera > themanwithsauce - has as many vehicles as job titles 06/12/2014 at 10:52

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Ha! You are right.

Mattbob > macanamera 06/12/2014 at 10:52

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you sound about right. Marketing just confuses everything. I think you have to add the word sequential or series to refer to setups with the two sizes.

Chris_K_F drives an FR-Slow > macanamera 06/12/2014 at 10:52

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Yes.

macanamera > Mattbob 06/12/2014 at 10:54

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Yeah. The only difference to be had in turbocharged cars is number (obviously) and arrrangement (series/sequential vs parallel)

macanamera > Chris_K_F drives an FR-Slow 06/12/2014 at 10:54

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Thank you.

Chris Clarke > macanamera 06/12/2014 at 10:55

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I've never really researched it, but always assumed bi-turbo meant 2 separate and independent turbos, while twin turbo meant 2 mated together. I generally always say twin turbo regardless because I'm a fan of alliteration.

Nibbles > macanamera 06/12/2014 at 10:56

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Twin Turbo - two turbos

Sequential Turbo - two turbos in a mechanical centipede (think about that one for a while)

Biturbo - two pretentious turbos

TwinPowerTurbo - TwoPretentiousTurbos

Hyrbid Turbo - lol the leafblower worked

Mattbob > PatBateman 06/12/2014 at 10:57

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SUPERCHARGER MAN!!!!!!!!!!!!!

http://www.comicvine.com/supercharger/4…

macanamera > Nibbles 06/12/2014 at 10:59

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Biturbo - two pretentious turbos

TwinPowerTurbo - TwoPretentiousTurbos

I loved this lol

Alfalfa > macanamera 06/12/2014 at 11:00

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It's always seemed pretty simple to me. Twin turbo would logically mean that both turbos are the same, and sequential means they run in sequence. I never really looked into biturbo, I've always assumed that it meant the same thing as twin turbo. Car companies inventing their own words is nothing new. I mean, Kompressor? What's up with that? Your average Mercedes owner won't know enough about forced induction to know the difference, they just know that it makes their engine "too loud". Then they sacrilegiously disconnect it.

WolfmanJimCBW > macanamera 06/12/2014 at 11:12

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Obviously quadturbo is the only way to go.

BKRM3 > macanamera 06/12/2014 at 11:13

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I'm not sure I understand what you're saying about BMW in particular. The N54 engine uses two physically separate turbos and is NOT referred to as a "TwinPower" turbo. The N55 engine, which IS referred to as TwinPower etc, uses a twin-scroll SINGLE turbo. They're not the same thing at all.

macanamera > BKRM3 06/12/2014 at 11:15

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The only point I am trying to make is that Twin Turbo= Biturbo. I don't want to wade into the depths of what BMW calls anything, honestly.

Racescort666 > macanamera 06/12/2014 at 11:29

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It's marketing and whatever the manufacturer wants to call it. bi=two=twin is correct and there are more common ways of turbocharger configurations that blanket terms apply to. However, if you want to speak about a specific configuration, it is always best to specify parallel vs sequential.

Side note, DO NOT confuse a twin scroll turbo for a twin turbo. They are not the same thing.

The scroll is the gas passageway in the cast turbine section. The turbo on the left is a twin scroll because it has 2 scrolls (and thus 2 ports) and the turbo on the right is a single scroll.

macanamera > Racescort666 06/12/2014 at 11:32

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Yep, well aware of the difference between twin scroll and twin turbo. Thanks.

RazoE > macanamera 06/12/2014 at 11:48

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Don't forget about compound turbos.

LuczOr > macanamera 06/12/2014 at 11:48

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You are correct. Twin Turbo or Biturbo or any other moniker you have seen displayed anywhere are marketing names (which likely have copyrights or trademarks by the respective companies that made the term up).

On the technical engineering side, when we hear twin turbo, the first thought is a parallel system for engines configured in a V, while we usually specify "sequential turbos" when they are in series/sequence for whatever engine configuration (which are likely PATENTED, not copyrighted, by the companies/individuals that invented them).

The difference is marketing terms vs. descriptions of technology.

