TT [Hot!] 600 HP Audi TT Clubsport Brings 2.5 TFSI with Electric Turbo to Worthersee

JHF · May 8, 2015

Audi has unveiled the future of performance TFSI engines today, with a concept coupe that's coming to the Worthersee GTI Treffen. It's called the TT Clubsport and under its hood is a 2.5 TFSI which uses an electric biturbo setup.

The advantages promised are just fantastic. After launch, the car sprints 16 meters (52.5 ft) in just 2.5 seconds, which is 6 meters (19.7 ft) further than a comparable car without this innovation. That is a difference of around one and one-half car lengths.

We haven't even gotten to the best part yet, as the output of this 2.5-liter inline-5 is rated at 600 hp of power and 650 Nm (479.4 lb-ft) of torque, the latter from 3,000 to 7,000 rpm. That translates to 240 hp and 260 Nm (191.8 lb-ft) per liter of displacement or about twice what you get with a regular TTS coupe.

Given these numbers, it's not surprising that the TT Clubsport, which is as light as a race car, needs only 3.6 seconds to reach 100 km/h and has a top speed of 310 km/h (192.6 mph). Can you imagine a car that shares its platform with the humble Golf keeping up with a Ferrari?

Audi was the first car company to show electric turbocharging technology for road cars. The RS5 TDI was built to celebrate the 25th anniversary of their turbodiesels and used a kind of electric supercharger to boost a 3.0 TDI to V8 levels of performance. The production debut should take place within the next year, on the SQ7 SUV.

Now they want to do the same with petrol engines. The 2.5 TFSI supposedly reached its full potential in the 367 horsepower RS3. But with the e-turbo setup, the same engine could potentially motivate an R8.

How does this setup work? At low revs, electricity is used to feed more air into the intake system. It's said that the e-turbo provides 200 Nm (148 lb-ft) of extra torque compared to what an atmospheric 2.5L engine would have. . A dedicated 48volt electrical sub-system supplies electrical energy to the turbocharger. It's fed by a compact lithium-ion battery in the luggage compartment the energy that is generated by recuperation when coasting.

Will the TT-RS get this engine? No. But development chief Prof. Dr. Hackenberg says the “technology close to production readiness” so fingers crossed, we will see the 2.5 biturbo on a future model.

“In our TDI engines, we are close to production readiness with this technology. We are now presenting it in a TFSI – here too, we are the first automaker in the world to do this. For our fans at Wörthersee, we have packaged the electric biturbo in a very sporty show car.”

Editor's note: What a beautiful concept. It's probably what the TT-RS will look like, minus the flared wheel arches and gigantic wing. And check out that Audi R8 6-speed manual gearbox!

http://www.autoevolution.com/news/6...-turbo-to-worthersee-photo-gallery-95253.html

Centurion · May 8, 2015

What's the benefit of electric turbos?

donkeykong · May 8, 2015

Decreasing lag for one.

Giannis · May 8, 2015

Centurion said:
What's the benefit of electric turbos?

You don't have to wait for exhaust pressure to build up, therefore you have minimal lag.

I have high hopes for electric turbos. Old turbocharged engines could be fun, battling with the lag and then handling the punch of those old Saab 900 2.0T engines for example.

But modern turbos, while the lag is being constantly lessened, run out of steam as you approach the redline. Electric turbos could be the answer and help maintain a linear power delivery, N/A like.

Centurion · May 8, 2015

Giannis said:
You don't have to wait for exhaust pressure to build up, therefore you have minimal lag.

I have high hopes for electric turbos. Old turbocharged engines could be fun, battling with the lag and then handling the punch of those old Saab 900 2.0T engines for example.

But modern turbos, while the lag is being constantly lessened, run out of steam as you approach the redline. Electric turbos could be the answer and help maintain a linear power delivery, N/A like.

Why not just go for a supercharger? They deliver a linear boost in power don't they?

Gianclaudio · May 8, 2015

Centurion said:
Why not just go for a supercharger? They deliver a linear boost in power don't they?

Because turbos have a higher efficiency in benefit/energy required to drive them, compared to superchargers....

Giannis · May 8, 2015

Centurion said:
Why not just go for a supercharger? They deliver a linear boost in power don't they?

Gianclaudio said:
Because turbos have a higher efficiency in benefit/energy required to drive them, compared to superchargers....

Exactly.

Increasing intake pressure requires power, which with superchargers is drawn from the crankshaft. With turbochargers, it's drawn from exhaust gasses, which is otherwise wasted. Therefore, turbochargers are more efficient than superchargers.

With electric turbos, I expect some sophisticated power management, so efficiency should be even higher, let alone the lag issue.

Centurion · May 8, 2015

Giannis said:
Exactly.

Increasing intake pressure requires power, which with superchargers is drawn from the crankshaft. With turbochargers, it's drawn from exhaust gasses, which is otherwise wasted. Therefore, turbochargers are more efficient than superchargers.

With electric turbos, I expect some sophisticated power management, so efficiency should be even higher, let alone the lag issue.

Thanks. I had a second read and the battery powering the turbo is apparently very compact so the weight penalty is minimal.

JHF · May 8, 2015

http://fourtitude.com/news/Audi_New...t-car-tremendous-thrust-right-from-the-start/

MarcinM · May 8, 2015

3.6 seconds to 100 km/h with better power to weight ratio than 911 turbo S????

JHF · May 8, 2015

MarcinM said:
3.6 seconds to 100 km/h with better power to weight ratio than 911 turbo S????

Well, if the old TT-RS did hits 0-100 km/h in 3.9 s (4.6 s by factory claims) by the tests, so this one is much more faster than the factory claims. Maybe the same with Turbo 911 S, but still, I think the 911 Turbo S is faster than this one

Rolf · May 9, 2015

For a 600PS car with lowish weight the acceleration of 0-100 in 3.6 sec seems slow, the 610PS R8 V10 does it in 3.2sec and is a bigger and heavier car with less torque as well.

martinbo · May 9, 2015

Regarding the 0-100 times, you need to take into account that this car is a manual, firstly, and secondly one needs to take the specific AWD drivetrain into consideration - 600 hp is a lot for Haldex to deal with. I think 3.6 secs is thus more than acceptable in light of this configuration.

The induction plumbing is fun! The autoevolution article fails to mention that the larger 2nd turbo is exhaust gas driven which can be misleading due to the words electric biturbo. Yes, it is electric. Yes, it is a biturbo setup. But only one of the turbos is electrically driven. [We already know this from the RS5 TDI concept but clarity is important.]

@Giannis, @Centurion - like I said the induction plumbing is cute. At first glance it appears that the electric compressor (not really a turbocharger - more correctly an electrically powered axial flow supercharger) sends non-intercooled air directly into the inlet manifold but this is not the case. Zooming the engine pic shows that the electric compressor gets its inlet air from the intercooler (which doesn't happen on a conventional turbo setup) and not from the air-filter inlet side. So, the air temperature increases associated with pressurisation are mitigated via this method. Cool.

Giannis · May 9, 2015

martinbo said:
like I said the induction plumbing is cute. At first glance it appears that the electric compressor (not really a turbocharger - more correctly an electrically powered axial flow supercharger) sends non-intercooled air directly into the inlet manifold but this is not the case. Zooming the engine pic shows that the electric compressor gets its inlet air from the intercooler (which doesn't happen on a conventional turbo setup) and not from the air-filter inlet side. So, the air temperature increases associated with pressurisation are mitigated via this method. Cool.

@martinbo - I am baffled as to why would Audi engineers choose to feed the electric charger with already intercooled air.

First pressurizing the intake air and then cooling it is the standard tactic and sequence, because that's how it should work. The air temperature rises vastly as it is pressurized, and then it needs to be brought into reasonable numbers, as to achieve a certain engine efficiency. An engine's efficiency depends on the temperature of both the intake air and the exhaust gasses. The bigger the difference between those two temperature, the higher the efficiency.

I can only think of one reason as to why this plumbing was selected. Lag is also caused by the inertia of the air contained in the plumbing. The bigger the intercooler and the longer the plumbing, the more lag you have. In order to minimize the effect of the plumbing size, you need to have the air charger as close to the throttle butterfly as possible (in terms of path/ not actual distance). So, by choosing to place the electric air charger after the intercooler, it seems like they want to minimize the lag effect as much as possible, and the effect will be more significant than the final intake air temperature difference.