Sequential Turbos

The 1.9 Diesel that comes in new saabs have sequential turbos.

http://www.drive.com.au/Editorial/Ar...rticleId=52969

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The turbo housing is integrated into the exhaust manifold. From idle to 1500rpm the smaller turbine generates boost, while between 1500rpm and 3000rpm both turbines spin. Above 3000rpm only the larger turbine is engaged.

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I saw/heard one in my car park the other day and it sounded great. The turbo whoosh was almost twice as loud as my 125kw TDI.

I asked Paul at Mueller and Mueller in Sydney if you could do sequential turbos on a Golf and he laughed at me.

Surely it can be done. Imagine having that torque feeling from idle. You would need 4MOTION to handle it!

That said home come NZ get 4MOTION TDI Golfs and we still have bloody Russell Crowe?! ;)

link

Dont worry about that sequential turbo rubbish. Just run a small turbo into a big turbo see what 100psi will do for ya

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Originally Posted by Jaymz

Dont worry about that sequential turbo rubbish. Just run a small turbo into a big turbo see what 100psi will do for ya

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your link didn't work jaymz....try this

http://videos.streetfire.net/video/Y...UEL_140470.htm

imagine the torque on that thing..... 52,876 Nm :D

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Originally Posted by [-Polo GTI-]

your link didn't work jaymz....try this

http://videos.streetfire.net/video/Y...UEL_140470.htm

imagine the torque on that thing..... 52,876 Nm :D

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Nice one thanks. How good do those turbos sound:D

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Originally Posted by Jaymz

Dont worry about that sequential turbo rubbish. Just run a small turbo into a big turbo see what 100psi will do for ya

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I think he should fit a DPF ;)

So running a small turbo into a big turbo? Is that different to sequential?

With sequential, the turbos are staged. This is usually seen in a engine with cylinders in a straigh line. The small turbo will kick in early as it needs very liitle gas flow to turn the turbine and then when there is enough gas flow the bigger turbo will kick in and the small will turn off.

The infamous 2JZ from Toyota did this very well.

The 1.4TSI does this also with the supercharger disengaging when there is enough gas flow to turn the turbine and make boost pressure in the compressor.

Running a turbo straight into a turbo is old skool cool and I have seen this in early tractor racing. Think of it as supplying positive boost pressure straight into a turbo, as you can imagine massive boost preesures can be obtained. Generally you will only see it in diesels as petrol engines really struggle with 100psi of pressure!:)

Yeah that's how I understood it.

So how hard would it be to do on a MKV TDI Golf?

From my poking around it seems llike there would be enough room for it.

I would have thought the hardest part would be getting it to work with the variable vanes in stock turbo. I imagine they would be have to be in a different position if they started on postive pressure.

Problem is with something hybrid like that is, cost v's benefit. It would truely blow the budget sky high.
You would be a lot better off fitting either a high flow version of the standard turbo or spending hrs on tdiclub to find a turbo and injectors on there that will suit your application.
If you are after better torque down low then in theory you only have to get the standard turbo boosting earlier.
Tuning will help but if you do the airbox mod that the other guys have done on here and fit a free flow exhaust you will definately boost earlier too.

Another turbo that is designed to boost earlier and for longer will almost definately have the same result as a sequential setup if not better. It will definately cost a lot less.
Have a look at some of the dyno graphs from some of the big turbo boys from tdiclub, you will see they have better response than our GT's, have a flatter torque curve and a lot more of it.
In theory if we used one of those turbos that they have we should have better response again as we have the better engine.

A bit off topic, but I can't find the original A3 TDI clubsport thread....
We need to find the specifics of these mods J-man!

Engine specifics of the A3 2.0 TDI clubsport concept car.
************************************************** ************************************************** **************
The drive train

The high-performance TDI under the bonnet of the Audi A3 TDI clubsport quattro is like nothing that has gone before it. From its displacement of just 1,968 cc, it summons up an output of 165 kW (224 hp). Torque – the true measure of effortless motoring ability – peaks at an exhilarating 450 Nm (331.90 lb-ft), which is on tap from just 1,750 rpm; in other words, the very bottom of the rev range. As for in-gear flexibility, the diesel model leaves its gasoline-powered rivals standing.