BiTurbo228 - Dr Frankenstein of Spitfires > themanwithsauce - has as many vehicles as job titles 06/12/2014 at 11:50

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This. I get very frustrated when I look on eBay for crusty Italian shitboxes* and all I get is shiny Mercedes cocaine-transporters.

*I love the biturbo, but this is most people's perception

HammerheadFistpunch > macanamera 06/12/2014 at 11:50

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Its like the AWD vs 4WD debate. Its all marketing. Traditionally 4wd has meant truck and awd has meant road bias, just like twin turbo has traditionally meant separate turbos and bi-turbo has meant compound. but its only an informal convention, there is no weight to it. the 2JZ-GTE in the Mark IV supra was a compound but it was marketed as twin turbo, for example.

Sn210 > WolfmanJimCBW 06/12/2014 at 11:51

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quad-turbo!

HammerheadFistpunch > macanamera 06/12/2014 at 11:52

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I've got a twin scroll.... air conditioner.

V8Demon - Prefers Autos for drag racing. Fite me! > Nibbles 06/12/2014 at 11:54

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The mental image my mind concocted for "mechanical centipede" can unfortunately never be forgotten.

SoutherthanThou > PatBateman 06/12/2014 at 11:57

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I'm surprised more things aren't supercharged... it makes so much sense.

WolfmanJimCBW > Sn210 06/12/2014 at 12:01

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Yay for EB

macanamera > HammerheadFistpunch 06/12/2014 at 12:08

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Cools the shit out of that air, virtually no lag until the air gets cold.

HammerheadFistpunch > macanamera 06/12/2014 at 12:17

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Im thinking of getting a really loud BOV too, maybe a new downpipe.

macanamera > HammerheadFistpunch 06/12/2014 at 12:19

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maybe a few monster stickers

DocWalt > macanamera 06/12/2014 at 12:43

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Wiki is right. Fuck all that other nonsense

bagelsjustbagels > LuczOr 06/12/2014 at 15:51

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Hey Man sorry for the randomness, but did you ever mate that LS up with the toyota?
I'd love to know.

Thanks! - Adam

LuczOr > bagelsjustbagels 06/12/2014 at 16:09

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Right now I'm in the process of selling off all the Camaro parts to fund the swap project. I've sold off about $2300 worth of parts and have to sell another $1000 and I will be able to buy up all the parts so I can slam it all together in a few days. When it's all done, I will start writing posts again and continue the series.

Maybe I will do an update this week just to keep anyone who cares in the loop.

beardsbynelly - Rikerbeard > macanamera 06/13/2014 at 02:10

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Doppelt Kompressor doesn't fit so neatly on a badge.

Aaron Simms > WolfmanJimCBW 11/21/2014 at 13:49

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Bugatti Veyron pls.

Jinbaittai > macanamera 05/18/2015 at 00:46

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IIRC BMW’s “twinpower turbo” name is used for their twin turbo AND single turbo setups. Justifiably so on single turbo because it is a “twin scroll.”

Jinbaittai > Alfalfa 05/18/2015 at 00:51

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Kompressor is a real word, just from another language (i.e. German).

Leon711 > macanamera 05/28/2015 at 03:39

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TIL in my early days at university I attached an electric motor to a compressor section of a turbo. we spun it up to speed but it never saw a car.

TheOnelectronic > Alfalfa 05/28/2015 at 03:43

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EDIT- Dangit, related stories fooled me AGAIN!

beardsbynelly - Rikerbeard > macanamera 05/28/2015 at 04:02

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the Germans use biturbo ‘cause its easier and quicker to say than doppelt-kompressor

Satoshi "Zipang" Katsura > macanamera 06/19/2015 at 05:15

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Just call it single or twin/biturbo!

jarrodbaker7 > macanamera 10/09/2015 at 15:01

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I’m no expert on car engines, but I do speak english. Just think about the definition of the words. Bi and Twin both mean two.

Biturbo is just way to classify an engine with two turbos, it has nothing to do with the orientation of the turbos.

Twin turbo, however, is more specific, the word twin means two separate, but identical parts. Again, doesn’t describe the orientation of the two turbos, just that they are physically identical.

