Time for another entry in the SU Hi-Po Challenge.
This one’s from Thyl, out of Germany.
It includes a few additional thoughts at the end, which take in information he learned after sending in the first draft.
So, what I propose as a halo car is a dignified high speed travel limousine based on the 9-5 Aero6, with only minor upgrades:
1. Engine: The 2.8 T with two turbos and about 400 hp. I suggest to use the engine from the Aero-X; as I assume that this engine was developed to a degree allowing daily use. If not, maybe some minor tweaks need to be done to improve durability, depending on what is available with GM/Holden.
2. Aerodynamics: Bring down drag coeeficient to 0.24. This is the most important aspect, since it will have significant influence on maximum speed (+/- 10-15 km/h) and on acceleration on motorways above 120 km/h. It will also be the most expensive aspect to develop, and will require redesigning the bumper to allow better airflow, modifying the grille with automatic flaps and maybe with acrylic inlays (greenish iceblock design) to make it smoother; providing better under-car-airflow including cladding and diverters from the front wheels; if possible, coverings on the wheels, and maybe more complicated stuff like lowering the hood (pyrotechnical pedestrian protection lifts the hood in case of a collision), etc. I however believe that in the long run, this field requires improvements to the 9-5 line anyway, and the other models in the range would hence also benefit from such development. Could be offered as an aerodynamic kit, like the one for the previous 9-3 that originated with the Viggen. Since I am pretty sure that at least some of the above measures have already been developed at Saab, cost might still be kept under control. Further, for sceptics, the aerodynamic kit for the 9-3 Viggen had a similar improvement to the drag coeeficient, from 0.34 to 0.31, and when looking at the overall shape of the 9-5, I think it should be doable.
3. Transmission: If the automatic transmission cannot absorb the torque, offer just the manunal transmission.
4. Speed: no speed restriction at 250 km/h. This is more than it seems, because it is also a clear political statement. There are manufacturers that follow this unwritten agreement to restrict maximum speed (e.g. VW, Audi, BMW, Mercedes, Volvo, Jaguar) and others that don’t (e.g. Porsche, Maserati, Bentley, to name only those that offer salons), even though most of the cars can also be purchased inofficially without restriction. By not restricting the speed, Saab would set a clear signal that they intend to belong to that sporty group of high class players, not to the boring rational guys. Ie., they would change sides, at least for this one car.
5. Styling: call the car the “Draken” and develop badges for the hood and steering wheel where the griffen is replaced by a dragon in the same style.
6. Tyres: Speed index Y for restricted speed of 285 km/h, or ZR without speed restrictions (as an option)
7. Suspension: No changes. This is not a super sports car, but still a salon.
Price guestimates. From what I found concerning biturbo conversions in the tuning sector, I would guestimate that the engine conversion to a biturbo version as such could reasonably be offered at around 10000-15000 Euro, including “hardening” the engine. Aerodynamic stuff is more complicated than the Viggen kit, and I would guess 5000 Euro. Better brakes (standard components) and tyres (Y) might add another 5000 Euro. Don’t know about exhaust.
The overall concept of moderately powerful engine, excellent aerodynamics and high top speed would be unique. Most competitors have a worse aerodynamics (not Mercedes though) and use heavier and more complex V8 engine to achieve 400 hp. The concept would play nicely with Saab’s alleged strong traditions of turbocharged, light engines and good (aircraft like, if you will) aerodynamics at a reasonable price. Funny, now that I have written this, I ended up rather close to the Viggen ;-), but less sporty. And XWD/HiPerStrut will help stabilize this stuff without requiring as many modifications.
Risks: Aerodynamic instability might ruin the whole idea. See Citroen C6.
Thylmuc again with some additional remarks on my concept…..
Sadly, I was informed that there is no real 400 hp engine in the Aero-X, so I cannot say how much it would cost to develop it, nor whether it will be possible at all:-(( I was unable to find any tuner that offered a biturbo conversion for the Insignia OPC. Maybe the engine really explodes at 400 hp.
Nevertheless, applying that old physics stuff, “required power=0.5*air density*speed E 3*frontal area*drag coefficient”, and doing some to-and-fro and a lots of ratios, I calculated some maximum speeds (starting from the Turbo4 XWD at 161 kW and a cw of 0.28):
Top speed of Turbo6 XWD without restriction would be 256 km/h
Top speed of hirsched Turbo6: 264 km/h
Top speed of Turbo6 at a cw of 0.24, as suggested: 269 km/h
Top speed of hirsched Turbo 6 at cw of 0.24: 278 km/h
And the concept, 300 kW at 0.24: 298 km/h
Which is not too shaby, I would say. Hope my brain worked correct…