What are Hybrid Turbos and has anyone fitted them to an S4?

[SonicDeathmonkey]

In laymans terms, what are hybrid turbos and has anyone fitted them to a B5 S4?

What benefits do they offer and how much would they cost Vs. standard KO4 upgrades?

Cheers,
Steve

 

[Caesium]

A hybrid turbocharger combines the quick boost response required at low engine revs, with the extra air-flow capacity needed for more power at higher revs - with excellent Turbo Technics reliability.
Hybrid turbochargers are not a new idea. Turbo Technics started producing hybrids as long ago as 1985, and today continues to lead this specialised field. A language has even evolved to describe the components employed in hybrid turbos - words such as cut-back, 360°, screw-down and quick release.
For most road going cars, a standard specification, good quality Service Exchange Turbocharger is sufficient. Hybrid turbos only become necessary when significant performance improvement is required, normally on a modified engine. Most hybrid turbochargers will look identical to standard units from the outside. The changes occur inside, by using different aerodynamic configurations, both in the compressor and turbine housings.
As a Garrett turbo dealer, Turbo Technics are in a unique position to choose from a comprehensive range of components. This allows our engineers to "blueprint" turbocharger components to achieve the desired characteristics needed for a particular application. Obviously there are limits, but this ability sets Turbo Technics apart from others in producing very effective hybrid turbos.
Most turbocharged engines respond well to increased boost pressure, but only if the engine is modified to capitalise on the change. The same can be said of turbochargers. A hybrid turbo on a standard engine may offer a small benefit, but will be more effective on a modified engine. Unfortunately, increasing the boost pressure also increases the internal loading within the turbocharger significantly. In order to compensate for this, a "screwed down" thrust bearing is sometimes used. This prevents the bearing from "lifting" at high load which can lead to oil starvation and component failure.
To continue up the hybrid ladder of performance, a "360°" thrust bearing is used. This is an entirely new bearing, manufactured by Turbo Technics, and originally developed for our competition customers, such as Ford Motorsport. It has a greater bearing contact face to withstand the high loads, which would otherwise destroy a standard bearing very quickly.
Turbo Technics will occasionally specify a "cut-back" shaft wheel. This is the main exhaust-driven turbine wheel inside the turbocharger. To limit its speed to acceptable, reliable levels, and to improve the airflow, the blades are "cut back". This is a very high precision machining operation, requiring highly accurate grinding and balancing. The Turbo Technics designed and manufactured VSR balancing machine ensures that exact limits are achieved every time, regardless of the vehicle to which the turbo will be fitted, from the humble Mondeo turbo diesel to a full works Group A' Escort Cosworth.
Another way in which a hybrid turbocharger can improve an engine’s performance is by improving response, or reducing turbo lag. By designing a more efficient turbocharger compatible with the engine's characteristics, Turbo Technics offer hybrid turbos which can transform a cars driveability.

 

[icenutter]

Or more simply - a better turbo in the casing of a normal turbo.

 

[SonicDeathmonkey]

OK, so I get the picture now.

Has anyone bouth a pair of these hybrids and fitted them to an S4? If so, what was the cost of the parts and where from?

The blurb suggests that to get the most out of the hybrid turbo, you need other engine mods. For an S4, would this simply be RS4 bits like ICs, fuel rail etc?

Taking two very similar cars, one with hybrid turbos ( I guess based on the KO4?) and one with standard, what sort of difference would the hybrids make?

 

[jonnya]

See MRC tuning for fitting hybrids and www.buehnengineering.com for
getting them. Hybrids are essentially a combination of different turbo parts
into a compatible housing. For the S4 this is typically a combination of
compressor and turbine wheels in a modified K04 housing. Personally, I
would go for modified RS4 K04's for reliability.

 

[icenutter]

Taking two very similar cars, one with hybrid turbos ( I guess based on the KO4?) and one with standard, what sort of difference would the hybrids make?

If the had the same ecu map the difference would be minimal. The hybrid one might have a bit less lag as it might be lighter and better balanced.

However with a remap, the hybrid one could be taken much further so the difference could be quite large.

This is why other mods are normally recommended with a hybrid turbo - the injectors may not be able to supply enough fuel, the intercoolers might be overwhelmed etc etc.