(ex.)

-having two identical turbos, in a sequential setup(this is pointless,but just for example) is a “Twin Turbo” and a “Biturbo” engine.

Bottom Line: “Twin Turbo” is a subcategory of “Biturbo.” Therefore: if Biturbo=Twin Turbo then Twin Turbo=Biturbo

samssun > macanamera 11/05/2015 at 05:49

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Well, marketers can call things whatever they want (Audi’s supercharged 3.0T?), but it makes no sense to call a sequential setup “twin”. Twin means matching, bi means two.

I guess you could argue that biturbo encompasses any two turbo setup (with twin turbo a subset), but why not just simplify and say biturbo means non-twin turbos?

Ricardo Landgrave > macanamera 11/13/2015 at 13:42

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Old thread, but didn’t see this answer:

Bi-Turbo: As the name implies, two turbos under the bonnet . These turbos are NOT necessarily the same size , but neither are they necessarily different. I think it would be etymologically correct to call both parallel and sequential turbos Bi-Turbo, but I prefer to use Bi-Turbo to name a system that runs sequentially with [obviously] differently sized turbos.

Twin-Turbo: Pretty straight forward, two identical turbos doing an identical work and powered by different cylinders . In my opinion, this should never be used to refer to a sequential turbo system , as it creates confusion, even if the turbos are identical, because they would do different jobs still. And I don’t see the point on a sequential turbo system with equally sized turbos.

In other words, you are wrong, your friend was probably right or maybe even wronger .

505 - morphine not found > macanamera 11/30/2015 at 04:26

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I always thought that “twin” is two equal size turbos, while “bi” is two unequal size turbos, with one being smaller and spooling up faster for low-down power. But yes, mostly marketing speak, see modern 4-door Coupés and Shooting brakes.

One thing though TwinPowerTurbo in BMW speak is the twin-scroll turbo, so not the same as the Merced BiTurbo AMG engines.

Drakkon- Most Glorious and Upright Person of Genius > macanamera 11/30/2015 at 06:23

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I knew a girl who was bi-turbo in college once. Now she’s all suburban ‘n’ shit.

Drakkon- Most Glorious and Upright Person of Genius > HammerheadFistpunch 11/30/2015 at 06:26

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I never thought AWD and 4x4 were mix and match (not in the US anyway)

AWD was automated and blind to the driver. 4x4, even in Subaru speak required the driver to select it.

Other that UK where everything is 4x4, who mixed the terms?

Twinpowermeansoneturbo > macanamera 11/30/2015 at 08:40

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To clarify, BMW’s twinpowerturbo is actually a single turbo. It’s just twinscroll. (Hence my kinja name) confusingly enough though, they use the name for some engines which are true twin turbos but use twinpowerturbo technology.

Raymundo > Drakkon- Most Glorious and Upright Person of Genius 11/30/2015 at 09:31

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^ What he said. AWD is automated so that the wheels are technically engaged all the time. I suppose the argument could be made that in a varying system where power is biased to the front or rear under certain conditions, this could leave half the drivetrain recieving 0% of the power at any given moment, but the fact remains that all wheels are engaged all of the time. In a 4x4 system, the power delivered to the drivetrain is user selected, and in most cases for daily commuting the system is left in a two wheel drive configuration.

EL_ULY > macanamera 11/30/2015 at 09:32

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I’m not Bi

KusabiSensei - Captain of the Toronto Maple Leafs > macanamera 11/30/2015 at 09:59

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TwinPowerTurbo is also used by BMW to refer to their single turbo setups which have twin-scroll compressors.

Go figure.

McMike > macanamera 11/30/2015 at 10:40

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HammerheadFistpunch > Drakkon- Most Glorious and Upright Person of Genius 11/30/2015 at 11:28

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People who want to sell you stuff. There isn’t a mechanical difference, just a “focus group” difference.

