The basis is the BMW Z4 3.0i, in which however "no stone is left unturned". The most striking optical feature is the enclosed bodywork, now 13 cm wider, in colours orange / cream.
The life-giving organ is the upgraded version of the 4941 cc eight cylinder, four-valve engine from the M5. In conjunction with technology partner, Schnitzer the engineers have equipped the TOPSTER with special intake and exhaust camshafts. The cylinder heads have also been fine-machined, the compression raised to 11.5 : 1 and the control unit is reprogrammed.
To improve the exhaust gas flow, a high performance exhaust system has been developed. The power plant has had to be re-positioned and the entire oil circuit had to be optimised, so it was necessary to modify the oil sump and oil pump. Finally, the air flow was improved. By means of new intake pipes and 2 air filter boxes, the entire intake tract could be optimized.
Furthermore the rear axle (ratio of 3.62:1) has a variable differential lock from 0-100 % depending on the load of the V8 TOPSTER.
Perfect retardation is provided by the brake kit. This uses brake disks of Ø 365x32 mm at the front and Ø 328x20 mm at the rear in conjunction with special brake calipers. Even after several "hard brakes", the system achieves deceleration values of 1 g and more.
In the TOPSTER the driving dynamics are improved by the 9-position adjustable racing suspension.
The V8 TOPSTER keeps contact with the asphalt through the racing rims Type IV. With sizes 9.0Jx20" offset 18 with tyres 255/30 R 20 (front) and 11.0Jx20" offset 0 with tyres 305/25 R 20 (rear), the TOPSTER can corner at speeds otherwise reserved for a thoroughbred Touring Car.
The reshaped bonnet with its unmissable power bulge and air outlet, already guarantees maximum cooling air flow. Also a new development is the front skirt which improves downforce. Its large air inlet with integral grille ensures additional cooling for the engine and front brakes. Consequently the side skirts house air ducts for the rear brakes. The monstrous rear skirt accommodates not only an underfloor wing, but also the exhaust system. The specially developed roof further reinforces the body of the V8 TOPSTER and develops a new body side line - similar to a coupé. The integral rear roof wing in conjunction with the two-piece rear wing improves the downforce of the entire body.
The interior of the V8 TOPSTER is a combination of developments in the range available for many BMW models, and special one-off products. These include the racing bucket seats as well as the airbag sports steering wheel, gear lever gaiter and handbrake cover which are made in Alcantara with orange stitching. A carbon-fibre interior and chromed cover for the standard roll-over bar and the aluminium accessories are however components of the standard range for the Z4.
The AC Schnitzer V8 TOPSTER was developed as a technology showcase. In the equipment level and form shown here, this concept car would cost around € 185,000.00. Series production is not planned.