Its one more indication of how much more advanced in this year's Evo 2 car compared with the Evo 1 which itself has brought SEAT so much success. The Evo 2 seems more like a tubular structure with a body around it while the Evo 1 was more like a shell stiffened by a roll cage. On to that new crossmember goes a new steering rack, with far fewer turns of the steering wheel lock to lock than standard, with most drivers liking two and a half. Power assistance is upped thanks to far greater hydraulic pressure from the power
steering pump and the amount of assist is tailored to each driver, usually at the beginning of the season, via different shims in the pump. In the SEAT team, as John Down explains, "Gwyndaf likes nice light steering while Barbara Armstrong likes much firmer steering."
Everywhere you look on this production based class the end result is far removed from any road-going car. John Down again "About the only thing you could buy off the shelf in the parts department would be the glass and headlights." Everything else is different or modified. Take the rear wings; surely they look different? You're right, they are flared to cove the wider track and far larger wheels and are made of lighter gauge steel.
The engine is production based but that gives quite the wrong impression. Although it has to be the same two litres and remain normally aspirated rather than turbocharged it's still quite different from the 16valve 1984cc 150bhp unit found in the Ibiza Cupra Sport road car. The standard block and head have to be retained but the head is reworked with larger inlet and exhaust ports, along with larger valves made in titanium.
Crankshaft and connecting rods are new, and made out of very high strength steel. The rods are also as light as possible, as are the pistons to minimise the reciprocating weight spinning around and help the engine rev as quickly as possible to 9000rpm. Naturally the camshaft timing is nowhere near that on the standard car.
As an example of how much work goes into the engines, the sump alone takes 40 hours to build up. It's full of very complicated baffling to stop the oil draining away from the pump in violent cornering because even a split second's lack of pressure ruins the engine. Race engineers would prefer dry sumping where the oil is pumped around from a separate tank but these cars have to stay closer to road car design.
Other features are just as far away from the production car, such as the ￡2700 worth of carbon clutch and associated flywheel, or the two rail fuel injection system which can switch from four to eight injectors to produce maximum power. It's no surprise these engines need frequent attention and SEAT are regularly air freighted to the specialist engine builders Mader back in Switzerland for an expensive rebuild, typically after two rallies and a test session.
These engines are extremely valuable assets and they've protected by water-to-oil heat exchangers rather than conventional radiators alone to keep temperatures as steady as possible. Rally teams run two different engine specifications, one with more outright power, (something beyond 270bhp, but no one gives away precise figures in this business), for fast tarmac events where the car might be geared for 125mph. The gravel spec engine in contrast will have less power but more torque, with the car geared for a lower maximum nearer 110mph.
To give the drivers the best chance to exploit all this power the standard five speed gearbox is thrown out and replaced by a Hewland six-speed sequential unit closer in spirit to a motorbike gearbox and the driver only has to move the lever one way to change gear at lightning speed.
It's the interior of the Ibiza which really brings home just how different these cars are, All the standard interior and trim is junked. Extra mouldings are made up to supplement the standard left-hand-drive dashboard moulding to take a huge array of equipment.
There's a large bank of relays on the right, the trip fuses (which the co-driver can reset in a split second when on the go), radio, and trip meter. The driver's given additional information too - a digital rev counter reading beyond 9000rpm.
As Gwyndaf and Barbara will be almost always be too busy to look at that, shifting close to full power with right foot to the floor, there's a reminder light mounted on top of the dash. That indicates when the engine is at full power in each gear and it's time to shift, while there's another to show when the gearbox is in neutral (again as with a motorbike, and vital with a sequential type gearshift for the mechanics as well as the driver). There's even a display to indicate which of the six gears is in use.
As you watch the car take shape in the SEAT Cupra Sport workshop it looks bullet proof but many of these components won't be around long at all, strong as they appear. They are 'lifed' as in the aircraft world, in other words used only for a certain time and then changed regardless of apparent condition because the risk of failure is too great. Driveshafts will only be used once despite being over ￡1000 each. In the same case with the steering and suspension joints while other parts not automatically lifed are X-rayed and crack tested as a precaution.
With a modern rally car nothing is left to chance but the designers, engineers and mechanics can only do so much. Then it's down to the driver and navigator. |
发表于 2009-6-9 03:21
楼主
发表于 2009-6-9 13:35
这个可以知道。。。