Sequential Turbos

[benough]

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

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

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.

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

[Jaymz]

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

[RhysQ]

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

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

[Jaymz]

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

Nice one thanks. How good do those turbos sound

[benough]

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

I think he should fit a DPF

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

[Jaymz]

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!

[benough]

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.

[Jaymz]

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.