HammerheadFistpunch > Raymundo 11/30/2015 at 11:32

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And yet, I drove to work this morning in a “full time 4wd” vehicle that is nearly mechanically identical in operation to my previous “symmetrical AWD” one (inline driveline components linked to permanently engaged “all wheels driven” via a center differential and viscous coupler). i.e. my Land Cruiser requires no intervention to be in “4wd” in the exact same way my Forester required no intervention. It has low range gearing, its true, but Australian foresters had a low range option as well and were still “AWD”. My point being that its a marketing thing, not a mechanical thing.

sm70- why not Duesenberg? > macanamera 11/30/2015 at 12:24

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And then you add in BMW, which is a twin-scroll single turbo.

WiscoProud > HammerheadFistpunch 11/30/2015 at 12:47

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The one distinction I've always used for 4x4 vs. AWD is a locking center differential. If its normally open, but can be locked, I say 4x4. If no lock, then AWD. I guess that's why some would say automatic 4wd instead of AWD. In reality, its just semantics.

HammerheadFistpunch > WiscoProud 11/30/2015 at 12:49

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It really is just semantics, after all, discoveries didn’t have locking center diffs for a brief while. Also, my old rav4 had a locking center diff

WiscoProud > HammerheadFistpunch 11/30/2015 at 12:53

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I would argue that those Discoveries aren’t worthy of calling themselves 4x4. The old Rav4s were a lot better than people gave them credit for.

Personally, unless I can lock the center diff and give 50% to the front and back, its AWD to me. I love my cruiser, but if there wasn’t an option to lock the center, even with ATRAC it would just be a better AWD.

HammerheadFistpunch > WiscoProud 11/30/2015 at 12:53

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fair enough, but I think that’s a personal choice more than a hard line. Like how I call my cruiser a truck.

Saracen > macanamera 11/30/2015 at 12:55

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I have always prefered to use “twin turbo”, and in clarifying how the system works, the terms “parallel” and “sequential”.

===

Though, I suppose one could make an argument that “twin turbo” should be analagous to parallel turbos, since “twin” imples that the two turbochargers are identical in size...and “biturbo” doesn’t necessarily carry that implication.

WiscoProud > HammerheadFistpunch 11/30/2015 at 13:37

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Oh no doubt. I call my cruiser a truck as well. I thought is that while it doesn’t have a bed, its big, 4wd, body on frame, and has the same payload as a Dodge Ram 1500 crew cab.

Shiftright > PatBateman 11/30/2015 at 13:38

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I’m a Tornado man all the way!

HammerheadFistpunch > WiscoProud 11/30/2015 at 13:40

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yes, people can’t seem to differentiate “truck” and “pickup truck” these days. Oh well, semantics.

TurboZ31 > macanamera 11/30/2015 at 14:14

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Yes, biturbo means 2 turbos. Twinturbo means 2 turbos. Turbo means indeterminate number of turbos. You can easily find examples that show sequential or symmetrical has nothing to do with it. I see the AWD vs 4WD people have started up... next lets talk about the difference between a motor and an engine. While we are at it... why do you park on a driveway and drive on a parkway.

Juan Tawn > macanamera 11/30/2015 at 14:33

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Sounds like people want marketing terms to mean a certain thing.

The difference between sequential and parallel is real. That said, how do you feel about twin scroll? LOL

Satoshi "Zipang" Katsura > Nibbles 11/30/2015 at 14:43

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I had to laugh at the last two.

RazoE > macanamera 11/30/2015 at 14:44

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Twin turbo and twin ENTRY turbo are also two different things.

RazorGP > WolfmanJimCBW 11/30/2015 at 14:58

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You mean octa-turbo. it would be 2 paired per bank with a smaller one each bank to spool faster and each would be doubled for sequential induction.

Jake - Has Bad Luck So You Don't Have To > macanamera 02/20/2016 at 10:54

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They mean the exact same thing.

mr2gud2u > macanamera 04/16/2016 at 12:33

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Good post. I'm kind of an NA guy, so never knew or thought about the difference between the two.

Scott > macanamera 04/19/2016 at 12:16

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And just to through another wrench in the mix? what about something like Lancia Delta S4, with Twincharging.

-this space for rent- > macanamera 04/24/2016 at 09:25

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If there are two turbos of the same size, twinturbo.