The mighty TDI bestows the Audi A3 TDI clubsport quattro – which tips the scales at just 1,475 kilograms (3251.82 lb) – with pulling power befitting of a sports car. The sprint from 0 to 100 km/h (62.14 mph) is over in a fleeting
6.6 seconds and the speedometer needle keeps rising all the way to 240 km/h (149.13 mph).

The four-valve sports engine is smart too; it responds spontaneously to the throttle and pampers the occupants with the low-vibration running of its mechanics. On an acoustic level, however, it proudly proclaims its abilities for all to hear: the exhaust system is a new development, with controllable resonance chambers on both tailpipes to amplify the rich, sonorous sound.

The engineers took as a basis the undersquare engine (bore x stroke = 81.0 x 95.5 millimeters) with an output of either 103 kW (140 hp) or 125 kW (170 hp), depending on the configuration, and added to it an optimized turbocharger. The advanced design of its blades allows it to supply more air; as in the series-production version, the variable geometry of the turbine’s blades ensures spontaneous response.

The 2.0 TDI, which is managed by one of the most sophisticated control units currently available on the market, is brimming with high tech. Fuel injection is handled by a common-rail system with piezoelectric injectors and eight-hole nozzles. The high-precision metering of as many as five injections of fuel per power stroke has the effect of audibly reducing the noise level. The system operates at a pressure of 1,800 bar – this results in extremely fine atomization of the fuel which, together with the revised piston geometry, makes the combustion process a highly efficient one.

The engine’s intake manifold houses swirl flaps that generate a tumbling action in the inflowing air; electric motors regulate the flaps’ position so that this tumbling motion is always perfectly suited to the current load and engine speed. Two balancer shafts in the engine reduce the degree of vibration in the crank drive. The drive unit for the belt that propels the two camshafts has also been reworked with a view to improving the engine’s acoustics.

check this out

http://www.youtube.com/watch?v=mjgaxdl-z-g

The engine in the A3 2.0 TDI clubsport concept car reads very impressive indeed, but I was a bit concerned about the "spontaneous response" ensured by the variable geometry of the turbine’s blades. I might be slightly old-fashioned, but I prefer engines that go faster and slower when I tell them to, not as and when they want. Still, for those sorts of outputs I suppose I could be a bit more easy-going :)

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Originally Posted by cogdoc

A bit off topic, but I can't find the original A3 TDI clubsport thread....
We need to find the specifics of these mods J-man!

Engine specifics of the A3 2.0 TDI clubsport concept car.
************************************************** ************************************************** **************
The drive train

The high-performance TDI under the bonnet of the Audi A3 TDI clubsport quattro is like nothing that has gone before it. From its displacement of just 1,968 cc, it summons up an output of 165 kW (224 hp). Torque – the true measure of effortless motoring ability – peaks at an exhilarating 450 Nm (331.90 lb-ft), which is on tap from just 1,750 rpm; in other words, the very bottom of the rev range. As for in-gear flexibility, the diesel model leaves its gasoline-powered rivals standing.

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I thought about this the other day. I imagine the motors would be quite similiar.

At least it gives us a ceiling to aim for :)

The 2L audi info is very impressive. Some nice concepts in there. I would love any more info if anyone finds it.

As for the sequential turbo stuff, im sorry but in my opinion you would be throwing money down a hole. The VNT turbos are there to do the job of sequential turbos. The variable pitch of the vanes allow it to act like a small turbo at low flow but still deal with high flow like a big turbo.

I can understand why muller laughed. Sure, you could do it, but it would be expensive and the improvements would be minimal. If you want improvements i think you would much better off looking into upgraded fuel maps and boost control with the existing turbo, or a large VNT.

remember its simple.... more air+ more fuel = getupandgo :driver: