Twin Turbos

[Willy Nilly]

Some engines are "twin turbo" so what does that actually mean, aside from have 2 turbos?

Does the boost from one turbo supply the other one? If that is the case, which way is the driving exhaust gas going, because surely it will have lost power going through a second turbo?

There is a (quite large) V12 that has twin turbos on each bank, so 4 turbos, which I assume work as seperate pairs.

Does it give more boost or are their other reasons?

So many questions.

[ecsrobin]

isnt it that one is smaller than the other to reduce lag?

[f1nn]

Depends on the engine.

Mine has two, equal sized turbos on a six cylinder engine. Each turbo is fed by the exhaust gas from 3 cylinders.

[Mike335i]

Depends on the set up. My car has 2 small turbos which spool quicker to reduce the lag yet still provide a reasonable amount of boost. They run in parallel.

Other systems have one small and one large that run sequentially.

[ambuletz]

small turbo spools up easier/quicker/at lower RPM but not much of a great boost in HP.
large turbo requires higher RPM to spool up but gives greater HP gains.

[C.A.R.]

You don't see many sequential turbo setups any more - is this because of advances in turbo technology? Thinking back to the 90s lots of performance cars were twin turbo in this fashion (I think...)

[V8RX7]

DELETED: Comment made by a member who's account has been deleted.

I don't understand what the advantage is of this type, 3 cylinders driving a small turbo or 6 cylinders driving a large turbo would seem to be the same in performance / spool terms.

I presume there must be a benefit because there are cost, weight, complexity penalties having two instead of one.

Obviously on a V engine there are obvious "layout" benefits to twin turbos.

[Welshbeef]

V8RX7 said:

I don't understand what the advantage is of this type, 3 cylinders driving a small turbo or 6 cylinders driving a large turbo would seem to be the same in performance / spool terms.

I presume there must be a benefit because there are cost, weight, complexity penalties having two instead of one.

Obviously on a V engine there are obvious "layout" benefits to twin turbos.

In the 335i it's two small Turbos so your getting max torque from very low revs I think on the TT 335i you have a torque plateau from 1,250rpm all the way to near max revs which is superb.

[Section 8]

What annoys me is when traders sell 320d's with TWIN TURBO emblazened over the windscreen/web ad!! NO IT IS NOT!!!!! Twin power turbo does not mean a double turbo charger set up unless it is the twin turbo 125d/ 325d/ 335i etc . Likewise when i had an MR2 GTS and evryone kept telling me it was twin turbo, even people i would consider petrolheads. No it says twin entry not twin turbo you mong!!

[popeyewhite]

It's just a matter of terminology, twin turbo and bi-turbo mean exactly the same according to Oppositelock:
http://oppositelock.kinja.com/twin-turbo-vs-biturb...

[Elysium]

popeyewhite said:

It's just a matter of terminology, twin turbo and bi-turbo mean exactly the same according to Oppositelock:
http://oppositelock.kinja.com/twin-turbo-vs-biturb...

And they are wrong. Twin means 'matching' my last car a first generation 335i was a twin turbo because it had two matching turbos.

Bi just means two. My current car is an Audi BiTDI. It has one small and one large turbo arranged sequentially. It is a biturbo, but not a twin turbo.

The article is also wrong regarding BMW twin power turbos. They say twin power because they use a single twin scroll turbocharger.

[Mr E]

Some of the larger BMW derv units are triple turbo if memory serves.

(In fact, a quick google suggests some are now quad turbo).

The only other quad turbo production cars I can think of are the EB110 and the Veryon.

[Screechmr2]

Elysium said:

And they are wrong. Twin means 'matching' my last car a first generation 335i was a twin turbo because it had two matching turbos.

Bi just means two. My current car is an Audi BiTDI. It has one small and one large turbo arranged sequentially. It is a biturbo, but not a twin turbo.

The article is also wrong regarding BMW twin power turbos. They say twin power because they use a single twin scroll turbocharger.

Twin doesn't mean matching. Therefore twin turbo can be two different sized turbos.

[Welshbeef]

Elysium said:

popeyewhite said:

It's just a matter of terminology, twin turbo and bi-turbo mean exactly the same according to Oppositelock:
http://oppositelock.kinja.com/twin-turbo-vs-biturb...

And they are wrong. Twin means 'matching' my last car a first generation 335i was a twin turbo because it had two matching turbos.

Bi just means two. My current car is an Audi BiTDI. It has one small and one large turbo arranged sequentially. It is a biturbo, but not a twin turbo.

The article is also wrong regarding BMW twin power turbos. They say twin power because they use a single twin scroll turbocharger.

Bi Turbo as you describe it is incorrect

The C5 RS6 is a 4.2v8 Bi Turbo but they are two identical Turbos one servicing each bank of 4 in the v


My 535d is twin turbo. It is a sequential setup ditto your audi.

[aka_kerrly]

Just to confuse things even more you also have cars like a Toyota MR2 which has a twin entry turbo which people often think means there are 2 turbos!!

[f1nn]

Jesus.

Twin Turbo, means there are two turbos.

BI Turbo, means that there are two turbos.

Twin Power, or even Twin entry Turbos, I'd expect are just a fancy name for one Turbo.

[V8RX7]

Welshbeef said:

V8RX7 said:

I don't understand what the advantage is of this type, 3 cylinders driving a small turbo or 6 cylinders driving a large turbo would seem to be the same in performance / spool terms.

I presume there must be a benefit because there are cost, weight, complexity penalties having two instead of one.

Obviously on a V engine there are obvious "layout" benefits to twin turbos.

In the 335i it's two small Turbos so your getting max torque from very low revs I think on the TT 335i you have a torque plateau from 1,250rpm all the way to near max revs which is superb.

Yes but one turbo - twice the size but being fed twice the air (from all 6 cylinders) would surely do exactly the same ?

[Mr E]

V8RX7 said:

Yes but one turbo - twice the size but being fed twice the air (from all 6 cylinders) would surely do exactly the same ?

But would be larger for the same peak flow, and therefore laggier and have higher boost threshold.

[V8RX7]

Mr E said:

V8RX7 said:

Yes but one turbo - twice the size but being fed twice the air (from all 6 cylinders) would surely do exactly the same ?

But would be larger for the same peak flow, and therefore laggier and have higher boost threshold.

Would it ?

Sorry you've lost me.

3 cylinders feed a turbo size 1
6 cylinders feed a turbo size 2

What exactly is the advantage ?

I presume there must be one but I don't see how doubling the turbo size and doubling the flow affects anything.

[Elysium]

Screechmr2 said:

Elysium said:

And they are wrong. Twin means 'matching' my last car a first generation 335i was a twin turbo because it had two matching turbos.

Bi just means two. My current car is an Audi BiTDI. It has one small and one large turbo arranged sequentially. It is a biturbo, but not a twin turbo.

The article is also wrong regarding BMW twin power turbos. They say twin power because they use a single twin scroll turbocharger.

Twin doesn't mean matching. Therefore twin turbo can be two different sized turbos.

Yes it does. This is what it says in the dictionary:

Dictionary said:

something containing or consisting of two matching or corresponding parts