 

[whisky180]

If the had the same ecu map the difference would be minimal. The hybrid one might have a bit less lag as it might be lighter and better balanced.

However with a remap, the hybrid one could be taken much further so the difference could be quite large.

This is why other mods are normally recommended with a hybrid turbo - the injectors may not be able to supply enough fuel, the intercoolers might be overwhelmed etc etc.

i have k04/rs6 hybrid turbos on my car and admitted u need to do plumbing works (intercoolers, injectors, fuel pump, exaust and remap) but i am running 470bhp without any more lag than k03 s4's and boy does it fly, ps 470 soon to be 540 but that maxes out the turbos, any more means full rs6 hybrid turbos

 

[ZeroK66]

On a standard S4 there is no benifit to running hybrids. Without doing the heads you are not really going to see better results that standard K04's or lightly tampered with K04's. I am running ported & clearanced K04's and I can run 500BHP. Hybrids cost as much as double K04's!! If you plan on replacing the heads (Which has to be done while the engine is out - so dont think it is soemthing you can do later and you are future proofing - I nearly made that mistake) then it is worthwhile. Standard heads - just run modded standard K04's - they cost about £1800 rather than 2.5-3.5k for hybrids. Unless you buy whisky's old turbos (covered about 3k I think) for a good price

 

[SonicDeathmonkey]

So does an RS6 run KO4s? If so, what is the difference between these KO4s and the RS4 KO4s?

What would an RS4 head cost? parts only?

When the KO3s go, I am looking to do some work. If the engine is out, might as well do some serious stuff!

 

[jonnya]

So does an RS6 run KO4s? If so, what is the difference between these KO4s and the RS4 KO4s?

What would an RS4 head cost? parts only?

When the KO3s go, I am looking to do some work. If the engine is out, might as well do some serious stuff!

I suggest you speak to MRC or do some reading up on AW. You're better off
starting with an objective and seeing what is required to achieve it than
working the other way around. How much are you looking to spend? -
doing this isn't cheap - the MRC500 is ~13500GBP drive in drive out.

To try and answer some of your questions specifically:
1) There are lots of different types of K04 - it's more of a compressor
family than a specific model. Speak to an expert (Jacob@Buehn)

2) RS4 heads. Rare as rocking horse **** used. Brand new, probably about
5 grand fully built (that's how much vagparts used to list them for). If you
fit RS4 heads you need RS4 intake manifold, TB, intake piping etc. Probably
another 1500 - 2000GBP.

I don't know what mods you currently have. If you do the above you will
have to upgrade the exhaust manifolds, exhaust and FMIC otherwise you
have wasted your money on everything else. That's why MRC charge 13500.

The simplest (and, IMHO, the most cost effective) is to pick up RS4 IC's
from ebay, straight KO4's from an RS4, fuel pump (and injectors preferably)
- gut the precats and get a remap. When the engine is out look at changing
the clutch. You could probably get that all done for 4 grand and have
400 - 450 BHP.

It all boils down to how much you are prepared to spend on a car that is
probably ~7 years old and worth less than 10 grand.

 

[whisky180]

So does an RS6 run KO4s? If so, what is the difference between these KO4s and the RS4 KO4s?

What would an RS4 head cost? parts only?

When the KO3s go, I am looking to do some work. If the engine is out, might as well do some serious stuff!

for a full informed and impartial opinion ring Doug at MRC 01295 077308, he did both Zero's and my car and would be recommended by both of us. we have both gone down different routes to high power his staying S4 mine going RS4. it all depends where u draw the line on how much power u want and how much cash u want to spend. zero's engine on K04's is maxed out at just over 500 mine on the hybrids maxes out at about 560 and with RS6 blowers 580 and loads more torque

 

[whisky180]

2) RS4 heads. Rare as rocking horse **** used. Brand new, probably about
5 grand fully built (that's how much vagparts used to list them for). If you
fit RS4 heads you need RS4 intake manifold, TB, intake piping etc. Probably
another 1500 - 2000GBP.


i picked up all my rs4 bits second hand, i got the full intake kit, heads and gearbox for £2300! agreed rare as rocking horse s**t but they do come up now and then and as these cars are getting older will come up more often and cheaper