[highwayblaze]

Originally Posted by Harrie

Two stage turbos are usually twin turbo systems where two turbochargers are used

So does it have two wastegates/blowoff valves or just one. Two phuuushhh sounds ???
Two stage same as stage II??? In that case what are Stage - I or Stage-II ECU's?

[porsche_fan]

Turbos are generally classified as
1.) Free Floating(No WG or boost control mechanism)
2.) WG turbos, with the wastegate, whose function has been explained in great detail.
3.) variable geometry turbos, mostly available in diesels, but now porsche's put two in the new 911 turbo.

So, if a WG turbo is being used, then irrespective of the no. used, it will have a waste gate.

mostly, two turbos will have two blow off valves too.

two stage turbocharging is currently used only on heavy diesels, which involves two turbos one after the other, used to produce very high pressure ratios(upto 4:1).

sequential turbocharging involves two turbos side-by-side, in which there is a small turbo which operates at low engine RPM and a larger turbo which takes over as the air flow through the engine increases(which may cause the smalller turbo to choke). this system is complicated to implement and control, but gives the best driveability of all and is the only turbo charging system which can boast of having negligible lag.

[black12rr]

Now.. who all supply them in india ? how much ? how easy to fit ? ..just curious ..

[murlidar]

Could you please throw some light on Tata Indica Turbo?

[ST7677]

Bump...

Now.. who all supply them in india ? how much ? how easy to fit ? ..just curious ..

Was also curious what boost do people usually run on stock internals and is reliability compromised?

[binz]

Got this when i was doin a bit of light reading on the subject,

Very nice topic btw!

[Rehaan]

Originally Posted by ST7677

Was also curious what boost do people usually run on stock internals and is reliability compromised?

Check this thread out - How Much Boost in India

cya
R

[ST7677]

Thanks Rehaan, I have been through that thread, but it looks more of bragging rights / extreme boosts.

I wanted to know how much boost is advisable for a daily driving petrol car in India with no (minimum) compromise to reliability.
It will be great if a Polling thread can be started to see how many T-Bhpians are running a turbo, at what boost, What kits on what cars and if they have faced any issues?

[ST7677]

In custom turbo setup, how is exhaust manifold created and how is Engine management done?

[Vid6639]

Have you gone through this thread?

http://www.team-bhp.com/forum/modify...-your-car.html

[ST7677]

Have been thru all turbo threads in details but didn't get answer to these questions...

In custom turbo setup, how is exhaust manifold created and how is Engine management done?

I ask this because, exhaust manifold connects engine to the turbo and it doesn't seem like a simple thing to fabricate. There may not be ready made ones available for all engines, specially the new engines or not so popular ones.

Secondly ECU remapping/flashing to control the engine operations is again something that does not come ready made for a custom turbo charged engine. Having the right map is a crucial aspect in getting the tuning correct to run the engine optimally. How is this done?

[Carrera555]

Hey Guys,

Just gone through the whole thred & was immensly informative.

I have a query here, whats the exact diffrence betweed FGT (Fixed Geometry Turbo) & VGT (Variable Geometry Turbo)?
AFAIK, VGT has 2 or 3 stages of turbines, size wise into the same turbo charger, so that it can give the boost from 1800 RPM till almost the red line. Is that correct?

Cheers,

[1self]

Carrera555, VGT has a set of moveable vanes at the turbine which control the rate of exhaust gas flow to the turbine blades. No wastegate is needed. It is generally used in premium & sporty diesel cars & very high end petrol sports cars (Porche turbo).

The effectiveness of the turbo at all rpm ranges is vastly increased with this system. It is also a LOT more complex, more expensive than fixed geomerty turbo.

FGT does not have this vane system. Such turboes need to be carefully chosen with engine compatibility & power goals in mind.

The pic is one example of VGT turbo working mechanism.

[Carrera555]

1self, thanks for the explaination. But I am still not clear with the concept.

How do the vanes work? From the picture it looks as if the vanes act as an obstruction for the exhaust gas to reach the turbine. Does these vane's flip due to the pressure of the exhaust gas?

[1self]

This is one more pic to show you how the system works. The vanes are rigidly connected by metal links to the controller.