Because twins.

Life and Times of Magoo: The People's Champ > Nibbles 04/28/2016 at 15:40

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This is the only thing needed in this whole thread Lol

AFondoConFe > macanamera 04/28/2016 at 15:50

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Last quote is the correct one (not wiki).

Rusty Vandura - www.tinyurl.com/keepoppo > macanamera 05/12/2016 at 15:13

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Yes, and it’s two times less than a quad turbo.

Rusty Vandura - www.tinyurl.com/keepoppo > HammerheadFistpunch 05/12/2016 at 15:17

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I’ve read many things on Oppo, and missed many more, but this discussion is pretty esoteric. Not a criticism, just an observation. I guess what would turn me off about it is how obviously marketing-based the issue is and, therefor, how meaningless. @themanwithsauce plays it well above: biturbo = Maserati.

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo 05/12/2016 at 15:28

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pretty much how I feel about 4wd vs awd

Rusty Vandura - www.tinyurl.com/keepoppo > HammerheadFistpunch 05/12/2016 at 15:39

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I could see making a distinction based upon the era. 4WD is an older term and speaks to me of solid axles under a truck. AWD would be something like independent suspension and prop shafts on a Subaru. But an endless debate? And we’d be talking about a technology application instead of what a badge implies. Meh. Whatevs.

HammerheadFistpunch > Rusty Vandura - www.tinyurl.com/keepoppo 05/12/2016 at 15:42

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pretty much.

unnecessary human being > Racescort666 05/23/2016 at 11:39

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what about bmw twin power turbo?

just kidding. they used to be parallel twin turbo and now they’re twin scroll single turbo. unless it’s a v8 in which case they’re bi-turbo, i guess.

rhobere > macanamera 05/23/2016 at 12:03

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The name “biturbo” was probably invented because of systems that use two different size turbos since two non-identical turbos are not twins. So in other words all twin turbos are biturbos, but not all biturbos are twin turbos. I could be wrong about that, but the pedant in me doesn't like referring to a system that uses two different size turbos as a twin turbo.

xyz126 > macanamera 12/21/2016 at 15:55

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Sry man, but this is soooo stupid. Twin turbo means twins=two of the same size. Each fill its cylinder blank(for example in a V6 turbo1 fills 1-3 cylinders, turbo2 fills 4-6 cylinders.

In a biturbo(or in newer constructions, triturbo) there is a smaller and a larger one. A smaller turbo can spool up faster, so they will be much less lag. Biturbo have two types, in the first, they work together, the smaller generates pressure, and it boosts the larger.
In the other type, they work separately. The smallers spools, the large one is separated, and when the small t. reached a high enough pressure, the bypass opens and the large one starts working

Calin > macanamera 12/22/2016 at 15:13

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I’m sorry to say but you are the victim of bad advertising.

bi-turbo means that you have 2 turbos that are the same size, so they both start working at the same time, same revs, so you get a boost in long distance acceleration.

twin-turbo means that you have 2 turbos that are NOT the same size. You have a smaller one, that starts at lower revs, so you get a quicker acceleration off the line and then you have a second one, which is normally bigger which helps with your acceleration at higher revs.

if you would put both cars on the dyno, you would see the difference easily. and besides this essential difference, you also have the build of the turbo with one or two driving chambers.

FireFlyXC > macanamera 03/21/2017 at 16:58

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I would have said that twin-turbo would refer to 2 turbos the same size, since the word twin refers two of the same thing, and that bi-turbo refers to 2 turbos of different sizes, since bi is a prefix of 2 but not necessarily the same.

But that’s just my interpretation.

Fazillah > macanamera 02/09/2018 at 01:36

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Twin means:

something containing or consisting of two matching or corresponding parts, in particular. Thus twin turbo would mean that it had 2 matching turbos, most likely one for each cylinder bank.

Bi means:

Having 2. Thus this could be for sequential turbos where they are both different.

Three Julez > macanamera 06/29/2019 at 10:38

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Twin turbos literally explain themselves.. Twin = two, bi = two. The term is interchangeable. No you’re not wrong lol