We join Auto Reserve at Donington Park for a shakedown track day to test-drive their race-prepared 500bhp supercharged S-Type
JAGUAR BREAKERS and spares specialist Auto Reserve near Derby dipped their toe in the Jaguar racing scene last year with a diesel-powered XJ X350 (see our July 2022 issue for Paul Walton’s driving impressions) that seems to have caught everyone’s attention after they finished third overall in the Jaguar Challenge Championship.
Not content with having one race car, the team has been working on building the S-Type seen here, which has a mouth-watering list of modifications that means there’s very little left which you could call standard.
Whilst the steel monocoque body of the S-Type is retained, panels such as the doors, bonnet and boot lid have been lightened by removing their steel-reinforced sections
or in the case of the doors, replacing the steel outer skins with aluminium. There’s no carpeting or soundproofing. Apart from the windscreen, there’s no glass, having replaced all of it with polycarbonate, so the only interior ventilation is courtesy of a small sliding window that’s part of the driver’s main door window and a couple of holes in the rear window.
And that really is the only means of interior ventilation because the heating and air-conditioning system has been removed in a bid to lose weight. Even the original wiring loom has been removed, along with the heavy hydraulic power steering system, replaced with an electric steering motor from a Vauxhall Corsa.
With the interior having been stripped and those other weight-saving tactics, AR reckon it has managed to shed almost 350kg from the car, which is not as easy as it sounds considering there’s a multipoint roll cage inside. And that’s no ordinary roll cage, having been designed by AR using CAD software and made using their industrial tube bender.
Competing in Class A of the Jaguar Challenge Championship, JEC rules stipulate the engine can be modified by increasing the displacement, fitting larger pistons and performance camshafts and machining the inlet and exhaust ports for the cylinder heads, but AR want to keep costs down in this area, so have resorted to using a standard 4.2-litre V8 and its supercharger.
They have, however, fitted a fully programmable ECU to help optimise fuelling and ignition timing, and to make the most of the hard-to-miss modified induction system under the bonnet.
I’m amazed when mechanic Mark Bennett tells me he reverse-fitted the standard supercharger that’s mounted in the top middle of the engine so that he could route two pipes and hoses from it to a couple of front-mounted Skoda Fabia VRS intercoolers with returns to force feed the air into the engine. And that’s only half the story, because he had to be creative with the parts he could find, which involv
