Twin Turbo vs. Single Turbo?

[DC47A]

Let me Know what everyone thinks, about the ever popular debate single turbo or twin turbo. Especially these days with the new ball bearing turbos pretty much eliminating that dreaded twin turbo lag of the past.

[ANDRÜ]

Well the point of a twin turbo setup is to reduce lag, which it does. The "dreaded turbo lag of the past" would be form a single turbo. Twin typically solves solves this problem.

[DC47A]

See i thought it was the total opposite. You have to spool both turbo witch takes more time and emission hence the lag. I guess you learn something new everyday!

[LDORADO325]

With all the extra work in fabrication and parts cost for twin turbo, the single turbo is the way to go. Most high hp cars use a single turbo setup.

-Mike

[RacerJames666]

I concurr with ldorado on that issue.....one less turbo to cook.....
and a lysholm or roots type blower is the best choice for "slap it on and go" performance

[gnastydent]

well when you think about it the twin turbo has 3 cylinders powering it comparied to the 6 powering the single. single large ball bearing turbo like the t51 kai

[twinm3]

ONCE YOU GO BOOST YOU NEVER GO BACK!!!

[Nisse977]

It it better for the turbo-spolup when it is only 3-cylinders that i banging in to the impeller. 6-cyl it to smooth if you understand what i mean. Why do you think the old Alpina B10 Biturbo had two turbos, and why does the new 335i have two. Toyota Supra, Nissan Skyline and so on.
I have a friend that is working on Saab. He is mapping the turbo engines for them, and he says it is a little bit better to have twinturbo on a strait six engine than just to have one. But like i said, one works good also, but maybe you will have little more lag.

Another thing is if you have one turbo with two intakes... then it is also best to have 3-cyl in one hole and the other 3 in the other. So just don´t put al cylinders to one pipe.

But ofcourse like you said, it is easier and cheaper to only have one turbo.

Read the book Performance Tuning Forced Induction by A. Graham Bell then you understand more
Product: Forced Induction Performance Tuning

[Highboosted]

Depends. That's my final answer.

Want to have the fastest Skyline? Twin turbo setup in parallel.

Want the fastest Supra? Single turbo.

Want a torque monster? Positive displacement supercharger.

Want the bolt-on-and-go compromise? Centrifugal supercharger.

Want the "dyno queen" monster? Huge single. (Larger the compressor and turbine, the more efficient)

Have a V style engine? Best bet is twins, because going single gets tricky and expensive.


PS The 335i has twins for packaging and emissions purposes according to BMW. Smaller compressors allows them to close-couple the turbos, ports, and catalysts (lights off the cats faster), which is the only way they could make it meet the new regs on emissions, and it allows them fit it all in the engine bay. A single would make the runners longer, and the downpipe to the cat longer (because the single would not fit directly next to the engine), which would make it not pass emissions. If lag was the major concern, they would have used a Garrett VGT turbo like Ford and Porsche did.

[DC47A]

I really want to thank High Boosted and Nisse for brining two really good posts together! You both brought some great information together!!!

[gnastydent]

i think its just a sales thing also, if you own a supra or a skyline then you got money and if someone say 1 turbo your like, o ok a labarin has a turbo but when you say twin it like omg 2 turbo that must be like twice the boost. i still go with single large because you can push more boost faster cause 2 med size turbos will take longer than 1 single large turbo. and you also got to think about the air flowed to the intake because it maybe 30 at the turbo but 25 at the throttle body i just think personally i choose 1 single large air flowing monster it also way less confusing in setting up the maps.

[E30stain]

as far as in know...
*single large turbo = longer spool up but bigger top end power
*twin turbo in series = smaller one spools up gives engine more low down power to spool larger one up quicker (only know a couple of drag cars with this setup... knowledge of this comes from very very very big diesel engines on ferries ect. that dads driven.\
*twin turbo in parrallel = 3cyl on each turbo... many different applications of this setup can be set up for low down power or huge immense amounts of power although the turbos of today are big and efficient enough to not need this sort of setup.

im not an expert so if someone wants to correct what ive just said :P oh and the series setup is really weird but the engines its used on are that big and boosted that the oil actually has to be heated and then pumped through the engine for a good 15-30mins before startup... so yeah not the best setup to consider on a car let alone one to be used on street.

[Nisse977]

Yes most dragcars has one single turbo. But Vidar Strand has twinturbo setup on his M3 E36 dragcar with S38 engine (E34 M5 engine).

Look here!
V.S Motor - Vidar Strand

BMW M3 E36 3,9 - 1422bhp / 1610Nm (1186ft.lbs torque) - engine buildt by V.S Motor




And here you have some movies when he was driving it on some car meetings in Sweden 2006. the best time was 7,64s @ 293km/h on 1/4mile That´s a fast Beemer!
V.S Motor - Vidar Strand

[TRANCe36]

WHY IS ONE OF THE OPTIONS TURBO + SUPERCHARGER, WOW

[itsabimmerthing]

I wouldnt ever twincharge, but it has been done. A shop twin charged a mini cooper with excellent results. Many people take the 4agze supercharged mr2, and slap a turbo with it. VW actualy has a new car comming out with twin charging technology. Its not impossible, and not that far from being a fad.